18,344 research outputs found
Steady-state dynamics and effective temperatures of quantum criticality in an open system
We study the thermal and non-thermal steady state scaling functions and the
steady-state dynamics of a model of local quantum criticality. The model we
consider, i.e. the pseudogap Kondo model, allows us to study the concept of
effective temperatures near fully interacting as well as weak-coupling fixed
points. In the vicinity of each fixed point we establish the existence of an
effective temperature --different at each fixed point-- such that the
equilibrium fluctuation-dissipation theorem is recovered. Most notably,
steady-state scaling functions in terms of the effective temperatures coincide
with the equilibrium scaling functions. This result extends to higher
correlation functions as is explicitly demonstrated for the Kondo singlet
strength. The non-linear charge transport is also studied and analyzed in terms
of the effective temperature.Comment: 5 pages, 4 figures; Supplementary Material (7 pages, 1 figure
Energy loss analysis of an integrated space power distribution system
The results of studies related to conceptual topologies of an integrated utility-like space power system are described. The system topologies are comparatively analyzed by considering their transmission energy losses as functions of mainly distribution voltage level and load composition. The analysis is expedited by use of a Distribution System Analysis and Simulation (DSAS) software. This recently developed computer program by the Electric Power Research Institute (EPRI) uses improved load models to solve the power flow within the system. However, present shortcomings of the software with regard to space applications, and incompletely defined characteristics of a space power system make the results applicable to only the fundamental trends of energy losses of the topologies studied. Accountability, such as included, for the effects of the various parameters on the system performance can constitute part of a planning tool for a space power distribution system
DNS of Laminar to Turbulent Transition on NACA 0012 Airfoil with Sand Grain Roughness
The Lattice-Boltzmann-based solver PowerFLOW is used to perform direct numerical simulations of the transitional flow over an airfoil at Reynolds number equal to 0.657 million. The leading edge of the airfoil is covered with sand particles, represented by polyhedra, to mimic the grit used in experiments. The sensitivity of the laminar to turbulent transition to the size of these particles, grid resolution, spanwise length is evaluated and rectangular trips are also tested
Chiral corrections to baryon properties with composite pions
A calculational scheme is developed to evaluate chiral corrections to
properties of composite baryons with composite pions. The composite baryons and
pions are bound states derived from a microscopic chiral quark model. The model
is amenable to standard many-body techniques such as the BCS and RPA
formalisms. An effective chiral model involving only hadronic degrees of
freedom is derived from the macroscopic quark model by projection onto hadron
states. Chiral loops are calculated using the effective hadronic Hamiltonian. A
simple microscopic confining interaction is used to illustrate the derivation
of the pion-nucleon form factor and the calculation of pionic self-energy
corrections to the nucleon and Delta(1232) masses.Comment: 29 pages, Revtex, 4 ps figure
Production of optical phase space vortices with non-locally distributed mode converters
Optical vortices have been observed in a wide variety of optical systems.
They can be observed directly in the wavefront of optical beams, or in the
correlations between pairs of entangled photons. We present a novel optical
vortex which appears in a non-local plane of the two-photon phase space,
composed of a single degree of freedom of each photon of an entangled pair. The
preparation of this vortex can be viewed as a "non-local" or distributed mode
converter. We show how these novel optical vortices of arbitrary order can be
prepared in the spatial degrees of freedom of entangled photons.Comment: To appear in upcoming special issue "Orbital Angular Momentum" of the
Journal of Optic
Quark model with chiral-symmetry breaking and confinement in the Covariant Spectator Theory
We propose a model for the quark-antiquark interaction in Minkowski space
using the Covariant Spectator Theory. We show that with an equal-weighted
scalar-pseudoscalar structure for the confining part of our interaction kernel
the axial-vector Ward-Takahashi identity is preserved and our model complies
with the Adler-zero constraint for pi-pi-scattering imposed by chiral symmetry.Comment: 4 pages, 2 figures; 21st International Conference on Few-Body
Problems in Physics, May 18 - 22, 2015, Chicago, US
On the duality in CPT-even Lorentz-breaking theories
In this paper, we generalize the duality between self-dual and
Maxwell-Chern-Simons theories for the case of a CPT-even Lorentz-breaking
extension of these theories. The duality is demonstrated with use of the gauge
embedding procedure, both in free and coupled cases, and with the master action
approach. The physical spectra of both Lorentz-breaking theories are studied.
The massive poles are shown to coincide and to respect the requirements for
unitarity and causality at tree level. The extra massless poles which are
present in the dualized model are shown to be nondynamical.Comment: 17 pages, version accepted to EPJ
- …