69,964 research outputs found
Magnetotransport from the fluid/gravity correspondence
We continue our construction of a hydrodynamical description of a holographic
model with broken translation invariance. Using the fluid/gravity
correspondence we derive the constitutive relations of the boundary theory in
the presence of a magnetic field. This allows us to obtain novel results for
the low-frequency magnetothermoelectric response coefficients. We discuss the
DC limit of our hydrodynamics in detail, and show that our approach is
equivalent to the `horizon-fluid' of Donos and Gauntlett.Comment: 16 pages + appendix and references, v2: references adde
Special limits and non-relativistic solutions
We study special vanishing horizon limit of `boosted' black D3-branes having
a compact light-cone direction. The type IIB solution obtained by taking such a
zero temperature limit is found to describe a nonrelativistic system with
dynamical exponent 3. We discuss about such limits in M2-branes case also.Comment: 10 pages; V2: various changes in interpretations including title; no
change in mathematical results, V3: minor font typo in eq.(7) remove
Striped phases from holography
We discuss new types of second order phase transitions in holography by constructing striped black holes in D = 4 with AdS4 asymptotics. In the context of AdS/CFT, they provide the gravity duals to field theory phases in which translational symmetry is spontaneously broken due to the formation of current density waves. These black holes are associated to three dimensional CFTs at finite temperature and deformed by a uniform chemical potential. We numerically solve a non-linear system of PDEs in order to construct the black hole geometries and extract some of their thermodynamic properties
Non-Abelian T-duality for nonrelativistic holographic duals
We find new type II backgrounds with non-relativistic symmetries via
non-Abelian T-duality. First we consider geometries with Galilean symmetries in
type IIA, which have been identified as non-relativistic generalizations of the
ABJM background and massive IIA supergravities. We then consider the
non-Abelian T-duality transformation on the backgrounds with Lifshitz symmetry
constructed by Donos and Gauntlett. Using gauge/gravity duality we study
aspects of the field theory dual to these backgrounds.Comment: 43 pages, 4 figures; typos and one eq. corrected, references adde
Galilean type IIA backgrounds and a map
We obtain non-relativistic AdS4 X CP3 solutions with dynamical exponent 3 in
type IIA string theory, both with and without Romans mass. The
compactifications to four dimensions are found to describe Proca fields in
anti-de Sitter spacetime. This leads us to conclude that the massive and
massless IIA theories should be identified in four dimensions and the Romans
mass should be identified with the `flux' along CP3 in a definite manner. From
supergravity point of view, it is suggestive of some four-dimensional symmetry
that rotates Romans mass into the flux along CP3. We also provide M-theory
Galilean ABJM background which gives rise to the nonrelativistic type IIA
solution.Comment: 10 pages;v2: major revisions, errors on supersymmetry corrected and
references added; to be published in MPL
Analytic DC thermo-electric conductivities in holography with massive gravitons
We provide an analytical derivation of the thermo-electric transport
coefficients of the simplest momentum-dissipating model in gauge/gravity where
the lack of momentum conservation is realized by means of explicit graviton
mass in the bulk. We rely on the procedure recently described by Donos and
Gauntlett in the context of Q-lattices and holographic models where momentum
dissipation is realized through non-trivial scalars. The analytical approach
confirms the results found previously by means of numerical computations.Comment: 9 pages, no figures, minor comments added, version to appear on PR
Doping the holographic Mott insulator
Mott insulators form because of strong electron repulsions, being at the
heart of strongly correlated electron physics. Conventionally these are
understood as classical "traffic jams" of electrons described by a short-ranged
entangled product ground state. Exploiting the holographic duality, which maps
the physics of densely entangled matter onto gravitational black hole physics,
we show how Mott-insulators can be constructed departing from entangled
non-Fermi liquid metallic states, such as the strange metals found in cuprate
superconductors. These "entangled Mott insulators" have traits in common with
the "classical" Mott insulators, such as the formation of Mott gap in the
optical conductivity, super-exchange-like interactions, and form "stripes" when
doped. They also exhibit new properties: the ordering wave vectors are detached
from the number of electrons in the unit cell, and the DC resistivity diverges
algebraically instead of exponentially as function of temperature. These
results may shed light on the mysterious ordering phenomena observed in
underdoped cuprates.Comment: 27 pages, 9 figures. Accepted in Nature Physic
Momentum relaxation from the fluid/gravity correspondence
We provide a hydrodynamical description of a holographic theory with broken
translation invariance. We use the fluid/gravity correspondence to
systematically obtain both the constitutive relations for the currents and the
Ward identity for momentum relaxation in a derivative expansion. Beyond leading
order in the strength of momentum relaxation, our results differ from a model
previously proposed by Hartnoll et al. As an application of these techniques we
consider charge and heat transport in the boundary theory. We derive the low
frequency thermoelectric transport coefficients of the holographic theory from
the linearised hydrodynamics.Comment: 19 pages + appendix, v2: references added, typos corrected, v3:
version published in JHE
Thermoelectric DC conductivities with momentum dissipation from higher derivative gravity
We present a mechanism of momentum relaxation in higher derivative gravity by
adding linear scalar fields to the Gauss-Bonnet theory. We analytically
computed all of the DC thermoelectric conductivities in this theory by adopting
the method given by Donos and Gauntlett in [arXiv:1406.4742]. The results show
that the DC electric conductivity is not a monotonic function of the effective
impurity parameter : in the small limit, the DC conductivity is
dominated by the coherent phase, while for larger , pair creation
contribution to the conductivity becomes dominant, signaling an incoherent
phase. In addition, the DC heat conductivity is found independent of the
Gauss-Bonnet coupling constant.Comment: 1+19 pages, 2 figures,typos in Eq.(40) correcte
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