1,741 research outputs found
Do correlations create an energy gap in electronic bilayers? Critical analysis of different approaches
This paper investigates the effect of correlations in electronic bilayers on
the longitudinal collective mode structure. We employ the dielectric
permeability constructed by means of the classical theory of moments. It is
shown that the neglection of damping processes overestimates the role of
correlations. We conclude that the correct account of damping processes leads
to an absence of an energy gap.Comment: 4 page
A Novel Generic Framework for Track Fitting in Complex Detector Systems
This paper presents a novel framework for track fitting which is usable in a
wide range of experiments, independent of the specific event topology, detector
setup, or magnetic field arrangement. This goal is achieved through a
completely modular design. Fitting algorithms are implemented as
interchangeable modules. At present, the framework contains a validated Kalman
filter. Track parameterizations and the routines required to extrapolate the
track parameters and their covariance matrices through the experiment are also
implemented as interchangeable modules. Different track parameterizations and
extrapolation routines can be used simultaneously for fitting of the same
physical track. Representations of detector hits are the third modular
ingredient to the framework. The hit dimensionality and orientation of planar
tracking detectors are not restricted. Tracking information from detectors
which do not measure the passage of particles in a fixed physical detector
plane, e.g. drift chambers or TPCs, is used without any simplifications. The
concept is implemented in a light-weight C++ library called GENFIT, which is
available as free software
The QCD equation of state at finite density from analytical continuation
We determine the equation of state of QCD at finite chemical potential, to
order , for a system of 2+1 quark flavors. The simulations are
performed at the physical mass for the light and strange quarks on several
lattice spacings; the results are continuum extrapolated using lattices of up
to temporal resolution. The QCD pressure and interaction measure are
calculated along the isentropic trajectories in the plane
corresponding to the RHIC Beam Energy Scan collision energies. Their behavior
is determined through analytic continuation from imaginary chemical potentials
of the baryonic density. We also determine the Taylor expansion coefficients
around from the simulations at imaginary chemical potentials.
Strangeness neutrality and charge conservation are imposed, to match the
experimental conditions.Comment: 5 pages, 4 figure
Properties of nonaqueous electrolytes Sixth summary report, 20 Sep. 1967 - 19 Mar. 1968
Physical properties and structural studies on propylene carbonate, dimethyl formamide, and acetonitrile solvent electrolyte
Plasma Oscillations and Expansion of an Ultracold Neutral Plasma
We report the observation of plasma oscillations in an ultracold neutral
plasma. With this collective mode we probe the electron density distribution
and study the expansion of the plasma as a function of time. For classical
plasma conditions, i.e. weak Coulomb coupling, the expansion is dominated by
the pressure of the electron gas and is described by a hydrodynamic model.
Discrepancies between the model and observations at low temperature and high
density may be due to strong coupling of the electrons.Comment: 4 pages, 4 figures. Accepted Phys. Rev. Let
Fluctuations and correlations in high temperature QCD
We calculate second- and fourth-order cumulants of conserved charges in a temperature range stretching from the QCD transition region towards the realm of (resummed) perturbation theory. We perform lattice simulations with staggered quarks; the continuum extrapolation is based on Nt=10–24 in the crossover region and Nt=8–16 at higher temperatures. We find that the hadron resonance gas model predictions describe the lattice data rather well in the confined phase. At high temperatures (above ∼250 MeV) we find agreement with the three-loop hard thermal loop results
Scaling in a continuous time model for biological aging
In this paper we consider a generalization to the asexual version of the
Penna model for biological aging, where we take a continuous time limit. The
genotype associated to each individual is an interval of real numbers over
which Dirac --functions are defined, representing genetically
programmed diseases to be switched on at defined ages of the individual life.
We discuss two different continuous limits for the evolution equation and two
different mutation protocols, to be implemented during reproduction. Exact
stationary solutions are obtained and scaling properties are discussed.Comment: 10 pages, 6 figure
Phases in Strongly Coupled Electronic Bilayer Liquids
The strongly correlated liquid state of a bilayer of charged particles has
been studied via the HNC calculation of the two-body functions. We report the
first time emergence of a series of structural phases, identified through the
behavior of the two-body functions.Comment: 5 pages, RevTEX 3.0, 4 ps figures; Submitted to Phys. Rev. Let
Controllability and controller-observer design for a class of linear time-varying systems
“The final publication is available at Springer via http://dx.doi.org/10.1007/s10852-012-9212-6"In this paper a class of linear time-varying control systems is considered. The time variation consists of a scalar time-varying coefficient multiplying the state matrix of an otherwise time-invariant system. Under very weak assumptions of this coefficient, we show that the controllability can be assessed by an algebraic rank condition, Kalman canonical decomposition is possible, and we give a method for designing a linear state-feedback controller and Luenberger observer
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