Selective cooling by impulse perturbations in a simple toy model

TL;DR

This paper demonstrates that a carefully designed impulse perturbation can transiently cool low-energy degrees of freedom in a simple, exactly-solvable toy model of coupled quantum Ising systems, with potential implications for controlling quantum states.

Contribution

It introduces a novel method of transiently cooling low-energy sectors using impulse perturbations in a simple, exactly-solvable quantum toy model, highlighting resonance effects.

Findings

Properly tuned oscillation frequency enhances cooling efficiency.

Low-energy sector can develop spontaneous symmetry-breaking after perturbation.

Cooling effect is optimized at resonance with spin-exchange excitation.

Abstract

We show in a simple exactly-solvable toy model that a properly designed impulse perturbation can transiently cool down low-energy degrees of freedom at the expenses of high-energy ones that heat up. The model consists of two infinite-range quantum Ising models, one, the \textit{high-energy} sector, with a transverse field much bigger than the other, the \textit{low-energy} sector. The finite-duration perturbation is a spin-exchange that couples the two Ising models with an oscillating coupling strength. We find a cooling of the low-energy sector that is optimised by the oscillation frequency in resonance with the spin-exchange excitation. After the perturbation is turned off, the Ising model with low transverse field can even develop spontaneous symmetry-breaking d