Proca seminars series
from
Thursday 11 November 2021 (09:00)
to
Monday 1 July 2024 (10:30)
Monday 8 November 2021
Tuesday 9 November 2021
Wednesday 10 November 2021
Thursday 11 November 2021
09:00
TBA
TBA
09:00 - 10:30
TBA
10:00
Detecting dark matter signals by radio observational data
-
Man Ho Chan
(
Education University of Hong Kong
)
Detecting dark matter signals by radio observational data
Man Ho Chan
(
Education University of Hong Kong
)
10:00 - 11:30
Abstract: In the past few years, some studies claimed that annihilating dark matter with mass 30-50 GeV can explain the GeV gamma-ray excess in our Galaxy and the gamma-ray spectrum of some other sources. In this talk, we present our latest analysis using the radio continuum spectral data of the central halo of the Ophiuchus cluster and the radio halo of the A4038 cluster. We have found that 40-50 GeV dark matter annihilating via the b quark channel can best explain the radio continuum spectral data of the data. The statistical significance can be larger than 6 sigma, which indicates a very strong signal of dark matter annihilation.
Friday 12 November 2021
Saturday 13 November 2021
Sunday 14 November 2021
Monday 15 November 2021
Tuesday 16 November 2021
Wednesday 17 November 2021
Thursday 18 November 2021
10:00
The gravitational spin Hall effect of light
-
Marius Oancea
(
Max Planck Inst for Gravitational Physics, Potsdam
)
The gravitational spin Hall effect of light
Marius Oancea
(
Max Planck Inst for Gravitational Physics, Potsdam
)
10:00 - 11:00
Abstract: The propagation of electromagnetic waves in vacuum is often described within the geometrical optics approximation, which predicts that wave rays follow null geodesics. However, this model is valid only in the limit of infinitely high frequencies. At large but finite frequencies, diffraction can still be negligible, but the ray dynamics becomes affected by the evolution of the wave polarization. Hence, rays can deviate from null geodesics, which is known as the gravitational spin Hall effect of light. By considering the WKB approximation for Maxwell's equations, I will briefly present the main steps of a covariant derivation of the polarization-dependent ray equations describing the gravitational spin Hall effect of light. I will also discuss the relation of these equations with the well-known MPD equations, as well as the observer dependence of the position of massless spinning particles.
Friday 19 November 2021
Saturday 20 November 2021
Sunday 21 November 2021
Monday 22 November 2021
Tuesday 23 November 2021
Wednesday 24 November 2021
Thursday 25 November 2021
10:00
Symmetric teleparallel gravity - the limit of a Proca theory?
-
Tomi Koivisto
(
University of Tartu
)
Symmetric teleparallel gravity - the limit of a Proca theory?
Tomi Koivisto
(
University of Tartu
)
10:00 - 11:00
Abstract: Alternative geometrical formulations of General Relativity, and the corresponding alternative interpretations of the gravitational interaction, are reviewed. It is shown that General Relativity can be understood as an integrable gauge theory of translations in the "symmetric teleparallel" geometry. This framework allows the canonical resolution of the long-standing foundational problem of the localisation of gravitational energy. The resolution is clarified from the perspectives of the Noether theorems and the pre-metric formalism. The integrability (i.e. flatness, or "teleparallelism") is the property of a massive connection at large distances. This suggests the natural interpretation of teleparallel gravity as the limit of a (non-Abelian generalisation of) Proca theory, where the Planck mass is the mass of the connection. Spacetime has a resolution limit, since the integrability breaks down at microscopic distances near the Planck scale.
Friday 26 November 2021
Saturday 27 November 2021
Sunday 28 November 2021
Monday 29 November 2021
Tuesday 30 November 2021
Wednesday 1 December 2021
Thursday 2 December 2021
10:00
Carroll Symmetry & Memory Effect for gravitational waves
-
Peter Horvathy
(
Institut Denis Poisson, Tours/Orleans Univ
)
Carroll Symmetry & Memory Effect for gravitational waves
Peter Horvathy
(
Institut Denis Poisson, Tours/Orleans Univ
)
10:00 - 11:00
Abstract: The motion of test particles after the passage of a Gravitational Wave could (in principle) provide a way to detect the Wave. The isometries of a plane gravitational wave, identified as Levy-Leblond's „Carroll” group, act as symmetries for the particle subject to the wave ; the associated conserved quantities determine the trajectories.
Friday 3 December 2021
Saturday 4 December 2021
Sunday 5 December 2021
Monday 6 December 2021
Tuesday 7 December 2021
Wednesday 8 December 2021
Thursday 9 December 2021
10:00
Conserved quantities for Non-relativistic systems via the Eisenhart-Duval lift
-
M. Elbistan
(
Bogazici Univ Istanbul & Institut Denis Poisson, Tours/Orleans Univ
)
Conserved quantities for Non-relativistic systems via the Eisenhart-Duval lift
M. Elbistan
(
Bogazici Univ Istanbul & Institut Denis Poisson, Tours/Orleans Univ
)
10:00 - 11:00
Abstract: In this talk I will discuss conserved quantities of some non-relativistic systems originating from symmetries of a particular class of pp-waves called exact plane gravitational waves. In particular, I will consider periodic gravitational waves and corresponding non-relativistic systems called ion traps. I will show how the symmetries of the former yield conserved quantities for the latter.
Friday 10 December 2021
Saturday 11 December 2021
Sunday 12 December 2021
Monday 13 December 2021
10:00
Cosmic inflation from broken conformal symmetry
-
Shao-Jiang Wang
(
Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing
)
Cosmic inflation from broken conformal symmetry
Shao-Jiang Wang
(
Institute of Theoretical Physics, Chinese Academy of Sciences, Beijing
)
10:00 - 11:00
Abstract: A period of rapidly accelerating expansion is expected in the early Universe implemented by a scalar field slowly rolling down along an asymptotically flat potential preferred by the current data. In this paper, we point out that this picture of the cosmic inflation with an asymptotically flat potential could emerge from the Palatini quadratic gravity by adding the matter field in such a way to break the local gauged conformal symmetry in both kinetic and potential terms. The metric Einstein gravity with a positive cosmological constant could be recovered either in the absence of the matter field or by adding the matter field in a way that preserves the local gauged conformal symmetry (refs. 2110.14718, 2003.08516, 1810.05536).
Tuesday 14 December 2021
Wednesday 15 December 2021
Thursday 16 December 2021
10:00
Connections between Weyl geometry, quantum potential, and quantum entanglement
-
Shi-Dong Liang
(
Sun Yat-Sen University SYSU, CN
)
Connections between Weyl geometry, quantum potential, and quantum entanglement
Shi-Dong Liang
(
Sun Yat-Sen University SYSU, CN
)
10:00 - 11:00
Abstract: We study the relationships between the Weyl geometry, quantum entropy and quantum entanglement based on the Weyl geometry.
Friday 17 December 2021
Saturday 18 December 2021
Sunday 19 December 2021
Monday 20 December 2021
Tuesday 21 December 2021
Wednesday 22 December 2021
Thursday 23 December 2021
Friday 24 December 2021
Saturday 25 December 2021
Sunday 26 December 2021
Monday 27 December 2021
Tuesday 28 December 2021
Wednesday 29 December 2021
Thursday 30 December 2021
Friday 31 December 2021
Saturday 1 January 2022
Sunday 2 January 2022
Monday 3 January 2022
Tuesday 4 January 2022
Wednesday 5 January 2022
Thursday 6 January 2022
10:00
Higher-spin BMS symmetries
-
Xavier Bekaert
(
Institut Denis Poisson, Tours Univ & Universite d’Orleans
)
Higher-spin BMS symmetries
Xavier Bekaert
(
Institut Denis Poisson, Tours Univ & Universite d’Orleans
)
10:00 - 11:00
Abstract: We study higher-spin extensions of the Carrollian definition of BMS symmetry and their relation to the asymptotic kinematics of a massless scalar field near null infinity. In particular, we revisit Sachs's unitary representation of the BMS group, generalise it to any dimension, and use it to define a higher-spin algebra in Minkowski spacetime.
Friday 7 January 2022
Saturday 8 January 2022
Sunday 9 January 2022
Monday 10 January 2022
Tuesday 11 January 2022
Wednesday 12 January 2022
Thursday 13 January 2022
10:00
Curvature-Matter Couplings in Modified Gravity
-
Francesco Lobo
(
University of Lisbon
)
Curvature-Matter Couplings in Modified Gravity
Francesco Lobo
(
University of Lisbon
)
10:00 - 11:00
Abstract: We review a plethora of modified theories of gravity with generalized curvature-matter couplings. The explicit nonminimal couplings, for instance, between an arbitrary function of the scalar curvature and the Lagrangian density of matter, induces a non-vanishing covariant derivative of the energy-momentum tensor, implying non-geodesic motion and consequently leads to the appearance of an extra force. Applied to the cosmological context, these curvature-matter couplings lead to interesting phenomenology, where one can obtain a unified description of the cosmological epochs. In addition to this, these models are extremely useful for describing dark energy-dark matter interactions, and for explaining the late-time cosmic acceleration. We explore the physical and cosmological implications of the nonconservation of the energy-momentum tensor by using the formalism of irreversible thermodynamics of open systems in the presence of matter creation/annihilation.
