University of Crete HEP Seminars
Recordings can be found in this link
Emergent fields from Hidden sectors
Speaker: | Pascal Anastasopoulos |
Institution: | Vienna University |
Time: | Tuesday 11 February 2020, 14:15 |
Venue: | 2nd floor seminar room |
Abstract: | Hidden theories coupled to the SM may provide emergent fields, that are composites/bound-states of the hidden fields. This is motivated by paradigms emerging from the AdS/CFT correspondence but it is a more general phenomenon. We explore the general setup and we focus on axions, graviphotons (or dark photons) and neutrinos. |
Consistent truncations of supergravity and twisted 4d Superconformal Field Theories
Speaker: | Chris Rosen |
Institution: | University of Barcelona |
Time: | Thursday 20 February 2020, 14:15 |
Venue: | 2nd floor seminar room |
Abstract: | Superconformal field theories (SCFTs) in four dimensions are a cornerstone of contemporary theoretical physics. In the last decade, interesting classes of such theories have been constructed by compactifying six dimensional SCFTs on a Riemann surface. These theories, as well as some of their less supersymmetric deformations, are notable in that they lack a Lagrangian description. A powerful method for exploring the physics of such theories is provided by the methods of gauge/gravity duality. We illustrate this approach by first reviewing how the four dimensional fixed point theories are described by solutions to eleven dimensional supergravity. We then describe new solutions of the 11d theory that holographically encode deformations of the 4d SCFTs. Our techniques allow one to study these deformations in a five dimensional gauged supergravity theory, which arises as a consistent truncation of the 11d theory and greatly simplifies calculations. |
Uplifting Runaways and the Tadpole Problem
Speaker: | Severin Lust |
Institution: | Ecole Polytechnique |
Time: | Tuesday 25 February 2020, 14:15 |
Venue: | 2nd floor seminar room |
Abstract: | I will discuss a mechanism which can lead to a possible instability of the KKLT construction for de Sitter vacua. The sphere at the tip of a warped deformed conifold throat can be destabilized by antibranes placed in the throat. Consequently, the stabilization of moduli should not be treated independently from the antibrane uplift in KKLT-like scenarios. A similar bound can be found for numerically constructed Klebanov-Strassler black holes. This conifold destabilization mechanism can be avoided by turning on a large amount of flux on the sphere, but tadpole cancelation constraints the hierarchy of scales in a type IIB flux compactification. Even though sufficiently large tadpole bounds can be realized in string theory, they always come at the expense of a large number of moduli. The stabilization of these moduli by fluxes contributes to the tadpole condition as well, reducing the maximal flux on the KS-throat. I will discuss this problem for the example of M-theory on K3 x K3. |
Supersymmetric phases of N = 4 SYM at large N
Speaker: | Alejandro Cabo-Bizet |
Institution: | KCL London |
Time: | Tuesday 03 March 2020, 14:15 |
Venue: | 2nd floor seminar room |
Abstract: | We show the existence of an infinite family of complex saddle-points at large N, for the matrix model of the superconformal index of SU(N) N = 4 super Yang-Mills theory on S3 x S1 with one chemical potential t. The saddle-point configurations are labelled by points (m,n) on the lattice Lambda t = Z t + Z with gcd(m, n) = 1. The eigenvalues at a given saddle are uniformly distributed along a string winding (m, n) times along the (A, B) cycles of the torus C/Lambda t . The action of the matrix model extended to the torus is closely related to the Bloch-Wigner elliptic dilogarithm, and its values at (m,n) saddles are determined by Fourier averages of the latter along directions of the torus. The actions of (0,1) and (1,0) agree with that of pure AdS5 and the Gutowski-Reall AdS5 black hole, respectively. The actions of the other saddles take a surprisingly simple form. Generically, they carry non vanishing entropy. The Gutowski-Reall black hole saddle dominates the canonical ensemble when t is close to the origin, and other saddles dominate when t approaches rational points. |
Under the spell of gauge theory
Speaker: | Elli Pomoni |
Institution: | DESY |
Time: | Thursday 12 March 2020, (Colloqium 17:00) |
Venue: | 3rd floor seminar room |
