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Quantum tricriticality and phase transitions in spin-orbit coupled Bose-Einstein condensates
Yun Li1, Lev P Pitaevskii, Sandro Stringari
1Dipartimento di Fisica, Università di Trento and INO-CNR BEC Center, I-38123 Povo, Italy.
Physical Review Letters
|September 26, 2012
Summary
We explored spin-1/2 bosons with spin-orbit coupling, revealing a tricritical point. This point separates distinct quantum phases in Bose gases, influenced by density and Raman coupling.
Area of Science:
- Quantum physics
- Condensed matter physics
- Atomic physics
Background:
- Spin-orbit coupling is crucial in ultracold atomic gases.
- Understanding interacting Bose gases requires exploring their phase diagrams.
- Mean-field approximations simplify complex many-body interactions.
Purpose of the Study:
- To investigate the phase diagram of spin-1/2 bosons with equal Rashba and Dresselhaus couplings at zero temperature.
- To identify and characterize a tricritical point in the system.
- To analyze the influence of interaction strength, density, and Raman coupling on quantum phases.
Main Methods:
- Mean-field approximation for inter-boson interactions.
- Analysis of the system's phase diagram at T=0.
- Investigation of quantum phases through momentum distribution, spin polarization, and density fringe analysis.
Main Results:
- A characteristic tricritical point is predicted at critical density and Raman coupling values.
- This point separates three distinct quantum phases: spin mixed, phase separated, and zero momentum states.
- The study analyzes the momentum distribution, spin polarization (longitudinal and transverse), and density fringes for each phase.
Conclusions:
- The interplay of spin-orbit coupling, interactions, and external fields dictates the rich phase diagram of Bose gases.
- The identified tricritical point offers a unique platform for studying quantum phase transitions.
- The findings provide insights into controlling and manipulating quantum states in ultracold atomic systems.
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