Central European Institute for Cosmology and Fundamental Physics
 

Upcoming seminars


Cosmo: Wednesday, 19/02/2025, 11:30
Jens C. Niemeyer (Institute for Astrophysics, Georg-August-University Gottingen, Gottingen)
 
Waves vs. particles in gravitational structure formation  
 
Scenarios of structure formation with axion-like particle dark matter have distinctive signatures on scales ranging from kiloparsecs to astronomical units. They are governed chiefly by the particle mass and therefore very predictive. For ultra-light fields, lower bounds on the particle mass have been obtained from different regimes of "wavyness" involving very diverse systematics. Similar phenomena might have appeared in an early matter-dominated epoch after inflation with delayed reheating. Here, the inflaton field itself fragments gravitationally, forming structures on microscopic scales that closely resemble cosmological large-scale structure.

Strings: Monday, 10/02/2025, 14:00, Room 226
Karapet Mkrtchyan (Imperial College, London)
Democracy and duality
 
I will summarise the results of the ongoing program on democratic formulation of field theory, treating electric and magnetic degrees of freedom on equal footing. Main results include democratic formulation of arbitrary non-linear electrodynamics, and p-form generalisations in arbitrary dimensions, including p-forms of maximal Supergravities in 10d and 11d. Special case of the self-dual field is given a simple covariant Lagrangian formulation. In 2d, we find extensions of chiral scalars of Florianini-Jackiw (s=1) and Alekseev-Shatashvili (s=2) to any s as boundary degrees of freedom for spin-s fields in 3d. We provide covariant Lagrangian formulation for these 2d theories.

Strings: Monday, 17/02/2025, 14:00, Room 226
Alessandro Georgoudis (Queen Mary University, London)
Hexagons for Short operators
 
In this talk I will present a integrability-based conjecture for the three-point functions of single-trace operators in planar N=4 super-Yang-Mills theory at finite coupling, focusing on the case where two operators are protected. This proposal is based on the hexagon representation for structure constants of long operators, which we completed to incorporate operators of any length using data from the TBA/QSC formalism. I will then present some test of our conjecture and if time permits some new results for structure constants.
Strings: Monday, 24/02/2025, 14:00, Room 226
Nicolo Petri (INFN, Turin)
Metric positivity and the Swampland
 
The formulation of abstract notions about physical theories to study their universal features is a typical strategy of modern high-energy physics. In this regard, a widely accepted belief is that geometrical notions, like metrics and distances between vacua configurations of physical theories, should always exist. However, defining a consistent metric and distance between vacua in gravitational theories is an important open problem. In my talk, I will examine this issue in relation to the 'AdS conjecture', a key development within the Swampland program. The main goal is to introduce a consistent procedure for defining and computing metrics on the space of gravity vacua, providing a clear way to measure distance. Starting with simple vacua in string theory, I will demonstrate how these new concepts can be constructed explicitly. The key idea underlying the procedure involves considering the off-shell quadratic variation of the string theory action and evaluating it over the space of on-shell solutions. Finally, I will discuss how this framework offers insights into the ongoing debate about the consistency of scale-separated vacua in string theory.

Strings: Monday, 10/03/2025, 14:00, Room 226
Paul Luis Roehl (DAMTP, Cambridge)
TBA
 
TBA

Strings: Monday, 17/03/2025, 14:00, Room 226
Thales Azevedo (Universidade Federal do Rio de Janeiro, Rio de Janeiro)
TBA
 
TBA

Strings: Monday, 24/03/2025, 14:00, Room 226
Aranya Bhattacharya (Jagiellonian University, Krakow)
Measuring chaos in highly excited string scattering amplitudes
 
Highly excited string scattering(HESS) can be thought of as dual to black hole (BH) scattering, as conjectured by Susskind, Horowitz, and Polchinski. In recent times, Rosenhaus and Gross have pointed out that there is a notion of chaos/randomness in these fully quantum scattering amplitudes, which can be explained from the perspective of a multiparticle scattering process with a number of particles being very high. Due to the HESS-BH duality, this acts as a stronger-than-semiclassical indicator of chaos in black holes. I will discuss how this idea, initially discussed qualitatively, can be made quantitative by studying the position of the peaks and treating them as eigenvalues of a fictitious Hamiltonian. I will discuss various probes such as level statistics, scattering form factors, and the spread complexity of the fictitious Hamiltonian evolution as quantitative indicators of chaos by comparing them with random matrix universality classes.

Strings: Monday, 07/04/2025, 14:00, Room 226
Diego Trancanelli (University of Modena, Modena)
Conformal defects and RG flows in ABJM
 
Defects play a central role in many contexts, from condensed matter to quantum gravity. The situations in which the bulk theory is conformal and the defect inherits part of this symmetry -- the so-called defect conformal field theories (dCFTs) --  have recently received a lot of attention, also thanks to new powerful methods to tackle them, like supersymmetric localization, integrability or the bootstrap. A dCFT may be deformed by turning on marginally relevant operators, which trigger RG flows connecting different fixed points. A natural arena where this phenomenon can be explored are 3-dimensional Chern-Simons theories coupled to matter. These are in fact known to display a plethora of Wilson loops that can be used to define 1-dimensional dCFTs living on their contours. In this talk we discuss a few examples from an intricate web of RG flows connecting the dCFTs defined on the BPS and non-BPS Wilson loops of ABJM theory. We compute the anomalous dimensions of the deforming operators, establish g-theorems along the flows, and also discuss the role played by cohomological anomalies and framing. Based on: 2211.16501, 2305.01647, 2312.13283, 2410.10970. 

Strings: Monday, TBA, 14:00, Room 226
Saebyeok Jeong (CERN, Geneva)
Miura operators as R-matrices from M-brane Intersections
 
I will discuss how M2-M5 intersections in the twisted M-theory background yield R-matrices of quantum toroidal algebra of gl(1). These intersections are also identified as Miura operators, providing the Miura transformation for the q-deformed W- and Y-algebras. Consequently, the intertwining relation of the q-deformed Maulik-Okounkov R-matrix is illuminated as a Yang-Baxter equation, in particular. Also, I will explain the M2-M5 intersection (equivalently the Miura operator) gives rise to the qq-characters of the 5d N=1 gauge theory, illuminating an algebraic meaning of the latter.

Strings: Monday, 05/05/2025, 14:00, Room 226
Giuseppe Policastro (Ecole Normale Supérieure, Paris)
TBA
 
TBA

Strings: Monday, 26/05/2025, 14:00, Room 226
Seyed Morteza Hosseini (Queen Mary University of London, London)
TBA
 
TBA

Cosmo: Wednesday, 05/02/2025, 11:00
Tanja Rindler-Daller (University of Vienna - Institute for Astronomy)
TBA
 
TBA

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