Abstract: | Gauge theories provide the theoretical framework we use to describe the world we live in. Even though it is the most successful physical theory that men ever invented, it is still not known how to use it in order to explain a plethora of important phenomena such as confinement. In this talk I will take you on a trip through the modern developments in theoretical physics aiming to break this impasse. I will show to you how, based on very simple principles like symmetry and duality, remarkable progress has been made. |
Type-B Anomaly Matching and the 6D (2,0) Theory
Speaker: | Elli Pomoni |
Institution: | DESY |
Time: | Tuesday 17 March 2020, 14:15 |
Venue: | 2nd floor seminar room |
Abstract: | In this talk, we will study type-B conformal anomalies associated with 1/2 -BPS Coulomb-branch operators in 4D N = 2 superconformal field theories. When the vacuum preserves the conformal symmetry these anomalies coincide with the two-point function coefficients in the Coulomb branch chiral ring. They are non-trivial functions of exactly-marginal couplings that can be obtained from the S^4 partition function. We will examine the fate of these anomalies in vacua of the Higgs-branch moduli space, where conformal symmetry is spontaneously broken. We argue non-perturbatively that these anomalies are covariantly constant on conformal manifolds. In some cases, this can be used to show that they match in the broken and unbroken phases. Thus, we will uncover a new class of data on the Higgs branch of 4D N = 2 conformal field theories that are exactly computable. An interesting application of this matching occurs in N = 2 circular quivers which deconstruct the 6D (2,0) theory on a torus. In that context, we argue that 4D supersymmetric localisation can be used to calculate non-trivial data involving 1/2 -BPS operators of the 6D theory as exact functions of the complex structure of the torus. |
How Cosmological Coleman-Weinberg Potentials Depend on the Geometry of Inflation
Speaker: | Richard Woodard |
Institution: | University of Florida |
Time: | Thursday 26 March 2020, 14:15 |
Venue: | 2nd floor seminar room (webinar) |
Abstract: | Cosmological Coleman-Weinberg potentials are induced by coupling the inflaton of scalar-driven inflation to ordinary matter in order to facilitate reheating. These potentials are not Planck-suppressed, and are far too steep to be consistent with inflation. However, they cannot be subtracted with local, lower derivative counterterms because they depend on the geometry of inflation in a complicated way. Explicit results have previously only been obtained for de Sitter background, in which the Hubble parameter is strictly constant. In this talk I describe an approximate computation which gives the result for arbitrary Hubble parameter. This paper is based on arXiv:1506.07306, 1806.02533, 1908.03814 and 1908.05558. |
Supersymmetry anomalies
Speaker: | Ioannis Papadimitriou |
Institution: | KIAS |
Time: | Tuesday 31 March 2020, 14:15 |
Venue: | 2nd floor seminar room (webinar) |
Abstract: | Supersymmetric quantum field theories with an anomalous flavor or R-symmetry have a 't Hooft anomaly in Q-supersymmetry, i.e. the supercurrent is not conserved. I will first derive this anomaly by coupling the theory to either background vector multiplets or background supergravity in four dimensions, and solving the corresponding Wess-Zumino consistency conditions. A second derivation will be given in terms of anomaly inflow from a suitable supersymmetric Chern-Simons theory in one dimension higher. Although the supersymmetry anomaly can often be viewed as consequence of the Wess-Zumino gauge for the background supermultiplets, this does not mean that it is unphysical. I will show that the auxiliary fields in the off-shell superspace multiplet play the role of symmetry compensators, simply repackaging the same physical information. In particular, the supersymmetry anomaly implies that the supersymmetry transformation of the supercurrent receives quantum corrections, which in turn leads to a central extension of the supersymmetry algebra on curved backgrounds that admit Killing spinors. I will conclude by discussing how this modified algebra affects the supersymmetric partition function. |
Recording: | The recorded talk can be found here in BBB format and Mp4 format |
Black Holes as a Hologram
Speaker: | Ioannis Papadimitriou |
Institution: | KIAS |
Time: | Wednesday 1 April 2020, 14:00 (Colloqium) |
Venue: | 2nd floor seminar room (webinar) |