Friday 14 January 2022
Saturday 15 January 2022
Sunday 16 January 2022
Monday 17 January 2022
Tuesday 18 January 2022
Wednesday 19 January 2022
Thursday 20 January 2022
10:00
Black holes, bosonic stars and ultralight dark matter
-
Carlos A. Herdeiro
(
University of Aveiro
)
Black holes, bosonic stars and ultralight dark matter
Carlos A. Herdeiro
(
University of Aveiro
)
10:00 - 11:30
Abstract: We discuss, with concrete examples and real data, how strong gravity systems and observables could assess the nature of dark matter, or at least part of it. In the theoretical modelling, I will focus on fuzzy dark matter, bosonic stars and black holes with synchronised hair. The real data examples will concern the GW190521 gravitational wave event and the EHT measurement of the M87* shadow.
Friday 21 January 2022
Saturday 22 January 2022
Sunday 23 January 2022
Monday 24 January 2022
Tuesday 25 January 2022
Wednesday 26 January 2022
Thursday 27 January 2022
10:00
Testing General Relativity with black hole X-ray data
-
Bambi Cosimo
(
Fudan U, Shanghai and Tubingen Univ
)
Testing General Relativity with black hole X-ray data
Bambi Cosimo
(
Fudan U, Shanghai and Tubingen Univ
)
10:00 - 11:00
Abstract: The theory of General Relativity has successfully passed a large number of observational tests. The theory has been extensively tested in the weak-field regime with experiments in the Solar System and observations of binary pulsars. The past 5-6 years have seen significant advancements in the study of the strong-field regime, which can now be tested with gravitational waves, X-ray data, and mm Very Long Baseline Interferometry observations. In my talk, I will summarize the state-of-the-art of the tests of General Relativity with black hole X-ray data, discussing its recent progress and future developments.
Friday 28 January 2022
Saturday 29 January 2022
Sunday 30 January 2022
Monday 31 January 2022
Tuesday 1 February 2022
Wednesday 2 February 2022
Thursday 3 February 2022
10:00
Modified theories of gravity - foundations and models
-
Christian Boehmer
(
University College London
)
Modified theories of gravity - foundations and models
Christian Boehmer
(
University College London
)
10:00 - 11:30
Abstract: In the first part of the talk I am discussing General Relativity, in particular its basic ingredients and its mathematical structure. This will naturally lead the way to consider various modifications or extensions of General Relativity, many of which have been studied recently. Next I will discuss modified gravity models based on generalised geometries and on actions no longer linear in curvature. The main part of the talk will discuss how these many different theories can be studied using a single unified approach which also shows the equivalence of some of these models. Boundary terms in the action will play a crucial role in establishing the equivalence between different theories. This setup will also allow us to discuss models where local Lorentz invariance can be broken and also models where local diffeomorphisms can be broken. In general this is done by introducing appropriate length scales.
Friday 4 February 2022
Saturday 5 February 2022
Sunday 6 February 2022
Monday 7 February 2022
Tuesday 8 February 2022
Wednesday 9 February 2022
Thursday 10 February 2022
10:00
Pair Productions in Charged Black Holes
-
Chiang-Mei Chen
(
Taiwan National Central University
)
Pair Productions in Charged Black Holes
Chiang-Mei Chen
(
Taiwan National Central University
)
10:00 - 11:30
Abstract: We study the spontaneous pair production, including the Schwinger mechanism and the Hawking radiation, of charged scalar particles from the near horizon region of (near) extremal charged black holes in the probe field limit. Analytical expressions for pair production, vacuum persistence and absorption cross section are found, and the spectral distribution is given a thermal interpretation. The pair production in near-extremal black holes has a factorization into the Schwinger effect in AdS and in Rindler space, measuring the deviation from extremality.
Friday 11 February 2022
Saturday 12 February 2022
Sunday 13 February 2022
Monday 14 February 2022
Tuesday 15 February 2022
Wednesday 16 February 2022
Thursday 17 February 2022
10:00
The Neutron Star Zoo
-
Stephen Chi-Yung Ng
(
Hong-Kong University
)
The Neutron Star Zoo
Stephen Chi-Yung Ng
(
Hong-Kong University
)
10:00 - 11:30
Abstract: A massive star ends its life as a violent supernova explosion. The compact core left over could form an ultra-dense object called a neutron star. Neutron stars are more massive than the Sun but as small as a city, and they possess the strongest magnetic field in the Universe. These remarkable properties make them ideal laboratories for studying physics under extreme conditions. Since the first pulsar was discovered in the 1960s, all neutron stars were thought to spin rapidly and emit broadband radiation. However, the emergence of different populations, including magnetars, dim isolated neutron stars, central compact objects, and millisecond pulsars, over the past decades has revolutionized this simple picture. In this talk, I will describe the diverse properties of the neutron star populations and highlight some recent results from multi-wavelength studies. I will also discuss attempts to unify different classes of objects.
Friday 18 February 2022
Saturday 19 February 2022
Sunday 20 February 2022
Monday 21 February 2022
Tuesday 22 February 2022
Wednesday 23 February 2022
Thursday 24 February 2022
10:00
Entangled relativity
-
Olivier Minazzoli
(
Cote d'Azur Observ., Nice
)
Entangled relativity
Olivier Minazzoli
(
Cote d'Azur Observ., Nice
)
10:00 - 11:30
Abstract: Entangled relativity is a new theory of relativity that does not allow gravity to be treated separately from matter fields. Unlike general relativity, the theory therefore satisfies the last of Einstein's three original demands for an acceptable theory of relativity, which he named Mach's Principle. Indeed, unlike in general relativity, inertia cannot be defined ex nihilo in entangled relativity, because the definition of the theory demands the existence of matter in the first place. Apart from that, the theory does not assume any new ingredient with respect to general relativity: for instance, spacetime is described by a four-dimensional manifold, the metric tensor encodes the mechanical properties of space as well as the inertia of bodies and gravitation, and its curvature is generated by matter fields. In fact, the theory even possesses one less free parameter w.r.t. general relativity, as Newton's constant no longer is a fundamental constant in entangled relativity, but results from the primordial evolution of the universe. The theory also has the nice property to possess general relativity as one of its limits (for fairly generic situations when the density is not way higher than the central density of neutron stars).
Friday 25 February 2022
Saturday 26 February 2022
Sunday 27 February 2022
Monday 28 February 2022
Tuesday 1 March 2022
Wednesday 2 March 2022
Thursday 3 March 2022
10:00
The universe evolution and modified gravity: an introduction.
-
Sergey Odintsov
(
Barcelona, ICREA/IEEC
)
The universe evolution and modified gravity: an introduction.
Sergey Odintsov
(
Barcelona, ICREA/IEEC
)
10:00 - 11:30
Abstract: A basic introduction to modified gravity is presented. Special attention is paid to F(R) gravity. The realistic, "exponential F(R)" gravity is also discussed. It is shown how it may describe the whole universe evolution from inflation to dark epoch. Ghost-free extended F(R) and F(G) gravities are briefly introduced. The reconstruction of F(R) gravity from inflationary indices is discussed. This seminar is aimed at young people and is based on the review: "Modified Gravity Theories on a Nutshell: Inflation, Bounce and Late-time Evolution" by S. Nojiri, V. K. Oikonomou and S. Odintsov, e-Print: 1705.11098 [gr-qc] Phys Rept 692 (2017) 1.
Friday 4 March 2022
Saturday 5 March 2022
Sunday 6 March 2022
Monday 7 March 2022
Tuesday 8 March 2022
Wednesday 9 March 2022
Thursday 10 March 2022
Friday 11 March 2022
Saturday 12 March 2022
Sunday 13 March 2022
Monday 14 March 2022
Tuesday 15 March 2022
Wednesday 16 March 2022
Thursday 17 March 2022
10:00
Metric-Affine Chern-Simons Modified Gravity (a first look)
-
Gonzalo Olmo
(
Valencia U.
)
Metric-Affine Chern-Simons Modified Gravity (a first look)
Gonzalo Olmo
(
Valencia U.
)
10:00 - 11:30
Abstract: Modifying GR by means of a Chern-Simons term coupled to a scalar field offers an interesting opportunity to explore parity violations in the gravitational sector. As usual, the original representation of this theory appeared in the metric formalism, though there are good reasons to reconsider it within a metric-affine approach. By doing so, one may improve the original action in order to make it projectively invariant. Though the connection equation is hard to tackle, we manage to obtain an approximate solution around a Schwarzschild background, which allows us to explore small perturbations and quasi normal modes. We compare our findings with those obtained in the metric formulation and in GR, finding that the metric-affine version presents certain features that could facilitate their detectability via gravitational waves observations.
