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Simulating Concordant Computations



Bryan K. Eastin


A quantum state is called concordant if it has zero quantum discord with respect to any part. By extension, a concordant computation is one such that the state of the computer, at each time step, is concordant. In this paper, I describe a classical algorithm that, given a product state as input, permits the efficient simulation of any concordant quantum computation composed of gates acting on two or fewer qubits. This shows that a quantum computation composed of two-qubit gates must generate quantum discord if it is to efficiently solve a problem that requires super-polynomial time classically. While I employ the restriction to two-qubit gates sparingly, a crucial component of the simulation algorithm appears not to be extensible to gates acting on higher dimensional systems.
Physical Review A (Atomic, Molecular and Optical Physics)


concordant computations, discord, simulation, two-qubit


Eastin, B. (2010), Simulating Concordant Computations, Physical Review A (Atomic, Molecular and Optical Physics), [online], (Accessed May 27, 2024)


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Created June 23, 2010, Updated February 19, 2017