11,891 research outputs found
Fate of non-Fermi liquid behavior in QED at finite chemical potential
The damping rate of two-dimensional massless Dirac fermions exhibit non-Fermi
liquid behavior, , due to gauge field at zero
temperature and zero chemical potential. We study the fate of this behavior at
finite chemical potential. We fist calculate explicitly the temporal and
spatial components of vacuum polarization functions. The analytical expressions
imply that the temporal component of gauge field develops a static screening
length at finite chemical potential while the transverse component remains
long-ranged owing to gauge invariance. We then calculate the fermion damping
rate and show that the temporal gauge field leads to normal Fermi liquid
behavior but the transverse gauge field leads to non-Fermi liquid behavior
at zero temperature. This energy-dependence is more
regular than and does not change as chemical potential
varies.Comment: 12 pages, 1 figur
Multiresolution spatiotemporal mechanical model of the heart as a prior to constrain the solution for 4D models of the heart.
In several nuclear cardiac imaging applications (SPECT and PET), images are formed by reconstructing tomographic data using an iterative reconstruction algorithm with corrections for physical factors involved in the imaging detection process and with corrections for cardiac and respiratory motion. The physical factors are modeled as coefficients in the matrix of a system of linear equations and include attenuation, scatter, and spatially varying geometric response. The solution to the tomographic problem involves solving the inverse of this system matrix. This requires the design of an iterative reconstruction algorithm with a statistical model that best fits the data acquisition. The most appropriate model is based on a Poisson distribution. Using Bayes Theorem, an iterative reconstruction algorithm is designed to determine the maximum a posteriori estimate of the reconstructed image with constraints that maximizes the Bayesian likelihood function for the Poisson statistical model. The a priori distribution is formulated as the joint entropy (JE) to measure the similarity between the gated cardiac PET image and the cardiac MRI cine image modeled as a FE mechanical model. The developed algorithm shows the potential of using a FE mechanical model of the heart derived from a cardiac MRI cine scan to constrain solutions of gated cardiac PET images
Gap solitons of a super-Tonks-Girardeau gas in a one-dimensional periodic potential
We study the stability of gap solitons of the super-Tonks-Girardeau bosonic
gas in one-dimensional periodic potential. The linear stability analysis
indicates that increasing the amplitude of periodic potential or decreasing the
nonlinear interactions, the unstable gap solitons can become stable. In
particular, the theoretical analysis and numerical calculations show that,
comparing to the lower-family of gap solitons, the higher-family of gap
solitons are easy to form near the bottoms of the linear Bloch band gaps. The
numerical results also verify that the composition relations between various
gap solitons and nonlinear Bloch waves are general and can exist in the
super-Tonks-Girardeau phase.Comment: 7 pages,6 figure
Is a Positive Review Always Effective? Advertising Appeal Effect in the Persuasion of Online Customer Reviews
Despite the expected value of online customer reviews as an emerging advertising medium, the manner of enforcing its effectiveness on customersâ purchase behavior is still a question not well answered. To address the question, we propose a new central route cue called âadvertising appealâ to examine attitude and intention to purchase a product or service based on the reasoning of the elaboration likelihood model. We also propose that consumersâ consumption goal and attitude certainty separately moderate the advertising appeal effect on purchase intention through a degree of favorable attitude. We test these hypotheses by conducting a laboratory experiment with 50 participants. In this experiment, we manipulate two kinds of advertising appeals and consumption goals. This study demonstrates that attribute-based appeal reviews are more influential than emotion-based appeal reviews in the persuasion process, regardless of the individualsâ consumption goals. However, the advertising appeal effect on purchase intention is more pronounced for hedonic consumers than for utilitarian consumers
Phase Diagram of Rydberg atoms in a nonequilibrium optical lattice
We study the quantum nonequilibrium dynamics of ultracold three-level atoms
trapped in an optical lattice, which are excited to their Rydberg states via a
two-photon excitation with nonnegligible spontaneous emission. Rich quantum
phases including uniform phase, antiferromagnetic phase and oscillatory phase
are identified. We map out the phase diagram and find these phases can be
controlled by adjusting the ratio of intensity of the pump light to the control
light, and that of two-photon detuning to the Rydberg interaction strength.
When the two-photon detuning is blue-shifted and the latter ratio is less than
1, bistability exists among the phases. Actually, this ratio controls the
Rydberg-blockade and antiblockade effect, thus the phase transition in this
system can be considered as a possible approach to study both effects.Comment: 5 pages,5 figure
Quantum entropy of the Kerr black hole arising from gravitational perturbation
The quantum entropy of the Kerr black hole arising from gravitational
perturbation is investigated by using Null tetrad and \'t Hooft\'s brick-wall
model. It is shown that effect of the graviton\'s spins on the subleading
correction is dependent of the square of the spins and the angular momentum per
unit mass of the black hole, and contribution of the logarithmic term to the
entropy will be positive, zero, and negative for different value of .Comment: 8 pages, 1 figure, Latex. to appear in Phys. Rev.
Non-Markovian Quantum Trajectories of Many-Body Quantum Open Systems
A long-standing open problem in non-Markovian quantum state diffusion (QSD)
approach to open quantum systems is to establish the non-Markovian QSD
equations for multiple qubit systems. In this paper, we settle this important
question by explicitly constructing a set of exact time-local QSD equations for
-qubit systems. Our exact time-local (convolutionless) QSD equations have
paved the way towards simulating quantum dynamics of many-body open systems
interacting with a common bosonic environment. The applicability of this
multiple-qubit stochastic equation is exemplified by numerically solving
several quantum open many-body systems concerning quantum coherence dynamics
and dynamical control.Comment: 8 pages, 2 figures. manuscript revised and reference update
Entropies of Rotating Charged Black Holes from Conformal Field Theory at Killing Horizons
The covariant phase technique is used to compute the constraint algebra of
the stationary axisymmetric charged black hole. A standard Virasoro subalgebra
with corresponding central charge is constructed at a Killing horizon with
Carlip's boundary conditions. For the Kerr-Newman black hole and the
Kerr-Newman-AdS black hole, the density of states determined by conformal
fields theory methods yields the statistical entropy which agrees with the
Bekenstein-Hawking entropy.Comment: 12 pages, no figure, RevTe
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