Floquet's Refrigerator: Conformal Cooling in Driven Quantum Critical Systems

TL;DR

This paper introduces a novel Floquet-based cooling method for quantum critical systems, enabling rapid local cooling and entropy transfer, with exact solutions and numerical validation demonstrating its effectiveness.

Contribution

It presents a new conformal Floquet cooling protocol for quantum critical systems, providing exact analytical solutions and numerical benchmarks.

Findings

Efficient local cooling to zero temperature in finite regions.

Entropy and energy transfer to complementary regions.

Agreement between analytical solutions and numerical models.

Abstract

We propose a general method of cooling -- periodic driving generated by spatially deformed Hamiltonians -- and study it in general one-dimensional quantum critical systems described by a conformal field theory. Our protocol is able to efficiently cool a finite-temperature Gibbs (mixed) state down to zero temperature at prescribed sub-regions exponentially rapidly in Floquet time cycles. At the same time, entropy and energy are transferred and localized to the complementary regions that shrink with time. We derive these conclusions through an exact analytic solution of the full time evolution of reduced density matrices. We also use numerics in free-fermion lattice models as a benchmark and find remarkable agreement. Such conformal Floquet refrigerators open a promising new route to cooling synthetic quantum systems.