Dynamical Casimir effect for magnons in a spinor Bose-Einstein condensate

TL;DR

This paper demonstrates that a driven magnetic field in a spinor Bose-Einstein condensate can amplify quantum fluctuations, causing magnetization and squeezing effects analogous to the dynamical Casimir effect.

Contribution

It introduces a novel analogy between magnon excitation in spinor BECs and the dynamical Casimir effect, supported by numerical simulations.

Findings

Quantum fluctuations are amplified by a time-dependent magnetic field.

Magnetization occurs perpendicular to the magnetic field, breaking rotational symmetry.

The excited quantum field exhibits squeezing.

Abstract

Magnon excitation in a spinor Bose-Einstein condensate by a driven magnetic field is shown to have a close analogy with the dynamical Casimir effect. A time-dependent external magnetic field amplifies quantum fluctuations in the magnetic ground state of the condensate, leading to magnetization of the system. The magnetization occurs in a direction perpendicular to the magnetic field breaking the rotation symmetry. This phenomenon is numerically demonstrated and the excited quantum field is shown to be squeezed.