Variational Quantum Algorithm for Non-equilibrium Steady States

  • Nobuyuki Yoshioka
  • ,
  • Yuya O. Nakagawa
  • ,
  • Kosuke Mitarai
  • ,
  • Keisuke Fujii

We propose a quantum-classical hybrid algorithm to simulate the
non-equilibrium steady state of an open quantum many-body system, named the
dissipative-system Variational Quantum Eigensolver (dVQE). To employ the
variational optimization technique for a unitary quantum circuit, we map a
mixed state into a pure state with a doubled number of qubits and design the
unitary quantum circuit to fulfill the requirements for a density matrix. This
allows us to define a cost function that consists of the time evolution
generator of the quantum master equation. Evaluation of physical observables
is, in turn, carried out by a quantum circuit with the original number of
qubits. We demonstrate our dVQE scheme by both numerical simulation on a
classical computer and actual quantum simulation that makes use of the device
provided in Rigetti Quantum Cloud Service.

Arxiv Url
Arxiv Url
http://arxiv.org/pdf/1908.09836v4 本文へのリンクあり