Hamiltonian Design in Atom-Light Interactions with Rubidium Ensembles: A Quantum Information Toolbox

TL;DR

This paper explores how to engineer Hamiltonians in atom-light interactions with rubidium ensembles to enable advanced quantum information processing tasks like spin squeezing and quantum memory.

Contribution

It introduces a method to control Hamiltonian symmetries via probe detuning in rubidium ensembles, expanding quantum information toolbox capabilities.

Findings

Different detunings produce Hamiltonians with distinct symmetries.

Identified conditions for effective spin squeezing and quantum cloning.

Demonstrated potential for quantum memory and atom number measurement.

Abstract

We study the coupling between collective variables of atomic spin and light polarization in an ensemble of cold 87Rb probed with polarized light. The effects of multiple hyperfine levels manifest themselves as a rank-2 tensor polarizability, whose irreducible components can be selected by means of probe detuning. The D1 and D2 lines of Rb are explored and we identify different detunings which lead to Hamiltonians with different symmetries for rotations. As possible applications of these Hamiltonians, we describe schemes for spin squeezing, quantum cloning, quantum memory, and measuring atom number.