Publications (71)
Counting all dyons in N =4 string theory
Atish Dabholkar, Joao Gomes, Sameer Murthy
For dyons in heterotic string theory compactified on a six-torus, with electric charge vector Q and magnetic charge vector P, the positive integer I = g.c.d.(Q \wedge P) is an inva…
Dyonic black hole degeneracies in string theory from Dabholkar-Harvey degeneracies
Abhishek Chowdhury, Abhiram Kidambi, Sameer Murthy +2
The degeneracies of single-centered dyonic -BPS black holes (BH) in Type II string theory on K3 are known to be coefficients of certain mock Jacobi forms arisi…
Localization of supersymmetric field theories on non-compact hyperbolic three-manifolds
Benjamin Assel, Dario Martelli, Sameer Murthy +1
We study supersymmetric gauge theories with an R-symmetry, defined on non-compact, hyperbolic, Riemannian three-manifolds, focusing on the case of a supersymmetry-preserving quotie…
Localization of strings on group manifolds
Sameer Murthy, Edward Witten
The paper computes the partition function of Wess‑Zumino‑Witten models on compact Lie groups by applying supersymmetric localization, expressing it as a sum over abelian classical…
Corrections to the statistical entropy of five dimensional black holes
Alejandra Castro, Sameer Murthy
We compute the statistical entropy of the three charge (D1-D5-p) five dimensional black hole to sub-leading order in a large charge expansion. We find an agreement with the macrosc…
Quantum black hole entropy and the holomorphic prepotential of N=2 supergravity
Sameer Murthy, Valentin Reys
Supersymmetric terms in the effective action of N=2 supergravity in four dimensions are generically classified into chiral-superspace integrals and full-superspace integrals. For a…
Functional determinants, index theorems, and exact quantum black hole entropy
Sameer Murthy, Valentin Reys
The exact quantum entropy of BPS black holes can be evaluated using localization in supergravity. An important ingredient in this program, that has been lacking so far, is the one-…
A Farey tale for N=4 dyons
Sameer Murthy, Boris Pioline
We study exponentially suppressed contributions to the degeneracies of extremal black holes. Within Sen's quantum entropy function framework and focusing on extremal black holes wi…
Gravitational index of the heterotic string
Yiming Chen, Sameer Murthy, Gustavo J. Turiaci
The fundamental heterotic string has a tower of BPS states whose supersymmetric index has an exponential growth in the charges. We construct the saddle-point of the gravitational p…
ADE Double Scaled Little String Theories, Mock Modular Forms and Umbral Moonshine
Jeffrey A. Harvey, Sameer Murthy, Caner Nazaroglu
We consider double scaled little string theory on . These theories are labelled by a positive integer and an root lattice with Coxeter number . We count BPS…
Novel black saddles for 5d gravitational indices and the index enigma
Jan Boruch, Roberto Emparan, Luca V. Iliesiu +1
We construct a series of novel Euclidean multi-black-hole, black ring, black Saturn, and black lens solutions to supergravity that contribute as saddle-points to the grav…
Multicentered black hole saddles for supersymmetric indices
Jan Boruch, Luca V. Iliesiu, Sameer Murthy +1
The supersymmetric index in string theory can sometimes have a discontinuous integer-valued jump at co-dimension one surfaces in moduli space called walls of marginal stability. Wh…
Supersymmetric Index from Black Hole Entropy
Atish Dabholkar, Joao Gomes, Sameer Murthy +1
For BPS black holes with at least four unbroken supercharges, we describe how the macroscopic entropy can be used to compute an appropriate index, which can be then compared with t…
Quantum black holes: supersymmetry and exact results
Davide Cassani, Sameer Murthy
The explanation of black hole entropy as statistical entropy is one of the big successes of string theory. In this article we review recent progress in this subject, focussing on u…
All solutions of the localization equations for N=2 quantum black hole entropy
Rajesh Kumar Gupta, Sameer Murthy
We find the most general bosonic solution to the localization equations describing the contributions to the quantum entropy of supersymmetric black holes in four-dimensional N=2 su…
The giant graviton expansion in
Giorgos Eleftheriou, Sameer Murthy, Martà Rosselló
The superconformal index of -BPS states of U(N) super Yang-Mills theory has a known infinite -series expression with successive terms suppressed by . We deri…
F-Theory, Spinning Black Holes and Multi-string Branches
Babak Haghighat, Sameer Murthy, Cumrun Vafa +1
We study 5d supersymmetric black holes which descend from strings of generic supergravity in 6d. These strings have an F-theory realization in 6d as D3 branes w…
Twisting and localization in supergravity: equivariant cohomology of BPS black holes
Imtak Jeon, Sameer Murthy
We develop the formalism of supersymmetric localization in supergravity using the deformed BRST algebra defined in the presence of a supersymmetric background as recently formulate…
Nonperturbative black hole entropy and Kloosterman sums
Atish Dabholkar, Joao Gomes, Sameer Murthy
Non-perturbative quantum corrections to supersymmetric black hole entropy often involve nontrivial number-theoretic phases called Kloosterman sums. We show how these sums can be ob…
