7,182 research outputs found
Vehicle Communication using Secrecy Capacity
We address secure vehicle communication using secrecy capacity. In
particular, we research the relationship between secrecy capacity and various
types of parameters that determine secrecy capacity in the vehicular wireless
network. For example, we examine the relationship between vehicle speed and
secrecy capacity, the relationship between the response time and secrecy
capacity of an autonomous vehicle, and the relationship between transmission
power and secrecy capacity. In particular, the autonomous vehicle has set the
system modeling on the assumption that the speed of the vehicle is related to
the safety distance. We propose new vehicle communication to maintain a certain
level of secrecy capacity according to various parameters. As a result, we can
expect safer communication security of autonomous vehicles in 5G
communications.Comment: 17 Pages, 12 Figure
The effect of digital signage on shoppers' behavior: the role of the evoked experience
This paper investigates the role of digital signage as experience provider in retail spaces. The findings of a survey-based field experiment demonstrate that digital signage content high on sensory cues evokes affective experience and strengthens customers’ experiential processing route. In contrast, digital signage messages high on “features and benefits” information evoke intellectual experience and strengthen customers’ deliberative processing route. The affective experience is more strongly associated with the attitude towards the ad and the approach behavior towards the advertiser than the intellectual experience. The effect of an ad high on sensory cues on shoppers’ approach to the advertiser is stronger for first-time shoppers, and therefore important in generating loyalty. The findings indicate that the design of brand-related informational cues broadcast over digital in-store monitors affects shoppers’ information processing. The cues evoke sensory and affective experiences and trigger deliberative processes that lead to attitude construction and finally elicit approach behavior towards the advertisers
Neutron electric dipole moment: Constituent-dressing and compositeness
Contributions to the neutron's EDM, are calculated using a well-constrained
Ansatz for the nucleon's Poincare' covariant Fadde'ev amplitude. The
momentum-dependent quark dressing amplifies the contribution from the
current-quarks' EDMs; and dressed-quark confinement and binding make
distinguishable the effect of the two CP and T violating interactions: i
gamma_5 sigma_{mu nu} (p_1-p_2)_nu and gamma_5 (p_1+p_2)_mu, where p_{1,2} are
the current-quarks' momenta. The value of |d_n| obtained using the
current-quark EDMs generated by a minimal three Higgs doublet model of
spontaneous CP violation is close to the current experimental upper bound.Comment: 9 pages, LaTeX2e. Errors in Table 1 corrected; five references added.
To appear in Phys. Rev.
Pair excitations and parameters of state of imbalanced Fermi gases at finite temperatures
The spectra of low-lying pair excitations for an imbalanced two-component
superfluid Fermi gas are analytically derived within the path-integral
formalism taking into account Gaussian fluctuations about the saddle point. The
spectra are obtained for nonzero temperatures, both with and without imbalance,
and for arbitrary interaction strength. On the basis of the pair excitation
spectrum, we have calculated the thermodynamic parameters of state of cold
fermions and the first and second sound velocities. The parameters of pair
excitations show a remarkable agreement with the Monte Carlo data and with
experiment.Comment: 14 pages, 5 figure
Hall conductance of Bloch electrons in a magnetic field
We study the energy spectrum and the quantized Hall conductance of electrons
in a two-dimensional periodic potential with perpendicular magnetic field
WITHOUT neglecting the coupling of the Landau bands. Remarkably, even for weak
Landau band coupling significant changes in the Hall conductance compared to
the one-band approximation of Hofstadter's butterfly are found. The principal
deviations are the rearrangement of subbands and unexpected subband
contributions to the Hall conductance.Comment: to appear in PRB; Revtex, 9 pages, 5 postscript figures; figures with
better resolution may be obtained from http://www.chaos.gwdg.d
Large-momentum convergence of Hamiltonian bound-state dynamics of effective fermions in quantum field theory
Contributions to the bound-state dynamics of fermions in local quantum field
theory from the region of large relative momenta of the constituent particles,
are studied and compared in two different approaches. The first approach is
conventionally developed in terms of bare fermions, a Tamm-Dancoff truncation
