56,856 research outputs found
Comment on "Off-diagonal Long-range Order in Bose Liquids: Irrotational Flow and Quantization of Circulation"
In the context of an application to superfluidity, it is elaborated how to do
quantum mechanics of a system with a rotational velocity. Especially, in both
the laboratory frame and the non-inertial co-rotating frame, the canonical
momentum, which corresponds to the quantum mechanical momentum operator,
contains a part due to the rotational velocity.Comment: 2 page, comment on cond-mat/010435
Polar codes and polar lattices for the Heegard-Berger problem
Explicit coding schemes are proposed to achieve the rate-distortion function of the Heegard-Berger problem using polar codes. Specifically, a nested polar code construction is employed to achieve the rate-distortion function for doublysymmetric binary sources when the side information may be absent. The nested structure contains two optimal polar codes for lossy source coding and channel coding, respectively. Moreover, a similar nested polar lattice construction is employed when the source and the side information are jointly Gaussian. The proposed polar lattice is constructed by nesting a quantization polar lattice and a capacity-achieving polar lattice for the additive white Gaussian noise channel
A consistent description of kinetic equation with triangle anomaly
We provide a consistent description of the kinetic equation with triangle
anomaly which is compatible with the entropy principle of the second law of
thermodynamics and the charge/energy-momentum conservation equations. In
general an anomalous source term is necessary to ensure that the equations for
the charge and energy-momentum conservation are satisfied and that the
correction terms of distribution functions are compatible to these equations.
The constraining equations from the entropy principle are derived for the
anomaly-induced leading order corrections to the particle distribution
functions. The correction terms can be determined for minimum number of unknown
coefficients in one charge and two charge cases by solving the constraining
equations.Comment: RevTex 4, 11 pages; With minor changes: typos are corrected and one
reference is added. Accepted version to PR
The Vector and Axial-Vector Charmonium-like States
After constructing all the tetraquark interpolating currents with
and in a systematic way, we
investigate the two-point correlation functions to extract the masses of the
charmonium-like states with QCD sum rule. For the
charmonium-like state, GeV, which implies a possible
tetraquark interpretation for the state Y(4660). The masses for both the
and charmonium-like states are
around GeV, which are slightly above the mass of X(3872). For the
charmonium-like state, the extracted mass is GeV. We also discuss the possible decay modes and experimental search of
the charmonium-like states.Comment: 18 pages, 6 figures and 6 table
Nonadiabatic Geometric Quantum Computation Using A Single-loop Scenario
A single-loop scenario is proposed to realize nonadiabatic geometric quantum
computation. Conventionally, a so-called multi-loop approach is used to remove
the dynamical phase accumulated in the operation process for geometric quantum
gates. More intriguingly, we here illustrate in detail how to use a special
single-loop method to remove the dynamical phase and thus to construct a set of
universal quantum gates based on the nonadiabatic geometric phase shift. The
present scheme is applicable to NMR systems and may be feasible in other
physical systems.Comment: 4 pages, 3 figure
Does stability of relativistic dissipative fluid dynamics imply causality?
We investigate the causality and stability of relativistic dissipative fluid
dynamics in the absence of conserved charges. We perform a linear stability
analysis in the rest frame of the fluid and find that the equations of
relativistic dissipative fluid dynamics are always stable. We then perform a
linear stability analysis in a Lorentz-boosted frame. Provided that the ratio
of the relaxation time for the shear stress tensor, , to the sound
attenuation length, , fulfills a certain
asymptotic causality condition, the equations of motion give rise to stable
solutions. Although the group velocity associated with perturbations may exceed
the velocity of light in a certain finite range of wavenumbers, we demonstrate
that this does not violate causality, as long as the asymptotic causality
condition is fulfilled. Finally, we compute the characteristic velocities and
show that they remain below the velocity of light if the ratio
fulfills the asymptotic causality condition.Comment: 30 pages, 10 figures
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