Oh, that looks kind of funny up there. The screen up there should we. Or can we just alert your mindset. That's fine. Yeah. Oh, sorry. Too many. Too many screens. Okay, cool. Sure. All right, cool. Okay. Hello. Please take your seats. And welcoming Karen Ryan Anderson back to our last lecture for today. And he will wrap up today's introduction. Very, you know, intense introduction to quantum error correction. So, okay, go ahead. Thanks. Cool. Thanks. All right, so I will basically start off where Ben left off. However, I'm not a masochist or at least I don't like writing codes this way. If we take the same code, the torque code. Let's see. So we want to do for these things. And whatnot. And instead of Instead of having the checks on the vertices and the cubits on the edges and the Z checks on the, the, the. Plackets. If we put the cubits on the vertices, that's where I like to put them because they look like little points and kind of reminds me of cubits. Then we have these like X, X, X, X checks, Z, Z, Z. It's the same code. It's just a different representation. This is called the, the medial code, the medial mapping of the code. And we can take this tour code that Ben described. And if we want to do everything in 2D, like some devices kind of is more natural for them, then we can take me basically a slice of this course. And we can just add extra checks along the boundaries. And we get another version of the tour code this time, though, the planar surface code. And in particular, this is often known as the rotated planar surface code because the first version of it had more checks and you can like slice it in a different way and whatnot. That's not important. So this one is a 913 code. So it has one logical qubit unlike the Taurus that has two. Here we have, let's see, is this working? So it does go back and forth, but the little magic dot thing doesn't seem to work. Okay. No problem. Sorry. Here we have a logical X operator going from top to bottom. So here, instead of having, there is a version of a logical operator, logical X operator that that's kind of X, poly X on each of the qubits, each of the vertices. But here you can make the lower weight ones by just having a string of poly X's that you so you apply an X on each of the qubits from top to bottom. And they're equivalent logical operators that just run from top to bottom. So as long as you can connect those top and bottom boundaries with a set of X poly operators, it's equivalent to a logical X operator. And then likewise, the Z goes from like horizontally, it connects the boundaries from from left to right. So as long as you have a set of Z poly operators that do that, then it is equivalent to logical Z. Now these in these diagrams, I'm using similar diagrams like Ben discussed, I'm using the darker gray boxes to represent the operators where we measure joint X X's for those qubits that touch that polygon, this polygons, and for the lighter boxes, it's a joint Z operator that we're measuring. So these are the set of stabilizers written in pictorial form. So it's a lot nicer to work with than potentially this for larger codes. And yeah, so so we have n minus one unique or yeah, n minus one where n is the number of data qubits unique stabilizer generators. So that means, as Ben mentioned, each poly operator divides the space in half, orthogonally. And so that means that the space has two minus the number of things that divided in half. So that means, if you do n minus in parentheses n minus one, it all cancels and you get two to the end. So it's a logical two level system. So it is one logical qubit. So that's what the T two means there. But also described this thing. So this is a distance three color code, or the also known as the steam code for that, for the distance three version. And this is the distance five version of the color code. Notice there's lots of colors.  It is related to the surface code. Kind of very similar. It's also a topological code. Here, though, the polygons don't represent just one type of poly operator that we're going to measure one type of observable, it represents two types. So for example, this big attempt. The pointer doesn't work. So each polygon, or once again, the vertices represent the qubits, the data qubits, and the polygons represent both the observable where you're measuring joint X's for all those qubits as well as the other observable where you're measuring joint C for all these qubits. So it's a self dual code. It's a CSS code. So CSS means that you can write the set of generators, either as only a Z poly type or X poly type. So you have a combination of X and Z purely X and Z generators. And this is self dual because the X and Z look exactly the same. And of course you can multiply those together and get Y. So you could use, you could also measure the observables where there are joint Y operators for those polygons. Unlike surface code, there's more symmetry, which is both a blessing and a curse or well, both a benefit and a con for the color code. It means that it has a lot more logical operators that are possible. It also means that for each one of these boundaries, so you see this like X string and then this Y string and the Z string that kind of, if you imagine a triangle, these are often called triangular codes on like the square of the surface code. It connects the points on this triangle. Each one of these operators do, but each boundary, these three boundaries can have an X, Y or Z logical operators. So you can apply a set of poly operators that are either at all X's, which is equivalent to a logical X operator Y, which is equivalent to a logical Y operator and Z, which is equivalent to a logical Z operator. So it doesn't really have this polarization that the surface code has. It's a slight different, yeah, slightly different characteristic. So I should say, yeah, this is kind of going to start out as sort of introducing you to some familiar codes that you might study in quantum air correction, but then we're going to go deeper. So this is kind of using as a, to get you familiar and then start working on like what do these circuits look like and how does all that work?  It turns out if you, for the surface codes where you only have either X type or Z type observables and you put the qubits on the vertices, then you get graphs that are able to support these type of codes that are too colorable and that have a degree of four. So each vertex only has four edges at most. And then you can cut little codes out of these graphs so long as you like make sure that you have the right number of stabilizers and then similar for the color code, pretty bunch of pretty colors, but really that has to do with the three color ability, which also if you have both X and Z type checks for both of these for these polygons and you want to make sure that everything commutes and whatnot, you end up getting a three color book or graph. Okay, that's, that's, it's just to introduce that you might hear about color codes and surface codes, but there's all, there's a lot of other versions of those codes that haven't been, that don't tend to be studied. You can do a lot more with them. There's also non uniform tiling of the plans that you can also cut codes out of. It also doesn't really matter the geometry of these things don't matter. These are all equivalent graphs. So this 488 nomenclature right here just represents if you sit at a point and you kind of walk along and you look at all the polygons that touch that point, you have polygons of, of, you know, with four sides, eight sides, eight sides. So all these other graphs are equivalent. So you can lay these things out, you know, you could, if you have a computer that has long range connectivity, you could like ions, you could have all sorts of geometries if you want. So connectivity isn't really so important. These things just help us kind of visualize what the stabilizers look like in a sort of an abstract manner. So a lot of codes, but not necessarily all, although you can form families of them, a lot of codes have families of codes or belong to a family where you can kind of parameterize it by the distance of the code, which we've talked about before. We've mentioned the distance minus one divided by two, so just slightly less than half is the number of, of flips either from various poly, poly operators that it can handle before, or yeah, that the codes guaranteed to handle. It's possible that codes can handle more than that, but it's not guaranteed to handle all the, like the same, so the distance three code, for example, can potentially handle weight two errors, but not all weight two errors. It's just guaranteed that at that, that T value, it can definitely correct that. Beyond that, there's some probability whether it can correct those or not. Anyway, but, but so as, as you make these codes larger and larger, as you can see they can correct more and more errors, so that means they can suppress the logical error rate, you know, because we're spreading the information across many qubits. And, and let's see, let me verify what time. Okay. We're spreading information across many qubits, and so this means that since it can handle more and more errors, that means that given that, you know, errors pop in with a certain probability that means that we can squash them fast, you know, it's easier for us to squash them. It's, we can wait longer, or we have more of a chance to squash them, you know, before they build up. Here's an example of a family, two different families of the color code, so this is the distance three one is the steam code, which Ben talked about. Then you can also construct larger versions of the color code by cutting out, you know, the codes that are out of these graphs that I mentioned. Common ones are either this, this 488 lattice, which is on the top, or the 666 lattice on the bottom, which is an ominous number. Okay. You might have heard of this word threshold, and maybe you've heard of the concept of a pseudo threshold. So the pseudo threshold refers to the performance of a code, like for a single code instance, not the entire family. So, what we have here in this graph on the x-axis is the physical error rate, and on the y-axis is the logical error rate. And then this dotted line is when those two error rates equal each other. And so there's some point in which the code gets overwhelmed and the probability of higher rates errors happening is too high and you end up applying the wrong operation, you end up applying logical operations whenever you try to do your corrections instead of fixing the faults before they become an error. If it's low enough, then you can start suppressing the error rate. So you get like a p-squared effect, or if it's higher distance codes, like distance 5, you can go from p to p-cubed and so on. So you can keep on quadratically suppressing the noise, and so the place where this curve kind of hits this x, you know, the x equals y line when logical, the logical and physical error rates are equal are known as the pseudo-threshold. Pseudo-threshold because it's not a full threshold, the threshold refers to the family of codes. I sort of kind of mentioned this before, that for the repetition code, as the number of bits goes towards infinity, then you know that as long as less than half of those bits flip, the majority vote will send you to the right outcome. It is the same sort of idea with quantum error correction codes. What happens is as the distance increases, as I mentioned before, you get steeper and steeper slope, so you suppress the noise more, so you get higher power, you know, you go from, as I mentioned, be squared, be cubed, be to the fourth and so on. And eventually as the distance goes towards infinity, effectively you get a step function. And so that dotted line where that step function tells you that so long as the physical error rate is lower than that, there's some arbitrarily large code in which you can arbitrarily suppress the noise. Of course you won't live in asymptote, but you can choose a large enough code to do whatever you need given your physical error rates. So you obviously, if you can reduce your physical error rates, that's great and you want to do that because you kind of get more out of the code.  