Abstract: | Black holes constitute the ultimate testing ground of fundamental physics. A century after their discovery as solutions of Einstein's equations of gravity, they continue to challenge our deepest understanding of nature, as well as our experimental capabilities. It was not until the operation of the LIGO and Virgo gravitational wave detectors in the last few years that a direct observation of black holes became possible. A consistent mathematical framework for quantum gravity capable of addressing key questions such as the black hole information paradox and the microscopic origin of black hole entropy was developed also relatively recently, with the discovery of string theory and the AdS/CFT correspondence. I will describe black holes as thermodynamic systems and as renormalization group flows in the context of holographic dualities. This will lead us to a discussion of recent advances in the identification of the microscopic degrees of freedom responsible for the macroscopic entropy of supersymmetric and near extremal black holes in terms of strongly interacting quantum systems. |
A review on lambda-deformations I
Speaker: | Konstantinos Siampos |
Institution: | UOA |
Time: | Tuesday 07 April 2020, 14:15 |
Venue: | 2nd floor seminar room (webinar) |
Abstract: | We will revisit the construction of the lambda-deformed sigma models initiated in 1312.4560. These models are classically integrable, interpolating between exact current algebra CFTs at level k and the non-Abelian T-duals of principal chiral models. They are invariant under a weak-strong duality type symmetry which involves the deformation parameter lambda and the level k. Employing gravitational techniques, conformal perturbation and the aforementioned symmetry, we find the beta-functions and the anomalous dimensions of currents and current bilinears at leading order in the 1/k expansion. Afterwards, we will evaluate the 2- and 3-point correlation functions of the currents, deducing the OPEs and the equal-time commutators/Poisson brackets. These assume the underlying Poisson structure of the lambda-deformed sigma-models. Then we will consider generalized effective actions interpolating between exact CFTs. Employing CFT techniques we show how to compute, in the context of lambda-deformed CFTs, the exact in the deformation parameters C-function, satisfying Zamolodchikov's c-theorem. Extending the above results at two-loop in the 1/k expansion uncovers an extension of the duality type symmetry. Finally, we will illustrate how such deformations give rise to background solutions of type-II supergravity. Related papers: hep-th/9307030, 1312.4560, 1404.3748, 1407.2840, 1509.02946, 1604.08212, 1612.05012, 1707.05149, 1805.03731, 1906.00984, 1910.01056, 1911.02027 |
A review on lambda-deformations II
Speaker: | Konstantinos Siampos |
Institution: | UOA |
Time: | Thursday 09 April 2020, 14:15 |
Venue: | 2nd floor seminar room (webinar) |
Abstract: | We will revisit the construction of the lambda-deformed sigma models initiated in 1312.4560. These models are classically integrable, interpolating between exact current algebra CFTs at level k and the non-Abelian T-duals of principal chiral models. They are invariant under a weak-strong duality type symmetry which involves the deformation parameter lambda and the level k. Employing gravitational techniques, conformal perturbation and the aforementioned symmetry, we find the beta-functions and the anomalous dimensions of currents and current bilinears at leading order in the 1/k expansion. Afterwards, we will evaluate the 2- and 3-point correlation functions of the currents, deducing the OPEs and the equal-time commutators/Poisson brackets. These assume the underlying Poisson structure of the lambda-deformed sigma-models. Then we will consider generalized effective actions interpolating between exact CFTs. Employing CFT techniques we show how to compute, in the context of lambda-deformed CFTs, the exact in the deformation parameters C-function, satisfying Zamolodchikov's c-theorem. Extending the above results at two-loop in the 1/k expansion uncovers an extension of the duality type symmetry. Finally, we will illustrate how such deformations give rise to background solutions of type-II supergravity. Related papers: hep-th/9307030, 1312.4560, 1404.3748, 1407.2840, 1509.02946, 1604.08212, 1612.05012, 1707.05149, 1805.03731, 1906.00984, 1910.01056, 1911.02027 |
Homogeneous Holographic Viscoelastic Model, Who Are You ?
