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Updated: Jun 14, 2026
11:21
Cooling an Optically Trapped Ultracold Fermi Gas by Periodical Driving
Published on: March 30, 2017
Competition between suppression and production of Fermi acceleration
Denis Gouvêa Ladeira1, Edson D Leonel
1Campus Alto Paraopeba, Universidade Federal de São João Del-Rei, Fazenda do Cadete, CEP 36420-000, Ouro Branco, MG, Brazil.
Summary
Friction introduces a boundary in the Fermi accelerator model, determining if particles gain unlimited energy or if Fermi acceleration is suppressed. This finding impacts understanding particle dynamics in chaotic systems.
Area of Science:
- Physics
- Statistical Mechanics
- Dynamical Systems
Background:
- The Fermi accelerator model describes particle acceleration via a moving boundary.
- Unlimited average velocity is observed in the classical 1D Fermi accelerator with elastic collisions due to boundary discontinuities.
- The effect of non-conservative forces on Fermi acceleration is not fully understood.
Purpose of the Study:
- To investigate the influence of friction on particle behavior in the 1D Fermi accelerator model.
- To identify the conditions under which Fermi acceleration is suppressed or persists in the presence of friction.
- To analyze the phase space dynamics resulting from the introduction of a friction force.
Main Methods:
- Analysis of a classical particle in a 1D Fermi accelerator under a sawtooth external force.
- Inclusion of a friction force due to slip against a rough surface.
- Application of scaling arguments to describe Fermi acceleration.
- Phase space analysis to identify distinct dynamical regions.
Main Results:
- Introduction of friction creates a phase space boundary.
- Particles can experience either unlimited energy growth or suppressed Fermi acceleration depending on their initial conditions and the friction.
- The friction force modifies the expected unlimited energy growth observed in the elastic collision case.
Conclusions:
- Friction fundamentally alters the dynamics of the Fermi accelerator model.
- A critical boundary exists in phase space, separating regimes of persistent and suppressed Fermi acceleration.
- The presented formalism is adaptable to more complex systems like 2D billiards.
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