Diagnostics for the ground state phase of a spin-2 Bose-Einstein condensate

TL;DR

This paper introduces a method to determine the ground state phase of a spin-2 Bose-Einstein condensate by analyzing spin exchange dynamics, enabling phase identification near phase boundaries.

Contribution

The authors propose a novel technique to measure the singlet-pair energy in spin-2 BECs using initial population dynamics, suitable for short-lived hyperfine states.

Findings

Method successfully determines the singlet-pair coefficient.

Applicable to hyperfine states with short lifetimes.

Enables identification of ground state phases near phase boundaries.

Abstract

We propose a method to determine the singlet-pair energy of a spin-2 Bose-Einstein condensate (BEC). By preparing the initial populations in the magnetic sublevels 0, 2, -2 with appropriate relative phases, we can obtain the coefficient of the spin singlet-pair term from the spin exchange dynamics. This method is suitable for hyperfine states with short lifetimes, since only the initial change in the population of each magnetic sublevel is needed. This method therefore enables the determination of the ground state phase of a spin-2 87Rb BEC at zero magnetic field, which is considered to lie in the immediate vicinity of the boundary between the antiferromagnetic and cyclic phases. We also show that the initial state in which relative phases are controlled can be prepared by Raman processes.