Friday 18 March 2022
Saturday 19 March 2022
Sunday 20 March 2022
Monday 21 March 2022
Tuesday 22 March 2022
Wednesday 23 March 2022
Thursday 24 March 2022
10:00
Searching gravitational wave signals with autoregressive approach and deep learning
-
David Hui
(
Chungnam Natl. Univ. - South Korea
)
Searching gravitational wave signals with autoregressive approach and deep learning
David Hui
(
Chungnam Natl. Univ. - South Korea
)
10:00 - 11:30
Abstract: We are developing a novel framework of searching gravitational wave signal by coupling the stochastic autoregressive modeling and deep learning. This proposed framework holds the potential for an automatic pipeline for noise reduction, event candidate detections and template-free parameter estimation. We are also working on a deep learning algorithm by incorporating generative adversarial network. By increasing the training set and resolving the imbalance class problem, we can better separate the environmental/instrumental noise from the astrophysical signals. Currently, we are testing the method with LIGO O1/O2 data.
Friday 25 March 2022
Saturday 26 March 2022
Sunday 27 March 2022
Monday 28 March 2022
Tuesday 29 March 2022
Wednesday 30 March 2022
Thursday 31 March 2022
10:00
Beyond the Reissner-Nordstrom paradigm: static black holes with non-spherical horizons
-
Eugen Radu
(
University of Aveiro
)
Beyond the Reissner-Nordstrom paradigm: static black holes with non-spherical horizons
Eugen Radu
(
University of Aveiro
)
10:00 - 11:30
Abstract: Static (single) black holes (BHs) in electrovacuum can only have an electric monopole, and they are necessarily spherically symmetric. We discuss two different mechanisms to circumvent this result. In the first case, we show that static BHs in AdS-electrovacuum can have an arbitrary electric multipole structure, and present explicit examples of static BHs with no continuous (spatial) symmetries. The second example consists in asymptotically flat scalarized BHs in a class of Einstein-Maxwell-scalar (EMS) models. The corresponding BHs bifurcate from the Reissner-Nordstrom BH trunk, forming an infinite (countable) number of branches, and possess a large freedom in their multipole structure. Unlike the case of electrovacuum, the EMS model admits static, asymptotically flat, regular on and outside the horizon BHs without spherical symmetry and even without any spatial isometries, which are thermodynamically preferred over the electrovacuum state.
Friday 1 April 2022
Saturday 2 April 2022
Sunday 3 April 2022
Monday 4 April 2022
Tuesday 5 April 2022
Wednesday 6 April 2022
Thursday 7 April 2022
10:00
TBA
-
Matthew Lake
(
Frankfurt Institute for Advanced Studies
)
TBA
Matthew Lake
(
Frankfurt Institute for Advanced Studies
)
10:00 - 11:30
TBA
Friday 8 April 2022
Saturday 9 April 2022
Sunday 10 April 2022
Monday 11 April 2022
Tuesday 12 April 2022
Wednesday 13 April 2022
Thursday 14 April 2022
10:00
Cosmology with gravitational waves: current results and future prospects
-
Nicola Tamanini
(
Univ Toulouse CNRS & MPI, Albert Einstein Inst Postdam
)
Cosmology with gravitational waves: current results and future prospects
Nicola Tamanini
(
Univ Toulouse CNRS & MPI, Albert Einstein Inst Postdam
)
10:00 - 11:30
Abstract: Gravitational-wave (GW) cosmology has recently been established as a new observationally-driven research field, and is expected to expand rapidly in the future thanks to the increasing number of ever more accurate GW observations. In this talk I will review the current status of GW cosmological results obtained with the LIGO and Virgo interferometers, and will survey the results expected with future detectors. I will first introduce the most common methodologies employed to extract cosmological information from GW data, including new tests of LCDM which cannot be performed with more common electromagnetic observations. I will then show how these methods are employed to produce cosmological constraints with current GW data collected by LIGO and Virgo, and how they will usher an era of precise GW cosmology with next generation detectors, such as the Einstein Telescope on the Earth and LISA in space.
Friday 15 April 2022
Saturday 16 April 2022
Sunday 17 April 2022
Monday 18 April 2022
Tuesday 19 April 2022
Wednesday 20 April 2022
Thursday 21 April 2022
10:00
Planar Carrollian dynamics
-
Loic Marsot
(
Univ de Marseille U & Univ de Toulon CNRS
)
Planar Carrollian dynamics
Loic Marsot
(
Univ de Marseille U & Univ de Toulon CNRS
)
10:00 - 11:30
Abstract: It is known that the effective dynamics of a system restricted to a plane are in a sense richer than those in the "bulk" thanks to the observation of effective quasi particles in the plane, anyons. While this is a condensed matter result, one may wonder if similar effects arise in General Relativity on some hypersurfaces. A good candidate for the study of this phenomenon is Carroll geometry, as it turns out that important physical structures in Lorentzian spacetimes carry such geometry, such as black hole horizons, conformal null infinity, or even some hypersurfaces inside gravitational waves. Hence, we will look at the effective dynamics on such structures by considering intrinsic motions on 2+1 dimensional Carroll geometries. The distinct behavior of the planar case is due to the presence of two non trivial central extensions of the Carroll algebra. Elementary particles thus feature two additional (effective) physical parameters. Without these parameters (for instance in higher dimensions), it is known that Carroll particles have trivial motions, they do not move. However, we will show that these parameters lead to non trivial motions when particles are coupled to an external electromagnetic field.
Friday 22 April 2022
Saturday 23 April 2022
Sunday 24 April 2022
Monday 25 April 2022
Tuesday 26 April 2022
Wednesday 27 April 2022
Thursday 28 April 2022
10:00
Aspects of Gravitational Field and Cosmological Consequences Based on Finsler and Finsler-like Geometries.
-
Panayotis Stavrinos
(
National and Kapodistrian University of Athens
)
Aspects of Gravitational Field and Cosmological Consequences Based on Finsler and Finsler-like Geometries.
Panayotis Stavrinos
(
National and Kapodistrian University of Athens
)
10:00 - 11:30
Abstract: We present the gravitational dynamics with generalized field equations in Finsler and Finsler-like geometries. In this approach, the gravitational field is considered in the framework of extra dimensions with more degrees of freedom. The Einstein‐Finsler‐like gravity theories can be considered as natural candidates for the investigation of Lorentz violation, local anisotropies and provide a geometrical background for the emergence of dark matter and dark energy. In addition, modified gravity theories are extended in the framework of a geometry of an enriched spacetime with extra degrees of freedom. Friedmann equations are derived in a locally-anisotropic form of spacetime. In such theories, the concept of nonlinear connection, which connect the external and internal structures of spacetime, plays a crucial role. Some cosmological consequences are shown for the Finsler-Randers, Schwarzschild-Finsler-Randers models and generalized scalar-tensor theories.
Friday 29 April 2022
Saturday 30 April 2022
Sunday 1 May 2022
Monday 2 May 2022
Tuesday 3 May 2022
Wednesday 4 May 2022
Thursday 5 May 2022
10:00
Can Modified Gravity challenge LCDM?
-
Noemi Frusciante
(
Univ of Lisbon
)
Can Modified Gravity challenge LCDM?
Noemi Frusciante
(
Univ of Lisbon
)
10:00 - 11:30
Abstract: The late time cosmic acceleration is one of the most puzzling phenomena in modern cosmology. Its modeling within General Relativity (GR) through the cosmological constant (L) results in the LCDM scenario. Although the latter gives a precise description of the Universe, it is known that it still contains a number of unresolved problems. These lead researchers to look for modified gravity models, for example by including additional degrees of freedom. In this talk I will present the phenomenology and the cosmological bounds of theories consistent with the gravitational-wave event GW170817. In particular I will discuss models which solve the Hubble tension between Planck and local measurements and for which data show a statistically significant preference over LCDM.
Friday 6 May 2022
Saturday 7 May 2022
Sunday 8 May 2022
Monday 9 May 2022
Tuesday 10 May 2022
Wednesday 11 May 2022
Thursday 12 May 2022
10:00
An invariant approach to Weyl's unified field theory
-
Iarley Lobo
(
Paraiba University
)
An invariant approach to Weyl's unified field theory
Iarley Lobo
(
Paraiba University
)
10:00 - 11:30
In this talk we revisit the Weyl's unified field theory, published in 1918, shortly after general relativity was discovered. As it is well known, in order to extend the program of geometrization of physics started by Einstein to include the electromagnetic field, H. Weyl developed a new geometry which constitutes a kind of generalization of Riemannian geometry. However, despite its mathematical elegance and beauty, a serious objection was made by Einstein, who considered Weyl's theory not suitable as a physical theory since it seemed to lead to the prediction of a not yet observed effect, the so-called "second clock effect". In this talk, our aim is to discuss Weyl's proposal anew and examine its consistency and completeness as a physical theory. Finally, we propose new directions and possible conceptual changes in the original work. As a simple application, we solve the field equations assuming a Friedmann-Robertson-Walker universe and a perfect fluid as its source. Although we have entirely abandoned Weyl's attempt to identify the vector field with the 4-dimensional electromagnetic potential, which here must be simply viewed as part of the space-time geometry, we believe that in this way we could perhaps be led to a rich and interesting new modified gravity theory.