It's also good to be aware of if you're trying to run simulations where you're trying to like work out these thresholds like you sometimes see in papers. You need to look at, so the first sort of distances, like distance three, five, seven, there are curves kind of wiggle about. So eventually these curves kind of settle down into sort of a trend and you can kind of, you know, fit those curves to a function on higher order function and work out what the, what sort of the inflection point is which corresponds to this threshold. But the first sort of small codes have this small size effect. So the curves are kind of settling down at first. So you can't really use like distance three, distance five, distance seven in order to work out what your thresholds are. You have to kind of start out maybe at nine or 11 and then work up. So in case you do those sorts of simulations in the future, maybe for the hackathon, maybe not. Yeah. And this is how the logical error rate roughly scales. You can kind of see that if you ignore the p th which represents the the threshold error rate p represents the physical error rate, then d plus one over two is really the same thing as t plus one. So like I mentioned, a distance three code would suppress the noise by t plus one. So two p squared and so on. This is a shameless plug. I do have a package that does quantum error correction. You can take a look at it there. You can potentially use that to do simulations. Anyway, so I think Ben briefly touched on measurements, but I'll talk about those sort of again to a different way. I'm mainly focusing on how do these circuits work whenever we want to measure these observables for generic you know, poly operators that we want to measure. So this can like dot with a line and p is to represent a control poly. So that's equivalent to you know, if the qubit is in the zero state apply identity, the qubit's in the one state for the control apply the poly. And that you know, you could put an X in there and that's the equation for the C not or the control X gate, whatever you want to call it. So we're going to work out. Oh yeah, sorry. So we have this circuit here. And what that turns out to be is one way of measuring polys. So we introduce an encilla. We apply a Hadamart we do this control poly another Hadamart and then we measure in the Z basis. So why does that work? I think Ben maybe showed one way to prove this and I guess I'll prove it again another way might not hurt to see how this works. I think it's fairly straightforward proof. So if we start out on the left hand side, you know, this we're in a zero tensor psi state. So the zero is the control bit or going to be our control bit then we apply this Hadamart so we get a plus state. So this is this you know, this thing that's just we've seen it a bunch of times is the plus state superposition of zero and one and then if we apply this control control polygate we see that you know we leave leave psi alone if it's so I'm just I'm doing a couple of steps first I'm converting plus into you know a superposition of zero and one and so if it's zero we don't apply the poly we just do identity so we just have psi so that's that first part and then if it's one here then we apply the poly according to that you know equation above. Okay, hopefully that's straightforward and then we apply the Hadamart again we've that means we flip the control a little bit and that minus state is just you know if we put a minus here instead of a plus and then if we move that square root from the plus and minus states over to the side to multiply it with that one over the square of two then we get that one half and then here I'm just you know just rewriting plus and minus as you know zero plus one and then over on the right hand side zero minus one I'm just re substituting things in to get that and now we're going to rearrange the equation where we pull out the part where it's all zeros so we see is zero you know for each one of these terms we see a zero in front so I'm just going to group those over to the side and I'm going to group the one over to the other side because we're getting ready to measure in the z basis so it's convenient to do that and then I can pull the operators away from the psi so you know the first term is psi plus p times psi so I can just write that as i plus identity all times psi the other side i minus p times psi that's straightforward just a bunch of algebra steps and substitution and we're just getting ready to see what happens if we measure in zero and one so if we measure in zero and one if we get a plus outcome we know we collapse to the state where the control bit is zero and if we get a minus we collapse where the control bit is a one so that's just you know taking the same equation above and just based on those two conditions we get that those outcome and I'm ignoring maybe some normalization going on and we've seen these one half plus or minus p before from Ben but if you want to do the math so let's say my identity is just equivalent to taking the you know either the z or the x or the y basis and taking the you know the part of the state that the projects and you know that's the positive eigenvalue state the projector for that plus the minus eigenvalue projector and some of those together so together that projects to the entire state the entire space so that makes sense of its identity so we can just write it as the plus p projector and the minus p projector for where we can substitute p for x or z or y and then x, y and z can all be written like this in terms of their projectors this might make sense if we look at the z for example if a qubit is zero then we leave it alone it's one we add a phase to it that's where the minus sign is in the middle it turns out in their own basis states x and y also do the same thing because if you think about it what we label x, y and z it's just convention they should all look symmetric in their own basis states so they should all do the same thing so in general we can write down that p is equal to the plus p projector that's the minus p projector that'll do the same thing as some weird thing that flickered on the screen that'll do the same thing as yeah applying minus to the part of the space that's in the minus subspace and applying plus to the other side so hopefully that's all makes sense and then we can do a bunch of math to substitute those values in and it turns out that this is indeed you know one one half plus p is indeed the projector for the positive space of the poly operator and one half i minus p is the minus side of things cool bunch of annoying algebra and whatnot but in the end of the day who cares about that math what it tells you is that this circuit just through a few simple steps we can show that what this circuit really does is it projects us into the plus subspace of the poly operator or the minus one based on whether we get you know plus one or minus one that's really the important part it's easy enough to go through all that map and it's kind of boring but whatever so we just prove that it really is projecting us you know we get a plus one we really do get we really do get projected into the plus one part of the poly space and so on so that's cool and this argument in general works like it's not special that it's a single poly operator so for a single qubit it will work for the same thing for multiple qubits you can kind of can sort of easily see it but or you can take my word for it so that means if we're trying to measure a joint poly operator then in general we can use this circuit here so that's really what I wanted to get to so you can forget all that math if you want and just believe me that we can use the you know we can introduce an encila do a hadamard do these control polys another hadamard and measure it measure in the z basis and we are effectively projecting into these plus or minus of these poly operators or another way of thinking about it is we're measuring the eigenvalue of those poly operators so this is how we measure our parity measurements so they're all doing they're all the same concept effectively and we can see if we're trying for like for example the surface code or the torque code or whatever and we're trying to measure xxxx then this just becomes a bunch of control knots so we replace those polys with x's you can put the box there you can put the circle there it doesn't matter so you get this thing so this is the circuit for like the surface code whenever you're doing the x checks we can also see if we don't really want to think about all that math we just write down the circuit and believe that that if we input an x fault into this circuit then it'll just commute with everything and just fly through and so it's doing what we've seen before if an error if a fault commutes with the operator the operator doesn't detect it it only detects whenever things are coming up with it so if we apply a z operator using sort of the rules that we've seen before because z will hit those targets and propagate down and then it'll get flipped to an x operator the z measurements will pick up on x's it'll look like a change in the measurement outcome so we get a minus one and then we can also see if there's an odd number of z's that come in then we get an odd number of x's that hit the measurement and so it will only light up it'll only give us a minus sign if there's an odd number and then if there's an even number the minuses will cancel out if there's an odd number of errors you get minus one even number of errors you get plus one so it's doing the thing that we've already thought about before cool this is all leading to something like to think about how circuit level errors faults work so we can repeat all this stuff for z it's a save sort of story I mean it's just a symmetric but we can do these in terms of c-naughts so you more commonly see it with c-naughts going down so we could do these control z's that's a perfectly fine circuit using this sort of rule that we can just put in whatever poly but people tend to put in these identities these Hadamards between each one of these gates in order to convert it into a bunch of c-naughts that point down so if the c-naughts point down towards the encilla it's a z check if the c-naughts point up it's an x check and then same sort of thing we've already seen this effectively so yeah these are the typical circuits that we use there are other ways to measure syndromes and this is sometimes referred to as bare encilla syndrome method because we're using a single bare just a single syndrome or sorry a single encilla there are as I mentioned there's other ways like sure-style syndrome extraction student-style syndrome extraction needle-style syndrome extraction they require more encilla so they can be more overhead they have different advantages a lot of them require you to measure operators more than you would with the bare style although some of them have a single shot so it's much more to read but typically people study the bare-style syndrome extraction so we'll forget those other styles but just to make you aware there are other ways to do this too so it's not unique so go back to this oh yeah what about so far we've only considered input faults into these circuits what happens if that doesn't occur what if we put an x here we see that the x in this x check is x parity measurement that we're trying to measure the x fault will propagate up and it'll go over to the Hadamard on the measurement branch it'll flip to a z z commutes with z so it doesn't actually like doesn't flip the measurement result and so it's still plus one so you don't get any alert that a fault has happened but not only do we not get an alert about it but we get a weight one thing happening or weight one error or fault happening becoming a weight two fault that doesn't sound good because that potentially can lower the distance of our codes as effectively as though we have with probability p we have higher weight things occurring so that means we need a larger code to deal with that potentially and then of course the symmetric thing that we're trying to measure with probability p we're trying to measure the distance for the z check okay that potentially making nervous however for various codes there's ways to mitigate this so for a while it was believed that you just have to deal with this and make larger distance codes however it turned out I think it turns out that you can choose the schedule in which you do these c-nauts so that you do get these higher weight faults occurring like so we've already seen however by choosing the schedule you can make sure that these c-nauts you can measure all these operators in parallel and you can also make sure that you choose the direction in which the faults