Rotonlike instability and pattern formation in spinor Bose-Einstein condensates

TL;DR

This paper demonstrates that antiferromagnetic spin-1 Bose-Einstein condensates can exhibit rotonlike excitations leading to spontaneous pattern formation, explained through energy and spin conservation laws.

Contribution

It reveals the emergence of rotonlike minima and pattern formation in spinor BECs due to magnetic field-induced instabilities, supported by numerical simulations.

Findings

Rotonlike minima appear in the excitation spectrum.

Magnetic field induces roton mode instabilities.

Spontaneous formation of periodic and crystalline patterns.

Abstract

We show that metastable phases of an antiferromagnetic spin-1 condensate in a simple model with pure contact interactions can exhibit a rotonlike minimum in the excitation spectrum. The introduction of magnetic field gives rise to the instability of roton modes, which can lead to spontaneous emergence of regular periodic, polygonal, polyhedral or crystalline patterns, as shown in numerical simulations within the truncated Wigner approximation. An explanation of the occurrence of rotonlike instability is given based on the energy and spin conservation laws.