Friday 13 May 2022
Saturday 14 May 2022
Sunday 15 May 2022
Monday 16 May 2022
Tuesday 17 May 2022
Wednesday 18 May 2022
Thursday 19 May 2022
10:00
Multi-messenger astronomy of cosmic particle accelerators
-
Emma Kun
(
Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Budapest
)
Multi-messenger astronomy of cosmic particle accelerators
Emma Kun
(
Konkoly Observatory, Research Centre for Astronomy and Earth Sciences, Budapest
)
10:00 - 11:00
As a synergy of coordinated ground- and space-based observations targeting the four extragalactic messengers (electromagnetic radiation, cosmic rays, neutrinos, and gravitational waves (GWs)), multimessenger astronomy is a very useful tool for studying the most energetic phenomena of the universe. In my talk I will review recent findings and questions about the high-energy particle emission by cosmic particle accelerators, focusing on radio, X-ray, gamma and neutrino data.
Friday 20 May 2022
Saturday 21 May 2022
Sunday 22 May 2022
Monday 23 May 2022
Tuesday 24 May 2022
Wednesday 25 May 2022
Thursday 26 May 2022
10:00
Cosmological dynamical systems in modified gravity
-
Erik Jensko
(
University College London (Department of Mathematics)
)
Cosmological dynamical systems in modified gravity
Erik Jensko
(
University College London (Department of Mathematics)
)
10:00 - 11:30
Dynamical systems theory is a useful tool for assessing cosmological models. In this talk, I will look at applying it to second-order modified gravity theories in an approach that leads to several model-independent results. Moreover, as well as being model independent, the formulation is equally applicable to three second-order geometric modifications of gravity, teleparallel f(T) gravity, symmetric teleparallel f(Q) gravity, and the metric theory f(G) gravity. This is due to the equivalence of all three theories when working with the FLRW metric (in appropriate coordinates/tetrads). This approach reveals generic information about all possible models in any of the three theories, irrespective of the choice of function f. The existence and stability criteria for the fixed points are then analysed and discussed.
Friday 27 May 2022
Saturday 28 May 2022
Sunday 29 May 2022
Monday 30 May 2022
Tuesday 31 May 2022
Wednesday 1 June 2022
Thursday 2 June 2022
14:00
Quantum Conformal Gravity
-
Philip Mannheim
(
University of Connecticut (US)
)
Quantum Conformal Gravity
Philip Mannheim
(
University of Connecticut (US)
)
14:00 - 15:30
Conformal symmetry is a natural symmetry in physics since it is the full symmetry of the light cone. If all particles are to get their masses by symmetry breaking then conformal symmetry is the symmetry of the unbroken Lagrangian. Like Yang-Mills theories conformal symmetry has a local extension, namely conformal gravity, a pure metric-based candidate alternative to the non-conformal invariant standard Newton-Einstein theory of gravity. With its dimensionless coupling constant quantum conformal gravity is power counting renormalizable. Since its equations of motion are fourth-order derivative equations conformal gravity has long been thought to possess unacceptable ghost states of negative norm that would violate unitarity. However on constructing the quantum Hilbert space Bender and Mannheim found that this not to be the case. Conformal gravity is thus offered as a completely consistent and unitary quantum theory of gravity, one that requires neither the extra dimensions nor the supersymmetry of string theory. As formulated via local conformal invariance there is no intrinsic classical gravity, with gravity instead being intrinsically quantum-mechanical, with the observed classical gravity being output rather than input. The contribution of the graviton loops of conformal gravity enables conformal gravity to solve the cosmological constant problem. Like Yang-Mills the potential of conformal gravity contains both a Newtonian term and a linear potential. Together with a quadratic potential that the theory also contains conformal gravity is able to explain the systematics of galactic rotation curves without any need for galactic dark matter. Since all mass is to be dynamical there cannot be a fundamental double-well Higgs potential in the theory. Instead, the Higgs boson is generated dynamically, with the hierarchy problem then being solved.
Friday 3 June 2022
Saturday 4 June 2022
Sunday 5 June 2022
Monday 6 June 2022
Tuesday 7 June 2022
Wednesday 8 June 2022
Thursday 9 June 2022
10:00
Seeking the first radio-powerful AGN within the Epoch of Reionisation
-
Jose Afonso
(
University of Lisbon
)
Seeking the first radio-powerful AGN within the Epoch of Reionisation
Jose Afonso
(
University of Lisbon
)
10:00 - 11:30
The existence of powerful Active Galactic Nuclei (AGN) has now been established well within the first Gyr of the Universe, through the observations of tens of optically or near-infrared selected Quasi-Stellar Objects (QSOs) up to the currently highest redshift of z~8. Theoretical work has been developed showing how super-massive (M∼10^9 M_sun) black holes can exist at even earlier epochs, depending on a unknown but necessarily quick assembly and growth of a suitable “seed”. Some of these sources should be bright at radio wavelengths, and detectable well within the Epoch of Reionisation (EoR). These detections will be paramount to the understanding of the earliest stages of galaxy evolution but even more - they will allow the direct study of neutral hydrogen in the Epoch of Reionization, through the Square Kilometer Array project (SKA) observations of the HI 21cm forest against such background radio sources. However, recent radio surveys have shown that, even if very high redshift radio AGN may have been already detected, their identification has proven all but impossible. Attempts to "break this wall" are on-going, but at a frustratingly slow pace. In order to focus the development of future SKA and SKA-pathfinder surveys we have initiated a systematic exploitation of state-of-the-art galaxy formation and evolution models in order to understand how the identification of EoR radio AGN can finally be achieved. Finally, I will also discuss how radio and X-ray exploration of the EoR appear to be set to become increasingly connected in the near future.
Friday 10 June 2022
Saturday 11 June 2022
Sunday 12 June 2022
Monday 13 June 2022
Tuesday 14 June 2022
Wednesday 15 June 2022
Thursday 16 June 2022
10:00
Scale and Weyl invariance in metric-affine theories of gravity
-
Omar Zanusso
(
Univeristy of Pisa (Italy)
)
Scale and Weyl invariance in metric-affine theories of gravity
Omar Zanusso
(
Univeristy of Pisa (Italy)
)
10:00 - 11:30
Scale invariance is a desirable feature of any quantum field theory that wants to be complete in the ultraviolet and, as a consequence, more predictive. With this motivation in mind, we discuss a geometrical construction, based on the gauging of Weyl symmetry, of theories of gravity that are scale invariant. We pay particular attention to the behavior of affine degrees of freedom, such as spacetime's torsion, under Weyl transformations.
Friday 17 June 2022
Saturday 18 June 2022
Sunday 19 June 2022
Monday 20 June 2022
Tuesday 21 June 2022
Wednesday 22 June 2022
Thursday 23 June 2022
10:00
TBA -- seminar cancelled
TBA -- seminar cancelled
10:00 - 11:30
Friday 24 June 2022
Saturday 25 June 2022
Sunday 26 June 2022
Monday 27 June 2022
Tuesday 28 June 2022
Wednesday 29 June 2022
Thursday 30 June 2022
10:00
Enigmas of the Sp(h)in(x)
-
Jean-Marc Levy-Leblond
(
University of Nice
)
Enigmas of the Sp(h)in(x)
Jean-Marc Levy-Leblond
(
University of Nice
)
10:00 - 11:30
Beyond the well-known epistemological and foundational problems of quantum theory (measurement theory, entanglement, classical limit, etc.), there are others conceptual questions which have been somewhat neglected in the past decades. I will discuss six of these open questions, all connected with the notion of spin: the riddle of the position operator (or Dirac vs Wigner); the puzzle of the intrinsic magnetic moment; the spin-forces connection; the spin-statistics connection; the spin-charges connection; the non-renormalization of spin.
Friday 1 July 2022
Saturday 2 July 2022
Sunday 3 July 2022
Monday 4 July 2022
Tuesday 5 July 2022
Wednesday 6 July 2022
Thursday 7 July 2022
10:00
Metric-Affine Gravity as an effective field theory
-
Roberto Percacci
(
SISSA Trieste, Italy
)
Metric-Affine Gravity as an effective field theory
Roberto Percacci
(
SISSA Trieste, Italy
)
10:00 - 11:30
Abstract: I will present several aspects of general Metric-Affine gravity theories: different gauge choices, different choices of variables, the relation to metric theories of gravity, important special subcases, the choice of Lagrangian from the point of view of effective field theory, the occurrence of ghosts/tachyons and ways to avoid them. I will also mention Weyl theory as a special case.