occur so if we zoom up so that over on the left hand side we kind of see a little bit of the x operator running up and that purplish thing that's supposed to represent an error is perpendicular to it so that's an x error that's growing perpendicular to the logical x operator and then the green fault here is a z type fault but it's also perpendicular to the logical z operator so essentially we're not growing the errors in the direction in which they would lead to a logical error it kind of looks like if you look in the right direction you can see one thing effectively in that dimension also I should mention that you can also think of the surface code also like a repetition code where you're taking the bit flip and phase flip code and kind of see it along the edges and then kind of doing like a Cartesian product of the two so there's like by learning the repetition code you kind of see the same thing okay what about the color codes or the steam codes also for a while even longer because they're less studied than the surface codes people thought we had to deal with these bad errors these bad errors are sometimes known as hook errors because they kind of go up and over kind of like a hook so we do know of course using the same sort of circuitry if you have an X input error then it propagates down to or yeah this is a Z check we see the C nots going down the X error on this Z check will propagate down and the Z check will detect this X error and so in this code for example the X error is being applied to keep it 7 over in the corner and it anti commutes with this red Z check it flips it to a minus 1 it kind of like locates effectively assuming that it's a low weight error where the X error occurred however what happens if we measure this X check and an error occurred like we saw before in the middle of the check it propagates down and once again it's silent this check is but then we'll end up at some point measuring Z checks so over here is the results of if we then Z check so we get plus 1 plus 1 for the green and blue over on the left hand side because each one touches the X faults an even number of times so it doesn't flip it we're detecting parodies but it it touches that red Z check over on the right an odd number of time once so it flips that that looks exactly like what we just saw so you're more likely to choose a correction where you flip you apply an X to and if you do do that you'll get a string of X's it turns out that string of X's is also a logical operator so now we have a weight 1 error if you include the correction leading to a logical failure or a logical error it's in the proper error not a failure that's horrible so you might think okay I just have to increase the size of the code and deal with it turns out however that we can supplement our circuit we can introduce a flag in qubit an additional qubit and we can see that effectively if nothing happens it acts like an identity so those controls kind of can you can if you have controls touching in these sea knots they can go pass each other they commute so we can bring these sea knots over to each other in their identity so if nothing happens this is just a fancy identity however if this internal fault happens the X error does propagate down and we get a non-trivial result we get this outcome flipping so these flag these internal hook errors so this allows us to modify our circuit and get back the distance of the code so that's cool so yeah that's mainly the stuff that I was going to cover I actually don't know I assume it'll be what six o'clock that we stop at yeah okay okay cool so that's mainly what this kind of shows how you have to deal with fault tolerance so there's a lot of people that will use the phrase something is fault tolerant if you're kind of in the regime in which the code is suppressing noise I don't think that's a good use of the term it kind of conflates kind of it being beneficial of quantum error correction I usually like to reserve the word fault tolerance meaning you can handle any T errors or T faults and recover it yourself or K fault tolerance sometimes is called and that's a better annoyingly you'll see this even by people that know stuff that they'll use the same word fault tolerance to mean two or maybe three different things and that's kind of an annoying thing in the field so sometimes you have to be clear about what they actually mean anyway so that's a little rant but this effectively is showing how you have to do things in order to ensure fault tolerance you can ensure that your code is able to correct all faults to up to what the code was designed to be all right if you are doing the challenges for the quantum error correction stuff depending on the challenge you might want to think about doing simulations or you might after this just get interested or just read the QEC paper and want to know how what this QEC paper is actually saying you have to be careful about whenever you're reading QEC papers the error rates that they report because the error rates really depend on a lot of things like the circuitry that you're using as we've seen like different circuitry can lead to different performance but also sort of the classical algorithm that you're using to come off the corrections as well as the level the type of error model the type of noise that's being applied to the circuitry will change how the code performs all those things are super important so there's not one size fit all number for like the threshold of our code it's really dependent on stuff but often because it's a lot easier to simulate people will also use a simpler noise model and you shouldn't be confused by because like yeah let's just go through so this is a list of different common noise models from easier to harder and they typically the thresholds will be higher and then quickly drop as you look at more and more details so the simplest noise model that's not as much people look at but it's definitely more popular in classical error correction but some people do look at in quantum error correction because it is a useful noise model is the racer channel the racer noise model essentially what you do is you just you know take a qubit and you just completely depolarize it or you think about like removing it like projecting it out and then replacing it later on but you get to know that sounds horrible but you get to know in this model which qubits have done that so that extra information allows you to actually do a lot with like with that you can come up with classical algorithms or to fix your code come up with corrections a lot easier than some other noise models just by the fact that you know where the qubit got deleted is like if this happened in an actual physical device you have a way to herald whenever errors happen that helps you out a lot because you know as mentioned many times the quantum information in these codes is spread across the code and there's many different logical operators and so you can actually start deleting parts of the code and as long as you are able to reset them after these checks which project you back into a code space then you can recover from it so long as you don't delete too much of your code is because no one qubit holds the information it's the information spread across the system okay the next and pretty common noise model that people study is known as the code capacity model and that is basically tells you the capacity in a very abstract sense so you don't have any of the details we don't have any circuits here but you don't have any of the details of the circuitry you kind of pretend as though you have a magic way of just measuring these parity checks without any error so you can just get to do that and you just study what are the like if you have input errors so the stuff that we were originally talking about is the capacity checks and we just detect whether things commute or anti commute that's what this level of noise model is so you just choose which qubits with probability p have x, y, or z noise and then you measure the checks and then you get perfect measurements from that the next level of difficulty is it's a bit of a mouthful model and that's based on what is the overall phenomenon looking like so we do still have these input errors and we do have magic ways of just measuring these checks where we just detect the parity but now we add in the fact that we model that there's some probability in which the measurements can flip so we have a bit flip channel for these parity that alone makes the decoding process this classical algorithm that comes with corrections much harder and for a lot of codes except for codes that have what's called single shot syndrome extraction you typically have to measure these checks of these stabilizer generators multiple times measuring a repetition code in time you're just repeating it and you could do the majority vote on those things but there are more complex algorithms in order to do with the correlations and all sorts of stuff so you effectively do a repetition code in time so the repetition code once again is popping up just by the fact that you have these measurement flips happenings because you can't rely on the actual measurements so you have to deal with correcting the measurement outcomes as well and then we get of course to the circuit level where we start applying noise at the circuit level so you actually start to care about what your device actually is doing and there's various levels in which people actually run these models so even given the circuit model traditionally in the past however we and others are starting to model more exotic noise like leakage and crosstalk and coherent noise and so on to model what devices actually look like and that can of course change the performance of codes but in a more simple even for that system generally what you do is for each one of your ideal gates you have some error channel that you then apply afterwards so initialization bit flip or something single qubit unitaries you might apply some random poly or something else two qubit unitaries same sort of story measurement you might apply some poly before if you like resetting the qubit or kind of equivalently you could do a bit flip on the measurement results and so on so this is far more accurate and you can if I remember right the color code has a capacity threshold of 20% and then the surface code has a code capacity threshold of around 10% so the color code's better there but then due to the complexity of the circuitry once you start looking at all that the surface code tends to have depends on who you read and the level of modeling that they're doing but around 0.8% threshold once you look at the circuit so it's gone from 10% to 0.8 and then the color code is around 0.38 roughly 0.4% so half the threshold at the circuit level compared to the surface code so it's dropped significantly and what was better seemingly a better performing code is now less performing although there's constantly advances in the classical decoding algorithms which can potentially improve the results but things can change in the future which codes perform well and so on looks like we have seven minutes okay probably won't say yeah so I mentioned before that if you do start adding in noisy measurements which everything starting from the phenomenological model on have then you have to deal with decoding in space time so a common decoder that people study is min-weight perfect matching decoder you could try to encode all this stuff in a lookup table like we mentioned before where you just kind of like write down the set of syndromes you might see and then what corrections might you apply however you know obviously if you have here I'm using N to be the number of syndromes that you're measuring but if you're measuring the syndromes multiple times and there's a I guess really it's you'd have to multiply the number of time steps times the number of actual syndromes and the number of syndromes actually grow based on the distance usually d-squared or depends on the code like this blows up really fast and you can't really compute these things so you have to use an algorithm not just store the stuff in memory but actually an algorithm in order to look at these like changes in measurement results so these nodes here represent flips in the syndromes and you try to have to find what is the string of poly operators that most likely cause these flips that's what that sort of represents won't go into all that okay let's see six minutes I guess I