arXiv subjects

Subir Mukhopadhyay

Publications and source records attributed to Subir Mukhopadhyay.

At least 19 recordsLinked to original sources

arXiv2026

Equivariant Cohomology of Lie superalgebras

In this article, we give Maurer-Cartan characterizations of equivariant Lie superalgebra structures. We introduce equivariant cohomology and equivariant formal deformation theory of Lie superalgebras. As an application of equivariant cohomology we study the equivariant formal deformation theory of Lie superalgebras. As another application we characterize equivariant central extensions of Lie superalgebras using second equivariant cohomology. We give some examples of Lie superalgebras with an action of a group and equivariant formal deformations of a classical Lie superalgebras.

math.GM↗

arXiv2026

Spatially modulated instabilities of an AdS black hole

We analyze instabilities of an Einstein-Maxwell theory obtained from an N=2, D=5 supergravity. The theory admits a gauge Chern-Simons term in presence of which we consider perturbative instability of an AdS black hole solution. We find that the strength of the gauge Chern-Simons coupling saturates the threshold value for which the instability occurs, which we have observed both in the near horizon limit as well as analysis of the normal modes. Inclusion of terms upto fourth order in derivatives admits a mixed gauge-gravitational Chern-Simons term as well. Considering both the Chern-Simons terms, we find that momentum dependent instability sets in below a critical temperature giving rise to a bell-curve phase diagram which implies this would lead to a spatially modulated solution. We have considered all the terms upto quartic order of the derivatives and discuss the possible approach for further analysis.

hep-th↗

arXiv2026

Application of analytic functionals to mean field theory and Wilson-Fisher fixed point

We consider application of the analytic functional approach to the conformal field theories associated with mean field theory and Wilson-Fisher fixed point. We study the constraints imposed by the crossing symmetry on the coefficients of the operator product expansion. Making use of these constraints along with a few other additional inputs, we obtain expressions of the coefficients of the operator product expansion up to first order of $ε$.

hep-th↗

arXiv2024

Charged AdS black holes with higher derivative corrections in presence of string cloud

We have obtained charged asymptotically AdS black hole solutions in Einstein Gauss Bonnet gravity in presence of string cloud. It turns out that there exist three black holes in certain range of parameters for small enough chemical potential. However, for large chemical potential, these black holes merge into a single one. The free energy of the black holes is computed from the on shell Euclidean action by subtracting the contribution of an extremal black hole. We have studied the free energy and specific heat of the solutions, which shows that the medium sized black hole is unstable. As an application, we have studied the quark-antiquark potential in the dual gauge theory. This study provides necessary ingredients for study of the dual theories in the context of condensed matter systems.

hep-th↗

arXiv2024

Superconformal blocks for stress-tensor and chiral operators for 4D $\mathcal{N}=2$ superconformal field theories

We have computed superconformal partial wave for the mixed correlators involving $J$, $ϕ$ and $ϕ^\dagger$, where $J$ is the superconformal primary of 4D ${\mathcal N} = 2$ stress-tensor multiplet, $ϕ$ and $ϕ^\dagger$ are chiral and anti-chiral scalars respectively in the channel $\langle J J ϕϕ^\dagger \rangle$. We have used the superembedding formalism and computed conformal partial wave corresponding to the exchange of long multiplet using the supershadow approach. This study provides part of the ingredients necessary for the study of conformal bootstrap for mixed correlator in 4D ${\mathcal N} = 2$ superconformal field theories.

hep-th↗

arXiv2021

Holographic Fermi surfaces in charge density wave from D2-D8

D2-D8 model admits a numerical solution that corresponds to a charge density wave and a spin density wave. Considering that as the background, we numerically solve the Dirac equation for probe fermions. From the solution, we obtain the Green's function and study the behaviour of the spectral density. We begin with generic fermions and have studied the formation of the Fermi surface and where it develops a gap. In addition, we have incorporated an ionic lattice and study its effect on the Fermi surface. Then we analysed the worldvolume fermions. In this particular model we do not find Fermi surface for the dual operators.

hep-th↗

arXiv2020

Holographic charge density wave from D2-D8

We have considered D2-D8 model and obtain a numerical solution that exhibits spatially modulated phases corresponding to a charge density wave and a spin density wave. We have analysed behavior of the free energy density for different values of the chemical potential and the magnetic field.

hep-th↗

arXiv2020

AdS black holes with higher derivative corrections in presence of string cloud

We consider asymptotically AdS black hole solutions in presence of string clouds and higher derivative corrections. We find that it admits three black hole solutions within a region of the parameter space. In order to examine the stabilities of these solutions we consider a thermodynamic analysis. Using holography, we have studied the quark-antiquark distance and binding energy in the dual gauge theory.

hep-th↗

arXiv2019

Hyperscaling violating geometry with magnetic field and DC conductivity

We consider dyonic black hole in hyperscaling violating Lifshitz theories arised in a four dimensional Einstein-Maxwell-dilaton system along with axion fields. Considering the linearised equation of relevant fluctuations in metric and gauge fields, we analytically compute thermoelectric conductivity of the dual theory using Dirichlet boundary condition and find agreement with conductivities obtained in near horizon analysis. We also study temperature dependence of the conductivities.

