849 research outputs found
Hamilton-Jacobi Formulation of the Thermodynamics of Einstein-Born-Infeld-AdS Black Holes
A Hamilton-Jacobi formalism for thermodynamics was formulated by Rajeev [Ann.
Phys. 323, 2265 (2008)] based on the contact structure of the odd dimensional
thermodynamic phase space. This allows one to derive the equations of state of
a family of substances by solving a Hamilton-Jacobi equation (HJE). In the same
work it was applied to chargeless non-rotating black holes, and the use of
Born-Infeld electromagnetism was proposed to apply it to charged black holes as
well. This paper fulfills this suggestion by deriving the HJE for charged
non-rotating black holes using Born-Infeld theory and a negative cosmological
constant. The most general solution of this HJE is found. It is shown that
there exists solutions which are distinct from the equations of state of the
Einstein-Born-Infeld-AdS black hole. The meaning of these solutions is
discussed.Comment: 5 pages, 2 figure
Deconfining Phase Transition in 2+1 D: the Georgi-Glashow Model
We analyze the finite temperature deconfining phase transition in 2+1
dimensional Georgi-Glashow model. We show explicitly that the transition is due
to the restoration of the magnetic symmetry and that it is in the Ising
universality class. We find that neglecting effects of the charged bosons
leads to incorrect predictions for the value of the critical temperature and
the universality class of the transition, as well as for various correlation
functions in the high temperature phase. We derive the effective action for the
Polyakov loop in the high temperature phase and calculate the correlation
functions of magnetic vortex operators.Comment: 26 pages, 1 figure, discussion about spatial Wilson loops added, to
appear in JHE
Topologically massive gravity as a Pais-Uhlenbeck oscillator
We give a detailed account of the free field spectrum and the Newtonian limit
of the linearized "massive" (Pauli-Fierz), "topologically massive"
(Einstein-Hilbert-Chern-Simons) gravity in 2+1 dimensions about a Minkowski
spacetime. For a certain ratio of the parameters, the linearized free theory is
Jordan-diagonalizable and reduces to a degenerate "Pais-Uhlenbeck" oscillator
which, despite being a higher derivative theory, is ghost-free.Comment: 9 pages, no figures, RevTEX4; version 2: a new paragraph and a
reference added to the Introduction, a new appendix added to review
Pais-Uhlenbeck oscillators; accepted for publication in Class. Quant. Gra
All unitary cubic curvature gravities in D dimensions
We construct all the unitary cubic curvature gravity theories built on the
contractions of the Riemann tensor in D -dimensional (anti)-de Sitter
spacetimes. Our construction is based on finding the equivalent quadratic
action for the general cubic curvature theory and imposing ghost and tachyon
freedom, which greatly simplifies the highly complicated problem of finding the
propagator of cubic curvature theories in constant curvature backgrounds. To
carry out the procedure we have also classified all the unitary quadratic
models. We use our general results to study the recently found cubic curvature
theories using different techniques and the string generated cubic curvature
gravity model. We also study the scattering in critical gravity and give its
cubic curvature extensions.Comment: 24 pages, 1 figure, v2: A subsection on cubic curvature extensions of
critical gravity is added, v3: The part regarding critical gravity is
revised. Version to appear in Class. Quant. Gra
Newtonian Counterparts of Spin 2 Massless Discontinuities
Massive spin 2 theories in flat or cosmological () backgrounds
are subject to discontinuities as the masses tend to zero. We show and explain
physically why their Newtonian limits do not inherit this behaviour. On the
other hand, conventional ``Newtonian cosmology'', where is a
constant source of the potential, displays discontinuities: e.g. for any finite
range, can be totally removed.Comment: 6 pages, amplifies the ``Newtonian cosmology'' analysis. To appear as
a Class. Quantum Grav. Lette
Two-Frequency Jahn-Teller Systems in Circuit QED
We investigate the simulation of Jahn-Teller models with two non-degenerate
vibrational modes using a circuit QED architecture. Typical Jahn-Teller systems
are anisotropic and require at least a two-frequency description. The proposed
simulator consists of two superconducting lumped-element resonators interacting
with a common flux qubit in the ultrastrong coupling regime. We translate the
circuit QED model of the system to a two-frequency Jahn-Teller Hamiltonian and
calculate its energy eigenvalues and the emission spectrum of the cavities. It
is shown that the system can be systematically tuned to an effective single
mode Hamiltonian from the two-mode model by varying the coupling strength
between the resonators. The flexibility in manipulating the parameters of the
circuit QED simulator permits isolating the effective single frequency and pure
two-frequency effects in the spectral response of Jahn-Teller systems.Comment: 8 pages, 4 figures, figures revise
Deconfinement at N>2: SU(N) Georgi-Glashow model in 2+1 dimensions
We analyse the deconfining phase transition in the SU(N) Georgi-Glashow model
in 2+1 dimensions. We show that the phase transition is second order for any N,
and the universality class is different from the Z(N) invariant Villain model.
At large N the conformal theory describing the fixed point is a deformed
SU(N)_1 WZNW model which has N-1 massless fields. It is therefore likely that
its self-dual infrared fixed point is described by the Fateev-Zamolodchikov
theory of Z(N) parafermions.Comment: 25 pages, Late
Instanton molecules at high temperature - the Georgi-Glashow model and beyond
We show that correlators of some local operators in gauge theories are
sensitive to the presence of the instantons even at high temperature where the
latter are bound into instanton-anti-instanton "molecules". We calculate
correlation functions of such operators in the deconfined phase of the 2+1
dimensional Georgi-Glashow model and discuss analogous quantities in the
chirally symmetric phase of QCD. We clarify the mechanism by which the
instanton-anti-instanton molecules contribute to the anomaly of axial U(1) at
high temperature.Comment: 23 pages, 4 figures, minor changes are mad
Turkey's geopolitical role: The energy angle
[No abstract available
Simulation optimization: A comprehensive review on theory and applications
For several decades, simulation has been used as a descriptive tool by the operations research community in the modeling and analysis of a wide variety of complex real systems. With recent developments in simulation optimization and advances in computing technology, it now becomes feasible to use simulation as a prescriptive tool in decision support systems. In this paper, we present a comprehensive survey on techniques for simulation optimization with emphasis given on recent developments. We classify the existing techniques according to problem characteristics such as shape of the response surface (global as compared to local optimization), objective functions (single or multiple objectives) and parameter spaces (discrete or continuous parameters). We discuss the major advantages and possible drawbacks of the different techniques. A comprehensive bibliography and future research directions are also provided in the paper. © "IIE"
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