could either leave for questions or just keep on going I'll keep on going okay this I think maybe kind of be brief I'm not going to cover things still not in depth but so as I mentioned before codes don't have a universal gate set in general there might be some fancy ways but at least of getting around this and maybe some future codes that are more exotic that kind of change in time and morph and do weird things might I guess ignoring those sorts of codes Easton Canilla says on the thing that no code has a transversal set of gates that are fault tolerant and universal so that means we'll talk about what transversal means it's essentially that you're applying a single layer of gates so you just you don't have a deep layer of gates that you're applying in order to apply these logical operations you're just doing like one one operation per data cube up to that maybe less even so no simple you don't have these simple transversal gates that give you a universal set so that means effectively that you have a discrete set of gates that you have to do for a particular code but that would be a bummer and kind of mean that the QEC game is all about if there weren't workarounds so of course there are ways to go around like this Easton Canilla and other no go theorems a common thing that people look at is what's called magic state distillation so there is a actual proper phrase called magic and quantum error correction yeah and there you could also potentially because no one code has a universal set you can potentially use more than one code to kind of fill each other you know to fill up the the set of gates that you need in order to construct a universal gate set so you can potentially do code switching where you use one one code to do certain gates and then you switch the information over to another code that's potentially complicated and there have been papers that kind of show that magic state distillation might still have lower overheads even if you do those sorts of things but I mean there's still an active area of research there's other things like peaceful full times that also get around it and so on um let's see how much time three minutes okay transversal gates we've already seen some transversal gates like these poly operators you just playing a string of poly operators is a depth one circuit yeah so we can we've seen that that's both the color code and the surface code have these poly operate these logical poly operators this the surface code doesn't have a Hadamard which I think Ben briefly mentioned that's transversal unless you do permutations which I think he also mentioned um it does have a C knot gate that you can do transversally because it's a CSS code so all CSS codes can have these transversal C knot gates the color codes nice in that it has all these symmetries do you actually get all single qubit and two qubit gates as transversal operations um transversal so let's skip this poly stuff okay so the Hadamard example we apply Hadamard to all the data qubits then these x checks become z checks and the z checks become x checks it switches the poly type um and then our what was our x operator becomes our z operator because it's all becomes all z's and and vice versa so it is on the logical level switching between x and z like the Hadamard should do so it is a logical Hadamard however you notice that the code has now effectively rotated and we typically want the code to be back in its original state so if you're in a fixed 2d geometry device then you might have to do a set of operations to do those rotations or if you're in ion traps and you kind of get it for free because you don't really care like the labeling you just move things to gate zones um so we can see if we do somehow how are we do it rotate the code and we get the same thing as the original except the x's over on the other side however as I've mentioned before any string that connects the top and bottom boundary is equivalent you can multiply by stabilizers to get to move the thing over and it still has the same logical information so we've got back the code and we have indeed done the transversal Hadamard uh the color code can do it and it doesn't need to move things around because x's and z's are symmetric so everything's symmetric and you're good and all the boundaries can have the same sort of poly x y and z type stuff so you're all good one minute okay in one minute I can explain that that's well maybe not one minute but close to one minute I can explain the transversal C knot so how do you entangle two code blocks so there are other ways to do these entanglements as I mentioned as before but we'll just focus on transversal gate because it's a lot simpler so the transversal gate for all these CSS codes all you have to do is as been mentioned you put these the corresponding C knot in one block that's your control block that's representing one of your logical qubits to the corresponding qubit in the other block that's your target block so sort of like this so we have two codes and we're just stringing C knots between them and by these rules we can see that we'll take that X logical string and the X having these C knots I'm just concentrating on the C knots in the boundary there's C knots everywhere this control you know touching the corresponding qubits I'm just highlighting the C knots on the boundary but using the rules of the C knots you get the X to come down and so we get you know the X logical X on the top to be logical X on the top and bottom and so on like the logical X on the bottom remains the same doesn't change is there the same sort of rules on the physical that we see on the physical level on the logical level by doing these sets of operations cool and the same sort of story on the logical level but in the reverse for the Z side of things but in the reverse and now okay I'm over time but I'm almost done if we have two like X and Z checks on the top and bottom so S1 and S2 if we apply the C knot between the qubits then we do get a doubling of like S1 because the X flow down but as Ben has mentioned we can rewrite our generators where we can just multiply stabilizers by each other and so if we just multiply S1 by S2 and S2 hasn't changed because it doesn't flow up from the target then we get back to the original S1 prime in this case and S2 so we get effectively the same original stabilizers and the same source story for the Z thing but everything flows in the opposite direction so I'll share these these slides and you can see that here's a quick proof of why why CSS codes do have transversal operations that entangle code box sorry for going a couple minutes over well thank you very much for this nice final talk today we don't have anything planned after this so you are released for the evening there is going to be I think dinner served down at the Adriatico at like seven-ish but you should check in case you don't want to go somewhere else like Trieste and catch a bus but in any case there was a very nice day again day two I think you learned a lot and keep in mind you're learning here from experts right so it's very special that we can get you pulled into here from all the important work you're doing so both for you and Ben thank you very much for this afternoon session yeah good time it's a good time


Good afternoon, Pastor David and to you John. Thank you so much. Welcome everybody to a random moment with Pastor David Unfiltered. Thank you for tuning in. You know Pastor Pastor yesterday was a significant day in your life You celebrated 51 years of walking with the Lord. Yeah, I mean what an amazing that's a that's a long time, you know You know it is it is yeah, that's two years more than my age And so You know so you've experienced lots of ministry you've seen a lot of things within the church and you don't want to ask you with social media now being Part of the overall church in ways of communication and the ways to get church out into the out to the people With that in mind, what have you seen as the greatest difference in the church? 51 years ago Then you do that you see in the church today Well, that's a great question because there are numerous differences that I see in the church of when I first got saved versus the The way that church life seems to be today here in the United States and I think that my my perspective is Skewed in that I got saved in a revival. I got saved in a youth movement and you know and that's going to forever Affect the way I look at the church as it is today because I came out of a time that being a Christian was was pretty much everybody claimed to be and and yet the church was ineffective in and We had the church didn't seem to be proclaiming an answer for the kinds of lifestyles that my generation began to partake in and so We were looked at at that time the youth were looked at it's being lost and Hopeless and then the Time magazine had written written an article on the question is God dead I think in 67 and You know and that question was very real nihilism had begun to creep into the way kids were thinking existentialism was Was part of the way that we we thought and even in our music there was a song Called live for it today, you know and it was it was actually an existential song We didn't know the philosophy of existentialism. We simply Agreed with it, you know We were never meant to worry the way that people do, you know And then you go on and say live for today And so that was the way I grew up and also the church had lost out its impact But in the in the midst of all of that There were people praying for for the youth and so that's when God began to use Calvary Chapel ministries and and others to to reach the the lost youth and all and so from that perspective Things were a bit different, you know so today what it seems is that there's more of a Malays more of a More of a rejection of the thought of truth or the concept of an absolute truth or or the belief that there is something that really is right or really is wrong and You know, we have allowed our society to to produce Gods of foreign gods, if you will, Baals if you will, you know, where we have Worshiped at the idol of sexual immorality or or the molech where you you worship at the idol of killing children Which we do have today, you know, and the altar of Baal, which is a nature of God I mean we have that within American Philosophy they just don't realize that these are ancient demons that have basically found a place and rooted themselves In to our society and religious thinking. I mean, you know things as as Obvious as practice practicing Hinduism and all and special diets and refraining from certain meats and and Jesus speaks concerning those things He says it's not what goes into the man that deviles him It's what comes out of him He speaks of nature and human nature and all and so I think that people are confused about that today and Because they're not necessarily going to a Bible teaching church. They're going to Perhaps a place where they're speaking of current events or whatever, you know, whatever their their itch is They go and get it scratched But they're not necessarily being taught to love the word and grow in the word and growing God's grace They're they're not necessarily in the majority of churches being taught that John So that's a that's a huge difference from what it was like when I got saved Which was in a Calvary movement Which we were taught read your Bible and try and put it by put it in practice by the power of the Holy Spirit We were taught to do that. So over the last 51 years of my life That has been something I've I've I've tried to to practice and and so in our own fellowship You know, we have been built on the foundation of the word of God, but that doesn't mean people want to come here You know, we have seen over the years So many thousands who have come and so many thousands who have left and sometimes it's discouraging Sometimes it's greatly discouraging sometimes when I realize that that Americans have been fed a line of fear and They're hiding from every variant of this COVID virus and now the Omicron is something they're all afraid of many are afraid of because you get it on the news 24-7 even though it's like a cold even though there's been one fatality and that was Somebody who was suffering with a comorbidity Yet you have people I saw it on the news just yesterday. Oh, it's coming and and then you have, you know people even our president Warning everybody how selfish we who didn't receive the vaccination are etc. etc. It's it's