10,594 research outputs found
On the space of quantum fields in massive two-dimensional theories
For a large class of integrable quantum field theories we show that the
S-matrix determines a space of fields which decomposes into subspaces labeled,
besides the charge and spin indices, by an integer k. For scalar fields k is
non-negative and is naturally identified as an off-critical extension of the
conformal level. To each particle we associate an operator acting in the space
of fields whose eigenvectors are primary (k=0) fields of the massive theory. We
discuss how the existing results for models as different as Z_n, sine-Gordon or
Ising with magnetic field fit into this classification.Comment: 17 page
Stationary Black Holes in Supergravity: The Issue of Real Nilpotent Orbits
The complete classification of the nilpotent orbits of in
the representation , achieved in \cite{Dietrich:2016ojx}, is
applied to the study of multi-center, asymptotically flat, extremal black hole
solutions to the STU model. These real orbits provide an intrinsic
characterization of regular single-center solutions, which is invariant with
respect to the action of the global symmetry group , underlying
the stationary solutions of the model, and provide stringent regularity
constraints on multi-centered solutions. The known \emph{almost-BPS} and
\emph{composite non-BPS} solutions are revisited in this setting. We
systematically provide, for the relevant -nilpotent orbits of
the global Noether charge matrix, regular representatives thereof. This
analysis unveils a composition law of the orbits according to which those
containing regular multi-centered solutions can be obtained as combinations of
specific single-center orbits defining the constituent black holes. Some of the
-orbits of the total Noether charge matrix are characterized
as "intrinsically singular" in that they cannot contain any regular solution.Comment: 104 pages, LaTeX source and 29 figure
Holography of charged dilatonic black branes at finite temperature
We investigate bulk and holographic features of finite-temperature black
brane solutions of 4D anti-de Sitter Einstein-Maxwell-dilaton-gravity (EMDG).
We construct, numerically, black branes endowed with non trivial scalar hairs
for broad classes of EMDG. We consider both exponential and power-law forms for
the coupling functions, as well as several charge configurations: purely
electric, purely magnetic and dyonic solutions. At finite temperature the field
theory holographically dual to these black brane solutions has a rich and
interesting phenomenology reminiscent of electron motion in metals: phase
transitions triggered by nonvanishing VEV of scalar operators, non-monotonic
behavior of the electric conductivities as function of the frequency and of the
temperature, Hall effect and sharp synchrotron resonances of the conductivity
in presence of a magnetic field. Conversely, in the zero temperature limit the
conductivities for these models show a universal behavior. The optical
conductivity has a power-law behavior as a function of the frequency, whereas
the DC conductivity is suppressed at small temperatures.Comment: 29 pages 14 figures, typos corrected, reference adde
Stationary Black Holes: Uniqueness and Beyond
The spectrum of known black-hole solutions to the stationary Einstein
equations has been steadily increasing, sometimes in unexpected ways. In
particular, it has turned out that not all black-hole-equilibrium
configurations are characterized by their mass, angular momentum and global
charges. Moreover, the high degree of symmetry displayed by vacuum and
electro-vacuum black-hole spacetimes ceases to exist in self-gravitating
non-linear field theories. This text aims to review some developments in the
subject and to discuss them in light of the uniqueness theorem for the
Einstein-Maxwell system.Comment: Major update of the original version by Markus Heusler from 1998.
Piotr T. Chru\'sciel and Jo\~ao Lopes Costa succeeded to this review's
authorship. Significantly restructured and updated all sections; changes are
too numerous to be usefully described here. The number of references
increased from 186 to 32
Can type II Semi-local cosmic strings form?
We present the simplest possible model for a semi-local string defect in
which a U(1) gauged subgroup of an otherwise global SU(2) is broken to produce
local cosmic strings endowed with current-carrying properties. Restricting
attention to type II vortices for which the non current-carrying state is
unstable, we show that a condensate must form microscopically and
macroscopically evolve towards a chiral configuration. It has been suggested
that such configurations could potentially exist in a stable state, thereby
inducing large cosmological consequences based on equilibrium angular momentum
supported loop configurations (vortons). Here we show that the current itself
induces a macroscopic (longitudinal) instability: we conclude that type II
semi-local cosmic strings cannot form in a cosmological context.Comment: 11 pages, 5 figure
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