Friday 8 July 2022
Saturday 9 July 2022
Sunday 10 July 2022
Monday 11 July 2022
Tuesday 12 July 2022
Wednesday 13 July 2022
Thursday 14 July 2022
10:00
Scale and Weyl Invariance in Einstein-Cartan gravity
-
Georgios Karananas
(
Munich University, ASC
)
Scale and Weyl Invariance in Einstein-Cartan gravity
Georgios Karananas
(
Munich University, ASC
)
10:00 - 11:30
I will show how Einstein-Cartan gravity can accommodate both global scale and local scale (Weyl) invariance. To this end, I will present a wide class of models with non-propagaing torsion and a nonminimally coupled scalar field. In phenomenological applications the scalar field may be associated with the Higgs boson. For global scale invariance, an additional dynamical field — the dilaton — is needed to make the theory phenomenologically viable. In the case of Weyl symmetry, the dilaton is spurious and the theory reduces to a sub-class of one-field models. Eliminating non-propagating degrees of freedom, I will derive an equivalent theory in the metric formulation of gravity and briefly discuss possible implications for phenomenology.
Friday 15 July 2022
Saturday 16 July 2022
Sunday 17 July 2022
Monday 18 July 2022
Tuesday 19 July 2022
Wednesday 20 July 2022
Thursday 21 July 2022
14:00
On de Sitter moduli stabilisation and inflation from string compactifications
-
Fernando Quevedo
(
DAMTP, Cambridge University
)
On de Sitter moduli stabilisation and inflation from string compactifications
Fernando Quevedo
(
DAMTP, Cambridge University
)
14:00 - 15:30
An overview will be presented on the efforts to obtain an accelerating universe in string compactifications including some recent work on brane inflation and moduli stabilisation.
Friday 22 July 2022
Saturday 23 July 2022
Sunday 24 July 2022
Monday 25 July 2022
Tuesday 26 July 2022
Wednesday 27 July 2022
Thursday 28 July 2022
Friday 29 July 2022
Saturday 30 July 2022
Sunday 31 July 2022
Monday 1 August 2022
Tuesday 2 August 2022
Wednesday 3 August 2022
Thursday 4 August 2022
Friday 5 August 2022
Saturday 6 August 2022
Sunday 7 August 2022
Monday 8 August 2022
Tuesday 9 August 2022
Wednesday 10 August 2022
Thursday 11 August 2022
Friday 12 August 2022
Saturday 13 August 2022
Sunday 14 August 2022
Monday 15 August 2022
Tuesday 16 August 2022
Wednesday 17 August 2022
Thursday 18 August 2022
Friday 19 August 2022
Saturday 20 August 2022
Sunday 21 August 2022
Monday 22 August 2022
Tuesday 23 August 2022
Wednesday 24 August 2022
Thursday 25 August 2022
Friday 26 August 2022
Saturday 27 August 2022
Sunday 28 August 2022
Monday 29 August 2022
Tuesday 30 August 2022
Wednesday 31 August 2022
Thursday 1 September 2022
11:00
Minimal theories and modified gravity models
-
Antonio De Felice
(
Yukawa Institute for Theoretical Physics, Kyoto Univ, Japan
)
Minimal theories and modified gravity models
Antonio De Felice
(
Yukawa Institute for Theoretical Physics, Kyoto Univ, Japan
)
11:00 - 12:30
I will describe the minimal theories of modified gravity that I have been working on recently. In particular, I will describe why/how minimal theories might help resolve today's tensions in cosmology.
Friday 2 September 2022
Saturday 3 September 2022
Sunday 4 September 2022
Monday 5 September 2022
Tuesday 6 September 2022
Wednesday 7 September 2022
Thursday 8 September 2022
11:00
Black holes solutions in metric-affine gravity with dynamical torsion and nonmetricity
-
Sebastian Bahamonde
(
Tokyo Institute of Technology, Japan
)
Black holes solutions in metric-affine gravity with dynamical torsion and nonmetricity
Sebastian Bahamonde
(
Tokyo Institute of Technology, Japan
)
11:00 - 12:30
In this talk, I will introduce and explain the geometrical role of torsion and nonmetricity tensor by considering post-Riemannian manifolds to construct theories of gravity. Then the trinity of gravity will be presented. After that, I will discuss a gravitational model which allows the independent dynamical behaviour of the torsion and nonmetricity fields to be displayed in the framework of Metric-Affine gauge theory of gravity. It will be shown that it is possible to construct exact black hole solutions within this theory. Particularly, I will show the first known isolated gravitational spherically symmetric system characterized by a metric tensor with independent spin and dilation charges. Finally, I will show a new axially symmetric solution in our theory which describes a Plebansky-Damiansky type D black hole solution valid in the decoupling limit between the orbital and the spin angular momentum.
Friday 9 September 2022
Saturday 10 September 2022
Sunday 11 September 2022
Monday 12 September 2022
Tuesday 13 September 2022
Wednesday 14 September 2022
Thursday 15 September 2022
11:00
Shadowgraphy: the art of producing images of compact objects
-
Diego Rubiera-Garcia
(
Departamento de Fısica Teorica, Universidad Complutense de Madrid
)
Shadowgraphy: the art of producing images of compact objects
Diego Rubiera-Garcia
(
Departamento de Fısica Teorica, Universidad Complutense de Madrid
)
11:00 - 12:30
The optical appearance of a compact object illuminated by its accretion disk is determined by a delicate - and hard to simulate - interaction between the background geometry and the geometrical, optical, and emission properties of the disk. In this talk I will discuss the images generated in optically and geometrically thin disks with several choices for the emission profiles, acting over (spherically symmetric) compact objects of different types: (modified) black holes, wormholes, and boson stars. Our discussion places a fundamental role to the notion of critical curve(s), namely, the locus of unstable bound null geodesics, and how (when present) they affect the balance between the main emission of the disk and the higher-order structure created by those light rays turning more than one (half-)orbit around the compact object. We finally reflect upon the simplifications and caveats of our analysis, and on the change of testing these objects using very-long baseline interferometry.
Friday 16 September 2022
Saturday 17 September 2022
Sunday 18 September 2022
Monday 19 September 2022
Tuesday 20 September 2022
Wednesday 21 September 2022
Thursday 22 September 2022
11:00
Hidden symmetries from distortions of the conformal structure
-
Nikolas Dimakis
(
Center for Theoretical Physics, Sichuan University, China
)
Hidden symmetries from distortions of the conformal structure
Nikolas Dimakis
(
Center for Theoretical Physics, Sichuan University, China
)
11:00 - 12:30
In the study of geodesic motion, it is well known that the mass of the test particle breaks the symmetries generated by proper conformal Killing vectors; the latter generating integrals of motion only for null geodesics. In this work we study the fate of these broken symmetries. We show that, for a generic spacetime, they are substituted by nonlocal symmetry generators, while, under special geometric conditions, they result in hidden symmetries of the geodesic action. A prominent example of this situation is given by considering a general pp-wave spacetime. We then proceed by introducing an additional symmetry breaking effect and study its further consequences on the conformal structure. This is realized by departing from Lorentzian geometry and by adopting a Bogoslovsky-Finsler type of line element.
Friday 23 September 2022
Saturday 24 September 2022
Sunday 25 September 2022
Monday 26 September 2022
Tuesday 27 September 2022
Wednesday 28 September 2022
Thursday 29 September 2022
11:00
Observational signatures of hot spots orbiting horizonless objects
-
Joao Luis Rosa
(
University of Tartu, Estonia
)
Observational signatures of hot spots orbiting horizonless objects
Joao Luis Rosa
(
University of Tartu, Estonia
)
11:00 - 12:30
Pushed by a number of advances, electromagnetic observatories have now reached the horizon scale of supermassive black holes. The existence and properties of horizons in our universe is one of the outstanding fundamental issues that can now be addressed. Here we investigate the ability to discriminate between black holes and compact, horizonless objects, focusing on the lensing of hot spots around compact objects. We work in particular with boson and Proca stars as central objects, and show that the absence of a horizon gives rise to a characteristic feature -- photons that plough through the central object and produce an extra image. This feature should be universal for central objects made of matter weakly coupled to the standard model.
Friday 30 September 2022
Saturday 1 October 2022
Sunday 2 October 2022
Monday 3 October 2022
Tuesday 4 October 2022
Wednesday 5 October 2022
Thursday 6 October 2022
14:00
Geometrical formulations of gravity and its coupling to matter ***
-
Lavinia Heisenberg
(
ETH Zurich and Heidelberg ITP
)
Geometrical formulations of gravity and its coupling to matter ***
Lavinia Heisenberg
(
ETH Zurich and Heidelberg ITP
)
14:00 - 15:30
I will first introduce 3 alternative but completely equivalent formulations of GR, where gravity is assigned to either curvature, or torsion or to non-metricity (mentioning extensions of GR on the way). I will then discuss how matter can couple to these different geometries and whether the minimal coupling principle can be preserved. *** note the change of time to 14:00h
Friday 7 October 2022
Saturday 8 October 2022
Sunday 9 October 2022
Monday 10 October 2022
Tuesday 11 October 2022
Wednesday 12 October 2022
11:00
Challenges of an accelerating universe
-
Ignatios Antoniadis
(
LPTHE Univ Pierre et Marie Curie Paris & CNRS
)
Challenges of an accelerating universe
Ignatios Antoniadis
(
LPTHE Univ Pierre et Marie Curie Paris & CNRS
)
11:00 - 12:30
Abstract: I will discuss theoretical constraints on de Sitter vacua in effective field theories, supergravity and string theory, as well as implications in models of inflation.
