17,091 research outputs found
T-matrix formulation of real-space dynamical mean-field theory and the Friedel sum rule for correlated lattice fermions
We formulate real-space dynamical mean-field theory within scattering theory.
Thereby the Friedel sum rule is derived for interacting lattice fermions at
zero temperature.Comment: 7 pages, no figures, extended and corrected versio
Non-Zero Sum Games for Reactive Synthesis
In this invited contribution, we summarize new solution concepts useful for
the synthesis of reactive systems that we have introduced in several recent
publications. These solution concepts are developed in the context of non-zero
sum games played on graphs. They are part of the contributions obtained in the
inVEST project funded by the European Research Council.Comment: LATA'16 invited pape
Probing dense matter in neutron stars with axial w-modes
We study the problem of extracting information about composition and equation
of state of dense matter in neutron star interior using axial w-modes. We
determine complex frequencies of axial w-modes for a set of equations of state
involving hyperons as well as Bose-Einstein condensates of antikaons adopting
the continued fraction method. Hyperons and antikaon condensates result in
softer equations of state leading to higher frequencies of first axial w-modes
than that of nuclear matter case, whereas the opposite happens in case of
damping times. The presence of condensates may lead to the appearance of a new
stable branch of superdense stars beyond the neutron star branch called the
third family. The existence of same mass compact stars in both branches are
known as neutron star twins. Further investigation of twins reveal that first
axial w-mode frequencies of superdense stars in the third family are higher
than those of the corresponding twins in the neutron star branch.Comment: LaTeX; 23 pages including two tables and 11 figure
Kaluza-Klein solitons reexamined
In (4 + 1) gravity the assumption that the five-dimensional metric is
independent of the fifth coordinate authorizes the extra dimension to be either
spacelike or timelike. As a consequence of this, the time coordinate and the
extra coordinate are interchangeable, which in turn allows the conception of
different scenarios in 4D from a single solution in 5D. In this paper, we make
a thorough investigation of all possible 4D scenarios, associated with this
interchange, for the well-known Kramer-Gross-Perry-Davidson-Owen set of
solutions. We show that there are {\it three} families of solutions with very
distinct geometrical and physical properties. They correspond to different sets
of values of the parameters which characterize the solutions in 5D. The
solutions of physical interest are identified on the basis of physical
requirements on the induced-matter in 4D. We find that only one family
satisfies these requirements; the other two violate the positivity of
mass-energy density. The "physical" solutions possess a lightlike singularity
which coincides with the horizon. The Schwarzschild black string solution as
well as the zero moment dipole solution of Gross and Perry are obtained in
different limits. These are analyzed in the context of Lake's geometrical
approach. We demonstrate that the parameters of the solutions in 5D are not
free, as previously considered. Instead, they are totally determined by
measurements in 4D. Namely, by the surface gravitational potential of the
astrophysical phenomena, like the Sun or other stars, modeled in Kaluza-Klein
theory. This is an important result which may help in observations for an
experimental/observational test of the theory.Comment: In V2 we include an Appendix, where we examine the conformal
approach. Minor changes at the beginning of section 2. In V3 more references
are added. Minor editorial changes in the Introduction and Conclusions
section
Phase transitions in Ising model on a Euclidean network
A one dimensional network on which there are long range bonds at lattice
distances with the probability has been taken
under consideration. We investigate the critical behavior of the Ising model on
such a network where spins interact with these extra neighbours apart from
their nearest neighbours for . It is observed that there is
a finite temperature phase transition in the entire range. For , finite size scaling behaviour of various quantities are consistent with
mean field exponents while for , the exponents depend on
. The results are discussed in the context of earlier observations on
the topology of the underlying network.Comment: 7 pages, revtex4, 7 figures; to appear in Physical Review E, minor
changes mad
Games on graphs with a public signal monitoring
We study pure Nash equilibria in games on graphs with an imperfect monitoring
based on a public signal. In such games, deviations and players responsible for
those deviations can be hard to detect and track. We propose a generic
epistemic game abstraction, which conveniently allows to represent the
knowledge of the players about these deviations, and give a characterization of
Nash equilibria in terms of winning strategies in the abstraction. We then use
the abstraction to develop algorithms for some payoff functions.Comment: 28 page
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