13,512 research outputs found
Magnetoconductivity in Weyl semimetals: Effect of chemical potential and temperature
We present the detailed analyses of magneto-conductivities in a Weyl
semimetal within Born and self-consistent Born approximations. In the presence
of the charged impurities, the linear magnetoresistance can happen when the
charge carriers are mainly from the zeroth (n=0) Landau level. Interestingly,
the linear magnetoresistance is very robust against the change of temperature,
as long as the charge carriers mainly come from the zeroth Landau level. We
denote this parameter regime as the high-field regime. On the other hand, the
linear magnetoresistance disappears once the charge carriers from the higher
Landau levels can provide notable contributions. Our analysis indicates that
the deviation from the linear magnetoresistance is mainly due to the deviation
of the longitudinal conductivity from the behavior. We found two
important features of the self-energy approximation: 1. a dramatic jump of
, when the Landau level begins to contribute charge
carriers, which is the beginning point of the middle-field regime, when
decreasing the external magnetic field from high field; 2. In the low-field
regime shows a behavior and results the
magnetoresistance to show a behavior. The detailed and
careful numerical calculation indicates that the self-energy approximation
(including both the Born and the self-consistent Born approximations) does not
explain the recent experimental observation of linear magnetoresistance in Weyl
semimetals.Comment: The accepted version. Extending the previous version by including the
discussions of self-consistent Born approximatio
Probing Non-Abelian Statistics in nu=12/5 Quantum Hall State
The tunneling current and shot noise of the current between two Fractional
Quantum Hall (FQH) edges in the FQH state in electronic
Mach-Zehnder interferometer are studied. It is shown that the tunneling current
and shot noise can be used to probe the existence of parafermion
statistics in the FQH state. More specifically, the dependence of
the current on the Aharonov-Bohm flux in the Read-Rezayi state is asymmetric
under the change of the sign of the applied voltage. This property is absent in
the Abelian Laughlin states. Moreover the Fano factor can exceed 12.7 electron
charges in the FQH state . This number well exceeds the maximum
possible Fano factor in all Laughlin states and the Moore-Read
state which was shown previously to be and respectively.Comment: 10 pages, 6 figure
Localized structures in Kagome lattices
We investigate the existence and stability of gap vortices and multi-pole gap
solitons in a Kagome lattice with a defocusing nonlinearity both in a discrete
case and in a continuum one with periodic external modulation. In particular,
predictions are made based on expansion around a simple and analytically
tractable anti-continuum (zero coupling) limit. These predictions are then
confirmed for a continuum model of an optically-induced Kagome lattice in a
photorefractive crystal obtained by a continuous transformation of a honeycomb
lattice
Polarization and frequency disentanglement of photons via stochastic polarization mode dispersion
We investigate the quantum decoherence of frequency and polarization
variables of photons via polarization mode dispersion in optical fibers. By
observing the analogy between the propagation equation of the field and the
Schr\"odinger equation, we develop a master equation under Markovian
approximation and analytically solve for the field density matrix. We identify
distinct decay behaviors for the polarization and frequency variables for
single-photon and two-photon states. For the single photon case, purity
functions indicate that complete decoherence for each variable is possible only
for infinite fiber length. For entangled two-photon states passing through
separate fibers, entanglement associated with each variable can be completely
destroyed after characteristic finite propagation distances. In particular, we
show that frequency disentanglement is independent of the initial polarization
status. For propagation of two photons in a common fiber, the evolution of a
polarization singlet state is addressed. We show that while complete
polarization disentanglement occurs at a finite propagation distance, frequency
entanglement could survive at any finite distance for gaussian states.Comment: 2 figure
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