165 citations · 1.2k across the 32 of their papers we have counts for
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Scaling Symmetry and Carrollian Gravity
Hamid Afshar, Mehdi Ahmadi-Jahmani
We formulate matter-coupled scaling-Carroll gravity as a gauge theory and develop a conformal construction for generating local Carroll-invariant couplings. The construction relaxe…
Classification of Conformal Carroll Algebras
Hamid Afshar, Xavier Bekaert, Mojtaba Najafizadeh
We classify a one-parameter family, , of conformal extensions of the Carroll algebra in arbitrary dimension with being the anisotropic scaling expon…
The near horizon dynamics in three-dimensional Einstein gravity
Hamid R. Afshar, Narges Aghamir
We study the asymptotic dynamics of 3D gravity with Rindler boundary conditions both in flat and AdS spacetimes. We do this by using the angular quantization and Hamiltonian reduct…
Holography in CGHS supergravity
Hamid Afshar, Narges Aghamir
We study holographic aspects of 2D dilaton-supergravity in flat space-time using gauge theoretic BF formulation. The asymptotic symmetries in Bondi gauge and at finite temperature…
Flat JT Gravity and the BMS-Schwarzian
Hamid Afshar, Blagoje Oblak
We consider Minkowskian Jackiw-Teitelboim (JT) gravity in Bondi gauge at finite temperature, with non-zero vacuum energy. Its asymptotic symmetries span an extension of the warped…
Flat space holography in spin-2 extended dilaton-gravity
Hamid Afshar, Erfan Esmaeili, Hamid Safari
We present an interacting spin-2 gauge theory coupled to the two-dimensional dilaton-gravity in flat spacetime. The asymptotic symmetry group is enhanced to the central extension o…
Flat space holography and complex SYK
Hamid Afshar, Hernan Gonzalez, Daniel Grumiller +1
We provide the first steps towards a flat space holographic correspondence in two bulk spacetime dimensions. The gravity side is described by a conformally transformed version of t…
Exotic massive 3D gravities from truncation
Hamid Reza Afshar, Nihat Sadik Deger
We introduce a systematic way of constructing 3D exotic massive gravity theories in the first order formulation. Our method is based on truncating a single degree of freedom in the…
Warped Schwarzian theory
Hamid R. Afshar
We consider the (twisted) warped Virasoro group Diff() C() in the presence of its three cocycles. We compute the Kirillov-Kostant-Souriau symplectic 2-f…
Covariant Poisson's equation in torsional Newton-Cartan gravity
Mohammad Abedini, Hamid R. Afshar, Ahmad Ghodsi
We derive the covariant Poisson's equation of (d+1)-dimensional Newton-Cartan gravity with (twistless) torsion by applying the `non-relativistic conformal method' introduced in arX…
String Memory Effect
Hamid Afshar, Erfan Esmaeili, M. M. Sheikh-Jabbari
In systems with local gauge symmetries, the memory effect corresponds to traces inscribed on a suitable probe when a pure gauge configuration at infinite past dynamically evolves t…
Asymptotic Symmetries in -Form Theories
Hamid Afshar, Erfan Esmaeili, M. M. Sheikh-Jabbari
We consider -form gauge fields in flat -dimensions for which the radiation and the Coulomb solutions have the same asymptotic falloff behavior. Imposing appropriate…
Horizon fluff, semi-classical black hole microstates - Log-corrections to BTZ entropy and black hole/particle correspondence
H. Afshar, D. Grumiller, M. M. Sheikh-Jabbari +1
According to the horizon fluff proposal microstates of a generic black hole belong to a certain subset of near horizon soft hairs that cannot be extended beyond the near horizon re…
Soft hairy horizons in three spacetime dimensions
Hamid Afshar, Daniel Grumiller, Wout Merbis +3
We discuss some aspects of soft hairy black holes and a new kind of "soft hairy cosmologies", including a detailed derivation of the metric formulation, results on flat space, and…
Black Hole Horizon Fluffs: Near Horizon Soft Hairs as Microstates of Three Dimensional Black Holes
H. Afshar, D. Grumiller, M. M. Sheikh-Jabbari
We provide the first explicit proposal for all microstates of generic black holes in three dimensions (of Banados-Teitelboim-Zanelli-type): black hole microstates, termed "horizon…
Soft Heisenberg hair on black holes in three dimensions
Hamid Afshar, Stephane Detournay, Daniel Grumiller +4
Three-dimensional Einstein gravity with negative cosmological constant admits stationary black holes that are not necessarily spherically symmetric. We propose boundary conditions…
Near-Horizon Geometry and Warped Conformal Symmetry
Hamid Afshar, Stéphane Detournay, Daniel Grumiller +1
We provide boundary conditions for three-dimensional gravity including boosted Rindler spacetimes, representing the near-horizon geometry of non-extremal black holes or flat space…
A Schrödinger approach to Newton-Cartan and Hořava-Lifshitz gravities
Hamid R. Afshar, Eric A. Bergshoeff, Aditya Mehra +2
We define a `non-relativistic conformal method', based on a Schrödinger algebra with critical exponent z = 2, as the non-relativistic version of the relativistic conformal method.…
Interacting spin-2 fields in three dimensions
Hamid R. Afshar, Eric A. Bergshoeff, Wout Merbis
Using the frame formulation of multi-gravity in three dimensions, we show that demanding the presence of secondary constraints which remove the Boulware-Deser ghosts restricts the…
Extended massive gravity in three dimensions
Hamid R. Afshar, Eric A. Bergshoeff, Wout Merbis
Using a first order Chern-Simons-like formulation of gravity we systematically construct higher-derivative extensions of general relativity in three dimensions. The construction en…
Holographic Chern-Simons Theories
H. Afshar, A. Bagchi, S. Detournay +3
Chern-Simons theories in three dimensions are topological field theories that may have a holographic interpretation for suitable chosen gauge groups and boundary conditions on the…
Unitary W-algebras and three-dimensional higher spin gravities with spin one symmetry
Hamid Afshar, Thomas Creutzig, Daniel Grumiller +2
We investigate whether there are unitary families of W-algebras with spin one fields in the natural example of the Feigin-Semikhatov W^(2)_n-algebra. This algebra is conjecturally…
Higher spin theory in 3-dimensional flat space
Hamid Afshar, Arjun Bagchi, Reza Fareghbal +2
We present the first example of a non-trivial higher spin theory in 3-dimensional flat space. We propose flat-space boundary conditions and prove their consistency for this theory.…
Flat/AdS boundary conditions in three dimensional conformal gravity
Hamid R. Afshar
We present the asymptotic analysis of 3D conformal gravity as a SO(3,2) Chern-Simons gauge theory with Minkowskian (flat) and AdS boundary conditions. We further extend these bound…