Speaker: | Matteo Baggioli |
Institution: | IFT, Madrid |
Time: | Friday 10 April 2020, 11:15 |
Venue: | 2nd floor seminar room (webinar) |
Abstract: | Models with broken translational invariance have attracted a great deal of interest in the holographic community in recent years, especially in relation to their hydrodynamic description and their possible relevance for strange metal phenomenology. Particular emphasis has been given to the so-called homogeneous models, due to their appealing simplicity. Despite the sustained activity in the field, there still remain a number of open questions. In this talk, I will discuss three fundamental points: 1) What is the correct hydrodynamic description for these models ? 2) What are these models describing ? 3) What is the meaning of the universal phase relaxation found in the literature ? I will provide a concrete and definitive resolution to the first point and I will propose a possible physical interpretation which provides simple answers to the rest of the open issues. |
The black hole S-matrix and Chaos
Speaker: | Panos Betzios |
Institution: | UOC |
Time: | Tuesday 28 April 2019, 14:15 |
Venue: | 2nd floor seminar room (webinar) |
Abstract: | I will review the shockwave construction of 't Hooft, which takes into account a strong gravitational backreaction effect near the black hole horizon. This can lead to a unitary S-matrix for particles scattering on an eternal black hole background. I will then describe an explicit dynamical quantum mechanical system that results in the same S-matrix, whose Hamiltonian is related to the Dilation operator. In order to obtain a background with a single exterior, a global antipodal (CPT) identification of the Kruskal manifold was proposed by 't Hooft, that could in principle give a resolution to the information paradox for single sided asymptotically flat black holes. I will discuss the various problems present in this proposal and motivate a local form of the identification in phase space that takes into account the symmetries of the Hamiltonian. This provides a natural discretisation of the spectrum, that is shown to coincide with the zeros of the Riemann zeta and Dirichlet beta functions. It strengthens the proposal that our quantum Hamiltonian captures the dynamics of a Schwarzschild black hole, given the rich chaotic spectrum upon discretisation. It also explains why the spectrum appears to be erratic despite the unitarity of the scattering matrix. |
Recording: | The recorded talk can be found here in BBB format and Mp4 format |
Entanglement and Algebraic Transformations on Topological Quantum Field Theories
Speaker: | Matthew Buican |
Institution: | QMUL |
Time: | Thursday 30 April 2020, 14:15 |
Venue: | 2nd floor seminar room (webinar) |
Abstract: | I will describe certain natural algebraic transformations that one can perform on 2+1 dimensional topological quantum field theories (TQFTs) like Chern-Simons theories. These transformations allow one to sensibly explore the space of 2+1 dimensional TQFTs. In order to give these transformations physical meaning, I will explain how they preserve certain measures of entanglement. Throughout, I will connect these results to other areas of interest in the world of TQFT. |
Recording: | The recorded talk can be found here in BBB format and Mp4 format |
Strings at the horizon
Speaker: | Ulf Danielsson |
Institution: | Uppsala University |
Time: | Thursday 07 May 2020, 17:00 |
Venue: | 3d floor seminar room (Colloqium) |
Abstract: | The physics of horizons is one of the deepest problems in fundamental physics. In this talk we explore the mysteries associated with event horizons of black holes, as well as dark energy and the cosmic horizon. Has string theory provided solutions or is there still something missing? |
Vortex Lattices From Holography
Speaker: | Aristomenis Donos |
Institution: | Durham University |
Time: | Tuesday 12 May, 14:15 |
Venue: | 2nd floor seminar room (webinar) |
Abstract: | Vortices are fascinating stable configurations of electric currents that occur in the broken phase of superconductors. Based on an effective field theory approach, Abrikosov argued that when the force between them is repulsive, stable periodic configurations can form. In my talk I will consider similar constructions for superfluids away from the critical temperature. Moreover, I will discuss how known field theories can exhibit phases which are not captured by Abrikosov's considerations. |
Recording: | The recorded talk can be found here in BBB format and Mp4 format |
Anisotropic Holography
Speaker: | Dimitrios Giataganas |
Institution: | NKUA |
Time: | Tuesday 19 May, 14:15 |
Venue: | 2nd floor seminar room (webinar) |
Abstract: | Strongly coupled anisotropic systems have significantly richer structure than the isotropic ones. This is especially evident in the transport coefficients and in the phase diagram of anisotropic theories. We discuss such holographic theories, we comment on their observables and demonstrate how the isotropic universal relations are violated in presence of anisotropies. We also propose c-function candidates for the anisotropic RG flows and show that their monotonicity is not any more guaranteed by the energy conditions but depends on the theory characteristics. |
