Sampling from the thermal quantum Gibbs state and evaluating partition functions with a quantum computer.
We present a quantum algorithm to prepare the thermal Gibbs state of interacting quantum systems. This algorithm sets a universal upper bound D(alpha) on the thermalization time of a quantum system, where D is the system's Hilbert space dimension and alpha < or = 1/2 is proportional to the Helmholtz free energy density. We also derive an algorithm to evaluate the partition function of a quantum system in a time proportional to the system's thermalization time and inversely proportional to the targeted accuracy squared.
Poulin
David
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Département de Physique, Université de Sherbrooke, Québec, Canada, J1K 2R1.
Wocjan
Pawel
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