Milan Milosevic

[Thessaloniki 2024 ]Presentations

Evangelos Afxonidis – Slides

Title: Fractons and dipole symmetry breaking

Abstract: Fractons are limited mobility excitations appearing in dipole-conserving models. I will introduce quantum field theories for monopole and dipole charges, showing via large-N techniques that the effective action includes an immobile fractonic Nambu-Goldstone mode.

Naveena Kumara Athithamoole – Slides

Title: Dynamics of Gravitational Perturbations in Noncommutative Geometry

Abstract: This study investigates the dynamics of gravitational perturbations within the framework of Hopf algebra and noncommutative differential geometry. By focusing on a semi-Killing Drinfeld twist and a novel noncommutative Einstein equation, we analyze the polar gravitational perturbations on a noncommutative Schwarzschild background.

Vasil Avramov – Slides

Title: Various aspects of complexity of oscillators in a magnetic field

Abstract: The focus of the talk is on the notion of Nielsen complexity, which quantifies the closeness between two quantum states. We examine results for the quantum complexity of an harmonic oscillator in an external magnetic field and a thermofield double state constructed from the same system. We find several important limits and investigate the effects of the magnetic field on complexity.

Ertuğrul Ekiz – Slides

Title: Electric Carrollian Field Theories

Abstract: In this presentation, we will start with what is meant by Electric Carrollian Sector or Magnetic Carrollian Sector. Then, we discuss several important point of the Carrollian Field Theories. After reviewing Electric Carrollian Scalar Fields, we will discuss possible Electric Carrollian Fermion structure and their difference with Relativistic Fermions.

David Sola Gil – Slides

Title: Strong Cosmic Censorship in Kerr-Newman-de Sitter

Abstract: Christodoulou’s version of Strong Cosmic Censorship (SCC) seeks to restore predictability in General Relativity. This conjecture has been classically shown to be respected by Kerr de-Sitter black holes and violated by near-extremal Reissner-Nordström-de Sitter black holes. We will review SCC in the interpolating spacetime: Kerr-Newman-de Sitter, as studied in https://arxiv.org/pdf/2404.03724.

Antonios Kalogirou – Slides

Title: Ising Cosmology

Abstract: We propose that the deviation of the scalar spectrum index n_S of scalar fluctuations from unity may be controlled almost entirely by the critical exponent η of the d=3 Ising model. Furthermore, we compute the thermal propagators of the scalar field and propose that non-trivial thermal effects as seen by an ‘out’ observer can be encoded by η which fixes completely a number of cosmological observables.

Leonidas Karageorgos – Slides

Title: Renormalization of 2pt-function of Energy Momentum Tensor & RG flows.

Abstract: In this short presentation, I will discuss our research in progress, on renormalization issues concerning the two-point function of the Energy-Momentum Tensor for a Quantum Field Theory (QFT) in the vicinity of an interacting fixed point.

Stylianos Kastrinakis – Slides

Title: Conformal transformations on a graph and the associated metric

Abstract: A brief presentation will be given of the key points of the paper under publication “Graph theoretical approach to conformal correlators” by professor Nikos Irges and Stylianos Kastrinakis, namely the construction of a conformally covariant metric on a weighted graph, how the correlator of N scalar operators can be expressed as the determinant of this metric and the metric’s possible role in constraining conformal data.

Tatiana Mihaescu – Slides

Title: Entanglement and steering in Gaussian quantum states

Abstract: In this presentation I will engage with the topic of quantum correlations, such as entanglement and steering, in Gaussian quantum states. This type of continuous variable systems are most commonly encountered in quantum optics experiments, while also being applicable to quantum information tasks.

Theodoros Nakas – Slides

Title: Black-hole solutions with primary scalar hair

Abstract: We present explicit black holes endowed with primary scalar hair within the shift-symmetric subclass of Beyond Horndeski theories. We observe that when the scalar hair is close to zero, the solutions closely resemble the Schwarzschild spacetime, while as the scalar hair increases, the metric solutions gradually depart from General Relativity. Notably, for a particular relation between mass and scalar hair, the central singularity completely disappears, resulting in the formation of regular black holes or solitons. This talk is based on the paper https://inspirehep.net/literature/2712204

Gabriele Pisacane – Slides

Title: Neutron interferometry to probe the Dark sector of the universe

Abstract: Dark matter is one of the mysteries of modern physics. There are many candidates for its explanation, from micro black holes to axions. In this work we develop a possible method to analyze one of these candidates, the mirror matter, via geometric invariants.

