For possible afternoon program activities please look in the "Outdoor activities" for more information.
We show that the behaviour of 2D vacuum transitions is reminiscent of the CFT$_2$/CFT$_1$ correspondence. In doing so, we perform the calculation in 3 different methods, namely the Euclidean formalism of Coleman-de Luccia and Brown-Teitelboim, and the Hamiltonian method of Fischler, Morgan and Polchinski. The bounces from the Euclidean methods are always proportional to the central charge,...
Two-dimensional Conformal Field Theories (CFTs) are defined via a list of primary operators, along with their scaling dimensions, spins and OPE coefficients. This set of data, along with the central charge, uniquely defines any correlation function of the theory on an arbitrary Riemann surface. Using consistency conditions like crossing symmetry and modular invariance, one can show that there...
Two-dimensional Conformal Field Theories (CFTs) are defined via a list of primary operators, along with their scaling dimensions, spins and OPE coefficients. This set of data, along with the central charge, uniquely defines any correlation function of the theory on an arbitrary Riemann surface. Using consistency conditions like crossing symmetry and modular invariance, one can show that there...
Further progress in simulating heavy ion collisions via holography, beyond the collision of localized, broad, Gaussian shocks, is held back by numerical difficulties of solving 5D Einstein equations with initial conditions corresponding to localized projectiles with a large difference between longitudinal and transverse scales. Recent techniques are discussed which turn this obstacle into an...
We establish 1d Neumann-Rosochatius (NR) integrable model for rotating and pulsating string ansatz in some less conventional 2d nonlinear string sigma models, specifically, the fundamental string probing the gravity background of planar ABJ theory and the manifest SL(2, Z) covariant (p,q)-type bound states of fundamental string and D1 branes in $AdS_3\times S^3\times T^4$ background with mixed...
Despite two decades of efforts, constructing metastable de Sitter vacua in String Theory continues to be a great challenge and the almost twenty-year-old construction of Kachru, Kallosh, Linde and Trivedi (KKLT), although not uncontested, remains the prototypical example. This proposal is a three-step construction that combines fluxes, non-perturbative phenomena and anti-D3 branes in a warped...
The AdS/CFT correspondence states that certain CFTs admit a description in terms of a gravitational theory in asymptotically AdS geometries of one dimension more. one of the most fascinating examples of this correspondence is the ER = EPR proposal that relates entanglement in the boundary gauge theory to a gravitational wormhole connecting two asymptotic regions of an eternal black hole in its...
Reversing the logic of the bootstrap approach in Liouville CFT we explicitly compute the connection formulae for degenerate conformal blocks. In the semiclassical limit of the theory, this amounts to solving the connection problem of Fuchsian ODEs. Generalizing to irregular insertions we solve as well for various confluences. Concentrating on the Heun equation and its confluences, we can solve...
Reversing the logic of the bootstrap approach in Liouville CFT we explicitly compute the connection formulae for degenerate conformal blocks. In the semiclassical limit of the theory, this amounts to solving the connection problem of Fuchsian ODEs. Generalizing to irregular insertions we solve as well for various confluences. Concentrating on the Heun equation and its confluences, we can solve...
In the last few years, there has been enormous progress on the statistical description of the entropy of BPS black holes in AdS$_D$ for $D>3$ in terms of states in the dual field theory. The success of such developments relies on the existence of an extremisation principle in the bulk which maps to the evaluation of the partition function in the field theory in the large charge limit. I will...
Holographic investigations have revealed the importance of quantum chaos and random matrix theory in the unitary description of black holes. The spectral form factor associated with the $e^{S_{BH}}$ microstates that compose the black hole serve as a simple proxy for studying how perturbations to black holes thermalize. I will discuss how the details of the spectral statistics of the...
I will describe the “bootstrability” program, which combines integrability techniques in 4d N = 4 supersymmetric Yang-Mills (SYM) and the conformal bootstrap to study beyond-the-spectrum observables in a CFT.
