Extreme fragmentation of a Bose gas

TL;DR

This paper presents a practical scheme to rapidly create highly fragmented Bose gas states with hundreds of bosons in few modes using energy detuning and optimal control in the Bose-Hubbard model.

Contribution

It introduces a new method employing energy detuning and optimal control to efficiently generate highly fragmented Bose gas states in few-mode systems.

Findings

Achieved total fragmentation at high filling factors.

Created Fock states with hundreds of bosons in few modes.

Demonstrated rapid state preparation within a few tunneling times.

Abstract

Fragmentation of an interacting Bose gas refers to the macroscopic occupation of a finite set of single-particle eigenstates. This phenomenon is related to the notion of particle-number squeezing in quantum optics, an exquisite property of quantum states that can offer metrological gain. So far, fragmentation has only been partially achieved in experiments involving a large number $N$ of bosons in few modes. Here, we introduce a practical and efficient scheme to prepare fragmented states in systems realizing the $L$-mode Bose-Hubbard model. We demonstrate how a large energy detuning between the modes can be used as a practical control parameter to successfully fragment a Bose gas over an extremely short preparation time. Applying an optimal-control approach within realistic experimental constraints, we obtain total fragmentation at a high filling factor, realizing $\ket{N/L,...,N/L}$ Fock states with hundreds of bosons in very few modes over a few tunneling times.