2,139 research outputs found
Exactly Marginal Deformations of N=4 SYM and of its Supersymmetric Orbifold Descendants
In this paper we study exactly marginal deformations of field theories living
on D3-branes at low energies. These theories include N=4 supersymmetric
Yang-Mills theory and theories obtained from it via the orbifolding procedure.
We restrict ourselves only to orbifolds and deformations which leave some
supersymmetry unbroken. A number of new families of N=1 superconformal field
theories are found. We analyze the deformations perturbatively, and also by
using general arguments for the dimension of the space of exactly marginal
deformations. We find some cases where the space of perturbative exactly
marginal deformations is smaller than the prediction of the general analysis at
least up to three-loop order), and other cases where the perturbative result
(at low orders) has a non-generic form.Comment: 25 pages, 1 figure. v2: added preprint number, references adde
A Note on Softly Broken MQCD
We consider generic MQCD configurations with matter described by semi-infinte
D4-branes and softly broken supersymmetry. We show that the matter sector does
not introduce supersymmetry breaking parameters so that the most relevant
supersymmetry breaking operator at low energies is the gaugino mass term. By
studying the run-away properties of these models in the decoupling limit of the
adjoint matter, we argue that these softly broken MQCD configurations fail to
capture the infrared physics of QCD at scales below the gaugino mass scale.Comment: 10+1 pages, TeX. V2: small comments and acknowledgements added,
conclusions unchange
Decoding the matrix: Coincident membranes on the plane wave
At the core of nonperturbative theories of quantum gravity lies the
holographic encoding of bulk data in large matrices. At present this mapping is
poorly understood. The plane wave matrix model provides a laboratory for
isolating aspects of this problem in a controlled setting.
At large boosts, configurations of concentric membranes become superselection
sectors, whose exact spectra are known. From the bulk point of view one expects
product states of individual membranes to be contained within the full
spectrum. However, for non-BPS states this inclusion relation is obscured by
Gauss law constraints. Its validity rests on nontrivial relations in
representation theory, which we identify and verify by explicit computation.Comment: 43 pages, 2 figure
Generating Black Strings in Higher Dimensions
Starting with a Zipoy-Voorhees line element we construct and study the three
parameter family of solutions describing a deformed black string with arbitrary
tension.Comment: 11 pages, 2 figures, accepted for publication in J. Mod. Phys. Lett.
Phase structure of matrix quantum mechanics at finite temperature
We study matrix quantum mechanics at finite temperature by Monte Carlo
simulation. The model is obtained by dimensionally reducing 10d U(N) pure
Yang-Mills theory to 1d. Following Aharony et al., one can view the same model
as describing the high temperature regime of (1+1)d U(N) super Yang-Mills
theory on a circle. In this interpretation an analog of the deconfinement
transition was conjectured to be a continuation of the black-hole/black-string
transition in the dual gravity theory. Our detailed analysis in the critical
regime up to N=32 suggests the existence of the non-uniform phase, in which the
eigenvalue distribution of the holonomy matrix is non-uniform but gapless. The
transition to the gapped phase is of second order. The internal energy is
constant (giving the ground state energy) in the uniform phase, and rises
quadratically in the non-uniform phase, which implies that the transition
between these two phases is of third order.Comment: 17 pages, 9 figures, (v2) refined arguments in section 3 ; reference
adde
The Geometric Phase and Gravitational Precession of D-Branes
We study Berry's phase in the D0-D4-brane system. When a D0-brane moves in
the background of D4-branes, the first excited states undergo a holonomy
described by a non-Abelian Berry connection. At weak coupling this is an SU(2)
connection over R^5, known as the Yang monopole. At strong coupling, the
holonomy is recast as the classical gravitational precession of a spinning
particle. The Berry connection is the spin connection of the near-horizon limit
of the D4-branes, which is a continuous deformation of the Yang and anti-Yang
monopole.Comment: 23 pages; v3: typos correcte
Product CFTs, gravitational cloning, massive gravitons and the space of gravitational duals
The question of graviton cloning in the context of the bulk/boundary
correspondence is considered. It is shown that multi-graviton theories can be
obtained from products of large-N CFTs. No more than one interacting massless
graviton is possible. There can be however, many interacting massive gravitons.
This is achieved by coupling CFTs via multi-trace marginal or relevant
perturbations. The geometrical structure of the gravitational duals of such
theories is that of product manifolds with their boundaries identified. The
calculational formalism is described and the interpretation of such theories is
discussed.Comment: Latex, 25 pages. (v2) Minor corrections and references adde
Holography and entropy bounds in the plane wave matrix model
As a quantum theory of gravity, Matrix theory should provide a realization of
the holographic principle, in the sense that a holographic theory should
contain one binary degree of freedom per Planck area. We present evidence that
Bekenstein's entropy bound, which is related to area differences, is manifest
in the plane wave matrix model. If holography is implemented in this way, we
predict crossover behavior at strong coupling when the energy exceeds N^2 in
units of the mass scale.Comment: 19 pages; v2: references adde
Multi-Trace Operators and the Generalized AdS/CFT Prescription
We show that multi-trace interactions can be consistently incorporated into
an extended AdS/CFT prescription involving the inclusion of generalized
boundary conditions and a modified Legendre transform prescription. We find new
and consistent results by considering a self-contained formulation which
relates the quantization of the bulk theory to the AdS/CFT correspondence and
the perturbation at the boundary by double-trace interactions. We show that
there exist particular double-trace perturbations for which irregular modes are
allowed to propagate as well as the regular ones. We perform a detailed
analysis of many different possible situations, for both minimally and
non-minimally coupled cases. In all situations, we make use of a new constraint
which is found by requiring consistence. In the particular non-minimally
coupled case, the natural extension of the Gibbons-Hawking surface term is
generated.Comment: 27 pages, LaTeX, v.2:minor changes, v.3:comments added, v.4:several
new results, discussions, references and a section of Conclusions added.
Previous results unchanged, v.5: minor changes. Final version to be published
in Phys.Rev.
Statistical mechanical description of liquid systems in electric field
We formulate the statistical mechanical description of liquid systems for
both polarizable and polar systems in an electric field in the
-ensemble, which is the pendant to the thermodynamic description in
terms of the free energy at constant potential. The contribution of the
electric field to the configurational integral in
the -ensemble is given in an exact form as a factor in the
integrand of . We calculate the contribution of the
electric field to the Ornstein-Zernike formula for the scattering function in
the -ensemble. As an application we determine the field induced
shift of the critical temperature for polarizable and polar liquids, and show
that the shift is upward for polarizable liquids and downward for polar
liquids.Comment: 6 page
- …