hep-th↗

arXiv2019

Fermionic spectrum from a domain wall in five dimensions

We study fermions in a domain wall backgrounds in five dimensional supergravity, which is similar to zero temperature limit of holographic superconductor. We find the fermionic operators for small charges in the dual four dimensional theory have gapped spectrum.

hep-th↗

arXiv2009

A note on matrix model with IR cutoff and AdS/CFT

We propose an effective model of strongly coupled gauge theory at finite temperature on $R^3$ in the presence of an infrared cutoff. It is constructed by considering the theory on $S^3$ with an infrared cutoff and then taking the size of the $S^3$ to infinity while keeping the cutoff fixed. This model reproduces various qualitative features expected from its gravity dual.

hep-th↗

arXiv2009

Notes on R-charged black holes near criticality and gauge theory

After reviewing the thermodynamics and critical phenomena associated with AdS black holes carrying multiple R-charges in various dimensions, we do a Bragg-Williams like analysis of the systems around its critical points. This leads us to propose an effective potential governing the equilibrium properties of the boundary gauge theory. We also study certain non-equilibrium phenomena associated with these gauge theories. In particular, we compute the conductivities and diffusion coefficients for theories with multiple R-charges in four, three and six dimensions.

hep-th↗

arXiv2009

BLG theory with generalized Jordan triple systems

We use a generalized Jordan algebra of the second kind to study the recently proposed BLG theory of multiple M2-branes. We find the restriction imposed on the ternary product from its consistency with the BLG theory.

hep-th↗

arXiv2008

On Six Dimensional Fundamental Superstrings as Holograms

In this note we discuss a possible holographic dual of the two dimensional conformal field theory associated with the world-sheet of a macroscopic superstring in a compactification on four-torus. We assume the near horizon geometry of the black string has symmetries of $AdS_3\times S^3\times T^4$ and construct a sigma model in the bulk. Analyzing the symmetries of the bulk theory and comparing them with those of the CFT in a special light-cone gauge we find agreement between global symmetries. Due to non-standard gauge realization it is not clear how affine symmetries can be realized.

hep-th↗

arXiv2008

On 5D Small Black Holes

Using higher order corrections we argue that five dimensional N=2 and N=4 small black holes exhibit supersymmetry enhancement in near horizon geometry leading to eight and sixteen supercharges, respectively. Using this enhancement at supergravity level we can identify the global supergroup of the near horizon geometry. In particular we show how this supergroup distinguishes between small and large black holes in N=2 case.

hep-th↗

arXiv2008

Branes in hearts with perverse sheaves

Various topological properties of D-branes in the type--IIA theory are captured by the topologically twisted B-model, treating D-branes as objects in the bounded derived category of coherent sheaves on the compact part of the target space. The set of basic D-branes wrapped on the homology cycles of the compact space are taken to reside in the heart of t-structures of the derived category of coherent sheaves on the space at any point in the Kähler moduli space. The stability data entails specifying a t-structure along with a grade for sorting the branes. Considering an example of a degenerate Calabi-Yau space, obtained via geometric engineering, that retains but a projective curve as the sole non-compact part, we identify the regions in the Kähler moduli space of the curve that pertain to the different t-structures of the bounded derived category of coherent sheaves on the curve corresponding to the different phases of the topological branes.

hep-th↗

arXiv2007

Forbidden territories in the string landscape

Problems of stabilizing moduli of the type--IIB string theory on toroidal orientifolds $\T^6/\Z_2$, in presence of worldvolume fluxes on various D-branes, are considered. For $Z_2$ actions, introducing either O9 or O3 planes, we rule out the possibility of moduli stabilization in a wide class of models with $\mathcal{N}=1$ supersymmetry, characterized by the type of fluxes turned on along D-brane worldvolume. Our results, in particular, imply that Abelian worldvolume fluxes can not by themselves stabilize closed string moduli, in a consistent supersymmtric model, for above orientifold compactifications. We also discuss other $Z_2$ orientifolds of $T^6$ and show that certain other brane wrappings are also ruled out by similar consistency requirements. In specific setups we consider examples with D9-branes wrapping on a complex three-torus with its world-volume fluxes taken to be semi-homogeneous bundles and D7-branes wrapping holomorphic four-cycles of the complex three-torus carrying world-volume fluxes.

hep-th↗

arXiv2007

Phase transitions in higher derivative gravity and gauge theory: R-charged black holes

This is a continuation of our earlier work where we constructed a phenomenologically motivated effective action of the boundary gauge theory at finite temperature and finite gauge coupling on $S^3 \times S^1$. In this paper, we argue that this effective action qualitatively reproduces the gauge theory representing various bulk phases of R-charged black hole with Gauss-Bonnet correction. We analyze the system both in canonical and grand canonical ensemble.

hep-th↗