Zobrazeno 1 - 10
of 63
pro vyhledávání: '"Dahlhaus, J. P."'
Publikováno v:
Phys. Rev. X 4, 041007 (2014)
The quantum evolution after a metallic lead is suddenly connected to an electron system contains information about the excitation spectrum of the combined system. We exploit this type of "quantum quench" to probe the presence of Majorana fermions at
Externí odkaz:
http://arxiv.org/abs/1405.5865
Publikováno v:
Phys. Rev. Lett. 112, 196602 (2014)
The fractal spectrum of magnetic minibands (Hofstadter butterfly), induced by the moir\'e super- lattice of graphene on an hexagonal crystal substrate, is known to exhibit gapped Dirac cones. We show that the gap can be closed by slightly misaligning
Externí odkaz:
http://arxiv.org/abs/1401.4401
Publikováno v:
Phys. Rev. A 89, 042327 (2014)
One-dimensional discrete-time quantum walks show a rich spectrum of topological phases that have so far been exclusively analysed in momentum space. In this work we introduce an alternative approach to topology which is based on the scattering matrix
Externí odkaz:
http://arxiv.org/abs/1401.2673
Publikováno v:
Phys. Rev. Lett. 111, 037001 (2013)
The phase-dependent bound states (Andreev levels) of a Josephson junction can cross at the Fermi level, if the superconducting ground state switches between even and odd fermion parity. The level crossing is topologically protected, in the absence of
Externí odkaz:
http://arxiv.org/abs/1305.2924
Publikováno v:
Phys. Rev. Lett. 110, 017003 (2013)
The helical edge state of a quantum spin-Hall insulator can carry a supercurrent in equilibrium between two superconducting electrodes (separation L, coherence length xi). We calculate the maximum (critical) current I_c that can flow without dissipat
Externí odkaz:
http://arxiv.org/abs/1210.5412
Publikováno v:
Phys. Rev. B 86, 174520 (2012)
Time-reversal invariant superconductors having nodes of vanishing excitation gap support zero-energy boundary states with topological protection. Existing expressions for the topological invariant are given in terms of the Hamiltonian of an infinite
Externí odkaz:
http://arxiv.org/abs/1208.5491
Publikováno v:
New J. Phys. 14, 125011 (2012)
We show that weak antilocalization by disorder competes with resonant Andreev reflection from a Majorana zero-mode to produce a zero-voltage conductance peak of order e^2/h in a superconducting nanowire. The phase conjugation needed for quantum inter
Externí odkaz:
http://arxiv.org/abs/1206.6687
Publikováno v:
Phys. Rev. B 86, 094501 (2012)
It was pointed out by Tewari and Sau that chiral symmetry (H -> -H if e <-> h) of the Hamiltonian of electron-hole (e-h) excitations in an N-mode superconducting wire is associated with a topological quantum number Q\in\mathbb{Z} (symmetry class BDI)
Externí odkaz:
http://arxiv.org/abs/1206.3079
Publikováno v:
Phys. Rev. B 85, 165131 (2012)
The quantum kicked rotator is a periodically driven dynamical system with a metal-insulator transition. We extend the model so that it includes phase transitions between a metal and a topological insulator, in the universality class of the quantum sp
Externí odkaz:
http://arxiv.org/abs/1201.3361
Publikováno v:
Phys.Rev.B 84, 115133 (2011)
We construct a periodically time-dependent Hamiltonian with a phase transition in the quantum Hall universality class. One spatial dimension can be eliminated by introducing a second incommensurate driving frequency, so that we can study the quantum
Externí odkaz:
http://arxiv.org/abs/1106.5514