206 research outputs found

### Brane polarization is no cure for tachyons

Anti-M2 and anti-D3 branes placed in regions with charges dissolved in fluxes
have a tachyon in their near-horizon region, which causes these branes to repel
each other. If the branes are on the Coulomb branch this tachyon gives rise to
a runaway behavior, but when the branes are polarized into five-branes this
tachyon only appears to lower the energy of the polarized branes, without
affecting its stability. We analyze brane polarization in the presence of a
brane-brane-repelling tachyon and show that when the branes are polarized along
the direction of the tachyon the polarized shell is unstable. This implies that
tachyons cannot be cured by brane polarization and indicates that, at least in
a certain regime of parameters, anti-D3 branes polarized into NS5 branes at the
bottom of the Klebanov-Strassler solution have an instability.Comment: 10 pages, 1 figure, JHEP styl

### The polarization of M5 branes and little string theories with reduced supersymmetry

We construct an M-theory dual of a 6 dimensional little string theory with
reduced supersymmetry, along the lines of Polchinski and Strassler. We find
that upon perturbing the (2,0) theory with an R-current, the M5 branes polarize
into a wrapped Kaluza Klein monopole, whose isometry direction is along the R
current. We investigate the properties of this theory.Comment: 22 pages, late

### On the stability of the Quantum Hall soliton

In this note we investigate the stability of the classical ground state of
the Quantum Hall Soliton proposed recently in hep-th/0010105 . We explore two
possible perturbations which are not spherically symmetric and we find that the
potential energy decreases in both case. This implies that the system either
decays or is dynamically stabilized (because of the presence of magnetic
fields). If one makes an extra assumption that in the real quantum treatment of
the problem string ends and D0 branes move together (as electrons and vortices
in the Quantum Hall effect), a static equilibrium configuration is possible.Comment: 14 pages, 2 figures, LaTeX. Extra chapter added on a possible
dynamical stabilization is added following comments by L. Susskin

### Instabilities of microstate geometries with antibranes

One can obtain very large classes of horizonless microstate geometries
corresponding to near-extremal black holes by placing probe supertubes whose
action has metastable minima inside certain supersymmetric bubbling solutions.
We show that these minima can lower their energy when the bubbles move in
certain directions in the moduli space, which implies that these near-extremal
microstates are in fact unstable once one considers the dynamics of all their
degrees of freedom. The decay of these solutions corresponds to Hawking
radiation, and we compare the emission rate and frequency to those of the
corresponding black hole. Our analysis supports the expectation that generic
non-extremal black holes microstate geometries should be unstable. It also
establishes the existence of a new type of instabilities for antibranes in
highly-warped regions with charge dissolved in fluxes.Comment: 24 pages, 4 figure

### The Foaming Three-Charge Black Hole

We find a very large set of smooth horizonless geometries that have the same
charges and angular momenta as the five-dimensional, maximally-spinning,
three-charge, BPS black hole (J^2 = Q^3). Our solutions are constructed using a
four-dimensional Gibbons-Hawking base space that has a very large number of
two-cycles. The entropy of our solutions is proportional to Q^(1/2). In the
same class of solutions we also find microstates corresponding to zero-entropy
black rings, and these are related to the microstates of the black hole by
continuous deformations.Comment: 14 pages, harvma

### Regular 3-charge 4D black holes and their microscopic description

The perturbative $\alpha^{\prime}$ corrections to Type-IIA String Theory
compactified on a Calabi-Yau three-fold allow the construction of regular
three-charge supersymmetric black holes in four dimensions, whose entropy
scales with the charges as $S \sim \left( p^1 p^2 p^3\right)^{\frac{2}{3}}$.
We construct an M-theory uplift of these quantum black holes and show that they
can be interpreted as arising from three stacks of M2 branes on a conical
singularity. This in turns allow us relate them via a series of dualities to a
system of D3 branes carrying momentum and thus to give a microscopic
interpretation of their entropy.Comment: 20 pages, LaTe

### The propagator for a general form field in $AdS_{d+1}$

Using the known propagator equations for 0,1 and 2 forms in AdS_{d+1}, we
find the p-form field propagator equations in dimensions where the forms are
Poincare dual. Since the general equation obeyed by the propagators is linear
in dimension, this gives us the equation obeyed by the propagators for any d.
Furthermore, based on the Poincare duality formulas for 0,1,2 and 3 forms we
conjecture the general form of the Poincare duality formulas, and check them
against the previously found propagator equations. The whole structure is
self-consistent. Once we have the equations, we can easily obtain all the
p-form field propagators in AdS_{d+1}. The generalization to massive p-forms
can also be easily done.Comment: Extra chapter added on massive p-forms. 10 pages, REVTE

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