New forms of attraction: Attractor saddles for the black hole index
Jan Boruch, Luca V. Iliesiu, Sameer Murthy +1
The count of microstates for supersymmetric black holes is typically obtained from a supersymmetric index in weakly-coupled string theory. We find the saddles in the gravitational…
Revisiting the Logarithmic Corrections to the Black Hole Entropy
Luca V. Iliesiu, Sameer Murthy, Gustavo J. Turiaci
Logarithmic corrections to the entropy of extremal black holes have been successfully used to accurately match degeneracies from microscopic constructions to calculations of the gr…
Fermions on replica geometries and the - relation
Sunil Mukhi, Sameer Murthy
In arXiv:1706:09426 we conjectured and provided evidence for an identity between Siegel -constants for special Riemann surfaces of genus and products of Jacobi -functio…
No entropy enigmas for N=4 dyons
Atish Dabholkar, Monica Guica, Sameer Murthy +1
We explain why multi-centered black hole configurations where at least one of the centers is a large black hole do not contribute to the indexed degeneracies in theories with N=4 s…
On supersymmetry breaking in string theory from gauge theory in a throat
Sameer Murthy
We embed the supersymmetry breaking mechanism in N=1 SQCD of hep-th/0602239 in a smooth superstring theory using D-branes in the background R^4 \times SL(2)_{k=1}/U(1) which smooth…
The 4d superconformal index near roots of unity and 3d Chern-Simons theory
Arash Arabi Ardehali, Sameer Murthy
We consider the superconformal index of 4d gauge theories. The Hamiltonian index is defined in a standard manner as the Witten ind…
BRST quantization and equivariant cohomology: localization with asymptotic boundaries
Bernard de Wit, Sameer Murthy, Valentin Reys
We develop BRST quantization of gauge theories with a soft gauge algebra on spaces with asymptotic boundaries. The asymptotic boundary conditions are imposed on background fields,…
D-branes in non-critical superstrings and duality in N=1 gauge theories with flavor
Sameer Murthy, Jan Troost
We study D-branes in the superstring background R^{3,1} \times SL(2,R)_{k=1}/U(1) which are extended in the cigar direction. Some of these branes are new. The branes realize flavor…
Supersymmetric phases of 4d N=4 SYM at large N
Alejandro Cabo-Bizet, Sameer Murthy
We find a family of complex saddle-points at large N of the matrix model for the superconformal index of SU(N) N=4 super Yang-Mills theory on with one chemical pot…
On the localization manifold of 5d supersymmetric spinning black holes
Rajesh Kumar Gupta, Sameer Murthy, Manya Sahni
We analyze the localization equations relevant to the quantum entropy of spinning supersymmetric black holes in five-dimensional asymptotically flat space. The precise problem is t…
Liouville D-branes in Two-Dimensional Strings and Open String Field Theory
Debashis Ghoshal, Sunil Mukhi, Sameer Murthy
We study open strings in the noncritical bosonic string theory compactified on a circle at self-dual radius. These strings live on D-branes that are extended along the Liouvi…
Two-dimensional superstrings and the supersymmetric matrix model
John McGreevy, Sameer Murthy, Herman Verlinde
We present evidence that the supersymmetric matrix model of Marinari and Parisi represents the world-line theory of N unstable D-particles in type II superstring theory in two dime…
Single-centered black hole microstate degeneracies from instantons in supergravity
Sameer Murthy, Valentin Reys
We obtain holographic constraints on the microscopic degeneracies of black holes by computing the exact macroscopic quantum entropy using localization, including the effects of str…
Squashed Toric Manifolds and Higher Depth Mock Modular Forms
Rajesh Kumar Gupta, Sameer Murthy, Caner Nazaroglu
Squashed toric sigma models are a class of sigma models whose target space is a toric manifold in which the torus fibration is squashed away from the fixed points so as to produce…
Quantum entropy of BMPV black holes and the topological M-theory conjecture
Rajesh Kumar Gupta, Sameer Murthy, Manya Sahni
We present a formula for the quantum entropy of supersymmetric five-dimensional spinning black holes in M-theory compactified on , i.e., BMPV black holes. We use supersymmetr…
Moonshine in Fivebrane Spacetimes
Jeffrey A. Harvey, Sameer Murthy
We consider type II superstring theory on and study perturbative BPS states in the near-horizon background of two Neveu-Schwarz fivebranes w…
Mock modularity from black hole scattering states
Sameer Murthy, Boris Pioline
The exact degeneracies of quarter-BPS dyons in Type II string theory on are given by Fourier coefficients of the inverse of the Igusa cusp form. For a fixed magneti…
The gravitational index and allowable complex metrics
Pietro Benetti Genolini, Sameer Murthy
We study the Kontsevich-Segal-Witten criterion for allowable complex metrics, in the context of the gravitational path integral corresponding to the supersymmetric index. In variou…
Squashed toric sigma models and mock modular forms
Rajesh Kumar Gupta, Sameer Murthy
We study a class of two-dimensional N=(2,2) sigma models called squashed toric sigma models, using their Gauged Linear Sigma Models (GLSM) description. These models are obtained by…
