Fermions in Deep Optical Lattice under p-wave Feshbach Resonance

We investigate theoretically the energy levels of two identical Fermions in a harmonic potential well under p-wave Feshbach resonance. The magnetic fields needed to affect the energy levels differ strongly among the levels, and they can be at values far from the free space resonant field.Comment: 2 figure

Supercurrent and noise in point contact between two different superconductors

We show that, for a quantum point contact between two superconductors of different gap magnitudes, Andreev bound states do not exist for certain phase differences and gap ratios. Continuum states may dominate the transport, and the supercurrent noise is qualitatively different from the case of equal gaps.Comment: to appear in PR

A dilute mixture of atoms and molecules

We study a dilute gas with two species of Fermionic atoms of unequal concentrations, interacting via a short-range interaction with one deeply bound state. We study the properties of this system under the mean-field approximation. We obtain the effective interaction among the fermions and bosons, and discuss the collective modes of the system.Comment: errors removed, reference not update

Local stability conditions for asymmetric Fermi superfluid

Two different local stability conditions for an asymmetric superfluid has been discussed in the literature. We here consider the relations between them

Kinetic equation and magneto-conductance for Weyl metal in the clean limit

We discuss the semi-classical kinetic equation in the clean limit, with the presence of Berry curvatures and magnetic field B, with the aim of applying to Weyl semi-metals. Special attention is given to the conservation laws for the collision integrals. It is found that the magneto-resistance second order in B is in general negative, with or without Weyl points, though in the later case it is in general much smaller.Comment: 10 page

Comment on "Classifying Novel Phases of Spinor Atoms"

Comment on "Classifying Novel Phases of Spinor Atoms", Phys. Rev. Lett. 97, 180412 (2006) by R. Barnett, A. Turner and E. DemlerComment: 1 pag

Anisotropic Fermi Superfluid via p-wave Feshbach Resonance

We investigate theoretically Fermionic superfluidity induced by Feshbach resonance in the orbital p-wave channel. We show that, due to the dipole interaction, the pairing is extremely anisotropic. When this dipole interaction is relatively strong, the pairing has symmetry $k_z$. When it is relatively weak, it is of symmetry $k_z + i \beta k_y$ (up to a rotation about $\hat z$, here $\beta < 1$). A phase transition between these two states can occur under a change in the magnetic field or the density of the gas.Comment: 4 pages, 2 figure

Effects of voltage fluctuations on the current correlations in mesoscopic Y-shaped conductors

We study current fluctuations in a phase coherent Y-shaped conductor connected to external leads and voltage probes. The voltage probes are taken to have finite impedances and thus can cause voltage fluctuations in the circuit. Applying the Keldysh formulation and a saddle point approximation appropriate for slow fluctuations, we examine at zero temperature the feedback effects on the current fluctuations due to the fluctuating voltages. We consider mesoscopic Y-shaped conductors made of tunnel junctions and of diffusive wires. Unlike two-terminal conductors, we find that for the Y-shaped conductors the current moments in the presence of external impedances cannot be obtained from simple rescaling of the bare moments already in the second moments. As a direct consequence, we find that the cross correlation between the output terminals can become positive due to the impedances in the circuit. We provide formulas for the range of parameters that can cause positive cross correlations.Comment: Figures 2(b)(c) left out due to file size constraints (which, however, can be requested from authors). Submitted to Phys. Rev.

Current response of a topological insulator to a static Zeeman field

We study the magnetoelectric coupling at the surface of a topological insulator. We are in particular interested in the surface current induced by a static Zeeman/exchange field. This surface current can be related to the orbital magnetization of the system. For an insulator with zero Chern number, the orbital magnetization is independent of the details at the boundary. With the appearance of surface states in the topological insulator, it is not immediately obvious if the response is not affected by the conditions at the surface. We investigate this question using exact diagonalization to a lattice model. By applying a time-reversal symmetry-breaking term near the boundary, no matter if the surface states are gapped out, we still find no change in the surface current. This arises from cancelations between Pauli and Van-Vleck contributions between surface and bulk scattering states. We also show that the surface current response is independent of the chemical potential when it is within the bulk gap. Our results are consistent with the claim that orbital magnetization is a bulk property

Mesoscopic p-wave superconductor near the phase transition temperature

We study the finite-size and boundary effects on a p-wave superconductor in a mesoscopic rectangular sample using Ginzburg-Landau (GL) and quasi-classical (QC) Green's function theory. Except for a square sample with parameters far away from the isotropic weak-coupling limit, the ground state near the critical temperature always prefers a time-reversal symmetric state, where the order parameter can be represented by a real vector. For large aspect ratio, this vector is parallel to the long side of the rectangle. Within a critical aspect ratio, it has instead a vortex-like structure, vanishing at the sample center.Comment: Revised version published in Physical Review