Prahar Mitra

Prahar Mitra

Ph.D. Physics

About

27
Publications
1,250
Reads
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1,929
Citations
Introduction
Asymptotic Symmetries in Asmyptotically Flat Spacetimes, Quantum Gravity, Black Holes in AdS Spacetimes.
Additional affiliations
October 2020 - present
University of Cambridge
Position
  • Research Associate
Description
  • Black Holes in AdS
September 2017 - September 2020
Institute for Advanced Study
Position
  • PostDoc Position
August 2011 - present
Harvard University
Position
  • PhD Student
Education
September 2011 - May 2017
Harvard University
Field of study
  • Physics
August 2006 - May 2011
Birla Institute of Technology and Science Pilani
Field of study
  • Electronics and Electrical Engineering
August 2006 - May 2011

Publications

Publications (27)
Article
Full-text available
We perform a complete and systematic analysis of the solution space of six-dimensional Einstein gravity. We show that a particular subclass of solutions — those that are analytic near \( \mathcal{I} \)+ — admit a non-trivial action of the generalised Bondi-Metzner-van der Burg-Sachs (GBMS) group which contains infinite-dimensional supertranslations...
Preprint
Full-text available
Using the covariant phase space formalism, we construct the phase space for non-Abelian gauge theories in $(d+2)$-dimensional Minkowski spacetime for any $d \geq 2$, including the edge modes that symplectically pair to the low energy degrees of freedom of the gauge field. Despite the fact that the symplectic form in odd and even-dimensional spaceti...
Article
Full-text available
A bstract We do a systematic search of supergravity solutions that, via the AdS 5 /CFT 4 correspondence, are dual to thermal states in $$ \mathcal{N} $$ N = 4 SYM at finite chemical potential. These solutions dominate the microcanonical ensemble and are required to ultimately reproduce the microscopic entropy of AdS black holes. Using a mix of anal...
Preprint
Full-text available
We perform a complete and systematic analysis of the solution space of six-dimensional Einstein gravity. We show that a particular subclass of solutions -- those that are analytic near $\mathcal{I}^+$ -- admit a non-trivial action of the generalised Bondi-Metzner-van der Burg-Sachs (GBMS) group which contains \emph{infinite-dimensional} supertransl...
Preprint
Full-text available
We do a systematic search of supergravity solutions that, via the AdS$_5$/CFT$_4$ correspondence, are dual to thermal states in $\mathcal{N}=4$ SYM at finite chemical potential. These solutions dominate the microcanonical ensemble and are required to ultimately reproduce the microscopic entropy of AdS black holes. Using a mix of analytical and nume...
Article
We do a systematic search of supergravity solutions that, via the AdS$_5$/CFT$_4$ correspondence, are dual to thermal states in $\mathcal{N}=4$ SYM at finite chemical potential. These solutions dominate the microcanonical ensemble and are required to ultimately reproduce the microscopic entropy of AdS black holes. Using a mix of analytical and nume...
Article
Full-text available
We study exponentiated soft exchange in (d+2)-dimensional gauge and gravitational theories using the celestial conformal field theory formalism. These models exhibit spontaneously broken asymptotic symmetries generated by gauge transformations with noncompact support, and the effective dynamics of the associated Goldstone “edge” mode is expected to...
Preprint
Full-text available
We study exponentiated soft exchange in $d+2$ dimensional gauge and gravitational theories using the celestial CFT formalism. These models exhibit spontaneously broken asymptotic symmetries generated by gauge transformations with non-compact support, and the effective dynamics of the associated Goldstone "edge" mode is expected to be $d$-dimensiona...
Article
Full-text available
A bstract We perform a careful study of the infrared sector of massless non-abelian gauge theories in four-dimensional Minkowski spacetime using the covariant phase space formalism, taking into account the boundary contributions arising from the gauge sector of the theory. Upon quantization, we show that the boundary contributions lead to an infini...
Article
Full-text available
A bstract Previous analyses of asymptotic symmetries in QED have shown that the subleading soft photon theorem implies a Ward identity corresponding to a charge generating divergent large gauge transformations on the asymptotic states at null infinity. In this work, we demonstrate that the subleading soft photon theorem is equivalent to a more gene...
Preprint
We perform a careful study of the infrared sector of massless non-abelian gauge theories in four-dimensional Minkowski spacetime using the covariant phase space formalism, taking into account the boundary contributions arising from the gauge sector of the theory. Upon quantization, we show that the boundary contributions lead to an infinite degener...
Article
Full-text available
A bstract We show that Weinberg’s leading soft photon theorem in massless abelian gauge theories implies the existence of an infinite-dimensional large gauge symmetry which acts non-trivially on the null boundaries "Image missing" ± of ( d + 2)-dimensional Minkowski spacetime. These symmetries are parameterized by an arbitrary function ε ( x ) of t...
Article
Full-text available