Focussing on the 1d defect CFT living on the Maldacena-Wilson line in N = 4 SYM, I will show how the quantum spectral curve (QSC), a powerful integrability based method solves its...
Tremendous progress has been achieved during the last years in bootstrapping conformal correlators at strong coupling using analytical bootstrap methods and the AdS/CFT correspondence. In particular the development of Lorentzian inversion formulae revealed helpful in reconstructing four-point functions. In this work we present how this technology can be adapted to defect setups in order to...
In recent years, complexity has gained a lot of interest in the study of holography and has been subject to a number of holographic proposals. While first defined and studied in the context of quantum computation in terms of discrete operations in the form of gates, a continuous generalization of complexity has been introduced by Nielsen et al. In this picture, the complexity of given unitary...
It is more than 20 years since the advent of the famed AdS/CFT correspondence, which has given a firm footing to the idea of holography. Our physical world is, however, clearly not AdS. For many applications, especially astrophysical ones, the universe can be approximated by an asymptotically flat spacetime. It is thus of great importance to extend the notion of holography from its original...
We show how to construct an explicit map between boundary states and quantum gravity states in AdS/CFT via a specific field theory path integral on a bulk Cauchy slice, rather than on the asymptotic boundary. The field theory is constructed from the boundary CFT via an irrelevant deformation, which is the analogue of the well-known $T\bar{T}$ operator in two boundary dimensions. Our...
We show how to construct an explicit map between boundary states and quantum gravity states in AdS/CFT via a specific field theory path integral on a bulk Cauchy slice, rather than on the asymptotic boundary. The field theory is constructed from the boundary CFT via an irrelevant deformation, which is the analogue of the well-known $T\bar{T}$ operator in two boundary dimensions. Our...
We consider 2-to-2 celestial scattering amplitudes for massless external particles in d=4 dimensions using crossing symmetric dispersion relations employed in recent studies of the S-matrix bootstrap. The crossing symmetric dispersive representation of the amplitude has spurious singularities for complex values of the celestial cross-ratio z, which need to be removed in local QFTs. We show...
In the last years the discovery of the duality between JT quantum gravity and a double-scaled matrix model [1] has led to an intense cross-fertilization between the fields of holography and quantum chaos. Starting on the quantum chaos side, we investigate the implications imposed by the universal RMT behaviour of the matrix model [2] on JT gravity. Specifically we show how the consistency of...
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We analyze how deforming symmetric product orbifolds of two-dimensional $\mathcal{N}=2$ conformal field theories by an exactly marginal operator lifts higher spin currents present at the orbifold point. We find on the one hand that these currents are universally lifted regardless of the underlying CFT. On the other hand the details of the lifting are surprisingly non-universal, with dependence...
We advance two alternative proposals for the island contributions to the entanglement negativity of various pure and mixed state configurations in quantum field theories coupled to semiclassical gravity. The first construction involves the extremization of an algebraic sum of the generalized Renyi entropies of order half. The second proposal involves the extremization of the sum of the...
We present higher-spin algebras containing a Poincaré subalgebra and with the same set of generators as the Lie algebras that are relevant to Vasiliev’s equations in any space-time dimension D ≥ 3.
In this poster, I will briefly review renormalization group monotones (F-functions) of three dimensional quantum field theories and present our work on this topic. In our work (arXiv:2112.08715), we consider holographic F-functions in a top-down AdS/CFT setup involving flavored ABJM theory on a Euclidean 3-sphere. For quenched flavor, the holographic dual is type IIA supergravity with probe...
Fractons are quasiparticles with the distinctive feature of having only limited mobility. This bizarre trait and their unusual symmetries also make the coupling to curved spacetime nontrivial. I will show how aristotelian geometry provides the right framework, review the state-of-the-art on this issue, provide a novel no-go theorem for theories with linear dipole symmetry, spatial derivatives...
