Macroscopic spin tunneling and quantum critical behavior of a condensate in double-well potential

TL;DR

This paper investigates macroscopic quantum spin tunneling in a spinor condensate within a double-well potential, revealing how tunneling rates depend on transverse field strength and highlighting quantum critical behavior.

Contribution

It demonstrates the possibility of observing macroscopic spin tunneling and analyzes its dependence on external parameters, advancing understanding of quantum phase transitions in condensates.

Findings

Macroscopic spin tunneling can be observed in spinor condensates.

Tunneling rate is critically dependent on the transverse magnetic field.

Quantum critical behavior influences the tunneling dynamics.

Abstract

In a previous work (PRL 87, 140405), we have shown that a spinor condensate confined in a periodic or double-well potential exhibits ferromagnetic behavior due to the magnetic dipole-dipole interactions between different wells, and in the absence of external magnetic field, the ground state has a two-fold degeneracy. In this work, we demonstrate the possibility of observing macroscopic quantum spin tunneling between these two degenerate states and show how the tunneling rate critically depends on the strength of the transverse field.