This process causes the density matrix to change to the sum over n of the projection operator times the old density matrix times the projection operator.
This process causes the density matrix to change to the sum over n of the projection operator times the old density matrix times the projection operator. The outcomes of this process are positive eigenvalues of a Hermitian operator. Performing this process repeatedly can cause an unstable particle to stabilize in the Quantum Zeno effect. In the Copenhagen interpretation, this process causes a wavefunction to transform from having several eigenstates to a single eigenstate, a phenomenon called wavefunction collapse. According to the Heisenberg uncertainty principle this process performed on one conjugate variable decreases its accuracy for the other conjugate variable. For 10 points, name this process in which some quantity of a system is observed and determined.
This process causes the density matrix to change to the sum over n of the projection operator times the old density matrix times the projection operator.
measurement [or word forms; or reasonable equivalents, such as observation or looking at]