32,657 research outputs found
Exotic Topological States with Raman-Induced Spin-Orbit Coupling
We propose a simple experimental scheme to realize simultaneously the
one-dimensional spin-orbit coupling and the staggered spin-flip in ultracold
pseudospin- atomic Fermi gases trapped in square optical lattices. In the
absence of interspecies interactions, the system supports gapped Chern
insulators and gapless topological semimetal states. By turning on the -wave
interactions, a rich variety of gapped and gapless inhomogeneous topological
superfluids can emerge. In particular, a gapped topological Fulde-Ferrell
superfluid, in which the chiral edge states at opposite boundaries possess the
same chirality, is predicted.Comment: 11 pages, 6 figure
Characterising Probabilistic Processes Logically
In this paper we work on (bi)simulation semantics of processes that exhibit
both nondeterministic and probabilistic behaviour. We propose a probabilistic
extension of the modal mu-calculus and show how to derive characteristic
formulae for various simulation-like preorders over finite-state processes
without divergence. In addition, we show that even without the fixpoint
operators this probabilistic mu-calculus can be used to characterise these
behavioural relations in the sense that two states are equivalent if and only
if they satisfy the same set of formulae.Comment: 18 page
Universal Quantum Degeneracy Point for Superconducting Qubits
The quantum degeneracy point approach [D. Vion et al., Science 296, 886
(2002)] effectively protects superconducting qubits from low-frequency noise
that couples with the qubits as transverse noise. However, low-frequency noise
in superconducting qubits can originate from various mechanisms and can couple
with the qubits either as transverse or as longitudinal noise. Here, we present
a quantum circuit containing a universal quantum degeneracy point that protects
an encoded qubit from arbitrary low-frequency noise. We further show that
universal quantum logic gates can be performed on the encoded qubit with high
gate fidelity. The proposed scheme is robust against small parameter spreads
due to fabrication errors in the superconducting qubits.Comment: 7 pages, 4 figure
Period halving of Persistent Currents in Mesoscopic Mobius ladders
We investigate the period halving of persistent currents(PCs) of
non-interacting electrons in isolated mesoscopic M\"{o}bius ladders without
disorder, pierced by Aharonov-Bhom flux. The mechanisms of the period halving
effect depend on the parity of the number of electrons as well as on the
interchain hopping. Although the data of PCs in mesoscopic systems are
sample-specific, some simple rules are found in the canonical ensemble average,
such as all the odd harmonics of the PCs disappear, and the signals of even
harmonics are non-negative. {PACS number(s): 73.23.Ra, 73.23.-b, 68.65.-k}Comment: 6 Pages with 3 EPS figure
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