I will discuss how fracton physics can be studied systematically within the geometric framework of double field theory (DFT). I will argue that the restricted mobility and large degeneracy of quantum states can be attributed to the generalized geodesics and infinite-dimensional isometries present in non-Riemannian backgrounds of DFT. Moreover, it turns out that a DFT Yang-Mills or Maxwell...
The problem of explicitly computing Gopakumar-Vafa (GV) invariants of Calabi-Yau threefolds is, in most cases, challenging.
We propose a novel way to fully characterize the GV invariants of singular Calabi-Yau threefolds arising from deformations of ADE singularities, employing a completely linear-algebraic method that computes zero-modes of an adjoint Higgs scalar, associated to the...
4d holomorphic QFTs (such as those obtained from twisting N=1 QFTs) are endowed with extra structures and symmetries which are a 4d analogue of a 2d chiral algebra. In this talk, I will describe these holomorphic theories, higher structures that arise in studying loop corrections to the BRST differential, and a recursive "bootstrap" procedure for systematically computing these loop...
I argue for the existence of single-trace, two-matrix models that are dual at the level of the disk to Jackiw-Teitelboim gravity minimally coupled to a massive scalar field. One matrix is interpreted as the Hamiltonian of the boundary quantum mechanical theory, while the other matrix is an operator that is dual to the bulk field. In one of the models, before the double-scaling limit is taken,...
The conformal data of generic CFTs involving heavy charged operators can be organised as a series in inverse powers of the global charges involved. When extrapolating these expansions to light low-charge sectors, is it relevant to ask whether these series are divergent and Borel-summable. In this talk, I will show that the O(N) scalar CFT has a large-charge expansion which is not...
In the matrix quantum mechanics (MQM) dual to the non-supersymmetric 2d black hole, we identify a set of degenerate states as the black hole microstates. At leading order in large $N$, the log of number of these states (already calculated by Gross and Klebanov) matches the Bekenstein-Hawking entropy formula, and also agrees with one of two candidates found by Kazakov and Tseytlin. The mass...
We classify multi-partite entanglement measures and count them for large dimensional quantum systems. We compute these measures for two dimensional conformal field theories using twist operators and find that they are given by the lightest Virasoro conformal block in appropriate channel. In the limit of large central charge $c$, these blocks reduce to geodesic networks on the hyperbolic...
One dimensional CFTs are an exceptional laboratory in which we can test novel techniques in order to solve higher dimensional CFTs. They are also relevant from an holographic point of view, as in the case of the Wilson line defect in 4d N=4 Super Yang-Mills, which has an AdS_2 holographic dual. In this context, we focus on an under-explored subject: higher-point correlation functions. At weak...
A first order phase transition for photons and gravitons in a Casimir box is studied analytically from first principles with a detailed understanding of symmetry breaking due to boundary conditions. It is closely related to Bose-Einstein condensation and accompanied by a quantum phase transition whose control parameter is the chemical potential for optical helicity.
Krylov complexity is a notion of complexity that characterizes the spread of an operator over the algebra of observables by measuring its projection over a suitable orthonormal basis of this algebra built out of nested commutators of the Hamiltonian with the operator. Using this basis, operator dynamics can be mapped to a one-dimensional hopping problem. I will present recent results on the...
We find that the complexity of quantum many-body states, defined as a spread in the Krylov basis, may serve as a probe that distinguishes topological phases of matter. We illustrate this analytically in one of the representative examples, the Su-Schrieffer-Heeger model. Moreover, in the same setup, we analyze exactly solvable quench protocols where the evolution of the spread complexity shows...
On the bulk side of the AdS/CFT correspondence, there is a TFT that controls which combinations of line operators are mutually local in the gauge theory side. We show that this TFT can be used to reproduce the line-operator classification of 4d gauge theories of Aharony, Tachikawa, and Seiberg.