Shanmugapriya Prakasam – Slides

Title: Supersymmetric index for small black holes

Abstract: The macroscopic index computed in accordance with recently developed techniques at the two derivative level does not produce the desired matching with the well known microscopic counting for small black holes. In a subspace of the horizon of the black hole where the solution is singular, higher derivative corrections become important. A corrected macroscopic index including these higher derivative contributions produces the known microscopic results up to an overall numerical constant.

Filip Požar – Slides

Title: Twisted Hopf algebra modules are also twisted

Abstract: I will sketch a short proof of the fact that Drinfeld Twisted Hopf algebra’s modules can be obtained from the “untwisted” Hopf algebra’s modules by twisting them with the same Drinfeld element. This applies to the modules of spacetime functions, tensor algebra, vector fields etc.

Jonas Rongen – Whiteboard

Title: (Boost-Agnostic) Hydrodynamics

Abstract: Hydrodynamics can be understood as an effective field theoretical description of interacting systems close to thermal equilibrium in the long-wavelength limit. The dynamics of these systems are governed by the conservation of energy and momentum, and possibly a set of U(1) charge conservation laws. I will give a brief introduction to hydrodynamics in the absence of boost symmetry and its relation to holography.

Raoul Serao – Slides

Title: On the quantumness of gravity

Abstract: I will illustrate the role that entanglement can have in understanding one of the big open question in theoretical physics: quantum gravity. I will analyse the rising of a gravitational induced entanglement and the role of the decoherence in determining a minimum distance.

Dionysios – Stylianos Stefas – Slides

Title: Formulation of Gravity as a Gauge Theory on Covariant Noncommutative (Fuzzy) Spaces.

Abstract: This presentation explores the formulation of gravity as a gauge theory on covariant noncommutative (fuzzy) spaces. By extending the isometry group and employing a gauge theoretic approach an action is developed which, after a spontaneous symmetry breaking, provides a framework for noncommutative gravity.

Marko Stojanovic – Slides

Title: Constant roll inflation with tachyon field in the holographic RSII cosmology

Abstract: We consider a constant-roll inflation scenario, where the second slow-roll parameter remains constant. The scenario, when inflation is driven by a tachyon field, is focussed on the holographic second Randall-Sundrum (RSII) cosmology. The corresponding observational parameters, the scalar spectral index and the tensor-to scalar ratio, are determined and their values are compared with observational data.

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[Thessaloniki 2024] Program & Lecture notes

For the scientific program 10-15 June, please click here. The talks of the school are broadcasted and the recording of the school can be found here for MondayTuesdayWednesdayThursday and Friday respectively.

Introduction to the PhD program Goran Djordjevic slides.

The titles, abstracts and literature of the lectures follow:

1. Black holes and quantum physics [Tarek Anous]

This course will give a review of the latest half-century’s developments related to quantum aspects of black holes. We will start with the laws of black hole thermodynamics as developed by Bekenstein and Hawking, followed by an introduction to black hole radiation. I will then introduce the black hole information paradox as diagnosed by the page curve, as well as recent developments involving entanglement islands that suggest a resolution. In the final lecture, I will explain why I believe the information paradox remains unresolved.

Selected review articles:

Samir Mathur: The information Paradox, a pedagogical introduction https://arxiv.org/abs/0909.1038
Daniel Harlow: Jerusalem Lectures on black holes and Quantum Information https://arxiv.org/pdf/1409.1231.pdf
Almheiri, Hartman, Maldacena, Shaghoulian, Tajdini: The entropy of Hawking radiation https://arxiv.org/pdf/2006.06872.pdf

2. Introduction to AdS/CFT correspondence and holography [Nikolay Bobev]

I will summarize the basic ideas behind the celebrated gauge/gravity dualiy, known also as AdS/CFT, which arises out of string and M-theory. I will introduce some basic facts about string theory, supersymmetry, supergravity, anti de Sitter (AdS) space, and Conformal Field theory (CFT), I will then proceed to show how the duality can be used to calculate correlation functions in strongly interacting CFTs. I will also discuss some aspects of black hole thermodynamics in AdS and how this informs the physics of the dual CFT at finite temperature.