Recording: | The recorded talk can be found here in BBB format and Mp4 format |
Transport, Strong Coupling and Black Holes
Speaker: | Aristomenis Donos |
Institution: | Durham University |
Time: | Thursday 21 May, 17:15 |
Venue: | (webinar Colloqium) |
Abstract: | One of the most fascinating aspects of many body systems is the collective behaviour of their degrees of freedom under external sources. The question is not only of fundamental importance but also of practical and technological importance in condensed matter systems. Models of weakly coupled particles have been extremely successful in understanding universal properties of transport. In my talk I will explain how black holes can help us understand transport properties of strongly coupled systems and probe regimes which are intrinsically non-perturbative. |
Recording: | The recorded talk can be found here in BBB format and Mp4 format |
The connection problem for AdS2
Speaker: | Achilleas Porfyriadis |
Institution: | Harvard and Black Hole Initiative |
Time: | Tuesday 26 May, 16:15 |
Venue: | 2nd floor seminar room (webinar) |
Abstract: | I will talk about the problem of extending anti-de Sitter solutions away from the near-horizon region of (near-)extreme black holes and connecting them with solutions in the black holes far asymptotically flat region. In Part I of the talk I will present analytic solutions to the connection problem for coupled gravitational and electromagnetic perturbations of AdS2xS2 and near-AdS2xS2 in the extreme and near-extreme Reissner-Nordstrom black holes, respectively. In Part II of the talk I will discuss a calculation of backreaction in AdS2. In this calculation, an AdS2xS2 throat geometry reacts to a perturbation by a scalar field in such a way that, with leaky boundary conditions, it maintains its connection to the far asymptotically flat region of the black hole. |
Recording: | The recorded talk can be found here in BBB format and Mp4 format |
Bootstrapping theories with O(m)xO(n) global symmetry in three dimensions
Speaker: | Stefanos Kousvos |
Institution: | UOC |
Time: | Thursday 28 May 2020, 14:15 |
Venue: | 2nd floor seminar room (webinar) |
Abstract: | I will discuss recent work performed with Johan Henriksson and Andreas Stergiou studying O(m)xO(n) symmetric conformal field theories in three dimensions. Motivated by phase transitions in three-dimensional systems, as well as open theoretical questions, we will focus on the O(2)xO(n) case. We study different values of n, for n sufficiently large we find excellent agreement with Large n predictions for scaling dimensions of operators. For n=3 we find closed isolated regions (islands) in parameter space that do not correspond to the ordinary fixed points of the d=4-e expansion, we attribute these regions of parameter space to fixed points conjectured to arise due to resummations of perturbative beta functions. |
Recording: | The recorded talk can be found here in BBB format and Mp4 format |
Dynamics of Fluids without Boost Symmetries
Speaker: | Jelle Hartong |
Institution: | University of Edinburgh |
Time: | Tuesday 2 June 2020, 13:15 |
Venue: | 2nd floor seminar room (webinar) |
Abstract: | Standard textbook treatments of fluid dynamics assume the presence of a boost symmetry. This is either a Galilean boost symmetry or a Lorentzian one and leads to the Navier-Stokes equations or their relativistic counterpart. It is however not necessary to rely on a boost symmetry as one can treat velocity as the chemical potential associated with momentum conservation. In fact for fluids moving through a medium one expects boost symmetries to be generically broken. This includes the case of scale invariant Lifshitz fluids. In this talk I will present the general treatment of fluid dynamics without boost symmetries and I will show that there can be 10 dissipative and 6 non-dissipative transport coefficients (of which 2 are hydrostatic and 4 are not) for uncharged non-boost invariant fluid dynamics. Time permitting, I will discuss some general ideas regarding holographic realisations of non-boost invariant Lifshitz fluids. |
Recording: | The recorded talk can be found here in BBB format and Mp4 format |
Strong Cosmic Censorship versus Λ
Speaker: | Mihalis Dafermos |
Institution: | Cambridge and Princeton University |
Time: | Tuesday 9 June 2020, 13:15 |
Venue: | 2nd floor seminar room (webinar) |
Abstract: | The strong cosmic censorship conjecture is a fundamental open problem in classical general relativity, first put forth by Roger Penrose in the early 70s. This is essentially the question of whether general relativity is a deterministic theory. Perhaps the most exciting arena where the validity of the conjecture is challenged is the interior of rotating black holes, and there has been a lot of work in the past 50 years in identifying mechanisms ensuring that at least some formulation of the conjecture be true. It turns out that when a nonzero cosmological constant Λ is added to the Einstein equations, these underlying mechanisms change in an unexpected way, and the validity of the conjecture depends on a detailed understanding of subtle aspects of black hole scattering theory, surprisingly involving, in the case of negative Λ, some number theory. Does strong cosmic censorship survive the challenge of non-zero Λ? This talk will try to address this Question! |
