3,495 research outputs found
Direct Imaging of Spatially Modulated Superfluid Phases in Atomic Fermion Systems
It is proposed that the spatially modulated superfluid phase, or the
Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state could be observed in resonant
Fermion atomic condensates which are realized recently. We examine optimal
experimental setups to achieve it by solving Bogoliubov-de Gennes equation both
for idealized one-dimensional and realistic three-dimensional cases. The
spontaneous modulation of this superfluid is shown to be directly imaged as the
density profiles either by optical absorption or by Stern-Gerlach experiments.Comment: 4 pages, 3 figure
Knight shift detection using gate-induced decoupling of the hyperfine interaction in quantum Hall edge channels
A method for the observation of the Knight shift in nanometer-scale region in
semiconductors is developed using resistively detected nuclear magnetic
resonance (RDNMR) technique in quantum Hall edge channels. Using a gate-induced
decoupling of the hyperfine interaction between electron and nuclear spins, we
obtain the RDNMR spectra with or without the electron-nuclear spin coupling. By
a comparison of these two spectra, the values of the Knight shift can be given
for the nuclear spins polarized dynamically in the region between the relevant
edge channels in a single two-dimensional electron system, indicating that this
method has a very high sensitivity compared to a conventional NMR technique.Comment: 4 pages, 4 figures, to appear in Applied Physics Letter
Vortex state in double transition superconductors
Novel vortex phase and nature of double transition field are investigated by
two-component Ginzburg-Landau theory in a situation where fourfold-twofold
symmetric superconducting double transition occurs. The deformation from 60
degree triangular vortex lattice and a possibility of the vortex sheet
structure are discussed. In the presence of the gradient coupling, the
transition changes to a crossover at finite fields. These characters are
important to identify the multiple superconducting phase in PrOs_4_Sb_12.Comment: 4 pages, 4 figures, to appear in Phys. Rev. Let
Effect of thermal fluctuations on spin degrees of freedom in spinor Bose-Einstein condensates
We consider the effect of thermal fluctuations on rotating spinor F=1
condensates in axially-symmetric vortex phases, when all the three hyperfine
states are populated. We show that the relative phase among different
components of the order parameter can fluctuate strongly due to the weakness of
the interaction in the spin channel. These fluctuations can be significant even
at low temperatures. Fluctuations of relative phase lead to significant
fluctuations of the local transverse magnetization of the condensate. We
demonstrate that these fluctuations are much more pronounced for the
antiferromagnetic state than for the ferromagnetic one.Comment: 5 pages, 2 figures; final version, accepted for publication in Phys.
Rev.
Thermal Equilibria of Optically Thin, Magnetically Supported, Two-Temperature, Black Hole Accretion Disks
We obtained thermal equilibrium solutions for optically thin, two-temperature
black hole accretion disks incorporating magnetic fields. The main objective of
this study is to explain the bright/hard state observed during the bright/slow
transition of galactic black hole candidates. We assume that the energy
transfer from ions to electrons occurs via Coulomb collisions. Bremsstrahlung,
synchrotron, and inverse Compton scattering are considered as the radiative
cooling processes. In order to complete the set of basic equations, we specify
the magnetic flux advection rate. We find magnetically supported (low-beta),
thermally stable solutions. In these solutions, the total amount of the heating
via the dissipation of turbulent magnetic fields goes into electrons and
balances the radiative cooling. The low- solutions extend to high mass
accretion rates and the electron temperature is moderately cool. High
luminosities and moderately high energy cutoffs in the X-ray spectrum observed
in the bright/hard state can be explained by the low-beta solutions.Comment: 24 pages, 10 figures,accepted for publication in Astrophysical
Journa
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