20,206 research outputs found
Rapidly Rotating Fermi Gases
We show that the density profile of a Fermi gas in rapidly rotating potential
will develop prominent features reflecting the underlying Landau level like
energy spectrum. Depending on the aspect ratio of the trap, these features can
be a sequence of ellipsoidal volumes or a sequence of quantized steps.Comment: 4 pages, 1 postscript fil
Algebraic Model for scattering of three-s-cluster systems. II. Resonances in the three-cluster continuum of 6He and 6Be
The resonance states embedded in the three-cluster continuum of 6He and 6Be
are obtained in the Algebraic Version of the Resonating Group Method. The model
accounts for a correct treatment of the Pauli principle. It also provides the
correct three-cluster continuum boundary conditions by using a Hyperspherical
Harmonics basis. The model reproduces the observed resonances well and achieves
good agreement with other models. A better understanding for the process of
formation and decay of the resonance states in six-nucleon systems is obtained.Comment: 8 pages, 10 postscript figures, submitted to Phys. Rev.
Low temperature specific heat of the heavy fermion superconductor PrOsSb
We report the magnetic field dependence of the low temperature specific heat
of single crystals of the first Pr-based heavy fermion superconductor
PrOsSb. The low temperature specific heat and the magnetic phase
diagram inferred from specific heat, resistivity and magnetisation provide
compelling evidence of a doublet ground state and hence superconductivity
mediated by quadrupolar fluctuations. This establishes PrOsSb as a
very strong contender of superconductive pairing that is neither
electron-phonon nor magnetically mediated.Comment: 4 pages, 4 figure
The Nature and Properties of a Repulsive Fermi Gas in the "Upper Branch"
We generalize the Nozi\'eres-Schmitt-Rink (NSR) method to study the repulsive
Fermi gas in the absence of molecule formation, i.e., in the so-called "upper
branch". We find that the system remains stable except close to resonance at
sufficiently low temperatures. With increasing scattering length, the energy
density of the system attains a maximum at a positive scattering length before
resonance. This is shown to arise from Pauli blocking which causes the bound
states of fermion pairs of different momenta to disappear at different
scattering lengths. At the point of maximum energy, the compressibility of the
system is substantially reduced, leading to a sizable uniform density core in a
trapped gas. The change in spin susceptibility with increasing scattering
length is moderate and does not indicate any magnetic instability. These
features should also manifest in Fermi gases with unequal masses and/or spin
populations.Comment: 4 pages, 5 figures, number of typos correcte
Dissipative Dynamics of Collisionless Nonlinear Alfven Wave Trains
The nonlinear dynamics of collisionless Alfven trains, including resonant
particle effects is studied using the kinetic nonlinear Schroedinger (KNLS)
equation model. Numerical solutions of the KNLS reveal the dynamics of Alfven
waves to be sensitive to the sense of polarization as well as the angle of
propagation with respect to the ambient magnetic field. The combined effects of
both wave nonlinearity and Landau damping result in the evolutionary formation
of stationaryOA S- and arc-polarized directional and rotational
discontinuities. These waveforms are freqently observed in the interplanetary
plasma.Comment: REVTeX, 6 pages (including 5 figures). This and other papers may be
found at http://sdphpd.ucsd.edu/~medvedev/papers.htm
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