K. Sengupta

Tunneling conductance of graphene NIS junctions.

We show that, in contrast with conventional normal metal-insulator-superconductor (NIS) junctions, the tunneling conductance of a NIS junction in graphene is an oscillatory function of the effective barrier strength of the insulating region, in the limit of a thin barrier. The amplitude of these oscillations is maximum for aligned Fermi surfaces of the normal and superconducting regions and vanishes for a large Fermi surface mismatch. The zero-bias tunneling conductance, in sharp contrast to its counterpart in conventional NIS junctions, becomes maximum for a finite barrier strength. We also suggest experiments to test these predictions.

Fractional ac Josephson effect in p- and d-wave superconductors

For certain orientations of Josephson junctions between two px-wave or two d-wave superconductors, the subgap Andreev bound states produce a

Non-equilibrium Dynamics of Quantum Systems: Order Parameter Evolution, Defect Generation, and Qubit Transfer

4pi

Magnetotransport of Dirac fermions on the surface of a topological insulator

-periodic relation between the Josephson current I and the phase difference

ENTANGLEMENT PRODUCTION DUE TO QUENCH DYNAMICS OF AN ANISOTROPIC XY CHAIN IN A TRANSVERSE FIELD

phi

Fractional ac Josephson effect in unconventional superconductors

:

Unconventional scanning tunneling conductance spectra for graphene

Iproptosin(phi/2)

Majorana edge modes in the Kitaev model

. Consequently, the ac Josephson current has the fractional frequency

Theoretical prediction of the fractional ac Josephson effect in p- and d-wave superconductors

eV/hbar

Bose-Hubbard model on a star lattice

, where V is the dc voltage. In the tunneling limit, the Josephson current is proportional to the first power (not square) of the electron tunneling amplitude. Thus, the Josephson current between unconventional superconductors is carried by single electrons, rather than by Cooper pairs. The fractional ac Josephson effect can be observed experimentally by measuring frequency spectrum of microwave radiation from the junction. We also study junctions between singlet s-wave and triplet px-wave, as well as between chiral