Thursday 13 October 2022
11:00
Dark Light Boson Emission from Supernovae
-
Chang Sub Shin
(
IBS Daejeon & Chungnam National University, South Korea
)
Dark Light Boson Emission from Supernovae
Chang Sub Shin
(
IBS Daejeon & Chungnam National University, South Korea
)
11:00 - 12:30
Supernovae are good laboratories to investigate new physics beyond the Standard Model which contains light dark particles. This is because the additional energy leakage sources by the dark particle emission can change the star evolution significantly. We re-examined the dark light boson (axion, dark gauge boson) emission from supernovae especially focusing on the effects of local contact interactions, pion-mediated Thomson-like process, decay of dark particle outside/inside the star, and medium effects on the effective charge of the nucleon. We obtained new constraints. In this talk, I will explain the physics behind the constraints.
Friday 14 October 2022
Saturday 15 October 2022
Sunday 16 October 2022
Monday 17 October 2022
Tuesday 18 October 2022
Wednesday 19 October 2022
Thursday 20 October 2022
Friday 21 October 2022
Saturday 22 October 2022
Sunday 23 October 2022
Monday 24 October 2022
Tuesday 25 October 2022
Wednesday 26 October 2022
Thursday 27 October 2022
11:00
Distinguishing different axion models with precision low energy axion couplings
-
Kiwoon Choi
(
IBS, Center for Theoretical Physics of the Universe, Daejeon - South Korea
)
Distinguishing different axion models with precision low energy axion couplings
Kiwoon Choi
(
IBS, Center for Theoretical Physics of the Universe, Daejeon - South Korea
)
11:00 - 12:30
I discuss the low energy couplings of the three most common types of axions: KSVZ-type, DFSZ-type and string-theoretic axions, while focusing on the possibility to discriminate these three types of axions from each other by the measurable couplings to the photons, nucleons, and electrons.
Friday 28 October 2022
Saturday 29 October 2022
Sunday 30 October 2022
Monday 31 October 2022
Tuesday 1 November 2022
Wednesday 2 November 2022
Thursday 3 November 2022
Friday 4 November 2022
Saturday 5 November 2022
Sunday 6 November 2022
Monday 7 November 2022
Tuesday 8 November 2022
Wednesday 9 November 2022
Thursday 10 November 2022
11:00
Quantum Gravity and the Swampland
-
Emilian Dudas
(
Ecole Polytechnique Paris
)
Quantum Gravity and the Swampland
Emilian Dudas
(
Ecole Polytechnique Paris
)
11:00 - 12:30
The Swampland is defined as the set of consistent Quantum Field Theories that cannot be coupled to Quantum Gravity. The goal of the Swampland is to find or to conjecture, based on the intuition gained from String Theory, general principles that a field theory coupled to quantum gravity should respect. One example is the "gravity as the weakest force" (or "weak-gravity conjecture"). I will summarize some of the recent conjectures and their potential implications for particle physics and cosmology.
Friday 11 November 2022
Saturday 12 November 2022
Sunday 13 November 2022
Monday 14 November 2022
Tuesday 15 November 2022
Wednesday 16 November 2022
Thursday 17 November 2022
Friday 18 November 2022
Saturday 19 November 2022
Sunday 20 November 2022
Monday 21 November 2022
Tuesday 22 November 2022
Wednesday 23 November 2022
Thursday 24 November 2022
14:00
The old and the new muon g-2 puzzle
-
Antonio Masiero
(
University of Padova and INFN - Italy
)
The old and the new muon g-2 puzzle
Antonio Masiero
(
University of Padova and INFN - Italy
)
14:00 - 15:30
The recent muon g-2 measurement at Fermilab confirms the previous BNL result, hence emphasizing the longstanding discrepancy between the experimental value and the Standard Model (SM) prediction based on the use of e^+ e^- → hadrons data to evaluate the leading hadronic vacuum polarization (HVP). This is what I call the “old” muon g-2 puzzle. On the other hand, a recent lattice result by the BMW collaboration shows a tension with the above mentioned SM prediction (this constitutes the “new” g-2 puzzle). The BMWc result has recently been confirmed by other lattice computations, although only concerning a window of the whole energy range integration. In this talk I plan to summarize the overall situation concerning the two muon g-2 puzzles and, in particular, I discuss the possibility that new physics may contribute to the e^+ e^- → hadrons cross-section to solve or at least alleviate the new g-2 puzzle.
Friday 25 November 2022
Saturday 26 November 2022
Sunday 27 November 2022
Monday 28 November 2022
Tuesday 29 November 2022
Wednesday 30 November 2022
Thursday 1 December 2022
Friday 2 December 2022
Saturday 3 December 2022
Sunday 4 December 2022
Monday 5 December 2022
Tuesday 6 December 2022
Wednesday 7 December 2022
Thursday 8 December 2022
11:00
TBA
TBA
11:00 - 12:30
seminar cancelled by the speaker.
Friday 9 December 2022
Saturday 10 December 2022
Sunday 11 December 2022
Monday 12 December 2022
Tuesday 13 December 2022
Wednesday 14 December 2022
Thursday 15 December 2022
14:00
Seeking de Sitter vacua in the string landscape
-
George Leontaris
(
University of Ioannina - Greece
)
Seeking de Sitter vacua in the string landscape
George Leontaris
(
University of Ioannina - Greece
)
14:00 - 15:30
The implications of perturbative string loop corrections on the moduli stabilisation problem and de Sitter vacua are investigated within the framework of type IIB string theory. In particular, the role of one-loop logarithmic corrections arising from a configuration of intersecting D7-brane stacks and a localised Einstein-Hilbert term descending from the ten-dimensional string action are examined. It turns out that such contributions are capable of generating a minimum of the potential along the volume modulus. It is further shown how de Sitter vacua are ensured when D-terms associated with the universal abelian factors of D7 brane stacks are taken into account.
Friday 16 December 2022
Saturday 17 December 2022
Sunday 18 December 2022
Monday 19 December 2022
Tuesday 20 December 2022
Wednesday 21 December 2022
Thursday 22 December 2022
11:00
Axion quality problem and its solution
-
Seong Chan Park
(
Yonsei University Seoul, South Korea
)
Axion quality problem and its solution
Seong Chan Park
(
Yonsei University Seoul, South Korea
)
11:00 - 12:30
No global symmetry is exact in the presence of gravity. The global U(1) PQ symmetry for the QCD axion is explicitly broken by non-perturbative effects of gravity such as axionic wormholes. The gravitational violation of the PQ symmetry due to wormholes is large enough to invalidate the PQ mechanism, which is entitled as the axion quality problem. We suggest a novel solution to this quality problem based on non-minimal coupling in metric and Palatini formulation of gravity.
Friday 23 December 2022
Saturday 24 December 2022
Sunday 25 December 2022
Monday 26 December 2022
Tuesday 27 December 2022
Wednesday 28 December 2022
Thursday 29 December 2022
Friday 30 December 2022
Saturday 31 December 2022
Sunday 1 January 2023
Monday 2 January 2023
Tuesday 3 January 2023
Wednesday 4 January 2023
Thursday 5 January 2023
Friday 6 January 2023
Saturday 7 January 2023
Sunday 8 January 2023
Monday 9 January 2023
Tuesday 10 January 2023
Wednesday 11 January 2023
Thursday 12 January 2023
Friday 13 January 2023
Saturday 14 January 2023
Sunday 15 January 2023
Monday 16 January 2023
Tuesday 17 January 2023
Wednesday 18 January 2023
Thursday 19 January 2023
Friday 20 January 2023
11:00
On the Weyl gravity extension of Higgs inflation
-
Hyun Min Lee
(
Chung-Ang University Seoul - South Korea
)
On the Weyl gravity extension of Higgs inflation
Hyun Min Lee
(
Chung-Ang University Seoul - South Korea
)
11:00 - 12:30
We consider the embedding of Higgs inflation with a non-minimal coupling into the Weyl gravity. In this model, the effective current-current interactions from the heavy Weyl gauge field cancel the non-canonical Higgs kinetic term in Einstein frame, so the unitarity problem of the original Higgs inflation becomes less severe. For a simple case where the couplings of the heavy Weyl gauge field appears from the non-minimal couplings to the Ricci curvature scalar in Weyl gravity, we find that the resultant model for Higgs inflation is the same as in the Palatini formulation for Higgs inflation. The crucial difference of our model from the Palatini formulation for Higgs inflation is that there is a light Weyl gauge field coupled to the Higgs fields. We also generalize the unitarization of Higgs inflation with general covariant kinetic terms for the dilaton and the Higgs fields, and realize a successful Higgs inflation, interpolating between the Palatini formulation for Higgs inflation and a Higgs-like inflation. We also discuss the Higgs mechanism for the light Weyl gauge field with an extra singlet scalar and show some interesting signatures for Higgs physics.
