Simulation of Nonequilibrium Dynamics on a Quantum Computer

TL;DR

This paper introduces a hybrid quantum-classical algorithm to simulate the dynamics of out-of-equilibrium thermal states, combining classical density matrix approximation with quantum time evolution, demonstrated on small spin systems.

Contribution

It proposes a novel hybrid approach for simulating nonequilibrium quantum dynamics using classical and quantum computations together.

Findings

Successfully simulated five-spin Heisenberg model on a quantum virtual machine.

Performed out-of-equilibrium state evolution on a single-spin system with a real quantum processor.

Demonstrated feasibility of hybrid quantum-classical algorithms for quantum dynamics simulation.

Abstract

We present a hybrid quantum-classical algorithm for the time evolution of out-of-equilibrium thermal states. The method depends upon classically computing a sparse approximation to the density matrix, and then time-evolving each matrix element via the quantum computer. For this exploratory study, we investigate the time-dependent Heisenberg model with five spins on the Rigetti Forest quantum virtual machine and a one spin system on the Rigetti 8Q-Agave quantum processor.