Hall Viscosity and Electromagnetic Response

Carlos Hoyos and Dam Thanh Son
We show that, for Galilean invariant quantum Hall states, the Hall viscosity appears in the electromagnetic response at finite wave numbers q. In particular, the leading q dependence of the Hall conductivity at small q receives a contribution from the Hall viscosity. The coefficient of the q term in ... [Phys. Rev. Lett. 108, 066805 ] published .

Tunneling transport through superconducting wires with Majorana bound states

B. H. Wu and J. C. Cao
We investigate the transport of a topological superconducting wire hosting a pair of Majorana bound states between two normal leads. Both the model-independent scattering matrix theory and the Green's function method for a tight-binding model show that the transport properties are sensitive to the c ... [Phys. Rev. B 85, 085415 ] published .

Competing orders in the Dirac-like electronic structure and the nonlinear sigma model with a topological term

Pouyan Ghaemi and Shinsei Ryu
The Dirac-like electronic structure can host a large number of competing orders in the form of mass terms. In particular, two different order parameters can be said to be dual to each other, when a static defect in one of them traps a quantum number (or charge) of the other. We discuss that such com ... [Phys. Rev. B 85, 075111 ] published .

Avoidance of Majorana Resonances in Periodic Topological Superconductor-Nanowire Structures

Jay D. Sau, Chien Hung Lin, Hoi-Yin Hui, and S. Das Sarma
Semiconducting nanowires in proximity to superconductors are promising experimental systems for Majorana fermions which may ultimately be used as building blocks for topological quantum computers. A serious challenge in the experimental realization of the Majorana fermion in these semiconductor-supe ... [Phys. Rev. Lett. 108, 067001 ] published .

Non-Abelian Braiding of Lattice Bosons

Eliot Kapit, Paul Ginsparg, and Erich Mueller
We report on a numerical experiment in which we use time-dependent potentials to braid non-Abelian quasiparticles. We consider lattice bosons in a uniform magnetic field within the fractional quantum Hall regime, where nu, the ratio of particles to flux quanta, is near 1/2, 1, or 3/2. We introduce t ... [Phys. Rev. Lett. 108, 066802 ] published .

Giant negative magnetoresistance in high-mobility two-dimensional electron systems

A. T. Hatke, M. A. Zudov, J. L. Reno, L. N. Pfeiffer, and K. W. West
We report on a giant negative magnetoresistance in very high mobility GaAs/AlGaAs heterostructures and quantum wells. The effect is the strongest at B~=1 kG, where the magnetoresistivity develops a minimum emerging at T<~2 K. Unlike the zero-field resistivity which saturates at T~=2 K, the resistivi ... [Phys. Rev. B 85, 081304 ] published .

Single-valley quantum Hall ferromagnet in a dilute MgZnO/ZnO strongly correlated two-dimensional electron system

Y. Kozuka, A. Tsukazaki, D. Maryenko, J. Falson, C. Bell et al.
We investigate the spin susceptibility (gm) of dilute two-dimensional (2D) electrons confined at the MgZnO/ZnO heterointerface. Magnetotransport measurements show a four-fold enhancement of gm, dominated by the increase in the Lande g-factor. The g-factor enhancement leads to a ferromagnetic instabi ... [Phys. Rev. B 85, 075302 ] published .

Back-action of a driven nonlinear resonator on a superconducting qubit

Maxime Boissonneault, A. C. Doherty, F. R. Ong, P. Bertet, D. Vion et al.
We study the backaction of a driven nonlinear resonator on a multilevel superconducting qubit. Using unitary transformations on the multilevel Jaynes-Cummings Hamiltonian and quantum optics master equation, we derive an analytical model that goes beyond linear response theory. Within the limits of v ... [Phys. Rev. A 85, 022305 ] published .

Characterization of a Two-Transmon Processor with Individual Single-Shot Qubit Readout

A. Dewes, F. R. Ong, V. Schmitt, R. Lauro, N. Boulant et al.
We report the characterization of a two-qubit processor implemented with two capacitively coupled tunable superconducting qubits of the transmon type, each qubit having its own nondestructive single-shot readout. The fixed capacitive coupling yields the sqrt(iSWAP) two-qubit gate for a suitable inte ... [Phys. Rev. Lett. 108, 057002 ] published .

Quantum anomalous Hall effect with tunable Chern number in magnetic topological insulator film

Hua Jiang, Zhenhua Qiao, Haiwen Liu, and Qian Niu
We study the possibility of realizing quantum anomalous Hall (QAH) effect with tunable Chern number through doping magnetic elements in a multilayer topological insulator film. We find that high Chern number QAH phases exist in ideal neutral samples and can make transition to another QAH phase direc ... [Phys. Rev. B 85, 045445 ] published .