Plan:

Lecture 1: Motivation, strings, branes, supersymmetry, and supergravity

Lecture 2: Basics of AdS and CFT

Lecture 3: Correlation functions in AdS/CFT

Lecture 4: Black holes in AdS and thermal CFT physics

Literature:

I plan to follow mostly these three reviews

https://arxiv.org/abs/hep-th/9905111
https://arxiv.org/abs/hep-th/0201253
https://arxiv.org/abs/hep-th/0209067

3. Lectures on flat space holography [Daniel Grumiller]

The holographic principle posits that quantum gravity in D+1 dimensions is equivalent to quantum field theory in D dimensions. The AdS/CFT correspondence is its best-known implementation. It is natural to ask whether the holographic principle works in dS or flat space. These lectures address the latter. We review general aspects of holography and introduce the two main approaches to flat space holography, Carrollian and Celestial holography.

Selected review articles:

https://arxiv.org/abs/1609.06203
https://arxiv.org/abs/1709.09871
https://arxiv.org/abs/2310.12922

Material presented in the first, second, third and the fourth lectures. As well as the first and second set of the exercises.

4. Introduction to Conformal Field Theory [Slava Rychkov]

These lectures will give introduction to conformal field theories in various dimensions, with applications related to topics of particular interest, such as the conformal bootstrap program and boundary conformal field theory. We assume the audience to have basic knowledge of quantum field theory. Familiarity with string theory may help, although it is not a prerequisite.

Literature:

The main reference will be:
– D. Simmons-Duffin: Caltech Conformal Field Theory lecture notes

See also:

– J.D. Qualls: Lectures on Conformal Field Theory [arXiv: 1511.04074]
– S. Rychkov: EPFL Lectures on Conformal Field Theory in D>= 3 Dimensions [arXiv: 1601.05000]
– D. Simmons-Duffin: TASI Lectures on the Conformal Bootstrap [arXiv: 1602.07982]

5. Renormalization in CFT, AdS and dS [Kostas Skenderis]

In this set of lectures, I will discuss renormalization in several different, yet related, contexts. I will start by discussing renormalization of correction functions in CFT. Renormalization is needed due to UV divergences at coincident points, and I will discuss how to identify and then renormalize the divergences by working in momentum space. Such renormalization is responsible for conformal anomalies (among other things). The CFT UV divergences map to infrared divergences in AdS by the AdS/CFT correspondence and I will then show how to deal with them in AdS using holographic renormalization. QFT in AdS has also bulk UV divergences and our next topic would be to show how to renormalize those. The AdS infrared divergences have an analogue in de Sitter (and cosmology). In the de Sitter context, they appear as late time divergences in cosmological correlators, and I will discuss how to renormalize these divergences by wavefunction renormalization of the late-time bulk field.

Plan

Lecture 1: CFT in momentum space and renormalization

Lecture 2: Holographic renormalization

Lecture 3: Renormalizing bulk loops in AdS

Lecture 4: Renormalizing IR divergences in dS

Literature:

Lecture 1:

https://arxiv.org/abs/1304.7760
https://arxiv.org/abs/1510.08442

Lecture 2:
https://arxiv.org/abs/hep-th/0209067
https://arxiv.org/abs/hep-th/0209067

Lecture 3:
https://arxiv.org/abs/2208.11539

Lecture 4:
https://arxiv.org/abs/2207.02872
https://arxiv.org/abs/2312.17316

6. Introduction to Modern Cosmology [Vassilis Spanos]

These lectures will offer a primer on contemporary cosmology and astroparticle physics, highlighting recent developments in the field. Specifically, we will examine up-to-date insights into Dark Matter from both theoretical and observational perspectives. Additionally, we will explore the burgeoning field of gravitational waves, which is emerging as a potent instrument for investigating the early Universe.

Bibliography

1) Modern Cosmology, 2nd edition, S. Dodelson, F. Schmidt
2) Hannu Kurki-Suonio, Cosmology lectures
https://www.mv.helsinki.fi/home/hkurkisu/cosmology/Cosm_I.pdf
and
https://www.mv.helsinki.fi/home/hkurkisu/cosmology/Cosm_II.pdf

Material presented, slides.

