Tunable spin-orbit coupling and quantum phase transition in a trapped Bose-Einstein condensate

Area of Science:

• Atomic physics
• Condensed matter physics
• Quantum optics

Background:

• Spin-orbit coupling (SOC) is fundamental to phenomena from atomic structure to topological physics.
• Ultra-cold atoms offer a new platform for studying spin-orbit coupled superfluidity.
• Current experimental SOC strengths are not tunable.

Purpose of the Study:

• To propose a scheme for tuning SOC strength in ultra-cold atoms.
• To investigate the quantum phase transition (QPT) driven by tunable SOC and many-body interactions.
• To explore the analogy with the Dicke quantum phase transition.

Main Methods:

• Fast and coherent modulation of laser intensities to tune SOC strength.
• Utilizing many-body interactions in a harmonic trapped Bose-Einstein condensate (BEC).
• Characterizing the QPT via collective oscillation periods of the BEC.

Main Results:

• A method for dynamically controlling SOC strength in ultra-cold atoms is presented.
• Tunable SOC and interactions drive a QPT from spin-balanced to spin-polarized states in a BEC.
• Collective oscillation periods exhibit peaks and damping near the quantum critical point, signaling the QPT.

Conclusions:

• The proposed scheme enables tunable SOC in ultra-cold atom experiments.
• This platform facilitates the study of Dicke-like quantum phase transitions in BECs.
• Collective oscillations serve as a sensitive probe for quantum criticality.