Microscopic origin of the Bekenstein-Hawking entropy of supersymmetric AdS black holes
Alejandro Cabo-Bizet, Davide Cassani, Dario Martelli +1
We present a holographic derivation of the entropy of supersymmetric asymptotically AdS black holes. We define a BPS limit of black hole thermodynamics by first focussing on a…
Non-critical Heterotic Superstrings in Various Dimensions
Sameer Murthy
We construct heterotic string theories on spacetimes of the form R^{d-1,1} times N=2 linear dilaton, where d=6,4,2,0. There are two lines of supersymmetric theories descending from…
D-branes in Unoriented Non-critical Strings and Duality in SO(N) and Sp(N) Gauge Theories
Sujay K. Ashok, Sameer Murthy, Jan Troost
We exhibit exact conformal field theory descriptions of SO(N) and Sp(N) pairs of Seiberg-dual gauge theories within string theory. The N=1 gauge theories with flavour are realized…
Allowable complex metrics and the gravitational index of AdS black holes
Pietro Benetti Genolini, Oliver Janssen, Sameer Murthy
We discuss the Kontsevich-Segal-Witten criterion for the allowability of complex metrics, in the context of the gravitational path integral that calculates the supersymmetric index…
Localization on I: the 4d/5d connection in off-shell Euclidean supergravity
Axel Ciceri, Imtak Jeon, Sameer Murthy
We begin to develop the formalism of localization for the functional integral of supergravity on . We show how the condition of supersymmetry in the Euclidean $\m…
Quantum Black Holes, Wall Crossing, and Mock Modular Forms
Atish Dabholkar, Sameer Murthy, Don Zagier
We show that the meromorphic Jacobi form that counts the quarter-BPS states in N=4 string theories can be canonically decomposed as a sum of a mock Jacobi form and an Appell-Lerch…
Holographic shear correlators at low temperatures, and quantum
Alexandros Kanargias, Elias Kiritsis, Sameer Murthy +2
The strongly-coupled 3-dimensional theory, holographically dual to black branes at fixed chemical potential $\muext$ and temperature is considered in AdS Einstein-Ma…
Entanglement, Replicas, and Thetas
Sunil Mukhi, Sameer Murthy, Jie-Qiang Wu
We compute the single-interval Renyi entropy (replica partition function) for free fermions in 1+1d at finite temperature and finite spatial size by two methods: (i) using the high…
A holomorphic anomaly in the elliptic genus
Sameer Murthy
We consider a class of gauged linear sigma models (GLSMs) in two dimensions that flow to non-compact (2,2) superconformal field theories in the infra-red, a prototype of which is t…
Unitary matrix models, free fermion ensembles, and the giant graviton expansion
Sameer Murthy
We consider a class of matrix integrals over the unitary group with an infinite set of couplings characterized by a series , with $a_n \in \math…
Quantum black holes, localization and the topological string
Atish Dabholkar, Joao Gomes, Sameer Murthy
We use localization to evaluate the functional integral of string field theory on AdS_2xS^2 background corresponding to the near horizon geometry of supersymmetric black holes in 4…
Black holes and modular forms in string theory
Sameer Murthy
The study of black holes in string theory has led to the discovery of deep and surprising connections between black holes and modular forms -- which are two classical, a priori unr…
The large- limit of the 4d superconformal index
Alejandro Cabo-Bizet, Davide Cassani, Dario Martelli +1
We systematically analyze the large- limit of the superconformal index of superconformal theories having a quiver description. The index of these theories is kno…
Fermionic trace relations and supersymmetric indices at finite
Giorgos Eleftheriou, Ziming Ji, Sameer Murthy
We study invariants of bosonic and fermionic (Grassmann-valued) matrices under the adjoint action of , weighted by the fermion number. Such models naturally appear as the sup…
Gravitational index of the D1-D5-P black string
Silvia Georgescu, Sameer Murthy, Andrew Svesko
We present saddle-points of the Euclidean Gravitational Path Integral (GPI) corresponding to the supersymmetric index of the D1-D5-P black string. These saddles are complex, supers…
Topological Cigar and the c=1 String : Open and Closed
Sujay K. Ashok, Sameer Murthy, Jan Troost
We clarify some aspects of the map between the c=1 string theory at self-dual radius and the topologically twisted cigar at level one. We map the ZZ and FZZT D-branes in the c=1 st…
Notes on Non-Critical Superstrings in Various Dimensions
Sameer Murthy
We study non-critical superstrings propagating in dimensional Minkowski space or equivalently, superstrings propagating on the two-dimensional Euclidean black hole tensor…
The gravitational index of 5d black holes and black strings
Jan Boruch, Roberto Emparan, Luca V. Iliesiu +1
The supersymmetric index of 5d black strings and spinning black holes in M-theory is related to that of 4d black holes in type IIA supergravity when both theories are compactified…
D-branes in non-critical superstrings and minimal super Yang-Mills in various dimensions
Sujay K. Ashok, Sameer Murthy, Jan Troost
We construct and analyze D-branes in superstring theories in even dimensions less than ten. The backgrounds under study are supersymmetric R^{d-1,1} \times SL(2,R)_k / U(1) where t…
Which AdS3 configurations contribute to the SCFT2 elliptic genus?
