Many Google services we offer depend on sophisticated artificial intelligence technologies such as machine learning or pattern recognition. If one takes a closer look at such capabilities one realizes that they often require the solution of what mathematicians call hard combinatorial optimization problems. It turns out that solving the hardest of such problems requires server farms so large that they can never be built.



On the hardware side we are collaborating with D-Wave in Vancouver, Canada. D-Wave develops processors that realize the adiabatic quantum algorithm by magnetically coupling superconducting loops called rf-squid flux qubits. This design realizes what is known as the Ising model which represents the simplest model for an interacting many-body system and it can be manufactured using proven chip fabrication methods. Unfortunately, it is not easy to demonstrate that a multi-qubit system such as the D-Wave chip indeed exhibits the desired quantum behavior and experimental physicists from various institutions are still in the process of characterizing the chip.

Layout of the qubits in the C4 Chimera chip employed to train the car detector. The irregular graph structure results from the fabrication process not yet rendering all qubits functional.


The theory paper on which the demonstration is based can be found on the arXiv and a report describing the details of the implementation is here.