fear-mongering and and the church is the church in many places I think is yielded to the to the lies of the enemy because Because if they were to really do a little reading and research and get away from CNN they would see that It isn't what people are saying it is and so that concerns me when we got saved You know We weren't afraid, you know, and I still am not thank God. I'm not I'm not afraid. I I had COVID I just had my blood tested, you know to see if I have antibodies in on this particular system of determining antibodies that said in anything below one is you have done and One and above you have antibodies and I tested 8.9. So I have very strong antibodies and and and but even if I didn't I wouldn't be nervous about those things because God hasn't built me in the way that I should be afraid so Leaders ought not to be who follows a frightened leader You know in military if I had a leader who was afraid to go into battle You think I'd go into battle? No, if he is not willing to go into battle Why would I lay my life down and he wouldn't be willing to do the same? Because you know There's a difference between in battle and there's a difference between suicide and sacrifice and the military You learn that difference. You know what the sacrifices and you're you're willing to pay it because I was I was I was trained with a mentality that the reason I'm wearing the uniform is to protect my home protect my family you know at that time unmarried protect my my nation, you know and today I'm still in God's military and and I'm still in uniform and I'm still protecting them and that's what we do So I believe that the church needs to wake up to that to the sacrifices necessary Fellowship is necessary serving God is necessary and avoiding and forsaking that Probably should do some soul searching as to why that's taken place and if you were to describe briefly if You know within the 51 years has have you would have you seen the church being strengthened or their church being weakened? I believe that the church today has some very strong Leaders in various places, but overall Because there's not a hunger for teaching the word of God or the hearing of the word of God and John There are places and and I say this as a 51 year veteran of Christianity I speak as a man who's been attempting to teach the Bible for 48 years Pastoring this church over 40 years. So I have the stripes. I've earned the credibility So speaking from that perspective There are many young pastors who seem to think that pastoring means to have a nice office and take trips to Israel and You know have a good salary and they don't understand sacrifice sometimes They don't understand that you lay your life down for that flock. That's what shepherds do. I've seen it More often than I then I would like there are some great pastors out there who say, you know For me to live is Christ to die is gain and and I'm going to I'm gonna lay my life down for my sheep I'll be there for him, but I discovered a long time ago that even if you were to go to the point of laying your life down For the sheep, they don't care a good portion and that's what's happened to Christianity John a good portion of the church just don't care.  I don't know. It's hurtful in some ways, but But it's real, you know and for me keeping my hand to the plow and Loving in spite of the fact that many don't love you It's like what Paul said to the Corinthians and second Corinthians is that the more I love you the less I'm loved by you Well, I have learned many lessons like that the more you lay your life down The more people take advantage of that, you know to the point where in our fellowship, you know, I you remember John You know, I was here ministering to the people and even though they didn't know I was concerned for for the the salaries for you and all the rest of the staff and And and you know, somebody sided to go and try and start their own church and take people who were givers, you know when I was paying their salary and those are the hurtful things that happen and Did I see that at the beginning? No, it was a Jesus movement like that. No Have we morphed into something like that? Yeah, yeah, it's where there's no sense of I belong here. This is where I'm fed. I'm gonna serve here I'm gonna support this ministry That pastor needs his hands raised in prayer and and if he needs help, I'm gonna be next to him. No, that's not here In many churches. We have a great church here. I have to be honest with you. What has happened in ours is It is the church I prayed for John It has become the church I was asking God to give me and and those some have left I see those as the ones the Lord Removed and they went to wherever it is that they need to be and I'm grateful for that They need to be where the rat the ones who have remained have made this church a joy for me to pastor and in these latter days of my ministry I'm blessed by it Amen pastor. Thank you so much and again, you know, I commented yesterday There was a post on Facebook and I wonder how many lives have been transformed through the 50 and we know It's the power of the Lord Through your 51 years of ministry, how many lives have been transformed, you know, and I'm sharing with you 15 of those years at least in my life have been transformed under your ministry and and being my pastor and and and I'm wondering How many people's lives have been transformed? thousands You know and so thank you for that pastor and for keeping your hands on the plow. That's an amazing accomplishment 51 years walking with the Lord. I can do all things. Amen. I love it. If you're not called Ministry will roll over you will crush you if you are called every day is a joy You know, so for me 51 years of serving the Lord loving the Lord And all these years pastor in this church. Yeah, there's been hurts and there's been disappointments and and betrayals And I'm certain I've heard a lot of people myself without knowing it and perhaps for that I For that I do I do regret But at the same time, I know it's It's been a great 51 years I know you've been asked if you can do it all over again or if you would change anything I heard that question asked you before and you had mentioned I wouldn't change anything Well, I couldn't change anything and be the person I am today You know, I am the person I am today by the things that I've done or wish I had not done You know and and so at the very end of it, no Whatever it I've gone through over these years has made me who I am and I'm at peace with Christ Thank you so much pastor David and want to remind you that we have our evening services tomorrow at 7 p.m I'm not gonna tell you what book that you're gonna start just come on Wednesday and you guys will find out and Invite your friends and family and the New Year's Eve We have a guest speaker branding coming out and we're gonna have some great time of worship and hear God's Word And so another time to ring the New Year in invite your friends and family and again pastor Thank you so much for this time and church family. Thank you for tuning in. God bless you guys We look forward to seeing you and we're looking forward to another 51 years past God bless you guys. Thank you again pastor David


This 10th year of Daily Tech News show is made possible by its listeners, thanks to all of you, including Degracia A. Daniels, Irwin Sturt, Ken Hayes, and we have a new patron, Aisha. Welcome, Aisha. On this episode of DTNS, threads may be coming to a regional area near you. RCS gets a lot more love, and Google has some big announcements of its own. This is the Daily Tech News for Thursday, November 30th, 2023. From Studio Secret Bunker, I'm Sarah Lane. From Columbus, Ohio, I'm Rob Dunwood. From Austin, Texas, I'm Justin Robert Young. And I'm the show's producer, Roger Chang. We have all sorts of great political stuff to talk about, and it's good because Justin Robert Young is with us today. But as always, we start with the quick hits, so let's do that now. CEOs from companies like Metta, TikTok, Snap, Discord, and X are all set to testify in front of the U.S. Senate Judiciary Committee on what the committee calls failure to protect children online. Social media's negative impact on young people's mental health has been increasingly concerning for both parents and lawmakers. Metta and TikTok CEOs specifically are appearing voluntarily, but Senators Dick Durbin and at Lindsey Graham expressed frustration with the CEOs from Snap, Discord, and X for appearing only after being subpoenaed. Sam Altman is officially back as CEO of OpenAI, and Microsoft now joins the company's non-profit board with a non-voting observancy. OpenAI's new board includes Chair Brett Taylor plus Larry Summers and Adam DiAngelo, the only previous board holdover. OpenAI co-founder Ilya Suscover did not keep his board seat, according to Altman, but will remain at the company. Bloomberg also reports that OpenAI will continue a plan to let employees sell shares in the company through what's known as a tender offer. Certain investors reportedly dropped out of the tender offer following the Altman ouster. Employees now have until January 5th to opt in instead of needing to close in early December. At the Deal Book Summit in New York on Wednesday, Elon Musk addressed how some advertisers have paused ads on X because of anti-Semitic posts that Musk amplified on the platform. Musk said, if somebody's going to try to blackmail me with advertising, blackmail me with money, go bleep yourself.  Is that clear? I think it's clear because he said it twice. He then singled out Disney CEO Bob Iger, who was in the audience, saying, hi, Bob. Musk also said that others would boycott those advertisers if they thought the advertisers killed the company. Robotaxi Company crews announced plans to start operating again last week. The subsidiary of GM also plans to cut spending by hundreds of millions of dollars, according to GM Chair and CEO Mary Barra. Specifics on how crews plans to operate differently is set for the coming weeks, but the spending cuts are expected to result in widespread layoffs of Tru's 3,800 employees. U.S.-based real estate service of Fidelity National Financial, sometimes known as FNF, disclosed that it is contained a recent cyber attack that caused havoc for about a week. In an SEC filing, FNF said that the incident has been under control since November 26th after first occurring on November 21st, and it's restoring normal business with its customers. All right, let's talk about the expansion of threads. Justin, I know this is your favorite topic. The Wall Street Journal reports that threads, that's Meta's microblogging platform, often compared to as a direct competitor to X, is going to launch in the European Union in December. This is thread's largest expansion since its debut back in July in the U.S., and certain other markets wouldn't became available, but e-regulations have forced Meta to work a little bit differently in this particular market. The company will give users the choice to use threads without needing to link to an existing profile on Facebook or Instagram, that's how I signed up for it, and allows users to make their own posts more or less from scratch. So if you want to be part of the threads team, you don't necessarily have to be part of the Meta team as it stands now. Threads in the EU could lead to upwards of 40 million additional monthly users for the platform in 2024. Threads had a big uptick. All the headlines a week later were like, we can't believe how many people have signed up for threads. A lot of that had to do with the fact that people just had Facebook and Instagram accounts already, and then growth sort of stalled a bit, and everybody at Threads said, we're building slowly. So Justin, what do you make of this? I think that they're going to add a lot of people. I think that Threads and Meta has a tremendous audience advantage to get people on a platform. The question is whether or not the platform is worth it. And before I get into anything critical, let me say that my standard position on all of this is that we are going to live in an increasingly balkanized world when it comes to social media. It's going to be same as it ever was. When we first came onto the internet, there were a million little message boards, and everybody had their own little reason to be on it. We're going to have the same thing, but it's going to be social media instead of just text. That being said, Threads is not culturally relevant. Threads is a tech story. Threads