Hanbury Brown-Twiss Interferometry for Fractional and Integer Mott Phases

TL;DR

This paper demonstrates that Hanbury Brown-Twiss interferometry can effectively identify and analyze integer and fractional Mott insulator phases in optical superlattices, providing a practical tool for phase diagram determination.

Contribution

It introduces HBTI as a method to detect superfluid-insulator transitions and characterize Mott insulator phases in optical lattice systems.

Findings

HBTI exhibits high contrast fringes in insulating phases.

HBTI signals superfluid-insulator transitions.

HBTI probes shell structure in trapped systems.

Abstract

Hanbury-Brown-Twiss interferometry (HBTI) is used to study integer and fractionally filled Mott Insulator (MI) phases in period-2 optical superlattices. In contrast to the quasimomentum distribution, this second order interferometry pattern exhibits high contrast fringes in the it insulating phases. Our detailed study of HBTI suggests that this interference pattern signals the various superfluid-insulator transitions and therefore can be used as a practical method to determine the phase diagram of the system. We find that in the presence of a confining potential the insulating phases become robust as they exist for a finite range of atom numbers. Furthermore, we show that in the trapped case the HBTI interferogram signals the formation of the MI domains and probes the shell structure of the system.