186,736 research outputs found
Quantum key distribution with asymmetric channel noise
We show that one may take advantages in both robusty and key rate of
asymmetric channel noise.Comment: 2 figure
A protocol for secure and deterministic quantum key expansion
In all existing protocols of private communication with encryption and
decryption, the pre-shared key can be used for only one time. We give a
deterministic quantum key expansion protocol where the pre-shared key can be
recycled. Our protocol is exponentially secure. Our protocol costs less qubits
and almost zero classical communications with authentication steps being
included. Since our protocol can distribute the deterministic bits, it can also
be used for direct communication.Comment: 5 page
A remark on the local density approximation with the gradient corrections and the X method
We report that the solids with narrow valence bands cannot be described by
the local density approximation with the gradient corrections in the density
functional theory as well as the X method. In particular, in the case
of completely filled valence bands, the work function is significantly
underestimated by these methods for such types of solids. Also, we figured out
that these deficiencies cannot be cured by the
self-interaction-corrected-local-density-approximation method.Comment: 6 pages, 0 figure
Thermal Rectification in the Nonequilibrium Quantum-Dot-System
Quantum thermal transport in two-quantum-dot system with
Dzyaloshinskii-Moriya interaction (DM interaction) has been studied. The sign
of thermal rectification can be controlled through changing the energy
splitting or the DM interaction strength. The anisotropic term in the system
can also affect the sign of rectification. Compared with other proposals [Phys.
Rev. B 80, 172301 (2009)], our model can offer larger rectification efficiency
and show the potential application in designing the polarity-controllable
thermal diode with a small size system (N=2). Moreover, quantum correlations of
two-quantum-dots are investigated. We find that almost perfect quantum
correlations can be obtained in the large temperature bias region, and quantum
entanglement is more sensitive to the change of the DM interaction strength
than quantum discord.Comment: 6 pages, 6 figure
The maximum mass of dark matter existing in compact stars based on the self-interacting fermionic model
By assuming that only gravitation acts between dark matter (DM) and normal
matter (NM), we studied DM admixed neutron stars (DANSs) using the two-fluid
TOV equations. The NM and DM of compact stars are simulated by the relativistic
mean field (RMF) theory and non-self-annihilating self-interacting fermionic
model, respectively. The effects of the particle mass of fermionic DM and
the interaction strength parameter on the properties of DANSs are
investigated in detail. and are considered as the free parameters due
to the lack of information about the particle nature of DM so far. For a DANS,
we suggest a simple universal relationship M_D^{\max}=(0.267 y
+0.627-3.21\frac{M_N}{\M_{\odot}})( \frac{1\GeV}{{m_f}})^2 \M_{\odot} for
, where is the maximum mass of DM existing in DANSs and
is the mass of the neutron star without DM. For free fermion DM model
(=0), the relationship becomes
M_D^{\max}=(0.627-0.027\frac{M_N^2}{\M_{\odot}^2}) ( \frac{1\GeV}{{m_f}})^2
\M_{\odot}. The radius of DM shows a linear relationship with
in DANSs, namely R_D=(7.02 \frac{M_D^{\max}}{
\M_{\odot}}+1.36)~km. These conclusions are independent of the different NM
EOSs from RMF theory. Such a kind of universal relationship connecting the
nature of DM particle and mass of stars might shed light on the constraining
the nature of the DM by indirect method.Comment: 13 pages, 7 figure
A possible mechanism for the negative capacitance observed in organic devices
The mechanism of negative capacitance, e.g. inductance, induced by a
sufficient electrical field in the organic device is investigated. The cations
in organic bulk are proposed to be driven by the applied voltage and to
accumulate at the interface, and further to generate the surface states or
media states. These states result in a larger junction current through the
device, indicating the negative capacitances which are simulated in three
situations: impedance spectrum, capacitance measurement and current response.
This simple kinetic model may be helpful to understand why the negative
capacitance phenomenon is observed in various organic devices.Comment: 14 pages; 4 figure
Carath\'eodory theorems for Slice Regular Functions
In this paper a quaternionic sharp version of the Carath\'{e}odory theorem is
established for slice regular functions with positive real part, which
strengthes a weaken version recently established by D. Alpay et. al. using the
Herglotz integral formula. Moreover, the restriction of positive real part can
be relaxed so that the theorem becomes the quaternionic version of the
Borel-Carath\'{e}odory theorem. It turns out that the two theorems are
equivalent.Comment: arXiv admin note: text overlap with arXiv:1404.3117 by other author
Slice regular composition operators
In the article the class of slice regular functions is shown to be closed
under a new regular composition. The new regular composition turns out to be
globally defined in contrast to the locally defined version by Vlacci. Its
advantage over Vlacci's is demonstrated by its associated theory of composition
operators and dynamical systems for slice regular functions. Especially, the
corresponding Littlewood subordination principle and the Denjoy-Wolff type
theorem can be established
Effect of Dependent Scattering on Light Absorption in Highly Scattering Random Media
The approximate nature of radiative transfer equation (RTE) leads to a bunch
of considerations on the effect of "dependent scattering" in random media,
especially particulate media composed of discrete scatterers, in the last a few
decades, which usually indicates those deviations RTE (combined with ISA) lead
to from experimental and exact numerical results due to electromagnetic wave
interference. Here we theoretically and numerically demonstrate the effect of
dependent scattering on absorption in disordered media consisting of highly
scattering scatterers. By making comparison between the independent scattering
approximation-radiative transfer equation (ISA-RTE) and the full-wave coupled
dipole method (CDM), we find that deviations between the two methods increase
as scatterer density in the media increases. The discrepancy also grows with
optical thickness. To quantitatively take dependent scattering effect into
account, we develop a theoretical model using quasi-crystalline approximation
(QCA) to derive dependent-scattering corrected radiative properties, based on
the path-integral diagrammatic technique in multiple scattering theory. The
model results in a more reasonable agreement with numerical simulations. The
present work has profound implications for the coherent scattering physics in
random media with absorption, correctly modeling light absorptance in random
media and interpreting the experimental observations in various applications
for random media such as solar energy concentration, micro/nanofluids,
structural color generation, etc.Comment: 30 pages, 8 figures, submitte
Weak Magnetism Correction to Allowed Beta-decay for Reactor Antineutrino Spectra
The weak magnetism correction and its uncertainty to nuclear beta-decay play
a major role in determining the significance of the reactor neutrino anomaly.
Here we examine the common approximation used for one-body weak magnetism in
the calculation of fission antineutrino spectra, wherein matrix elements of the
orbital angular momentum operator contribution to the magnetic dipole current
are assumed to be proportional to those of the spin operator. Although we find
this approximation invalid for a large set of nuclear structure situations, we
conclude that it is valid for the relevant allowed beta-decays between fission
fragments. In particular, the uncertainty in the fission antineutrino due to
the uncertainty in the one-body weak magnetism correction is found to be less
than 1%. Thus, the dominant uncertainty from weak magnetism for reactor
neutrino fluxes lies in the uncertainty in the two-body meson-exchange magnetic
dipole current.Comment: 10 page, 9 figure
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