Saturday 21 January 2023
Sunday 22 January 2023
Monday 23 January 2023
Tuesday 24 January 2023
Wednesday 25 January 2023
Thursday 26 January 2023
Friday 27 January 2023
Saturday 28 January 2023
Sunday 29 January 2023
Monday 30 January 2023
Tuesday 31 January 2023
Wednesday 1 February 2023
Thursday 2 February 2023
Friday 3 February 2023
Saturday 4 February 2023
Sunday 5 February 2023
Monday 6 February 2023
Tuesday 7 February 2023
Wednesday 8 February 2023
Thursday 9 February 2023
Friday 10 February 2023
Saturday 11 February 2023
Sunday 12 February 2023
Monday 13 February 2023
Tuesday 14 February 2023
Wednesday 15 February 2023
Thursday 16 February 2023
Friday 17 February 2023
13:00
Inflation and Dark Matter with Weyl Symmetry
-
Yong Tang
(
Beijing, Chinese Academy of Sciences
)
Inflation and Dark Matter with Weyl Symmetry
Yong Tang
(
Beijing, Chinese Academy of Sciences
)
13:00 - 14:30
The cosmological observations of cosmic microwave background and large-scale structure indicate that our universe has a nearly scaling invariant power spectrum of the primordial perturbation. However, the exact origin for this primordial spectrum is still unclear. We present a theoretical framework and several viable models to explain cosmic inflation and dark matter simultaneously, both are important ingredients for the formation of cosmic structures. We also discuss the connection with usual Starobinsky inflation and difference in the prediction on the magnitude of primordial gravitational waves, which may be probed by future experiments on cosmic microwave background.
Saturday 18 February 2023
Sunday 19 February 2023
Monday 20 February 2023
Tuesday 21 February 2023
Wednesday 22 February 2023
Thursday 23 February 2023
Friday 24 February 2023
Saturday 25 February 2023
Sunday 26 February 2023
Monday 27 February 2023
Tuesday 28 February 2023
Wednesday 1 March 2023
Thursday 2 March 2023
Friday 3 March 2023
13:00
Aspects of Palatini Inflation and Quintessence
-
Alexandros Karam
(
NICPB National Institute Tallinn
)
Aspects of Palatini Inflation and Quintessence
Alexandros Karam
(
NICPB National Institute Tallinn
)
13:00 - 14:30
In this seminar we give an overview of various modified theories of gravity in the Palatini formalism and discuss their inflationary predictions. We then show how the Palatini formalism can be used to construct models of quintessential inflation where a single scalar field can play the role of the inflaton at early times and of dynamical dark energy at late times.
Saturday 4 March 2023
Sunday 5 March 2023
Monday 6 March 2023
Tuesday 7 March 2023
Wednesday 8 March 2023
Thursday 9 March 2023
Friday 10 March 2023
Saturday 11 March 2023
Sunday 12 March 2023
Monday 13 March 2023
Tuesday 14 March 2023
Wednesday 15 March 2023
Thursday 16 March 2023
Friday 17 March 2023
Saturday 18 March 2023
Sunday 19 March 2023
Monday 20 March 2023
Tuesday 21 March 2023
Wednesday 22 March 2023
Thursday 23 March 2023
Friday 24 March 2023
Saturday 25 March 2023
Sunday 26 March 2023
Monday 27 March 2023
Tuesday 28 March 2023
Wednesday 29 March 2023
Thursday 30 March 2023
Friday 31 March 2023
Saturday 1 April 2023
Sunday 2 April 2023
Monday 3 April 2023
Tuesday 4 April 2023
Wednesday 5 April 2023
Thursday 6 April 2023
Friday 7 April 2023
Saturday 8 April 2023
Sunday 9 April 2023
Monday 10 April 2023
Tuesday 11 April 2023
Wednesday 12 April 2023
Thursday 13 April 2023
Friday 14 April 2023
Saturday 15 April 2023
Sunday 16 April 2023
Monday 17 April 2023
Tuesday 18 April 2023
Wednesday 19 April 2023
Thursday 20 April 2023
Friday 21 April 2023
Saturday 22 April 2023
Sunday 23 April 2023
Monday 24 April 2023
Tuesday 25 April 2023
Wednesday 26 April 2023
Thursday 27 April 2023
Friday 28 April 2023
Saturday 29 April 2023
Sunday 30 April 2023
Monday 1 May 2023
Tuesday 2 May 2023
Wednesday 3 May 2023
Thursday 4 May 2023
Friday 5 May 2023
Saturday 6 May 2023
Sunday 7 May 2023
Monday 8 May 2023
Tuesday 9 May 2023
Wednesday 10 May 2023
Thursday 11 May 2023
Friday 12 May 2023
Saturday 13 May 2023
Sunday 14 May 2023
Monday 15 May 2023
Tuesday 16 May 2023
Wednesday 17 May 2023
Thursday 18 May 2023
Friday 19 May 2023
Saturday 20 May 2023
Sunday 21 May 2023
Monday 22 May 2023
Tuesday 23 May 2023
Wednesday 24 May 2023
Thursday 25 May 2023
Friday 26 May 2023
Saturday 27 May 2023
Sunday 28 May 2023
Monday 29 May 2023
Tuesday 30 May 2023
Wednesday 31 May 2023
Thursday 1 June 2023
Friday 2 June 2023
Saturday 3 June 2023
Sunday 4 June 2023
Monday 5 June 2023
Tuesday 6 June 2023
Wednesday 7 June 2023
Thursday 8 June 2023
Friday 9 June 2023
Saturday 10 June 2023
Sunday 11 June 2023
Monday 12 June 2023
Tuesday 13 June 2023
Wednesday 14 June 2023
Thursday 15 June 2023
Friday 16 June 2023
Saturday 17 June 2023
Sunday 18 June 2023
Monday 19 June 2023
Tuesday 20 June 2023
Wednesday 21 June 2023
Thursday 22 June 2023
Friday 23 June 2023
Saturday 24 June 2023
Sunday 25 June 2023
Monday 26 June 2023
Tuesday 27 June 2023
Wednesday 28 June 2023
Thursday 29 June 2023
Friday 30 June 2023
Saturday 1 July 2023
Sunday 2 July 2023
Monday 3 July 2023
Tuesday 4 July 2023
Wednesday 5 July 2023
Thursday 6 July 2023
Friday 7 July 2023
Saturday 8 July 2023
Sunday 9 July 2023
Monday 10 July 2023
Tuesday 11 July 2023
Wednesday 12 July 2023
Thursday 13 July 2023
Friday 14 July 2023
Saturday 15 July 2023
Sunday 16 July 2023
Monday 17 July 2023
Tuesday 18 July 2023
Wednesday 19 July 2023
Thursday 20 July 2023
Friday 21 July 2023
Saturday 22 July 2023
Sunday 23 July 2023
Monday 24 July 2023
Tuesday 25 July 2023
Wednesday 26 July 2023
Thursday 27 July 2023
Friday 28 July 2023
Saturday 29 July 2023
Sunday 30 July 2023
Monday 31 July 2023
Tuesday 1 August 2023
Wednesday 2 August 2023
Thursday 3 August 2023
Friday 4 August 2023
Saturday 5 August 2023
Sunday 6 August 2023
Monday 7 August 2023
Tuesday 8 August 2023
Wednesday 9 August 2023
Thursday 10 August 2023
Friday 11 August 2023
Saturday 12 August 2023
Sunday 13 August 2023
Monday 14 August 2023
Tuesday 15 August 2023
Wednesday 16 August 2023
Thursday 17 August 2023
Friday 18 August 2023
Saturday 19 August 2023
Sunday 20 August 2023
Monday 21 August 2023
Tuesday 22 August 2023
Wednesday 23 August 2023
Thursday 24 August 2023
Friday 25 August 2023
Saturday 26 August 2023
Sunday 27 August 2023
Monday 28 August 2023
Tuesday 29 August 2023
Wednesday 30 August 2023
Thursday 31 August 2023
Friday 1 September 2023
Saturday 2 September 2023
Sunday 3 September 2023
Monday 4 September 2023
Tuesday 5 September 2023
Wednesday 6 September 2023
Thursday 7 September 2023
Friday 8 September 2023
Saturday 9 September 2023
Sunday 10 September 2023
Monday 11 September 2023
Tuesday 12 September 2023
Wednesday 13 September 2023
Thursday 14 September 2023
Friday 15 September 2023
Saturday 16 September 2023
Sunday 17 September 2023
Monday 18 September 2023
Tuesday 19 September 2023
Wednesday 20 September 2023
Thursday 21 September 2023
Friday 22 September 2023
Saturday 23 September 2023
Sunday 24 September 2023
Monday 25 September 2023
Tuesday 26 September 2023
Wednesday 27 September 2023
Thursday 28 September 2023
Friday 29 September 2023
Saturday 30 September 2023
Sunday 1 October 2023
Monday 2 October 2023
Tuesday 3 October 2023
Wednesday 4 October 2023
Thursday 5 October 2023
Friday 6 October 2023
Saturday 7 October 2023
Sunday 8 October 2023
Monday 9 October 2023
Tuesday 10 October 2023
Wednesday 11 October 2023