is not influencing news. It's not influencing culture. And for whatever the chaos that is happening on X and whether or not it's being mismanaged, which I do think it is, that is culturally relevant. So if we're going to measure success by that, by whether or not people are paying attention, then Threads is not something that matters. Now, Facebook, or sorry, Meta, is an ad company, an ad sales company. Will they be able to monetize Threads better than X is being able to while the CEO is currently hurling expletives at advertisers? Quite possibly. Yes. I agree with what you're saying in spirit. I do think, however, Threads is coming. I think sometimes we forget. This thing is only six months old. It's a baby. So to compare it feature to feature to X, you can't really do that yet. To compare it to being the social water cooler, so to speak, the town square. It needs more than six months to become that. But I can tell you from my personal experience, my use of Threads has increased exponentially probably over the last, I'd say, month to six weeks. And I'm not alone. There are many people who I now see on this platform that I used to converse with in the other place that I'm now conversing with here. Yeah, I think what has struck me as interesting with Threads specifically, even though you got Blue Sky, you got Mastodon, you have lots of other social networks that also are competing with X for people who either just want to try something out or don't want to be on X at all. Threads now has folks that I like and follow and care about what they're saying, exclusively posting on Threads now. It doesn't mean that everybody is doing that, certainly not the case. And you still have all the fun stuff about the old Twitter, Late Night Twitter or Sports Twitter. That doesn't exist on Threads, at least as far as what I'm seeing now. But I feel like people are starting to dedicate a lot more time to making it that identical place. And again, like you said, Rob, this is in the first six months of it being a thing at all. Can I push back a little bit on that? Tell me about Facebook watches fifth birthday. Tell me about all these other features that have been started by this company and then abandoned because it didn't get the reach that they wanted. Meta's not in the business of doing small things in the way that Google's very frustratingly not in the business of doing small things. They need scale to sell advertising against. So if it's not catching in the way that they wanted to, they will kill it. Or they will just kill it by death of a lack of engineers. Here's the tipping point. The second that I see on X, a screen grab of something that has been taken from Threads that is not posted on X and it goes viral there on X, then I will believe that something is happening over there that is not currently happening on the platform that I pay the most attention to. Because right now that is on Instagram, but you don't really see that on Threads. Well, I don't know what their support is for images. Because I haven't been on there. I logged out and then I have not bothered to log back in, although Instagram does show me tantalizingly a post of people on Threads that are no longer on X that I am friends with. And whenever I click there, it says log into Threads and I say, I'll get to it. So Meta is also warning that foreign governments such as Russia, Iran and China will continue to curb inauthentic messaging campaigns from various social media accounts heading into the worldwide elections in 2024. But Meta also says the US government has stopped proactively sharing information with social networks, which often covers up major nation state influencer operations. Yeah, so Justin, we're heading into a pretty wild 2024. You know, how much does stuff like this move the needle as far as messaging and making sure that people are getting real messages? By way of every expert in this field, the way that foreign governments disrupt places that they want to disrupt is by amplifying hysterical ridiculous commentary about issues big and small. So considering the fact that I have not been on the show because I was in Europe, one of the places I was at was in Liverpool, I will quote one of their favorite sons war is over if you want it. If you don't want to be manipulated by misinformation, then please discount and absolutely stop yourself from posting hysterical, half informed opinions, because that is easy to replicate and easy to manipulate. That is what is coming. You can educate yourself by just being very, very sober and saying, maybe I shouldn't post right now. There is yet more meta news today. Meta is in the news today. The company sued the U.S. Federal Trade Commission, FTC, in Washington federal court over claims that it's in house trials violate the U.S. Constitution. Meta also asked a court to halt the FTC's bid to change a 2020 privacy settlement. This was the second attempt by Meta to block the proceeding in court. Justin, what is your gut say about how successful Meta will be in this? I think they need to do it because they need to push back against it, but this is going to get settled down the road. So let's switch gears a little bit. It's been a big month for rich communication services. A few weeks ago, Apple announced that it is bringing RCS to the iPhone sometime in 2024. And today, Google announced that over 1 billion monthly active users use RCS via Google messages. It's likely that Apple finally decided to add their protocol to the iPhone because the EU is likely to classify iMessage as a gatekeeper status, meaning that by law, Apple would have to make or should say iMessage interoperate with other messaging platforms. But iMessage isn't the only service to be classified with gatekeeper status. Yeah. So Meta's Messenger and also WhatsApp are also classified with gatekeeper status. So they are also going to have to interoperate with other messaging platforms going forward. Does this mean that RCS should be the protocol that all messaging platforms use to communicate since it's also a standard protocol backed by the GSMA? A lot of people say yes. Justin Robert Young, what do you say? I have very complicated feelings on this. Number one, I am a blue bubble supremacist and I do, I was upset on my holiday that I had to realize that there was going to be some element of erosion with green bubble people. But with that being said, I do think that this is, it's frustrating. Obviously, there is not an industry that the EU does not believe that they can regulate and when they're done regulating that, they'll regulate it again. I don't think that RCS is a secure standard and I don't know if these gatekeeper statuses are particularly helpful going forward if we want to look at making the mobile web better. I don't think that cementing RCS makes the mobile web better. So Justin, you're absolutely right. RCS is not in insecure. That is one of the big problems with it. And I was thinking about a platform like Signal. Signal, I used to use it a lot. It's very, very secure. But one of the benefits to it that at least on Android, you could use it as your default SMS application. And I believe just over a year ago, at least October last year, they got rid of SMS. Now, the reason they said this was because SMS was just so insecure that being a security platform or security messaging service, they just didn't want to continue to support that protocol. But if they were to add RCS, it's kind of like, well, you're going backwards because there is no, at least not right now. There's no in encryption in the spec. So I'm just curious, does it make sense for, if the EU says that if you're a gatekeeper, you have to interoperate, it probably makes sense that RCS would be the thing since it is a protocol that is run by the GSMA and not by any one individual company. But it's kind of like RCS right now, unless you're using Google's platform and you're doing so much of it, not inside of RCS, you're doing it inside of Google's messaging app, it's just not that great of a protocol. I mean, it's been around for a while now, and it's kind of old hat. So I'm just wondering, what are these companies going to do, is RCS the thing for them? Yeah, in a perfect world, and I always go back to Trillion in my Windows days where it was like, you just talk to whoever's online, I don't care where you're coming from, because we can all connect various chat services through Trillion. I know that this is different, but in a perfect world, this just is possible. Give me the iOS app that helps me do that. Give me the Android app that helps me do that, or something that's baked into either OS or both. That is the perfect world. But as you were mentioning, Rob, Signal's saying, that's not really what we do though. Our specialty is to be a lot more secure than that. They have a point. RCS isn't the end all be all. It's going to help some folks for sure. But that's not what a lot of these companies built their apps on. They built their apps on bypassing what was sort of available, but not that great. I want to thank you guys for building in so many of my greatest hits into my first show back. Hating on Android. Hating on threads.  Just my entire favorite list of things to talk about on DTNS. So folks, if you would like to stay up to date on the fast moving world of artificial intelligence, you need to listen to AI name this show and launch during DTNS experiment week in August. Each week Tristan Jettra and Teja Custody waved through the hype and the doom saying to keep you informed with the latest news in the AI world. Catch it all at AI NamedThisShow.com. So you got some more Google news. Google is still dominating the news today with big time. It's got updates with not only the Android but also to Wear OS and Google TV devices. Let's start with some non-RCS Google texting updates, Sarah. Yeah. So we've got voice moods, which lets users add backgrounds and animated emoji to voice messages. Not anything super groundbreaking, but it's fun. New reactions for messages are also designed to offer some options besides the standard kind of thumbs up type stuff. And change in chat bubble colors. You hear that, Justin and Robert Young? Yeah, might think they're on iOS after all. It's gonna feel like some folks hated. So yeah, we've also got some AI generated image descriptions for those with low vision, you know, coming out as a new feature. It's called talk back and can read out loud descriptions of images from either the internet or a photo you took yourself. Google is also adding new languages to its live caption feature, which expands on being able to take phone calls without needing to hear the speaker. Yeah. And Google's Wear OS also now lets you control more smart home devices and lights and groups of lights if you have them directly from your watch. So let's say you're away from home and you want to tell your connected smart home devices that you're away so that they do the thing that they're supposed to do, you can do that now. There's also new assistant routines feature that's designed to automate daily tasks. If you have them assistant at a glance on the watch face itself will show you information that's relevant to your day, such as weather, traffic patterns, things that Wear OS has designated that you are interested in because you interact with it often enough. But Google TV also getting an update, 10 new free channels to choose from further helps you get into the ecosystem. I mean, that's Google TV is hoping that you do that. 800 app supported channels overall at this point did not realize there were so many. So Justin, with you being the unabashed iPhone and Apple person, I have to have to speak up for the Android title of the world because I'm an Android user. Please do. And I just want to say that Google does some really cool stuff at Android. If you can get past the fact that it is not iOS, they do some really cool things on the platform. But just beyond what you do on Android, many of these things that Google announced, you can actually do them on an iOS device as well. You can do this on an iPad. You can do these things on an iPhone. Google has some really cool services out there that are available to all. And I think they're all adorable. I think that they're all just so great. And I wish the best for all my Android friends. If we can get to Google TV for a second, Google is an ad company and it's easy to forget it. But I am here to remind you. I don't think it's easy to forget. They remind you. They get