Quantum Friction: Cooling Quantum Systems with Unitary Time Evolution

TL;DR

This paper introduces local quantum friction, a novel method that uses modified Hamiltonian dynamics to efficiently cool and simulate large fermionic quantum systems, simplifying non-equilibrium quantum dynamics analysis.

Contribution

It presents a new form of quantum dissipation through local quantum friction that directly influences unitary evolution, enabling efficient cooling and simulation of many-body quantum systems.

Findings

Local quantum friction effectively cools quantum systems.

It accelerates many-body quantum simulations.

It simplifies solving time-dependent Schrödinger equations.

Abstract

We introduce a type of quantum dissipation -- local quantum friction -- by adding to the Hamiltonian a local potential that breaks time-reversal invariance so as to cool the system. Unlike the Kossakowski-Lindblad master equation, local quantum friction directly effects unitary evolution of the wavefunctions rather than the density matrix: it may thus be used to cool fermionic many-body systems with thousands of wavefunctions that must remain orthogonal. In addition to providing an efficient way to simulate quantum dissipation and non-equilibrium dynamics, local quantum friction coupled with adiabatic state preparation significantly speeds up many-body simulations, making the solution of the time-dependent Schr\"odinger equation significantly simpler than the solution of its stationary counterpart.