859 research outputs found
Cascaded Entanglement Enhancement
We present a cascaded system consisting of three non-degenerate optical
parametric amplifiers (NOPAs) for the generation and the enhancement of quantum
entanglement of continuous variables. The entanglement of optical fields
produced by the first NOPA is successively enhanced by the second and the third
NOPAs from -5.3 to -8.1 below the quantum noise limit. The dependence
of the enhanced entanglement on the physical parameters of the NOPAs and the
reachable entanglement limitation for a given cascaded NOPA system are
calculated. The calculation results are in good agreement with the experimental
measurements.Comment: 5 pages, 4 figure
Error analysis of a first-order IMEX scheme for the logarithmic Schr\"odinger equation
The logarithmic Schr\"odinger equation (LogSE) has a logarithmic nonlinearity
that is not differentiable at Compared with its
counterpart with a regular nonlinear term, it possesses richer and unusual
dynamics, though the low regularity of the nonlinearity brings about
significant challenges in both analysis and computation. Among very limited
numerical studies, the semi-implicit regularized method via regularising
as to overcome the
blowup of at has been investigated recently in literature.
With the understanding of we analyze the non-regularized first-order
Implicit-Explicit (IMEX) scheme for the LogSE. We introduce some new tools for
the error analysis that include the characterization of the H\"older continuity
of the logarithmic term, and a nonlinear Gr\"{o}nwall's inequality. We provide
ample numerical results to demonstrate the expected convergence. We position
this work as the first one to study the direct linearized scheme for the LogSE
as far as we can tell.Comment: 19 pages, 5 figure
Some Weak Convergence Theorems for a Family of Asymptotically Nonexpansive Nonself Mappings
A one-step iteration with errors is considered for a family of asymptotically nonexpansive nonself mappings. Weak convergence of the purposed iteration is obtained in a Banach space
Experimental observation of plasmons in a graphene monolayer resting on a two-dimensional subwavelength silicon grating
We experimentally demonstrate graphene-plasmon polariton excitation in a
continuous graphene monolayer resting on a two-dimensional subwavelength
silicon grating. The subwavelength silicon grating is fabricated by a
nanosphere lithography technique with a self-assembled nanosphere array as a
template. Measured transmission spectra illustrate the excitation of
graphene-plasmon polaritons, which is further supported by numerical
simulations and theoretical prediction of plasmonband diagrams. Our
grating-assisted coupling to graphene-plasmon polaritons forms an important
platform for graphene-based opto-electronics applications.Comment: 13 pages, 4 figures, revised version accepted by AP
Experimental Demonstration of Unconditional Entanglement Swapping for Continuous Variables
The unconditional entanglement swapping for continuous variables is
experimentally demonstrated. Two initial entangled states are produced from two
nondegenerate optical parametric amplifiers operating at deamplification.
Through implementing the direct measurement of Bell-state between two optical
beams from each amplifier the remaining two optical beams, which have never
directly interacted with each other, are entangled. The quantum correlation
degrees of 1.23dB and 1.12dB below the shot noise limit for the amplitude and
phase quadratures resulting from the entanglement swapping are straightly
measured.Comment: new versio
Impurity screening and stability of Fermi arcs against Coulomband magnetic scattering in a Weyl monopnictide
We present a quasiparticle interference study of clean and Mn surface-doped
TaAs, a prototypical Weyl semimetal, to test the screening properties as well
as the stability of Fermi arcs against Coulomb and magnetic scattering.
Contrary to topological insulators, the impurities are effectively screened in
Weyl semimetals. The adatoms significantly enhance the strength of the signal
such that theoretical predictions on the potential impact of Fermi arcs can be
unambiguously scrutinized. Our analysis reveals the existence of three
extremely short, previously unknown scattering vectors. Comparison with theory
traces them back to scattering events between large parallel segments of
spin-split trivial states, strongly limiting their coherence. In sharp contrast
to previous work [R. Batabyal et al., Sci. Adv. 2, e1600709 (2016)], where
similar but weaker subtle modulations were interpreted as evidence of
quasiparticle interference originating from Femi arcs, we can safely exclude
this being the case. Overall, our results indicate that intra- as well as
inter-Fermi arc scattering are strongly suppressed and may explain why-in spite
of their complex multiband structure-transport measurements show signatures of
topological states in Weyl monopnictides
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