A universal speed limit for spreading of coherence

Area of Science:

• Quantum physics
• Condensed matter physics
• Statistical mechanics

Background:

• Fundamental limits in physical processes drive physics breakthroughs.
• Bose-Einstein condensate (BEC) formation is a key many-body phenomenon.
• Understanding coherence spreading is crucial for BEC dynamics.

Purpose of the Study:

• To identify and characterize a fundamental limit for coherence spreading during BEC formation.
• To investigate the role of interatomic interactions on coherence propagation.
• To establish universal benchmarks for far-from-equilibrium physics.

Main Methods:

• Studied condensate formation in an isolated, homogeneous atomic gas.
• System was initially in an incoherent low-energy state, far from equilibrium.
• Varied interatomic interactions to observe their effect on coherence spreading.

Main Results:

• Coherence spreading rate approaches a universal limit, independent of interaction strength.
• The squared coherence length grows at a universal rate: h/m (Planck's constant / particle mass).
• Observations were robust across different initial states, densities, and system sizes.

Conclusions:

• A fundamental limit exists for coherence spreading in BEC formation.
• This limit is characterized by a universal growth rate related to quantum properties.
• Results offer benchmarks for non-equilibrium physics theories and inform quantum technologies.