A bstract We show that the subleading soft photon theorem in a (d + 2)-dimensional massless abelian gauge theory gives rise to a Ward identity corresponding to divergent large gauge transformations acting on the celestial sphere at null infinity. We further generalize our analysis to (d + 2)-dimensional non-abelian gauge theories and show that the...
Preprint
Previous analyses of asymptotic symmetries in QED have shown that the subleading soft photon theorem implies a Ward identity corresponding to a charge generating divergent large gauge transformations on the asymptotic states at null infinity. In this work, we demonstrate that the subleading soft photon theorem is equivalent to a more general Ward i...
Article
We describe a quench protocol that allows the rapid preparation of ground states of arbitrary interacting conformal field theories in 1+1 dimensions. We start from the ground state of a related gapped relativistic quantum field theory and consider sudden quenches along the spacelike trajectories t2-x2=T02 (parameterized by T0) to a conformal field...
Preprint
We show that the subleading soft photon theorem in a $(d+2)$-dimensional massless abelian gauge theory gives rise to a Ward identity corresponding to divergent large gauge transformations acting on the celestial sphere at null infinity. We further generalize our analysis to $(d+2)$-dimensional non-abelian gauge theories and show that the leading an...
Preprint
We show that Weinberg's leading soft photon theorem in massless abelian gauge theories implies the existence of an infinite-dimensional large gauge symmetry which acts non-trivially on the null boundaries ${\mathscr I}^\pm$ of $(d+2)$-dimensional Minkowski spacetime. These symmetries are parameterized by an arbitrary function $\varepsilon(x)$ of th...
Preprint
Full-text available
We describe a quench protocol that allows the rapid preparation of ground states of arbitrary interacting conformal field theories in $1+1$ dimensions. We start from the ground state of a related gapped relativistic quantum field theory and consider sudden quenches along the space-like trajectories $t^2 - x^2 = T^2_0$ (parameterized by $T_0$) to a...
Article
Full-text available
A bstract We consider the tree-level scattering of massless particles in ( d +2)-dimensional asymptotically flat spacetimes. The $$ \mathcal{S} $$ S -matrix elements are recast as correlation functions of local operators living on a space-like cut ℳ d of the null momentum cone. The Lorentz group SO( d + 1 , 1) is nonlinearly realized as the Euclide...
Article
Full-text available
A bstract In [1, 2] it was shown that the subleading soft photon theorem in tree level amplitudes in massless QED is equivalent to a new class of symmetries of the theory parameterized by a vector field on the celestial sphere. In this paper, we extend these results to the subleading soft photon theorem in any Effective Field Theory containing phot...
Article
We use the subleading soft-graviton theorem to construct an operator $T_{zz}$ whose insertion in the four-dimensional tree-level quantum gravity $\mathcal{S}$-matrix obeys the Virasoro-Ward identities of the energy momentum tensor of a two-dimensional conformal field theory (CFT$_2$). The celestial sphere at Minkowskian null infinity plays the role...
Article
Full-text available
We establish the existence of an infinite-dimensional fermionic symmetry in four-dimensional supersymmetric gauge theories by analyzing semiclassical photino dynamics in abelian ${\cal N}=1$ theories with charged matter. The symmetry is parametrized by a spinor-valued function on an asymptotic $S^2$ at null infinity. It is not manifest at the level...
Article
Full-text available
Recently it was conjectured that a certain infinite-dimensional “diagonal” subgroup of BMS supertranslations acting on past and future null infinity ( and ) is an exact symmetry of the quantum gravity S-matrix, and an associated Ward identity was derived. In this paper we show that this supertranslation Ward identity is precisely equivalent to Wein...
Article
Full-text available
Scattering amplitudes of any four-dimensional theory with nonabelian gauge group $\mathcal G$ may be recast as two-dimensional correlation functions on the asymptotic two-sphere at null infinity. The soft gluon theorem is shown, for massless theories at the semiclassical level, to be the Ward identity of a holomorphic two-dimensional $\mathcal G$-K...
Article
Full-text available
An infinite number of physically nontrivial symmetries are found for abelian gauge theories with massless charged particles. They are generated by large U(1) gauge transformations that asymptotically approach an arbitrary function \( \varepsilon \left(z,\overline{z}\right) \) on the conformal sphere at future null infinity ( ) but are independent...
Article
Full-text available
Recently it was conjectured that a certain infinite-dimensional "diagonal" subgroup of BMS supertranslations acting on past and future null infinity (${\mathscr I}^-$ and ${\mathscr I}^+$) is an exact symmetry of the quantum gravity ${\cal S}$-matrix, and an associated Ward identity was derived. In this paper we show that this supertranslation Ward...
Article
Full-text available
We use a mix of analytic and numerical methods to exhaustively study a class of asymptotically global AdS solitons and hairy black hole solutions in negative cosmological constant Einstein Maxwell gravity coupled to a charged massless scalar field. Our results depend sensitively on the charge 'e' of the scalar field. The solitonic branch of solutio...

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