ads and they sell ads. It's the only reason why they are in business. AdWords has been their golden goose and everything else that they have done, up to and including YouTube, they've never really been able to turn into the same kind of profit generator that AdWords is. And they face an existential crisis as the value of search is at least threatened. We'll see if it is significantly diminished by the idea of AI going forward. So something like this, a fast channel, which seems to be something that will be a major player in our entertainment landscape going forward, makes a lot of sense for Google. I am now a YouTube TV subscriber, very happily, although they were too good at detecting my VPN in Europe and I was not pleased with that on Football Sunday. But otherwise, I am happy with their service. I think that if they bring that same level of quality to fast channels and are able to leverage their ad sales against it, this is a natural play for them. I think it's a very good idea. Yeah, I'm a YouTube TV person as well. Trust me, the company does not pay me. I wish they did. But even though the price has gone up since when I first signed up in 2017, 2018, whenever it was, I was a little late to the game, but I was like, this is amazing. I love it. Great. Half the time, the ads are just weird little interstitial blank pages because they still haven't figured it out. Yeah, the zen. It's the zen moment before football comes back. All good. It's not going to be like that forever, but it's the best, I think, way to replicate some sort of cable situation. You have other options. You do, but it feels just like it's easy onboarding, makes sense, looks like cable. You get all the same things and it's not really cheaper anymore, but Google TV has a lot of ad supported options, much more than I realized. I'm going to have to dig into that a little bit because I will sit through an ad for free things. That's the thing that I will do. So here's the thing. Fast supported television. What is it? Free ad supported television? It is actually not bad. There's some really good content available on all of these different platforms. The Pluto TVs of the world. It is actually really good. It just reminds me of watching TV back when I was a kid, like in the 80s. Commercials just came on. You just watched them. What's really nice is that a lot of the content was built for commercials. The commercials come in right at the right time. It's not like they're just coming on in the middle of somebody saying something. You literally have a natural break in the content where a commercial is supposed to be and then the content comes back. They're doing it really well. And if you haven't looked at it yet, you probably should do yourself a favor and go take a look at some fast channels because it's, as I said, it is really good content. Even our rundown, our DTNS rundown, I mean, granted, it's just a rundown that works for us. But a lot of us have just been doing this for so long. It's like, we still build a rundown that technically was sort of based on a 30 minute television show, you know, with shocks and breaks because that's just, we know that that is, that's a friendly habit that people are used to and it kind of makes sense. Well, and beyond the fact that they're leveraging legacy television shows and it makes sense to put an ad for a Kickstarter right between when MacGyver is about to get ripped apart with a bandsaw and when he figures out a way to avoid it with a straw that he got from McDonald's, like that is what it is. But also, there's an existential question about FAST of what is worth it for a 24 hour channel? Because in our old cable model, you are thinking about, okay, well, you want certain kind of shows to air during the morning and certain kind of shows to air in the midday, certain kind of shows to air at night and then whatever graveyard shifts, late night television stuff with FAST, the channels that you hear people talking the most about are like the Godfather trilogy just plays on repeat. So no matter what, you can just turn on, you will see one of the Godfathers and it'll just keep going. Yeah, Godfather 2, Shawshank Redemption, it really doesn't matter what is happening. If it's on, I'm going to pause and watch at least 20, 30 minutes of it. So like, you know, I have FAST on one or two televisions in the house, it just runs. It's just, you know, whatever's on is just on. Yeah, I think it's smart. It's the same way I feel about radio in my car where it's like, this is all on demand. Well, I mean, not every song you're going to hear is, you know, you might have to find it, but especially that sort of talk radio stuff. That's all, that's all a podcast somewhere. I can control all of that myself. I can watch whatever television show, you know, to an extent at any time I want to, but when it's just on and I find it organically, I still feel like, oh, yay, Godfather 2. Okay, let's watch it.  So I think a lot of this, the linear stuff is it's not yet dead, mostly dead, but not yet. Sarah, I feel like this is a live with it in the making.   And I might, I would probably miss some things and discover a lot of other things. That's actually a really good one. I think that would be, that would be a way for you to explore this fast growing marketplace. Well, something I'm also really good at is being an avoider, particularly when it comes to packing. Packing for a trip is how my procrastination really rears its best head. Worry not though, if you're like me and you end up getting real stressed out before trying to make it to the airport five minutes before your flight leaves, Chris Christensen has an app for you. This is Chris Christensen from amateur traveler with another tech in travel minute. I can pack for a weekend trip in about five minutes and it takes me only about 15 minutes to pack for a three week trip because I use packing lists, but I know for some people this is overwhelming. So I've got an app that's going to give you a good start and that's pack point. If you download the pack point app, it then asks your gender and then asks where you're going, how long you're going to be there, you're going to have access to laundry, what kind of activities you're going to do, and then comes up with a pretty good starting point for a packing list. If it's a work trip, do you need the laptop? Do you need a VPN key fob? If you're going hiking, what do you need to wear? All of those sorts of things. Check it out. Pack point. This is Chris Christensen from amateur traveler.  I'll go to Duane Reed when I get there and just like buy things. I don't have little shampoo. I just don't have it. I don't want to do this. And let me tell you, when you're going between European airports, they got a whole new different set of rules compared to TSA. You have to take out your little things and put them in a plastic bag for some reason only through their version of TSA. I couldn't get down to 15 minutes for three weeks just because I got to go to dry cleaners and pick stuff up that I didn't think I was going to have to go to the dry cleaners and pick up. I got to wash stuff. I need the iron stuff and fold stuff. So yeah, for a three-week trip, I'm still looking at a couple of hours, no matter what the app or list the packing list is for me to use. Yeah. Wait, hold on. Wait, Rob, Rob, you're doing that before you leave? You're not doing that when you get to where you're going? When I get to where I'm going, I'm relaxing. There's no preparation of clothes when I get there. So yeah, I try to make sure all that stuff is done before I go. I was like, I'm not ironing again in Hawaii once I'm there. Yeah. I'm not ironing on vacation if I can avoid it. Oh, man. I mean, I don't iron a lot at any time. So the only time I have to iron is when it's wrinkled on travel. Well, this might move the needle for some of you as well. Natalie wrote in our mailbag today. She says, a few days ago, I found my go-to budgeting app, Mint, shutting down at the end of the year. Natalie says, I learned this through a Mint competitors ad. I haven't received any direct communication from Mint about this. Wanted to ask any of you use a budgeting app that you think would be a good replacement. Natalie says, I'm overwhelmed by the number of options out there and not looking forward to making the switch. I'm not a Mint user, but I used to be one, Natalie. So I looked up Mint's announcement to see if somehow they just never announced it. They did on sort of their news blog, which I would assume a lot of Mint users just never look at. This was back on October 31st. So it was out there. But if you didn't get a direct email, I could see where you just wouldn't know anything about it. But I wanted to ask the crew here if they have ideas for where Natalie should go. Hold on. Before we get to where Natalie should go, Natalie, I am with you. I am a Mint user. I only found out about it because I pay attention to tech news. I didn't realize until we were going over your email for this show that I never would have heard about it if it weren't for the fact that part of my living is made by analyzing the tech news. So this is an absolute travesty. I have nowhere to go. Please at reply me at Justin our young on Instagram or X and let me know where you're going. Natalie, I follow you. Perhaps Rob Dunwood, you have somewhere to send Natalie and Justin and myself. So here's the hard thing. So Mint was free. It's free 99. I have not seen anything that is as good as Mint that is free. There are quite a few services. Actually, just if you were to just stay with Quicken for I think like $2 a month, you will get a darn good Mint replacement. But you know, Quicken or into it, they're trying to get you into their premium products that you pay for. And that's why Mint is going away. It's not something they make money on. So they want to get you over to things that they make money on. So like I can't think of anything that is free that is good. But if you get into the $2 to $5 a month range, I mean, there is a myriad of really good services out there, but they are not free. They do have a charge. Yeah, into it is directly sending users or hoping that they they send users to credit karma, which is another one of their brands that I have not used. So I can't tell you if it's good or not. I don't know if anybody else here has used it. But but yeah, it's it's always a it's a bummer when something that you enjoy and think works well goes away. But it's a real bummer when that has to do with your personal finances. I mean, like this is how we all live. And also like like into it for the love of all that is holy. Mint's such a great brand. I trust Mint. I trust Mint with my bank accounts for years. To jettison that brand and then say no, go to credit karma, which sounds like the worst version of a Ponzi scheme. Like I am I am blown away by this decision from a branding perspective. Disgusting. Well, Justin, Robert Young, whether you are disgusted or positively pickled, we're always happy to have you on the show. So let us know where else they can keep up with your work. Friends, World's Greatest Con is a podcast from Dog and Pony show audio with Brian Brushwood. And we gave a surprise to all of our listeners last week during the Thanksgiving holiday and for all of your holiday travel needs, a two part episode on the founding of Epcot. A story that Disney's Epcot. Yes, Disney, but but not the Epcot that exists right now. Walt Disney's idea for a planned community, the perfect city that would never stop evolving. And by the way, the reason why Walt Disney World has all of the privileges that wound up becoming a gigantic controversy a few years ago in the state of Florida, it all rests in the new two part episode from World's Greatest Con Epcot one and two available right now on all podcasting platforms. So patrons, stick around for the extended show, Good Day Internet. Whether you live in Burlington, Vermont or not, Spotify Wrapped may apply to you this year. Just a reminder, you can catch our show live Monday through Friday. DTNS is live 4 p.m. Eastern at 2100 UTC every weekday. And you can find out more at dailytechnewshow.com slash live. We're back doing it all again tomorrow. We're talking about all the crazy and wild AI chat box that have taken advantage of OpenAI's custom GPT with AI named that shows Tristan Jucha joining us. Talk to you then. This show is part of the Frog Pants Network. Get more at frogpants.com. Bob hopes you have enjoyed this program.


