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UEC Int’l Mini-Conference No.53 49

Ground State of Spin-1 and Spin-2 Bose-Einstein Condensates

Uyen Ha Phuong MAI* and Hiroki SAITO
Department of Engineering Science
The University of Electro-Communications
Tokyo, Japan

Keywords: Bose-Einstein condensates, spinor, ground state

Abstract

A Bose-Einstein condensate (BEC) is a state of matter that forms when a very low-density boson gas is
cooled to temperatures that are close to absolute zero. Spinor Bose-Einstein condensate (BEC) is a type of
ultracold atomic gas in which atoms have an internal spin degree of freedom. Spinor BEC was first realized
in 1988 and inspired much new research on BEC atomic gas, especially the ground-state properties of
spinor BEC systems. Additionally, Monte Carlo is an efficient method for finding the minimal value in
physics. In this work, the Monte Carlo method is used to find respectively the energy of spin-1 and spin-2
BEC system's ground state, and their spin states are demonstrated by spherical-harmonic representation.
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For spin-1 BEC, the ground state is polar when scattering lengths coefficient c1 > 0 ( Na) or ferromagnetic
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when c1 < 0 ( Rb). For spin-2, when c1 > 0 and c1 < 0, the ground state is nematic for both Na and Rb.
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*The author is supported by SESS MEXT Scholarship