Abstract

We give new evidence that quantum computers -- moreover, rudimentary quantum computers built entirely out of linear-optical elements -- cannot be efficiently simulated by classical computers. In particular, we define a model of computation in which identical photons are generated, sent through a linear-optical network, then nonadaptively measured to count the number of photons in each mode. This model is not known or believed to be universal for quantum computation, and indeed, we discuss the prospects for realizing the model using current technology. On the other hand, we prove that the model is able to solve sampling problems and search problems that are classically intractable under plausible assumptions. Our first result says that, if there exists a polynomial-time classical algorithm that samples from the same probability distribution as a linear-optical network, then P#P=BPPNP, and hence the polynomial hierarchy collapses to the third level. Unfortunately, this result assumes an extremely accurate simulation.

Keywords

Quantum computerHierarchyComputer scienceComputationPolynomial hierarchyTime complexityComputational complexity theoryPolynomialQuantumTheoretical computer scienceAlgorithmMathematicsQuantum mechanicsPhysicsMathematical analysis

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Publication Info

Year
2011
Type
article
Pages
333-342
Citations
811
Access
Closed

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Cite This

Scott Aaronson, A. A. Архипов (2011). The computational complexity of linear optics. , 333-342. https://doi.org/10.1145/1993636.1993682

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DOI
10.1145/1993636.1993682