All right, there we go. So, RLand has been mentioned quite a few times throughout presentations this week, and I wanted to kind of talk about how it worked, like what's under the hood in a way that's accessible to most people. So, the key part is the rate limiting. So, it's basically controlling how fast you can interact with the system. So, an example would be interacting with Discord. If you're in a big Discord, there's a slowdown mode where you can only send one message every like 15 seconds or so, it's very similar. So, it is made up of a couple things. So, semaphore, which is the talk before this, which is basically just proving you're part of an anonymity set without revealing who you are. Shamir's secret sharing scheme, which is the majority of this talk, and some time or event delineation, which I'll get into in a minute. There's kind of three stages to how RLand works. So, there's a registration process, so like joining, which is basically just a Markle Tree. And signaling, which is your actual sending of messages, then there is the slashing or secret recovery. So, yeah, so like I just said, the registration process is just the Markle Tree. So, this is basically what semaphore is. So, it's just proving you're part of an anonymity set. And this can be done on or off chain. So, the signaling part, this is kind of the meat of all of this is, so it's a circum circuit. And the first public input is the epoch, which is like a time or it could be like a post on Reddit or something like that. Just some delineation in a time or an event. And then the actual message, and then a secret key. And out of that comes proof that your epoch and your message are accurate and verified with what you put into it. It proves that you belong to that Markle Tree, that membership group. And it spits out a secret chair. So, this secret chair is one of the most important parts of how RLand works. Basically, if you have a secret, you can plot that on a graph and on the y-axis.  The random, so you have to have a random point to construct your shares. And that is derived from the epoch. And these shares are generated from the message hash. So, the shares, basically the whole idea behind Schumer secret sharing scheme is you have, you have a secret, you break it up into parts and you distribute those parts publicly. And if you have enough of them, you can reconstruct the secret. So, with these two shares, you can reconstruct where that line is. So I'm gonna go through how that works. So if you have one share, you really don't know where that line is, right? If you have two shares, then you can see where it crosses the y-axis and you can determine what the secret is.  And this can be split up into multiple pieces. It doesn't just have to be a linear function. This could be a polynomial. So you can have multiple shares that you need to be able to recover. So you can say a person can send 15 messages per day, but that's it. So this is the actual circuit. I know this looks a little confusing, but if you kind of just look and see how all this is assembled, it's really not that bad. So you have the epoch, the message, and the secret key going in. And the center part here, I have a little laser pointer, this center part is the Schumer secret sharing scheme. And the right side, this is basically just the construction of the identity commitment. So it's your public identifier for being anonymous. And the left side, so this is just the nullifier. So it's basically the equivalent of a nonce. And some use cases for this that we thought of is you could do auctions where you can have only so many bids per item or whatever bids per user. You can have a bulletin board system like Reddit where you can only comment once per post or once per level of post. We've also thought about using this for preventing denial of service attacks for something like Cloudflare, where we can do that anonymously and decentralized. And then, so this is also used in a couple of applications that the PSE has developed, like Skidder. So we have ZK chat in there. So it's anonymous chat where it's rate limited. And so we have a JavaScript library for this. We're working on a Rust library in collaboration with the VAC team. And we're probably gonna write a Python version and a couple other bindings for languages. Yeah, so if you wanna look at the documentation or the code, there's the QR code. And if you have any questions, you can join our Discord. Again, I'm at Heart Engineer. And yeah, thank you. Thank you so much. We have still one minute and a half. Maybe one question. The audience, some Q&A. Any questions? Raise your hand here. Hello. How does this compare to, suppose if you use the ZXs approach where you keep one notes and you keep countering the notes and you keep including a counter and you improve that counter's lesson, some number. I don't know. I'll have to talk to you about that offline. I'll have to think about that for a minute. All right, thanks. Okay. Okay. Any other questions? All right. Thank you. Thank you.


I also want to thank our local MPs, Chris Biddle and Vance Badaway, as well as Eric Solheim, who we heard from, who's the Executive Director of the United Nations Environment Program for being here today and for joining us on the water. Eric, when I found out that the theme of this year's World Environment Day was connecting people to nature, I figured this was a good way to show that as global hosts, Canada is all in. And of course, I want to thank all the young people who joined us and the Palmer family for making sure that we had everything we needed for this morning's paddle. Thanks, everyone, because any day I get to kick off with a paddle is a great day of mile bucks. I think Catherine did a great job of sharing why World Environment Day is so important to Canada and to the entire planet. What I want to talk about is something a little different. I want to issue a more direct challenge to Canadians. To follow through on today's theme, to get outside and to connect with nature. I'm talking about feeling the sun on your face, the warmth of the wind, the coolness of the water. If you have children, bring them with you. If you don't have children, I'm sure you have friends who will be very happy to spend one day with you. What I'm asking you to do is go outside and get in touch with the environment for which we are fighting, because there is no more important fight than the one we are leading to protect this planet for us and for future generations. Now, I don't want to offer false hope, because the truth is we can't turn back the clock. We can't cool the atmosphere. That damage is done, damage that was said in motion generations ago. But neither should we be discouraged, because the future is still bright for those who have the courage to confront hard truths and the confidence to stay the course. Canada will not back down from our commitment to fight climate change. And we're not alone. Around the world, nearly every country is on our side. Business is on our side. Science is on our side. And together, our efforts will make a difference. Here in Canada, we work hard to respond to the threats of climate change and help people and communities that will be the hardest hit by these effects. We will continue to make investments that will promote an economy that has access to clean growth. Because the health of our economy depends on the health of our children. To those of you who are feeling worried today, worried about our planet's future and what that means for you and your family down the road, I want you to know that we hear you. Canada hears you. We share your concerns, and we know that inaction is not an option. We can't walk away from the reality of climate change, and we won't walk away from a global plan that has a realistic chance of fighting it. We have a responsibility to future generations, and we will uphold it. We have a chance to build an economy that is clean, that is growing, that is forward-looking. And we will not let that opportunity pass us by. And to young people, I want to say this. It's not just the future of the planet that we're fighting for. We're fighting for you, for your future. It's okay if you feel a little discouraged from time to time. I get it. But know that the future is not cast in stone. You still have a chance to make a difference, to take that frustration you're feeling and turn it into something positive, something that can't be undone or doubted or denied. The better world you deserve will not come to us without a fight. But it's a fight we'll win because it's a fight we have to win. And like everything Canadians do, we're going to win it together. Merci beaucoup tout le monde. Thank you very much.