10,112 research outputs found
Which quantum states are dual to classical spacetimes?
It is commonly accepted that states in a conformal field theory correspond to
classical spacetimes with Anti-de-Sitter asymptotics. In this work we give a
prescription for the CFT states with a dual classical spacetime and, using
basic holographic rules, show that they are holographically connected to
coherent states in the large-N limit, or by considering linearized
perturbations. We also point out implications in the spacetime emergence
mechanism, for instance, the (entangled) state dual to the black hole should be
properly described as a quantum superposition of products of these states. This
also complements the quantum interpretation of the Hawking-Page transition.Comment: 14 pages, 8 figure
TFD Extension of Open String Field Theory
We study the application of the rules of Thermo Field Dynamics (TFD) to the
covariant formulation of Open String Field Theory (OSFT). We extend the states
space and fields according to the duplication rules of TFD and construct the
corresponding classical action. The result is interpreted as a theory whose
fields would encode the statistical information of open strings.
The physical spectrum of the free theory is studied through the cohomology of
the extended BRST charge, and, as a result, we get new fields in the spectrum
emerging by virtue of the quantum entanglement and, noticeably, it presents
degrees of freedom that could be identified as those of closed strings. We also
show, however, that their appearing in the action is directly related to the
choice of the inner product in the extended algebra, so that different sectors
of fields could be eliminated from the theory by choosing that product
conveniently.
Finally, we study the extension of the three-vertex interaction and provide a
simple prescription for it whose results at tree-level agree with those of the
conventional theory.Comment: 25 pages, no figures. File format, typos, Abstract and references
modified. New subsection and concluding comments were added. To appear in
Phys. Rev.
On the relation between the propagators of dual theories
In this paper, we show that the propagator of the dual of a general
Proca-like theory, derived from the gauging iterative Noether Dualization
Method, can be written by means of a simple relation between known propagators.
This result is also a demonstration that the Lagrangian obtained by dualization
describes the same physical particles as the ones present in the original
theory at the expense of introducing new non-physical (ghosts) excitations.Comment: latex, 4 page
Mirror symmetry breaking as a problem in dynamical critical phenomena
The critical properties of the Frank model of spontaneous chiral synthesis
are discussed by applying results from the field theoretic renormalization
group (RG). The long time and long wavelength features of this microscopic
reaction scheme belong to the same universality class as multi-colored directed
percolation processes. Thus, the following RG fixed points (FP) govern the
critical dynamics of the Frank model for d<4: one unstable FP that corresponds
to complete decoupling between the two enantiomers, a saddle-point that
corresponds to symmetric interspecies coupling, and two stable FPs that
individually correspond to unidirectional couplings between the two chiral
molecules. These latter two FPs are associated with the breakdown of mirror or
chiral symmetry. In this simplified model of molecular synthesis, homochirality
is a natural consequence of the intrinsic reaction noise in the critical
regime, which corresponds to extremely dilute chemical systems.Comment: 9 pages, 3 figure
Bosonization and Duality in Arbitrary Dimensions: New Results
A generic massive Thirring Model in three space-time dimensions exhibits a
correspondence with a topologically massive bosonized gauge action associated
to a self-duality constraint, and we write down a general expression for this
relationship.
We also generalize this structure to dimensions, by adopting the
so-called doublet approach, recently introduced. In particular, a non-
conventional formulation of the bosonization technique in higher dimensions (in
the spirit of ), is proposed and, as an application, we show how fermionic
(Thirring-like) representations for bosonic topologically massive models in
four dimensions may be built up.Comment: Revised version, to appear in Phys. Rev.
Basalt/polypropylene composites: The effects of mechanical reprocessing on their morphological, thermal, rheological and mechanical behavior
Considering the increasing spread of basalt fibers on the market as bio-based alternative to glass and the massive use of polypropylene (PP) in the automotive sector, the end-of-life of PP/basalt composites through mechanical reprocessing was addressed. Their thermal, rheological and mechanical properties were investigated up to seven reprocessing cycles and the main relationship between their changes and composites fibers length reduction was disclosed. The composites displayed a parabolic increase in their melt volume rate for increasing reprocessing cycles and were characterized by an improved flowability compared to the neat matrix at the fifth cycle, i.e., 89.3 against 74.8 cm3/10min, due to the intimate contact between the fibers and the matrix which causes a stronger degradation in PP molecular weight. Concerning the mechanical response, the logarithmic decrease in stiffness and strength was not directly proportional to fibers length reduction due to a progressive better orientation of the fibers along the injection direction. Finally, the comparison of the mechanical results obtained with the data available for PP composites reinforced with vegetable fibers allowed to conclude that PP/basalt composites are competitive with this type of composites up to the fifth cycle, displaying a tensile modulus of 3.5 GPa and tensile strength of 38 MPa
Extension of finite volume compressible flow solvers to multidimensional, variable density zero Mach number flows
When attempting to compute unsteady, variable density flows at very small or zero Mach number using a standard finite volume compressible flow solver one faces at least the following difficulties: (i) Spatial pressure variations vanish as the Mach number
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