Dynamic generation of spin-squeezed states in bosonic Josephson junctions

TL;DR

This paper investigates the dynamical creation of spin-squeezed states in ultracold bosonic atoms within a double-well potential, providing analytical predictions and comparing with existing methods.

Contribution

It introduces a semiclassical approach to predict squeezing dynamics in Bose-Hubbard systems, highlighting rapid squeezing near unstable points.

Findings

Highly squeezed states can be generated quickly near unstable points.

Analytical formulas accurately predict squeezing scaling with atom number.

The method outperforms some standard techniques in producing spin-squeezed states.

Abstract

We analyze the formation of squeezed states in a condensate of ultracold bosonic atoms confined by a double-well potential. The emphasis is set on the dynamical formation of such states from initially coherent many-body quantum states. Two cases are described: the squeezing formation in the evolution of the system around the stable point, and in the short time evolution in the vicinity of an unstable point. The latter is shown to produce highly squeezed states on very short times. On the basis of a semiclassical approximation to the Bose-Hubbard Hamiltonian, we are able to predict the amount of squeezing, its scaling with $N$ and the speed of coherent spin formation with simple analytical formulas which successfully describe the numerical Bose-Hubbard results. This new method of producing highly squeezed spin states in systems of ultracold atoms is compared to other standard methods in the literature.