I will discuss the analytic bootstrap technique applied to holographic superconformal field theories. In particular I will focus on $\mathcal{N}=4$ Super Yang-Mills and study correlators of quarter-BPS operators. Despite the fact that they are less protected than their half-BPS counterparts, these correlators can be constrained via the chiral algebra twist and this information is enough to...
We revisit the no-hair theorems in Einstein-Scalar-Gauss-Bonnet theory with a general coupling function between the scalar and the Gauss-Bonnet term in four dimensional spacetime. We first resolve the conflict caused from the incomplete derivation of the old no-hair theorem by taking into account the surface term and restore its reliability. We also clarify that the novel no-hair theorem is...
Large black holes in anti-de Sitter space have positive specific heat and do not evaporate. In order to mimic the behavior of evaporating black holes, one may couple the system to an external bath. In this poster we explore a rich family of such models, namely ones obtained by coupling two holographic CFTs along a shared interface (ICFTs). We focus on the limit where the bulk solution is...
Charged and symmetry-resolved Rényi entropies are entanglement measures quantifying the degree of entanglement within different charge sectors of a theory with a conserved global charge. We use holography to determine the dependence of charged Rényi entropies on small shape deformations away from a spherical or planar entangling surface in general dimensions. This dependence is completely...
The study of cosmological singularities in the context of string theory has been widely addressed on different time-dependent spacetime backgrounds and has never proved completely successful. Here we investigate the Null Boost Orbifold, which reproduces a Big-Bang type singularity but unfortunately suffers from unusual divergences when dealing with scattering amplitudes both in the closed and...
In previous work, a first law of generalized entropy was derived from semiclassical gravitational dynamics around thermal setups using an assumed relation between the matter modular Hamiltonian and the gravitational stress tensor. Allowing for non-minimal coupling between curvature and any tensor matter fields, we show however, that the modular Hamiltonian of thermal states is given by the...
We study the effect of conserved charges on thermalization in quantum chaotic systems. Holographically, in the presence of a chemical potential, a non-monotonicity appears in the thermalization time as a function of chemical potential for small regions. To shed light on this behavior from the quantum side we study the dynamics of out of equilibrium states in finite-dimensional spin chains. Our...
We argue that an Euclidean supergravity vacuum solution of the form $\mathbb{R}\times S^1\times \mathbb{T}^8$ with imaginary self-dual $F_1$-flux through $\mathbb{R}\times S^1$ is the natural end to the chain of AdS$_d\times S^d\times \mathbb{T}^{10-2d}$-vacua with imaginary self dual $F_d$ flux, where $d\leq 5$. Such vacua come from the near-horizon of D($d-2$)/D($8-d$) branes and are...
We discuss four-derivative corrections to pure $\mathcal{N}=2$, $D=5$ gauged supergravity, up to field redefinitions. In particular, the possible four-derivative corrections can be parametrized on-shell by a basis of five terms. We have found that, up to factors of the two-derivative action, supersymmetry picks out a unique set of coefficients for these terms, ie, there is a unique...
We study the non-linear structure of Type IIB eight-derivative couplings involving the metric and the complexified three-form $G_3$. We show that, at the level of five-point string amplitudes, the kinematics in the maximally R-symmetry-violating sector is fully matched by standard superspace integrals and by superparticle amplitudes in M-theory on a two-torus. The latter approach is used to...
We investigate codimension-one vacua resulting from low energy effective actions in ten-dimensional string models without tachyons.
The main target is the non-supersymmetric Sugimoto USp(32) model, whose nine-dimensional solution is believed to contain backreacting 8-branes. We discuss the defects that interpolate between different vacua, possibly playing the role of the aforementioned...
One of the most important objectives of string theory is to account for the bulk entropy of the 3-charge black hole. Some microstates may not have a reliable supergravity description, and thus models that capture stringy physics may be essential. I will present an exact worldsheet model describing the propagation of a string in some non-BPS microstates, and show how to compute correlation...
