1,431 research outputs found
tt* Geometry and Closed String Tachyon Potential
We propose a closed string tachyon action including kinetic and potential
terms for non-supersymmetric orbifolds. The action is given in terms of
solutions to equations which captures the geometry of vacua of the
corresponding N=2 worldsheet theory. In certain cases the solutions are well
studied. In case of tachyons of , solutions to affine toda
equations determine the action. We study the particular case of in detail and find that the Tachyon action is determined in terms of a
solution to Painleve III equation.Comment: 10 page
Tachyon Condensation with B-field
We discuss classical solutions of a graviton-dilaton-B_{\mu\nu}-tachyon
system. Both constant tachyon solutions, including AdS_3 solutions, and
space-dependent tachyon solutions are investigated, and their possible
implications to closed string tachyon condensation are argued. The stability
issue of the AdS_3 solutions is also discussed.Comment: 10 pages, references adde
Tachyons in Compact Spaces
We discuss condensations of closed string tachyons localized in compact
spaces. Time evolution of an on-shell condensation is naturally related to the
worldsheet RG flow. Some explicit tachyonic compactifications of Type II string
theory is considered, and some of them are shown to decay into supersymmetric
theories known as the little string theories.Comment: 14 page
Identification of attenuation and antitermination regulation in prokaryotes
Many operons of biochemical pathways in bacterial genomes are regulated by processes called attenuation and antitermination. Though the specific mechanism can be quite different, attenuation and antitermination in these operons have in common the termination of transcription by a RNA 'terminator' fold upstream of the first gene in the operon. In the past, detecting regulation by attenuation or antitermination has often been a long process of experimental trial and error, on a case by case basis. We report here the prediction of over 290 upstream regions of genes with attenuation or antitermination regulation structures in the completed genomes of Bacillis subtilis and Escherichia coli for which extensive experimental studies have been done on attenuation and antitermination regulation. These predictions are based on a computational method devised from characteristics of known terminator fold candidates and benchmark regions of entire genomes. We extend this methodology to 24 additional complete genomes and are thus able to give a more complete picture of attenuation and antitermination regulation in bacteria
Notes on the Hamiltonian formulation of 3D Yang-Mills theory
Three-dimensional Yang-Mills theory is investigated in the Hamiltonian
formalism based on the Karabali-Nair variable. A new algorithm is developed to
obtain the renormalized Hamiltonian by identifying local counterterms in
Lagrangian with the use of fictitious holomorphic symmetry existing in the
framework with the KN variable. Our algorithm is totally algebraic and enables
one to calculate the ground state wave functional recursively in gauge
potentials. In particular, the Gaussian part thus calculated is shown to
coincide with that obtained by Leigh et al. Higher-order corrections to the
Gaussian part are also discussed.Comment: 26 pages, LaTeX; discussions on IR regulators and local counterterms
improved, references adde
Association of Over-The-Counter Pharmaceutical Sales with Influenza-Like-Illnesses to Patient Volume in an Urgent Care Setting
We studied the association between OTC pharmaceutical sales and volume of patients with influenza-like-illnesses (ILI) at an urgent care center over one year. OTC pharmaceutical sales explain 36% of the variance in the patient volume, and each standard deviation increase is associated with 4.7 more patient visits to the urgent care center (p<0.0001). Cross-correlation function analysis demonstrated that OTC pharmaceutical sales are significantly associated with patient volume during non-flu season (p<0.0001), but only the sales of cough and cold (p<0.0001) and thermometer (p<0.0001) categories were significant during flu season with a lag of two and one days, respectively. Our study is the first study to demonstrate and measure the relationship between OTC pharmaceutical sales and urgent care center patient volume, and presents strong evidence that OTC sales predict urgent care center patient volume year round. © 2013 Liu et al
Megabits secure key rate quantum key distribution
Quantum cryptography (QC) can provide unconditional secure communication
between two authorized parties based on the basic principles of quantum
mechanics. However, imperfect practical conditions limit its transmission
distance and communication speed. Here we implemented the differential phase
shift (DPS) quantum key distribution (QKD) with up-conversion assisted hybrid
photon detector (HPD) and achieved 1.3 M bits per second secure key rate over a
10-km fiber, which is tolerant against the photon number splitting (PNS)
attack, general collective attacks on individual photons, and any other known
sequential unambiguous state discrimination (USD) attacks.Comment: 14 pages, 4 figure
Closed String Tachyons and Semi-Classical Instabilities
We conjecture that the end point of bulk closed string tachyon decay at any
non-zero coupling, is the annihilation of space time by Witten's bubble of
nothing, resulting in a topological phase of the theory. In support of this we
present a variety of situations in which there is a correspondence between the
existence of perturbative tachyons in one regime and the semi-classical
annihilation of space-time. Our discussion will include many recently
investigated scenarios in string theory including Scherk-Schwarz
compactifications, Melvin magnetic backgrounds, and noncompact orbifolds. We
use this conjecture to investigate a possible web of dualities relating the
eleven-dimensional Fabinger-Horava background with nonsupersymmetric string
theories. Along the way we point out where our conjecture resolves some of the
puzzles associated with bulk closed string tachyon condensation.Comment: 31 pages, 5 figures 3 figures added, typos corrected and references
added. Discussion of Type 0/Heterotic s-duality extended and some other
points clarified Revision of discussion on Fabinger-Horava string
descendents, section on Scherk-Schwarz compactification of Horava-Witten
removed, some references adde
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