We identify a broad class of physical processes in an optical quantum circuit that can be efficiently simulated on a classical computer: this class includes unitary transformations, amplification, noise, and measurements. This simulatability result places powerful constraints on the capability to realize exponential quantum speedups as well as on inducing an optical nonlinear transformation via linear optics, photodetection-based measurement, and classical feedforward of measurement results, optimal cloning, and a wide range of other processes.
Bibliographical noteCopyright 2002 by The American Physical Society. Reprinted from Physical review letters.
Bartlett, S. D., & Sanders, B. C. (2002). Efficient classical simulation of optical quantum information circuits. Physical Review Letters, 89(20), 207903-1-207903-4. https://doi.org/10.1103/PhysRevLett.89.207903