Quantum Spin Dimers from Chiral Dissipation in Cold-Atom Chains

TL;DR

This paper explores how chiral dissipation in a cold-atom chain can induce the formation of spin dimers in a non-equilibrium steady state, with potential applications in quantum simulation and photonic systems.

Contribution

It introduces a novel atomic implementation of chiral spin chains showing dimer formation due to dissipation, extending understanding of non-equilibrium quantum states.

Findings

Chiral reservoir coupling enables unidirectional spin interactions.

Steady states with spin dimers are achievable in cold-atom setups.

Results are relevant for experiments with quantum emitters in photonic waveguides.

Abstract

We consider the non-equilibrium dynamics of a driven dissipative spin chain with chiral coupling to a 1D bosonic bath, and its atomic implementation with a two-species mixture of cold quantum gases. The reservoir is represented by a spin-orbit coupled 1D quasi-condensate of atoms in a magnetized phase, while the spins are identified with motional states of a separate species of atoms in an optical lattice. The chirality of reservoir excitations allows the spins to couple differently to left and right moving modes, which in our atomic setup can be tuned from bidirectional to purely unidirectional. Remarkably, this leads to a pure steady state in which pairs of neighboring spins form dimers that decouple from the remainder of the chain. Our results also apply to current experiments with two-level emitters coupled to photonic waveguides.