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Published on: June 1, 2016
Transport coefficients from the boson Uehling-Uhlenbeck equation
1The Center for Complex Quantum Systems, The University of Texas at Austin, Austin, Texas 78712, USA. egust@physics.utexas.edu
Summary
Researchers derived transport coefficients for quantum Bose gases using kinetic equations. Bulk viscosity remains zero, while shear viscosity and thermal conductivity are calculated for contact potentials.
Area of Science:
- Quantum statistical mechanics
- Kinetic theory of gases
Background:
- Understanding transport properties of quantum degenerate Bose gases is crucial.
- Bose-Einstein condensation (BEC) marks a phase transition in these systems.
Purpose of the Study:
- Derive expressions for bulk viscosity, shear viscosity, and thermal conductivity.
- Investigate these properties for a quantum degenerate Bose gas above the BEC critical temperature.
- Analyze the impact of Uehling-Uhlenbeck kinetic equation and collision operator properties.
Main Methods:
- Utilized the Uehling-Uhlenbeck kinetic equation.
- Derived transport coefficients considering contact potentials and hard sphere interactions.
- Computed shear viscosity and thermal conductivity numerically, accounting for collision operator eigenvalue cutoffs.
Main Results:
- Established expressions for bulk viscosity, shear viscosity, and thermal conductivity.
- Found an upper cutoff for eigenvalues of the Uehling-Uhlenbeck collision operator.
- Bulk viscosity for the degenerate Bose gas is identically zero, similar to classical gases.
- Numerically computed shear viscosity and thermal conductivity for contact interacting boson gases.
Conclusions:
- The Uehling-Uhlenbeck kinetic equation provides a framework for Bose gas transport properties.
- The zero bulk viscosity is a consistent feature across classical and quantum degenerate gases.
- Numerical computations offer insights into shear viscosity and thermal conductivity for specific interactions.
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