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Dynamics of thermalization in small Hubbard-model systems
Physical Review Letters
|January 15, 2011
Summary
Small fermionic systems can reach equilibrium states, even when far from it. This occurs via nonperturbative coupling, showing Gaussian relaxation, unlike perturbative predictions.
Area of Science:
- Condensed Matter Physics
- Quantum Mechanics
- Statistical Mechanics
Background:
- Understanding thermalization in isolated quantum systems is a fundamental challenge.
- The fermionic Hubbard model is a key model for studying strongly correlated electrons.
Purpose of the Study:
- To numerically investigate the thermalization and temporal evolution of a two-site subsystem of the fermionic Hubbard model.
- To explore the conditions under which small quantum systems can reach steady states resembling equilibrium.
Main Methods:
- Numerical simulations of the fermionic Hubbard model.
- Preparation of the system far from equilibrium at a definite energy.
- Analysis of the subsystem's temporal evolution and relaxation dynamics.
Main Results:
- A two-site subsystem can reach a steady state resembling equilibrium, even for small systems near quantum degeneracy.
- Nonperturbative coupling between the subsystem and the lattice leads to Gaussian temporal relaxation to equilibrium.
- This behavior contrasts sharply with predictions from perturbative approaches.
Conclusions:
- Thermalization to an equilibrium-like steady state is possible in small, isolated quantum systems.
- Nonperturbative couplings are crucial for observing this phenomenon, with Gaussian relaxation being a key characteristic.
- The findings suggest that such generic behavior in small systems may be robust across different coupling types.
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