Protecting Spin Coherence in a Tunable Heisenberg Model
Abstract
Using an ensemble of atoms in an optical cavity, we engineer a family of nonlocal Heisenberg Hamiltonians with continuously tunable anisotropy of the spin-spin couplings. We thus gain access to a rich phase diagram, including a paramagnetic-to-ferromagnetic Ising phase transition that manifests as a diverging magnetic susceptibility at the critical point. The susceptibility displays a symmetry between Ising interactions and XY (spin-exchange) interactions of the opposite sign, which is indicative of the spatially extended atomic system behaving as a single collective spin. Images of the magnetization dynamics show that spin-exchange interactions protect the coherence of the collective spin, even against inhomogeneous fields that completely dephase the non-interacting and Ising systems. Our results underscore prospects for harnessing spin-exchange interactions to enhance the robustness of spin squeezing protocols.
Cite
@article{arxiv.2003.06087,
title = {Protecting Spin Coherence in a Tunable Heisenberg Model},
author = {Emily J. Davis and Avikar Periwal and Eric S. Cooper and Gregory Bentsen and Simon J. Evered and Katherine Van Kirk and Monika H. Schleier-Smith},
journal= {arXiv preprint arXiv:2003.06087},
year = {2020}
}