44 research outputs found
Notes on Matter in Horava-Lifshitz Gravity
We investigate the dynamics of a scalar field governed by the Lifshitz-type
action which should appear naturally in Horava-Lifshitz gravity. The wave of
the scalar field may propagate with any speed without an upper bound. To
preserve the causality, the action cannot have a generic form. Due to the
superluminal propagation, a formation of a singularity may cause the breakdown
of the predictability of the theory. To check whether such a catastrophe could
occur in Horava-Lifshitz gravity, we investigate the dynamics of a dust. It
turns out that the dust does not collapse completely to form a singularity in a
generic situation, but expands again after it attains a maximum energy density.Comment: 14 pages, references adde
3D N=6 Gauged Supergravity: Admissible Gauge Groups, Vacua and RG Flows
We study N=6 gauged supergravity in three dimensions with scalar manifolds
for in great details. We
classify some admissible non-compact gauge groups which can be consistently
gauged and preserve all supersymmetries. We give the explicit form of the
embedding tensors for these gauge groups as well as study their scalar
potentials on the full scalar manifold for each value of along with
the corresponding vacua. Furthermore, the potentials for the compact gauge
groups, for ,
identified previously in the literature are partially studied on a submanifold
of the full scalar manifold. This submanifold is invariant under a certain
subgroup of the corresponding gauge group. We find a number of supersymmetric
AdS vacua in the case of compact gauge groups. We then consider holographic RG
flow solutions in the compact gauge groups and
for the k=4 case. The solutions
involving one active scalar can be found analytically and describe operator
flows driven by a relevant operator of dimension 3/2. For non-compact gauge
groups, we find all types of vacua namely AdS, Minkowski and dS, but there is
no possibility of RG flows in the AdS/CFT sense for all gauge groups considered
here.Comment: 43 pages, no figures references added, typoes corrected and more
information adde
Particle Kinematics in Horava-Lifshitz Gravity
We study the deformed kinematics of point particles in the Horava theory of
gravity. This is achieved by considering particles as the optical limit of
fields with a generalized Klein-Gordon action. We derive the deformed geodesic
equation and study in detail the cases of flat and spherically symmetric
(Schwarzschild-like) spacetimes. As the theory is not invariant under local
Lorenz transformations, deviations from standard kinematics become evident even
for flat manifolds, supporting superluminal as well as massive luminal
particles. These deviations from standard behavior could be used for
experimental tests of this modified theory of gravity.Comment: Added references, corrected a typing erro
Janus Black Holes
In this paper Janus black holes in AdS3 are considered. These are static
solutions of an Einstein-scalar system with broken translation symmetry along
the horizon. These solutions are dual to interface conformal field theories at
finite temperature. An approximate solution is first constructed using
perturbation theory around a planar BTZ black hole. Numerical and exact
solutions valid for all sets of parameters are then found and compared. Using
the exact solution the thermodynamics of the system is analyzed. The entropy
associated with the Janus black hole is calculated and it is found that the
entropy of the black Janus is the sum of the undeformed black hole entropy and
the entanglement entropy associated with the defect.Comment: 28 pages, 2 figures, reference adde
Bosonic Fractionalisation Transitions
At finite density, charge in holographic systems can be sourced either by
explicit matter sources in the bulk or by bulk horizons. In this paper we find
bosonic solutions of both types, breaking a global U(1) symmetry in the former
case and leaving it unbroken in the latter. Using a minimal bottom-up model we
exhibit phase transitions between the two cases, under the influence of a
relevant operator in the dual field theory. We also embed solutions and
transitions of this type in M-theory, where, holding the theory at constant
chemical potential, the cohesive phase is connected to a neutral phase of
Schr\"odinger type via a z=2 QCP.Comment: references added. minor changes. version published in JHE
Non-Abelian T-duality and consistent truncations in type-II supergravity
For a general class of SO(4) symmetric backgrounds in type II-supergravity,
we show that the action of non-Abelian T-duality can be described via
consistent truncation to seven dimensional theories with seemingly massive
modes. As such, any solution to these theories uplifts to both massive type IIA
and IIB supergravities presenting an invertible map between the two. For
supersymmetric backgrounds, we show that for spinors transforming under SO(4)
the non-Abelian T-duality transformation breaks the original supersymmetry by
half. We use these mappings to generate the non-Abelian T-duals of the
maximally supersymmetric pp-wave, the Lin, Lunin, Maldacena geometries and
spacetimes with Lifshitz symmetry.Comment: 41 pages, references added, published versio
Emergent Schrodinger geometries from mass-deformed CFT
We study an M-theory solution for the holographic flow of AdS4 times
Sasaki-Einstein 7-manifolds with skew-whiffing, perturbed by a mass operator.
The infrared solution contains the 5 dimensional Schrodinger geometry after
considering the gravity dual of the standard non-relativistic limit of
relativistic field theories. The mass deformation of the field theory is
discussed in detail for the case with 7 manifold being a round sphere.Comment: 20 pages, 1 figure. v2: references added, minor correction
Consistent truncation of d = 11 supergravity on AdS_4 x S^7
We study the system of equations derived twenty five years ago by B. de Wit
and the first author [Nucl. Phys. B281 (1987) 211] as conditions for the
consistent truncation of eleven-dimensional supergravity on AdS_4 x S^7 to
gauged N = 8 supergravity in four dimensions. By exploiting the E_7(7)
symmetry, we determine the most general solution to this system at each point
on the coset space E_7(7)/SU(8). We show that invariants of the general
solution are given by the fluxes in eleven-dimensional supergravity. This
allows us to both clarify the explicit non-linear ansatze for the fluxes given
previously and to fill a gap in the original proof of the consistent
truncation. These results are illustrated with several examples.Comment: 41 pages, typos corrected, published versio
Four-Dimensional SCFTs from M5-Branes
We engineer a large new set of four-dimensional N=1 superconformal field
theories by wrapping M5-branes on complex curves. We present new supersymmetric
AdS_5 M-theory backgrounds which describe these fixed points at large N, and
then directly construct the dual four-dimensional CFTs for a certain subset of
these solutions. Additionally, we provide a direct check of the central charges
of these theories by using the M5-brane anomaly polynomial. This is a companion
paper which elaborates upon results reported in arXiv:1112:5487.Comment: 45 pages, 11 figure
Enhanced Supersymmetry of Nonrelativistic ABJM Theory
We study the supersymmetry enhancement of nonrelativistic limits of the ABJM
theory for Chern-Simons level . The special attention is paid to the
nonrelativistic limit (known as `PAAP' case) containing both particles and
antiparticles. Using supersymmetry transformations generated by the monopole
operators, we find additional 2 kinematical, 2 dynamical, and 2 conformal
supercharges for this case. Combining with the original 8 kinematical
supercharges, the total number of supercharges becomes maximal: 14
supercharges, like in the well-known PPPP limit. We obtain the corresponding
super Schr\"odinger algebra which appears to be isomorphic to the one of the
PPPP case. We also discuss the role of monopole operators in supersymmetry
enhancement and partial breaking of supersymmetry in nonrelativistic limit of
the ABJM theory.Comment: 22 pages, references added, version to appear in JHE