Recording: | The recorded talk can be found here in BBB format and Mp4 format |
The holographic CFT masquerade
Speaker: | Mark Van Raamsdonk |
Institution: | University of Southern California |
Time: | Tuesday 23 June 2020, 19:00 |
Venue: | 2nd floor seminar room (webinar) |
Abstract: | We argue that given holographic CFT1 in some state with a dual spacetime geometry M, and given some other holographic CFT2, we can find states of CFT2 whose dual geometries closely approximate arbitrarily large causal patches of M, provided that CFT1 and CFT2 can be non-trivially coupled at an interface. Our CFT2 states are ``dressed up as'' states of CFT1: they are obtained from the original CFT1 state by a regularized quench operator defined using a Euclidean path-integral with an interface between CFT2 and CFT1. Our results are consistent with the idea that the precise microscopic degrees of freedom and Hamiltonian of a holographic CFT are only important in fixing the asymptotic behavior of a dual spacetime, while the interior spacetime of a region spacelike separated from a boundary time slice is determined by more universal properties (such as entanglement structure) of the quantum state at this time slice. Our picture requires that low-energy gravitational theories related to CFTs that can be non-trivially coupled at an interface are part of the same non-perturbative theory of quantum gravity. |
Recording: | The recorded talk can be found here in BBB format and Mp4 format |
The instability of Anti-de Sitter spacetime
Speaker: | Georgios Moschidis |
Institution: | University of California, Berkeley |
Time: | Tuesday 30 June 2020, 13:15 |
Venue: | 2nd floor seminar room (webinar) |
Abstract: | According to the AdS instability conjecture, there exist arbitrarily small perturbations to the initial data of AdS spacetime which, under evolution by the vacuum Einstein equations with reflecting boundary conditions on conformal infinity, lead to the formation of black holes after sufficiently long time. To this day, the question about the vacuum equations remains open (and poorly understood). However, during the last decade, a large number of numerical and heuristic works have been dedicated to addressing the conjecture in the presence of matter fields allowing spherically symmetric dynamics. In this talk, I will review the progress achieved so far in addressing the AdS instability conjecture and I will present a rigorous proof of the instability in the setting of the spherically symmetric Einstein--scalar field system. The proof will be based on the non-linear interactions of special configurations of matter beams. The possible extension of the main ideas to the vacuum case will also be discussed. |
Recording: | The recorded talk can be found here in BBB format and Mp4 format |
Liouville theory and Matrix models: A Wheeler DeWitt perspective
Speaker: | Panagiotis Betzios |
Institution: | University of Crete |
Time: | Thursday 2 July 2020, 13:15 |
Venue: | 2nd floor seminar room (webinar) |
Abstract: | We analyse the connections between the Wheeler DeWitt approach for two dimensional quantum gravity and holography, focusing mainly in the case of Liouville theory coupled to c = 1 matter. Our motivation is to understand whether some form of averaging is essential for the boundary theory, if we wish to describe the bulk quantum gravity path integral of this two dimensional example. The analysis hence, is in a spirit similar to the recent studies of Jackiw-Teitelboim (JT)-gravity. Macroscopic loop operators define the asymptotic region on which the holographic boundary dual is expected to reside. Matrix quantum mechanics (MQM) and the associated double scaled fermionic field theory on the contrary, is providing an explicit "unitary in superspace" description of the complete dynamics of such two dimensional universes with matter, including the effects of topology change. If we try to associate a Hilbert space to a single boundary dual, it seems that it cannot contain all the information present in the non-perturbative bulk quantum gravity path integral and MQM. |
Recording: | The recorded talk can be found here in BBB format and Mp4 format |
Energy transmission at holographic interfaces
Speaker: | Costas Bachas |
Institution: | ENS Paris |
Time: | Tuesday 14 July 2020, 13:00 |
Venue: | 2nd floor seminar room (webinar) |
Abstract: | I will describe the first gravitational calculation of the universal energy transmission and reflection coefficients of 2D conformal interfaces with holographic duals. The result is a monotonic function of the dual brane tension. It is consistent with the ANEC bound (which is stricter than the positivity bound in the Euclidean theory). |
Recording: | The recorded talk can be found here in BBB format and Mp4 format |