Non-equilibrium coherence dynamics in one-dimensional Bose gases.

Area of Science:

• Quantum physics
• Many-body systems
• Low-dimensional physics

Background:

• One-dimensional (1D) systems exhibit universal properties via the Luttinger liquid model.
• Equilibrium states in 1D systems are well-understood for both weak and strong interactions.
• Probing the dynamics of reaching equilibrium in 1D systems remains challenging.

Purpose of the Study:

• To experimentally investigate the coherence dynamics in isolated and coupled degenerate 1D Bose gases.
• To understand the non-equilibrium dynamics of superfluids in a controlled, low-dimensional setting.
• To compare experimental results with theoretical predictions for coherence decay.

Main Methods:

• Utilizing dynamic splitting to create phase-coherent 1D Bose gas systems.
• Observing time evolution of coherence via local phase shifts in interference patterns.
• Analyzing coherence decay in both isolated and coupled 1D Bose gas configurations.

Main Results:

• Isolated 1D Bose gases demonstrated universal sub-exponential coherence decay, matching theoretical predictions.
• Coupled 1D Bose gases exhibited coherence factors approaching a non-zero equilibrium value, consistent with Bogoliubov theory.
• Observed coherence dynamics in coupled systems as the matter wave analog of laser phase-locking.

Conclusions:

• 1D Bose gases serve as an ideal platform for studying non-equilibrium superfluid dynamics.
• Experimental findings validate theoretical models for coherence decay in isolated and coupled 1D systems.
• The study provides insights into fundamental quantum phenomena relevant to superconductors, superfluids, and spin systems.