Quasiparticles and excitons for the Pfaffian quantum Hall state

Ivan D. Rodriguez, A. Sterdyniak, M. Hermanns, J. K. Slingerland, and N. Regnault
We propose trial wave functions for quasiparticle and exciton excitations of the Moore-Read Pfaffian fractional quantum Hall states, both for bosons and for fermions, and study these numerically. Our construction of trial wave functions employs a picture of the bosonic Moore-Read state as a symmetri ... [Phys. Rev. B 85, 035128 ] published .

Quantum Hall effect in bottom-gated epitaxial graphene grown on the C-face of SiC

B. Jouault, N. Camara, B. Jabakhanji, A. Caboni, C. Consejo et al.
We demonstrate that the carrier concentration of epitaxial graphene devices grown on the C-face of a SiC substrate is efficiently modulated by a buried gate. The gate is fabricated via the implantation of nitrogen atoms in the SiC crystal. The charge neutrality point is observed close to gate voltag ... [Appl. Phys. Lett. 100, 052102 (2012)] published Mon Jan 30, 2012.

Resistivity saturation in a weakly interacting two-dimensional Fermi liquid at intermediate temperatures

Xiaoqing Zhou, B. Schmidt, L. W. Engel, G. Gervais, L. N. Pfeiffer et al.
We report an unusual temperature dependence in the magnetoresistance of a weakly interacting high mobility 2D electron gas (2DEG) under a parallel magnetic field and in the current configuration I[perpendicular]B. While the linear temperature dependence below 10 K and the exponential temperature dep ... [Phys. Rev. B 85, 041310 ] published .

Vortex interaction enhanced saturation number and caging effect in a superconducting film with a honeycomb array of nanoscale holes

M. L. Latimer, G. R. Berdiyorov, Z. L. Xiao, W. K. Kwok, and F. M. Peeters
The electrical transport properties of a MoGe thin film with a honeycomb array of nanoscale holes are investigated. The critical current of the system shows nonmatching anomalies as a function of applied magnetic field, enabling us to distinguish between multiquanta vortices trapped in the holes and ... [Phys. Rev. B 85, 012505 ] published .

Quantized nu=5/2 State in a Two-Subband Quantum Hall System

J. Nuebler, B. Friess, V. Umansky, B. Rosenow, M. Heiblum et al.
The evolution of the fractional quantum Hall state at filling 5/2 is studied in density tunable two-dimensional electron systems formed in wide wells in which it is possible to induce a transition from single- to two-subband occupancy. In 80 and 60 nm wells, the quantum Hall state at 5/2 filling of ... [Phys. Rev. Lett. 108, 046804 ] published .

Topological Hubbard Model and Its High-Temperature Quantum Hall Effect

Titus Neupert, Luiz Santos, Shinsei Ryu, Claudio Chamon, and Christopher Mudry
The quintessential two-dimensional lattice model that describes the competition between the kinetic energy of electrons and their short-range repulsive interactions is the repulsive Hubbard model. We study a time-reversal symmetric variant of the repulsive Hubbard model defined on a planar lattice: ... [Phys. Rev. Lett. 108, 046806 ] published .

Competing Topological Orders in the nu=12/5 Quantum Hall State

Parsa Bonderson, Adrian E. Feiguin, Gunnar Moller, and J. K. Slingerland
We provide numerical evidence that a p-ip paired Bonderson-Slingerland (BS) non-Abelian hierarchy state is a strong candidate for the observed nu=12/5 quantum Hall plateau. We confirm the existence of a gapped incompressible nu=12/5 quantum Hall state with shift S=2 on the sphere, matching that of t ... [Phys. Rev. Lett. 108, 036806 ] published .

Cross-Correlated Responses of Topological Superconductors and Superfluids

Kentaro Nomura, Shinsei Ryu, Akira Furusaki, and Naoto Nagaosa
We study nontrivial responses of topological superconductors and superfluids to the temperature gradient and rotation of the system. In two-dimensional gapped systems, the Streda formula for the electric Hall conductivity is generalized to the thermal Hall conductivity. Applying this formula to the ... [Phys. Rev. Lett. 108, 026802 ] published .

Competing hyperfine and spin-orbit couplings: Spin relaxation in a quantum Hall ferromagnet

S. Dickmann and T. Ziman
Spin relaxation in a quantum Hall ferromagnet, where filling is nu=1,1/3,1/5,... , can be considered in terms of spin-wave annihilation/creation processes. Hyperfine coupling with the nuclei of the GaAs matrix provides spin nonconservation in the two-dimensional electron gas and determines spin rel ... [Phys. Rev. B 85, 045318 ] published .

Edge-mode combinations in the entanglement spectra of non-Abelian fractional quantum Hall states on the torus

Zhao Liu, Emil J. Bergholtz, Heng Fan, and Andreas M. Lauchli
We present a detailed analysis of bipartite entanglement in the non-Abelian Moore-Read fractional quantum Hall state of bosons and fermions on the torus. In particular, we show that the entanglement spectra can be decomposed into intricate combinations of different sectors of the conformal field the ... [Phys. Rev. B 85, 045119 ] published .