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[Thessaloniki 2024] Committees

Organizing committee

  • Konstantinos Siampos (chair) (AUTH, Greece)
  • Anastasios Petkou (AUTH, Greece)
  • Ioannis Florakis (UOI, Greece)
  • John Rizos (UOI, Greece)
  • Ioannis Papadimitriou (NKUA, Greece)
  • Konstantinos Sfetsos (NKUA, Greece)

For further information please contact Konstantinos Siampos (ksiampos@auth.gr).

Program committee

  • Gian Giudice (CERN, Geneva, Switzerland)
  • Goran Djordjevic (Faculty of Science, Nis, Serbia)
  • Joan Elias Miro (ICTP, Trieste, Italy)
  • Kyriakos Papadodimas (CERN, Geneva, Switzerland)
  • Marko Simonovic (University of Florence, Florence, Italy)
  • Radoslav Rashkov (Faculty of Physics, Sofia University, Bulgaria)

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[Thessaloniki 2024] Participants

1. Ana Bokulić
2. Anastasia Iliopoulou
3. Andrei Marin
4. Angelos-Lamin Sisse
5. Antonios Kalogirou
6. Bartosz Pyszkowski
7. Cemal Berfu Şenışık
8. Christoforos Christoforidis
9. Danai Roumelioti
10. Danijel Obric
11. Danilo Rakonjac
12. David Sola Gil
13. Dimitrios Charamis
14. Dionysios – Stylianos Stefas
15. Djordje Milanović
16. Eleni Papadimitriou
17. Ertuğrul Ekiz
18. Evangelos Afxonidis
19. Evangelos Koutsakis
20. Evangelos Pyrkas
21. Federico Capeccia
22. Filip Požar
23. Gabriele Pisacane
24. George Prampromis
25. Georgia Vasileiou
26. Georgios Dianos
27. Georgios Kampanis
28. Giovanni Boldi
29. Ilayda Bulunur
30. Jacqueline Caminiti
31. Jonas Rongen
32. Katarina Trailović
33. Kezhu Guo
34. Laios Zafeiriou
35. Leonidas Karageorgos
36. Maria-Myrto Pegioudi
37. Marko Stojanovic
38. Milorad Bezanic
39. Miroslav Radomirov
40. Musa Çağatay Okyay
41. Mustafa Salih Zog
42. Narcisa-Diana Haiducu
43. Naveena Kumara Athithamoole
44. Pavle Stipsić
45. Raoul Serao
46. Robert Bourne
47. Shanmugapriya Prakasam
48. Simone Monda
49. Sokratis Varelogiannis
50. Songyuan Li
51. Sonja Dedic
52. Stefan Marković
53. Stefanos Vasileiadis
54. Steven Weilong Hsia
55. Stylianos Kastrinakis
56. Tatiana Mihaescu
57. Themistocles Zikopoulos
58. Theodoros Nakas
59. Vasil Avramov
60. Vladan Gecin

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[Thessaloniki 2024] School on Field theory and applications in HEP

The Third Cycle of the CERN – SEENET-MTP PhD program has begun in Niš on 7-8 June 2024. The program started with introductory lectures, primarily intended for final-year master’s students. The lecturers are Prof. Dr. Neven Bilić (Ruđer Bošković Institute, Zagreb) and Prof. Dr. Dragoljub Dimitrijević (University of Niš). More information about the preparatory program is available here.

The program continued with the school:

CERN – SEENET-MTP – ICTP School (June 9-16, 2024)
“School on Field Theory and Applications in HEP”

at Aristotle University of Thessaloniki. The lecturers are:

  • Goran Djordjević (University Nis) – Introduction to HEP PhD Program
  • Tarek Anous (QMUL, UK) – Black Holes and Quantum Physics
  • Nikolay Bobev (KU Leuven, Belgium) – Introduction to AdS/CFT Correspondence and Holography
  • Daniel Grumiller (TU Vienna, Austria) – Celestial Holography and Carrollian Physics
  • Slava Rychkov (IHES, Bures-sur-Yvette, France) – Introduction to Conformal Field Theory
  • Kostas Skenderis (U. Southampton, UK) – Current Trends in Theoretical High Energy Physics (Renormalization in CFT, AdS and dS)
  • Vassilis Spanos (NKUA, Greece) – Introduction to Modern Cosmology

The school gathers over 70 students, lecturers, and associates from more than 15 countries in the region and Europe. For the first time, there will be participants from overseas countries, through remote lectures.

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