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-$\beta$ 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