Sameer Murthy, Satoshi Nawata
According to the AdS/CFT duality, the superconformal index of a superconformal field theory should have an AdS interpretation as a Euclidean functional integral with periodic bound…
Stringy effects in black hole decay
Stanislav Kuperstein, Sameer Murthy
We compute the low energy decay rates of near-extremal three(four) charge black holes in five(four) dimensional N=4 string theory to sub-leading order in the large charge approxima…
Localization and wall-crossing of giant graviton expansions in AdS
Giorgos Eleftheriou, Sameer Murthy, Martà Rosselló
The -BPS indices of Super Yang-Mills theory with unitary, orthogonal, and symplectic groups all admit -expansions suggesting an interpretation in terms…
Strings in AdS: one-loop partition function and near-extremal BTZ thermodynamics
Christian Ferko, Sameer Murthy, Mukund Rangamani
We revisit the computation of the string partition function in AdS focussing on the appearance of spacetime (super) symmetries. We show how the asymptotic symmetries of the AdS…
Elliptic genera of ALE and ALF manifolds from gauged linear sigma models
Jeffrey A. Harvey, Sungjay Lee, Sameer Murthy
We compute the equivariant elliptic genera of several classes of ALE and ALF manifolds using localization in gauged linear sigma models. In the sigma model computation the equivari…
On the positivity of black hole degeneracies in string theory
Kathrin Bringmann, Sameer Murthy
Certain helicity trace indices of charged states in N=4 and N=8 superstring theory have been computed exactly using their explicit weakly coupled microscopic description. These ind…
Supersymmetric phases of AdS/CFT
Pietro Benetti Genolini, Alejandro Cabo-Bizet, Sameer Murthy
We exhibit an infinite family of supersymmetric phases in the three-dimensional ABJM superconformal field theory and the dual asymptotically AdS gravity. They are interpreted a…
Black hole microstate counting from the gravitational path integral
Luca V. Iliesiu, Sameer Murthy, Gustavo J. Turiaci
Reproducing the integer count of black hole micro-states from the gravitational path integral is an important problem in quantum gravity. In this paper, we show that, by using supe…
Strings and near-extremal black holes in theories with large superconformal symmetry
Sameer Murthy, Mukund Rangamani
We study the one-loop partition function of superstrings in the background. Specifically, we show that…
Modular symmetry of massive free fermions
Max Downing, Sameer Murthy, Gerard M. T. Watts
We construct an infinite set of conserved tensor currents of rank , , in the two-dimensional theory of free massive fermions, which are bilinear in the fermionic f…
The asymptotic growth of states of the 4d N=1 superconformal index
Alejandro Cabo-Bizet, Davide Cassani, Dario Martelli +1
We show that the superconformal index of N=1 superconformal field theories in four dimensions has an asymptotic growth of states which is exponential in the charges. Our analysis h…
Localization & Exact Holography
Atish Dabholkar, Joao Gomes, Sameer Murthy
We consider the AdS_2/CFT_1 holographic correspondence near the horizon of big four-dimensional black holes preserving four supersymmetries in toroidally compactified Type-II strin…
Fundamental Superstrings as Holograms
Atish Dabholkar, Sameer Murthy
The worldsheet of a macroscopic fundamental superstring in the Green-Schwarz light-cone gauge is viewed as a possible boundary hologram of the near horizon region of a small black…
The growth of the -BPS index in 4d SYM
Sameer Murthy
We study the Hamiltonian index of -BPS operators in 4d U(N) super Yang-Mills (SYM) theory numerically for . We show that the large-cha…