177 research outputs found

### Three-Dimensional Extended Bargmann Supergravity

We show that three-dimensional General Relativity, augmented with two vector
fields, allows for a non-relativistic limit, different from the standard limit
leading to Newtonian gravity, that results into a well-defined action which is
of the Chern-Simons type. We show that this three-dimensional `Extended
Bargmann Gravity', after coupling to matter, leads to equations of motion
allowing a wider class of background geometries than the ones that one
encounters in Newtonian gravity. We give the supersymmetric generalization of
these results and point out an important application in the context of
calculating partition functions of non-relativistic field theories using
localization techniques.Comment: 6 pages, v2: typo's corrected, reference updated, accepted for
publication in Phys. Rev. Let

### Non-relativistic fields from arbitrary contracting backgrounds

We discuss a non-relativistic contraction of massive and massless field
theories minimally coupled to gravity. Using the non-relativistic limiting
procedure introduced in our previous work, we (re-)derive non-relativistic
field theories of massive and massless spins 0 to 3/2 coupled to torsionless
Newton-Cartan backgrounds. We elucidate the relativistic origin of the
Newton-Cartan central charge gauge field $m_\mu$ and explain its relation to
particle number conservation.Comment: 19 page

### Newton-Cartan supergravity with torsion and Schr\"odinger supergravity

We derive a torsionfull version of three-dimensional N=2 Newton-Cartan
supergravity using a non-relativistic notion of the superconformal tensor
calculus. The "superconformal" theory that we start with is Schr\"odinger
supergravity which we obtain by gauging the Schr\"odinger superalgebra. We
present two non-relativistic N=2 matter multiplets that can be used as
compensators in the superconformal calculus. They lead to two different
off-shell formulations which, in analogy with the relativistic case, we call
"old minimal" and "new minimal" Newton-Cartan supergravity. We find
similarities but also point out some differences with respect to the
relativistic case.Comment: 30 page

### Newton-Cartan (super)gravity as a non-relativistic limit

We define a procedure that, starting from a relativistic theory of
supergravity, leads to a consistent, non-relativistic version thereof. As a
first application we use this limiting procedure to show how the Newton-Cartan
formulation of non-relativistic gravity can be obtained from general
relativity. Then we apply it in a supersymmetric case and derive a novel,
non-relativistic, off-shell formulation of three-dimensional Newton-Cartan
supergravity.Comment: 29 pages; v2: added comment about different NR gravities and more
refs; v3: more refs, matches published versio

### Torsional Newton-Cartan Geometry and the Schr\"odinger Algebra

We show that by gauging the Schr\"odinger algebra with critical exponent $z$
and imposing suitable curvature constraints, that make diffeomorphisms
equivalent to time and space translations, one obtains a geometric structure
known as (twistless) torsional Newton-Cartan geometry (TTNC). This is a version
of torsional Newton-Cartan geometry (TNC) in which the timelike vielbein
$\tau_\mu$ must be hypersurface orthogonal. For $z=2$ this version of TTNC
geometry is very closely related to the one appearing in holographic duals of
$z=2$ Lifshitz space-times based on Einstein gravity coupled to massive vector
fields in the bulk. For $z\neq 2$ there is however an extra degree of freedom
$b_0$ that does not appear in the holographic setup. We show that the result of
the gauging procedure can be extended to include a St\"uckelberg scalar $\chi$
that shifts under the particle number generator of the Schr\"odinger algebra,
as well as an extra special conformal symmetry that allows one to gauge away
$b_0$. The resulting version of TTNC geometry is the one that appears in the
holographic setup. This shows that Schr\"odinger symmetries play a crucial role
in holography for Lifshitz space-times and that in fact the entire boundary
geometry is dictated by local Schr\"odinger invariance. Finally we show how to
extend the formalism to generic torsional Newton-Cartan geometries by relaxing
the hypersurface orthogonality condition for the timelike vielbein $\tau_\mu$.Comment: v2: 38 pages, references adde

### Logarithmic AdS Waves and Zwei-Dreibein Gravity

We show that the parameter space of Zwei-Dreibein Gravity (ZDG) in AdS3
exhibits critical points, where massive graviton modes coincide with pure gauge
modes and new `logarithmic' modes appear, similar to what happens in New
Massive Gravity. The existence of critical points is shown both at the
linearized level, as well as by finding AdS wave solutions of the full
non-linear theory, that behave as logarithmic modes towards the AdS boundary.
In order to find these solutions explicitly, we give a reformulation of ZDG in
terms of a single Dreibein, that involves an infinite number of derivatives. At
the critical points, ZDG can be conjectured to be dual to a logarithmic
conformal field theory with zero central charges, characterized by new
anomalies whose conjectured values are calculated.Comment: 20 page

### Dirac actions for D-branes on backgrounds with fluxes

The understanding of the fermionic sector of the worldvolume D-brane dynamics
on a general background with fluxes is crucial in several branches of string
theory, like for example the study of nonperturbative effects or the
construction of realistic models living on D-branes. In this paper we derive a
new simple Dirac-like form for the bilinear fermionic action for any Dp-brane
in any supergravity background, which generalizes the usual Dirac action valid
in absence of fluxes. A nonzero world-volume field strength deforms the usual
Dirac operator in the action to a generalized non-canonical one. We show how
the canonical form can be re-established by a redefinition of the world-volume
geometry.Comment: 25 page

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