Quantum Slow Relaxation and Metastability due to Dynamical Constraints

Area of Science:

• Quantum physics
• Condensed matter physics
• Statistical mechanics

Background:

• Classical glasses exhibit slow cooperative relaxation due to kinetic constraints.
• Understanding thermalization and metastability in quantum systems is crucial.

Purpose of the Study:

• To investigate if dynamical constraints can induce slow thermalization and metastability in quantum many-body systems.
• To explore the analogy between classical glass relaxation and quantum system dynamics.

Main Methods:

• Studied two models: a 1D quantum constrained lattice gas and fully packed quantum dimers on a square lattice.
• Analyzed systems near a Rokhsar-Kivelson (RK) point where kinetic and potential energies are balanced.
• Investigated thermalization dynamics and entanglement growth in different regimes.

Main Results:

• Systems exhibit fast thermalization when kinetic energy dominates (near the RK point).
• Slow thermalization, metastability, and long-lived memory effects occur when potential energy dominates.
• Dynamical heterogeneity and spatially segregated entanglement growth were observed in the slow-thermalization regime.

Conclusions:

• Dynamical constraints are a general mechanism for slow thermalization and metastability in quantum many-body systems.
• These quantum systems can mimic the glass-like relaxation behaviors observed in classical glasses.
• The findings offer insights into the fundamental nature of thermalization and emergent phenomena in quantum matter.