2,759 research outputs found
Deformations of Multiparameter Quantum gl(N)
Multiparameter quantum gl(N) is not a rigid structure. This paper defines an
essential deformation as one that cannot be interpreted in terms of a
similarity transformation, nor as a perturbation of the parameters. All the
equivalence classes of first order essential deformations are found, as well as
a class of exact deformations. This work provides quantization of all the
classical Lie bialgebra structures (constant r-matrices) found by Belavin and
Drinfeld for sl(n). A special case, that requires the Hecke parameter to be a
cubic root of unity, stands out.Comment: 15 pages. Plain Te
Quasilocalized gravity without asymptotic flatness
We present a toy model of a generic five-dimensional warped geometry in which
the 4D graviton is not fully localized on the brane. Studying the tensor sector
of metric perturbation around this background, we find that its contribution to
the effective gravitational potential is of 4D type (1/r) at the intermediate
scales and that at the large scales it becomes 1/r^{1+alpha}, 0<alpha=< 1 being
a function of the parameters of the model (alpha=1 corresponds to the
asymptotically flat geometry). Large-distance behavior of the potential is
therefore not necessarily five-dimensional. Our analysis applies also to the
case of quasilocalized massless particles other than graviton.Comment: 9 pages, 1 figure; to be published in Phys. Rev.
A General SU(2) Formulation for Quantum Searching with Certainty
A general quantum search algorithm with arbitrary unitary transformations and
an arbitrary initial state is considered in this work. To serach a marked state
with certainty, we have derived, using an SU(2) representation: (1) the
matching condition relating the phase rotations in the algorithm, (2) a concise
formula for evaluating the required number of iterations for the search, and
(3) the final state after the search, with a phase angle in its amplitude of
unity modulus. Moreover, the optimal choices and modifications of the phase
angles in the Grover kernel is also studied.Comment: 8 pages, 2 figure
Comparative pan-genome analysis of Piscirickettsia salmonis reveals genomic divergences within genogroups
Indexación: Scopus.Piscirickettsia salmonis is the etiological agent of salmonid rickettsial septicemia, a disease that seriously affects the salmonid industry. Despite efforts to genomically characterize P. salmonis, functional information on the life cycle, pathogenesis mechanisms, diagnosis, treatment, and control of this fish pathogen remain lacking. To address this knowledge gap, the present study conducted an in silico pan-genome analysis of 19 P. salmonis strains from distinct geographic locations and genogroups. Results revealed an expected open pan-genome of 3,463 genes and a core-genome of 1,732 genes. Two marked genogroups were identified, as confirmed by phylogenetic and phylogenomic relationships to the LF-89 and EM-90 reference strains, as well as by assessments of genomic structures. Different structural configurations were found for the six identified copies of the ribosomal operon in the P. salmonis genome, indicating translocation throughout the genetic material. Chromosomal divergences in genomic localization and quantity of genetic cassettes were also found for the Dot/Icm type IVB secretion system. To determine divergences between core-genomes, additional pan-genome descriptions were compiled for the so-termed LF and EM genogroups. Open pan-genomes composed of 2,924 and 2,778 genes and core-genomes composed of 2,170 and 2,228 genes were respectively found for the LF and EM genogroups. The core-genomes were functionally annotated using the Gene Ontology, KEGG, and Virulence Factor databases, revealing the presence of several shared groups of genes related to basic function of intracellular survival and bacterial pathogenesis. Additionally, the specific pan-genomes for the LF and EM genogroups were defined, resulting in the identification of 148 and 273 exclusive proteins, respectively. Notably, specific virulence factors linked to adherence, colonization, invasion factors, and endotoxins were established. The obtained data suggest that these genes could be directly associated with inter-genogroup differences in pathogenesis and host-pathogen interactions, information that could be useful in designing novel strategies for diagnosing and controlling P. salmonis infection. © 2017 Nourdin-Galindo, Sánchez, Molina, Espinoza-Rojas, Oliver, Ruiz, Vargas-Chacoff, Cárcamo, Figueroa, Mancilla, Maracaja-Coutinho and Yañez.https://www.frontiersin.org/articles/10.3389/fcimb.2017.00459/ful
Quantum thermodynamics: thermodynamics at the nanoscale
A short introduction on quantum thermodynamics is given and three new topics
are discussed: 1) Maximal work extraction from a finite quantum system. The
thermodynamic prediction fails and a new, general result is derived, the
``ergotropy''. 2) In work extraction from two-temperature setups, the presence
of correlations can push the effective efficiency beyond the Carnot bound. 3)
In the presence of level crossing, non-slow changes may be more optimal than
slow ones.Comment: 5 pages. Talk given at Physics of Quantum Electronics (PQE2004),
Snowbird, by Th.M. Nieuwenhuize
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The latest (version 4.3) Mars Climate Database
Introduction: The Mars Climate Database (MCD) is a database of meteorological fields derived from General Circulation Model (GCM) numerical simulations of the Martian atmosphere and validated using available observational data. The MCD includes complementary post-processing schemes such as high spatial resolution interpolation of environmental data and means of reconstructing the variability thereof. The GCM is developed at Laboratoire de Météorologie Dynamique du CNRS (Paris, France) [1,2] in collaboration with the Open University (UK), the Oxford University (UK) and the Instituto de Astrofisica de Andalucia (Spain) with support from the European Space Agency (ESA) and the Centre National
d'Etudes Spatiales (CNES)
Hilbert space of wormholes
Wormhole boundary conditions for the Wheeler--DeWitt equation can be derived
from the path integral formulation. It is proposed that the wormhole wave
function must be square integrable in the maximal analytic extension of
minisuperspace. Quantum wormholes can be invested with a Hilbert space
structure, the inner product being naturally induced by the minisuperspace
metric, in which the Wheeler--DeWitt operator is essentially self--adjoint.
This provides us with a kind of probabilistic interpretation. In particular,
giant wormholes will give extremely small contributions to any wormhole state.
We also study the whole spectrum of the Wheeler--DeWitt operator and its role
in the calculation of Green's functions and effective low energy interactions.Comment: 23 pages, 2 figures available upon request, REVTE
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