Cooling of Many-Body Systems via Selective Interactions

TL;DR

This paper introduces a model for many-body spin systems with selective interactions that can be experimentally realized, enabling control over quantum states and inducing a cooling effect through engineered time-dependent couplings.

Contribution

It presents an exactly solvable model of N-spin systems with selective interactions, allowing for controlled state generation and cooling via engineered time-dependent parameters.

Findings

Exact transformation of dynamics into simpler spin problems

Ability to generate GHZ states under specific conditions

Engineered interactions induce cooling of the entire system

Abstract

We propose a model describing $N$ spin-1/2 systems coupled through $N$-order homogeneous interaction terms, in presence of local time-dependent magnetic fields. This model can be experimentally implemented with current technologies in trapped ions and superconducting circuits. By introducing a chain of unitary transformations, we succeed in exactly converting the quantum dynamics of this system into that of $2^{N-1}$ fictitious spin-1/2 dynamical problems. We bring to light the possibility of controlling the unitary evolution of the $N$ spins generating GHZ states under specific time-dependent scenarios. Moreover, we show that by appropriately engineering the time-dependence of the coupling parameters, one may choose a specific subspace in which the $N$-spin system dynamics takes place. This dynamical feature, which we call time-dependent selective interaction, can generate a cooling effect of all spins in the system.