891 research outputs found
Discrete Flux as Quantum Hair
We investigate Yang-Mills theory on a spatial torus at finite temperature in
the presence of discrete electric and magnetic fluxes using the AdS/CFT
correspondence. We calculate the leading dependence of the partition function
on the fluxes using the dual supergravity theory and comment upon the
interpretation of these fluxes as discrete quantum hair for black holes in AdS
spacetime.Comment: 15 pages, LaTex, no figure
Nonrenormalization of Mass of Some Nonsupersymmetric String States
It is argued that the quantum correction to the mass of some very massive,
nonsupersymmetric states vanishes in inverse proportion to their tree-level
mass to all orders in string loops. This approximate nonrenormalization can
explain the agreement between the perturbative degeneracy of these states and
the Sen entropy of the associated black holes.Comment: Additional details provided, in particular, of the analytic
continuation of the two point function. Discussion of higher loops
substantially amplified. References added, conclusions unchanged; 19 pages,
harvma
Higher Derivative Corrections, Dimensional Reduction and Ehlers Duality
Motivated by applications to black hole physics and duality, we study the
effect of higher derivative corrections on the dimensional reduction of
four-dimensional Einstein, Einstein Liouville and Einstein-Maxwell gravity to
one direction, as appropriate for stationary, spherically symmetric solutions.
We construct a field redefinition scheme such that the one-dimensional
Lagrangian is corrected only by powers of first derivatives of the fields,
eliminating spurious modes and providing a suitable starting point for
quantization. We show that the Ehlers symmetry, broken by the leading
corrections in Einstein-Liouville gravity, can be restored by including
contributions of Taub-NUT instantons. Finally, we give a preliminary discussion
of the duality between higher-derivative F-term corrections on the vector and
hypermultiplet branches in N=2 supergravity in four dimensions.Comment: 21 pages, uses JHEP3.cls; v3: minor corrections, final version
published in JHE
Two Centered Black Holes and N=4 Dyon Spectrum
The exact spectrum of dyons in a class of N=4 supersymmetric string theories
is known to change discontinuously across walls of marginal stability. We show
that the change in the degeneracy across the walls of marginal stability can be
accounted for precisely by the entropy of two centered small black holes which
disappear as we cross the walls of marginal stability.Comment: LaTeX file, 12 pages; v3: added footnote 2 regarding overall sign of
the index, expanded footnote 3, added reference
Adding Charges to N=4 Dyons
The spectrum of dyons in a class of N=4 supersymmetric string theories has
been found for a specific set of electric and magnetic charge vectors. We
extend the analysis to more general charge vectors by considering various
charge carrying collective excitations of the original system.Comment: LaTeX file, 16 page
Fundamental Superstrings as Holograms
The worldsheet of a macroscopic fundamental superstring in the Green-Schwarz
light-cone gauge is viewed as a possible boundary hologram of the near horizon
region of a small black string. For toroidally compactified strings, the
hologram has global symmetries of AdS_3 \times S^{d-1} \times T^{8-d}, (d
=3,..,8), only some of which extend to local conformal symmetries. We construct
the bulk string theory in detail for the particular case of d=3. The symmetries
of the hologram are correctly reproduced from this exact worldsheet description
in the bulk. Moreover, the central charge of the boundary Virasoro algebra
obtained from the bulk agrees with the Wald entropy of the associated small
black holes. This construction provides an exact CFT description of the near
horizon region of small black holes both in Type-II and heterotic string theory
arising from multiply wound fundamental superstrings.Comment: 46 pages, JHEP style. v2: Comments, references adde
Synthesis and antimicrobial activities of novel 1,4-benzothiazine derivatives
AbstractA series of 2H,4H-2-[3,5-dimethyl-4-(substituted) phenyl azo pyrazol-1-yl] carbonyl methyl-3-oxo-1,4-benzothiazine derivatives have been synthesized by the reaction of 2H,4H-2-hydrazino carbonyl methyl-3-oxo-1,4-benzothiazine with acetyl acetone derivatives using ultrasound in lesser time with higher yields. All the synthesized compounds were investigated for their antibacterial activities. The result indicated that the compounds show convincing activities against Gram-positive bacteria (Bacillus subtilis and Streptococcus lactis) when compared with standard drug (ampicillin trihydrate). These compounds were also synthesized by conventional method and their structures have been elucidated on the basis of spectral analyses and chemical reactions
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