on the particle number, and a momentum-space cutoff that requires counterterms
in the Fock-space Hamiltonian. The second approach to the same theory deals
with bound states of effective fermions, the latter being derived from a
suitable renormalization group procedure. An example of two-fermion bound
states in Yukawa theory, quantized in the light-front form of dynamics, is
discussed in detail. The large-momentum region leads to a buildup of
overlapping divergences in the bare Tamm-Dancoff approach, while the effective
two-fermion dynamics is little influenced by the large-momentum region. This is
illustrated by numerical estimates of the large-momentum contributions for
coupling constants on the order of between 0.01 and 1, which is relevant for
quarks.Comment: 22 pages, 9 figure
Interaction Effects in a One-Dimensional Constriction
We have investigated the transport properties of one-dimensional (1D)
constrictions defined by split-gates in high quality GaAs/AlGaAs
heterostructures. In addition to the usual quantized conductance plateaus, the
equilibrium conductance shows a structure close to , and in
consolidating our previous work [K.~J. Thomas et al., Phys. Rev. Lett. 77, 135
(1996)] this 0.7 structure has been investigated in a wide range of samples as
a function of temperature, carrier density, in-plane magnetic field
and source-drain voltage . We show that the 0.7
structure is not due to transmission or resonance effects, nor does it arise
from the asymmetry of the heterojunction in the growth direction. All the 1D
subbands show Zeeman splitting at high , and in the wide channel
limit the -factor is , close to that of bulk GaAs.
As the channel is progressively narrowed we measure an exchange-enhanced
-factor. The measurements establish that the 0.7 structure is related to
spin, and that electron-electron interactions become important for the last few
conducting 1D subbands.Comment: 8 pages, 7 figures (accepted in Phys. Rev. B
Metal-insulator transitions in cyclotron resonance of periodic nanostructures due to avoided band crossings
A recently found metal-insulator transition in a model for cyclotron
resonance in a two-dimensional periodic potential is investigated by means of
spectral properties of the time evolution operator. The previously found
dynamical signatures of the transition are explained in terms of avoided band
crossings due to the change of the external electric field. The occurrence of a
cross-like transport is predicted and numerically confirmed
Masses of ground and excited-state hadrons
We present the first Dyson-Schwinger equation calculation of the light hadron
spectrum that simultaneously correlates the masses of meson and baryon ground-
and excited-states within a single framework. At the core of our analysis is a
symmetry-preserving treatment of a vector-vector contact interaction. In
comparison with relevant quantities the
root-mean-square-relative-error/degree-of freedom is 13%. Notable amongst our
results is agreement between the computed baryon masses and the bare masses
employed in modern dynamical coupled-channels models of pion-nucleon reactions.
Our analysis provides insight into numerous aspects of baryon structure; e.g.,
relationships between the nucleon and Delta masses and those of the
dressed-quark and diquark correlations they contain.Comment: 25 pages, 7 figures, 4 table
Consequences of local gauge symmetry in empirical tight-binding theory
A method for incorporating electromagnetic fields into empirical
tight-binding theory is derived from the principle of local gauge symmetry.
Gauge invariance is shown to be incompatible with empirical tight-binding
theory unless a representation exists in which the coordinate operator is
diagonal. The present approach takes this basis as fundamental and uses group
theory to construct symmetrized linear combinations of discrete coordinate
eigenkets. This produces orthogonal atomic-like "orbitals" that may be used as
a tight-binding basis. The coordinate matrix in the latter basis includes
intra-atomic matrix elements between different orbitals on the same atom.
Lattice gauge theory is then used to define discrete electromagnetic fields and
their interaction with electrons. Local gauge symmetry is shown to impose
strong restrictions limiting the range of the Hamiltonian in the coordinate
basis. The theory is applied to the semiconductors Ge and Si, for which it is
shown that a basis of 15 orbitals per atom provides a satisfactory description
of the valence bands and the lowest conduction bands. Calculations of the
dielectric function demonstrate that this model yields an accurate joint
density of states, but underestimates the oscillator strength by about 20% in
comparison to a nonlocal empirical pseudopotential calculation.Comment: 23 pages, 7 figures, RevTeX4; submitted to Phys. Rev.
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