Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Physics
Screening And Plasma Oscillations In An Electron Gas In The Hydrodynamic Approximation, Eugene B. Kolomeisky, Joseph P. Straley
Screening And Plasma Oscillations In An Electron Gas In The Hydrodynamic Approximation, Eugene B. Kolomeisky, Joseph P. Straley
Physics and Astronomy Faculty Publications
A hydrodynamic theory of screening in a generic electron gas of arbitrary dimensionality is given that encompasses all previously studied cases and clarifies the predictions of the many-body approach. We find that long-wavelength plasma oscillations are classical phenomena with quantum-mechanical effects playing no explicit role. The character of the oscillations is solely dictated by the dimensionality of the electron system and its equation of state in the neutral limit. Materials whose excitations are described by the Dirac dispersion law—such as doped graphene or a Weyl semimetal—are no exception to this rule.
Dimer-Dimer Collisions At Finite Energies In Two-Component Fermi Gases, J P. D'Incao, Seth T. Rittenhouse, Nirav P. Mehta, Chris H. Greene
Dimer-Dimer Collisions At Finite Energies In Two-Component Fermi Gases, J P. D'Incao, Seth T. Rittenhouse, Nirav P. Mehta, Chris H. Greene
Physics and Astronomy Faculty Research
We discuss a major theoretical generalization of existing techniques for handling the three-body problem that accurately describes the interactions among four fermionic atoms. Application to a two-component Fermi gas accurately determines dimer-dimer scattering parameters at finite energies and can give deeper insight into the corresponding many-body phenomena. To account for finite temperature effects, we calculate the energydependent complex dimer-dimer scattering length, which includes contributions from elastic and inelastic collisions. Our results indicate that strong finite-energy effects and dimer dissociation are crucial for understanding the physics in the strongly interacting regime for typical experimental conditions. While our results for dimer-dimer relaxation …
Plasma Oscillations And Expansion Of An Ultracold Neutral Plasma, Scott D. Bergeson, S. Kulin, T. C. Killian, S. L. Rolston
Plasma Oscillations And Expansion Of An Ultracold Neutral Plasma, Scott D. Bergeson, S. Kulin, T. C. Killian, S. L. Rolston
Faculty Publications
We report the observation of plasma oscillations in an ultracold neutral plasma. With this collective mode we probe the electron density distribution and study the expansion of the plasma as a function of time. For classical plasma conditions, i.e., weak Coulomb coupling, the expansion is dominated by the pressure of the electron gas and is described by a hydrodynamic model. Discrepancies between the model and observations at low temperature and high density may be due to strong coupling of the electrons.