708 research outputs found
On the Status of Highly Entropic Objects
It has been proposed that the entropy of any object must satisfy fundamental
(holographic or Bekenstein) bounds set by the object's size and perhaps its
energy. However, most discussions of these bounds have ignored the possibility
that objects violating the putative bounds could themselves become important
components of Hawking radiation. We show that this possibility cannot a priori
be neglected in existing derivations of the bounds. Thus this effect could
potentially invalidate these derivations; but it might also lead to
observational evidence for the bounds themselves.Comment: 6 pages, RevTex, a few editorial change
Duality of Quasilocal Gravitational Energy and Charges with Non-orthogonal Boundaries
We study the duality of quasilocal energy and charges with non-orthogonal
boundaries in the (2+1)-dimensional low-energy string theory. Quasilocal
quantities shown in the previous work and some new variables arisen from
considering the non-orthogonal boundaries as well are presented, and the boost
relations between those quantities are discussed. Moreover, we show that the
dual properties of quasilocal variables such as quasilocal energy density,
momentum densities, surface stress densities, dilaton pressure densities, and
Neuve-Schwarz(NS) charge density, are still valid in the moving observer's
frame.Comment: 19pages, 1figure, RevTe
A Note on Thermodynamics and Holography of Moving Giant Gravitons
In our previous work (Phys. Rev. D63, 085010, hep-th/0011290), we showed that
the brane universe on the giant graviton moving in the near-horizon background
of the dilatonic D(6-p)-brane is described by the mirage cosmology. We study
thermodynamic properties of the moving giant graviton by applying
thermodynamics of cosmology and the recently proposed holographic principles of
cosmology. We find that the Fischler-Susskind holographic bound is satisfied by
the closed brane universe on the moving giant graviton with p>3. The Bekenstein
and the Hubble entropy bounds and the recently proposed Verlinde's holographic
principle applied to the brane universe on the giant graviton are also studied.Comment: 13 pages, LaTeX, revised version to appear in Phys. Rev.
Effective superpotential for U(N) with antisymmetric matter
We consider an N=1 U(N) gauge theory with matter in the antisymmetric
representation and its conjugate, with a tree level superpotential containing
at least quartic interactions for these fields. We obtain the effective
glueball superpotential in the classically unbroken case, and show that it has
a non-trivial N-dependence which does not factorize. We also recover additional
contributions starting at order S^N from the dynamics of Sp(0) factors. This
can also be understood by a precise map of this theory to an Sp(2N-2) gauge
theory with antisymmetric matter.Comment: 22 pages. v2: comment (and a reference) added at the end of section 2
on low rank cases; minor typos corrected. v3: 2 footnotes added with
additional clarifications; version to appear in journa
Chiral field theories from conifolds
We discuss the geometric engineering and large n transition for an N=1 U(n)
chiral gauge theory with one adjoint, one conjugate symmetric, one
antisymmetric and eight fundamental chiral multiplets. Our IIB realization
involves an orientifold of a non-compact Calabi-Yau A_2 fibration, together
with D5-branes wrapping the exceptional curves of its resolution as well as the
orientifold fixed locus. We give a detailed discussion of this background and
of its relation to the Hanany-Witten realization of the same theory. In
particular, we argue that the T-duality relating the two constructions maps the
Z_2 orientifold of the Hanany-Witten realization into a Z_4 orientifold in type
IIB. We also discuss the related engineering of theories with SO/Sp gauge
groups and symmetric or antisymmetric matter.Comment: 34 pages, 8 figures, v2: References added, minor correction
Brane cosmology with an anisotropic bulk
In the context of brane cosmology, a scenario where our universe is a
3+1-dimensional surface (the ``brane'') embedded in a five-dimensional
spacetime (the ``bulk''), we study geometries for which the brane is
anisotropic - more specifically Bianchi I - though still homogeneous. We first
obtain explicit vacuum bulk solutions with anisotropic three-dimensional
spatial slices. The bulk is assumed to be empty but endowed with a negative
cosmological constant. We then embed Z_2-symmetric branes in the anisotropic
spacetimes and discuss the constraints on the brane energy-momentum tensor due
to the five-dimensional anisotropic geometry. We show that if the bulk is
static, an anisotropic brane cannot support a perfect fluid. However, we find
that for some of our bulk solutions it is possible to embed a brane with a
perfect fluid though its energy density and pressure are completely determined
by the bulk geometry.Comment: 20 pages, 1 figur
Holographic Coulomb branch vevs
We compute holographically the vevs of all chiral primary operators for
supergravity solutions corresponding to the Coulomb branch of N=4 SYM and find
exact agreement with the corresponding field theory computation. Using the
dictionary between 10d geometries and field theory developed to extract these
vevs, we propose a gravity dual of a half supersymmetric deformation of N=4 SYM
by certain irrelevant operators.Comment: 16 pages, v2 corrections in appendi
Finite gravitational action for higher derivative and stringy gravities
We generalize the local surface counterterm prescription suggested in
Einstein gravity for higher derivative (HD) and Weyl gravities. Explicitly, the
surface counterterm is found for three- and five-dimensional HD gravities. As a
result, the gravitational action for asymptotically AdS spaces is finite and
gravitational energy-momentum tensor is well-defined. The holographic trace
anomaly for d2 and d4 boundary (gauge) QFT dual to above HD gravity is
calculated from gravitational energy-momentum tensor. The calculation of AdS
black hole mass in HD gravity is presented within above prescrition. The
comparison with the standard prescription (using reference spacetime) is done.Comment: LaTeX file, 21 page
Toward a Quantization of Null Dust Collapse
Spherically symmetric, null dust clouds, like their time-like counterparts,
may collapse classically into black holes or naked singularities depending on
their initial conditions. We consider the Hamiltonian dynamics of the collapse
of an arbitrary distribution of null dust, expressed in terms of the physical
radius, , the null coordinates, for a collapsing cloud or for an
expanding cloud, the mass function, , of the null matter, and their
conjugate momenta. This description is obtained from the ADM description by a
Kucha\v{r}-type canonical transformation. The constraints are linear in the
canonical momenta and Dirac's constraint quantization program is implemented.
Explicit solutions the constraints are obtained for both expanding and
contracting null dust clouds with arbitrary mass functions.Comment: 10 pages, 2 figures (eps), RevTeX4. The last two sections have been
revised and corrected. To appear in Phys. Rev.
Partition functions and elliptic genera from supergravity
We develop the spacetime aspects of the computation of partition functions
for string/M-theory on AdS(3) xM. Subleading corrections to the semi-classical
result are included systematically, laying the groundwork for comparison with
CFT partition functions via the AdS(3)/CFT(2) correspondence. This leads to a
better understanding of the "Farey tail" expansion of Dijkgraaf et. al. from
the point of view of bulk physics. Besides clarifying various issues, we also
extend the analysis to the N=2 setting with higher derivative effects included.Comment: 34 page
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