Thursday 12 October 2023
Friday 13 October 2023
Saturday 14 October 2023
Sunday 15 October 2023
Monday 16 October 2023
Tuesday 17 October 2023
Wednesday 18 October 2023
Thursday 19 October 2023
Friday 20 October 2023
Saturday 21 October 2023
Sunday 22 October 2023
Monday 23 October 2023
Tuesday 24 October 2023
Wednesday 25 October 2023
Thursday 26 October 2023
Friday 27 October 2023
Saturday 28 October 2023
Sunday 29 October 2023
Monday 30 October 2023
Tuesday 31 October 2023
Wednesday 1 November 2023
Thursday 2 November 2023
Friday 3 November 2023
Saturday 4 November 2023
Sunday 5 November 2023
Monday 6 November 2023
Tuesday 7 November 2023
Wednesday 8 November 2023
Thursday 9 November 2023
Friday 10 November 2023
Saturday 11 November 2023
Sunday 12 November 2023
Monday 13 November 2023
Tuesday 14 November 2023
Wednesday 15 November 2023
Thursday 16 November 2023
Friday 17 November 2023
Saturday 18 November 2023
Sunday 19 November 2023
Monday 20 November 2023
Tuesday 21 November 2023
Wednesday 22 November 2023
Thursday 23 November 2023
Friday 24 November 2023
Saturday 25 November 2023
Sunday 26 November 2023
Monday 27 November 2023
Tuesday 28 November 2023
Wednesday 29 November 2023
Thursday 30 November 2023
Friday 1 December 2023
Saturday 2 December 2023
Sunday 3 December 2023
Monday 4 December 2023
Tuesday 5 December 2023
Wednesday 6 December 2023
Thursday 7 December 2023
Friday 8 December 2023
Saturday 9 December 2023
Sunday 10 December 2023
Monday 11 December 2023
Tuesday 12 December 2023
Wednesday 13 December 2023
Thursday 14 December 2023
Friday 15 December 2023
Saturday 16 December 2023
Sunday 17 December 2023
Monday 18 December 2023
Tuesday 19 December 2023
Wednesday 20 December 2023
Thursday 21 December 2023
Friday 22 December 2023
Saturday 23 December 2023
Sunday 24 December 2023
Monday 25 December 2023
Tuesday 26 December 2023
Wednesday 27 December 2023
Thursday 28 December 2023
Friday 29 December 2023
Saturday 30 December 2023
Sunday 31 December 2023
Monday 1 January 2024
Tuesday 2 January 2024
Wednesday 3 January 2024
Thursday 4 January 2024
Friday 5 January 2024
Saturday 6 January 2024
Sunday 7 January 2024
Monday 8 January 2024
Tuesday 9 January 2024
Wednesday 10 January 2024
Thursday 11 January 2024
Friday 12 January 2024
Saturday 13 January 2024
Sunday 14 January 2024
Monday 15 January 2024
Tuesday 16 January 2024
Wednesday 17 January 2024
Thursday 18 January 2024
Friday 19 January 2024
Saturday 20 January 2024
Sunday 21 January 2024
Monday 22 January 2024
Tuesday 23 January 2024
Wednesday 24 January 2024
Thursday 25 January 2024
Friday 26 January 2024
Saturday 27 January 2024
Sunday 28 January 2024
Monday 29 January 2024
Tuesday 30 January 2024
Wednesday 31 January 2024
Thursday 1 February 2024
Friday 2 February 2024
Saturday 3 February 2024
Sunday 4 February 2024
Monday 5 February 2024
Tuesday 6 February 2024
Wednesday 7 February 2024
Thursday 8 February 2024
13:00
Constraining torsion theories with Weyl (gauge) invariance
-
Dario Sauro
(
University of Pisa (Italy)
)
Constraining torsion theories with Weyl (gauge) invariance
Dario Sauro
(
University of Pisa (Italy)
)
13:00 - 14:30
Torsionful theories of gravity with local SO(3,1)xD(1) invariance generally propagate two vector degrees of freedom, i.e., the torsion vector and the Weyl vector potential. We show that these are tightly intertwined by imposing a projective symmetry on the theory: this enables us to get rid of the Weyl potential and to interpret the torsion vector as the connection 1-form for Weyl gauge invariance. By further imposing a second type of projective invariance we can get rid of the torsion vector too, obtaining a conformal theory. Thence, we focus on the tensor irrep of the torsion, which is unaffected by Weyl transformations, and we derive its conformal quadratic action. We conclude by making remarks about the general features of Weyl gauge invariant theories with torsion.
Friday 9 February 2024
Saturday 10 February 2024
Sunday 11 February 2024
Monday 12 February 2024
Tuesday 13 February 2024
Wednesday 14 February 2024
Thursday 15 February 2024
14:00
TBA
TBA
14:00 - 15:30
TBA
Friday 16 February 2024
Saturday 17 February 2024
Sunday 18 February 2024
Monday 19 February 2024
Tuesday 20 February 2024
Wednesday 21 February 2024
Thursday 22 February 2024
Friday 23 February 2024
Saturday 24 February 2024
Sunday 25 February 2024
Monday 26 February 2024
Tuesday 27 February 2024
Wednesday 28 February 2024
10:00
UV-IR connections in scattering amplitudes: power of unitarity and causality
-
Anna Tokareva
(
Hangzhou Institute for Advanced Study, UCAS, China
)
UV-IR connections in scattering amplitudes: power of unitarity and causality
Anna Tokareva
(
Hangzhou Institute for Advanced Study, UCAS, China
)
10:00 - 11:30
Very basic assumptions about the structure of the fundamental theory describing the nature at high energies can allow for a set of valuable constraints on the low energy EFT. The constraints are independent of the concrete underlying fundamental theory at high energies. The low energy physics is bounded from the set of quite natural assumptions about the structure of the full theory, such as unitarity, causality and Lorentz invariance. In this talk I will consider the EFT of photons (or other U(1) gauge field) and compare different approaches to obtain bounds on its Wilson coefficients. I will present an analytic derivation of the implications of unitarity (linear and non-linear positivity bounds) and compare these constraints with the requirement of causal propagation of the photon modes around non-trivial backgrounds generated by external sources. I will show that the low energy causality condition can give complementary constraints to the positivity bounds. Applying both constraints together can significantly reduce the allowed region of the photon EFT parameters. Besides constraints on the IR theory, the analyticity and unitarity assumptions can set bounds on the UV theory. I will show this connection using the example of the graviton mediated scattering amplitudes. Surprisingly, the form of the forward limit singularities at low energies can give an insight into the of high energy limit of graviton scattering described by the unknown physics.
Thursday 29 February 2024
Friday 1 March 2024
Saturday 2 March 2024
Sunday 3 March 2024
Monday 4 March 2024
Tuesday 5 March 2024
Wednesday 6 March 2024
Thursday 7 March 2024
Friday 8 March 2024
Saturday 9 March 2024
Sunday 10 March 2024
Monday 11 March 2024
Tuesday 12 March 2024
Wednesday 13 March 2024
Thursday 14 March 2024
15:00
TBA
TBA
15:00 - 16:30
TBA
Friday 15 March 2024
Saturday 16 March 2024
Sunday 17 March 2024
Monday 18 March 2024
Tuesday 19 March 2024
Wednesday 20 March 2024
Thursday 21 March 2024
Friday 22 March 2024
Saturday 23 March 2024
Sunday 24 March 2024
Monday 25 March 2024
Tuesday 26 March 2024
Wednesday 27 March 2024
Thursday 28 March 2024
15:00
TBA
TBA
15:00 - 16:30
TBA
Friday 29 March 2024
Saturday 30 March 2024
Sunday 31 March 2024
Monday 1 April 2024
Tuesday 2 April 2024
Wednesday 3 April 2024
Thursday 4 April 2024
Friday 5 April 2024
Saturday 6 April 2024
Sunday 7 April 2024
Monday 8 April 2024
Tuesday 9 April 2024
Wednesday 10 April 2024
Thursday 11 April 2024
15:00
TBA
TBA
15:00 - 16:30
TBA
Friday 12 April 2024
Saturday 13 April 2024
Sunday 14 April 2024
Monday 15 April 2024
Tuesday 16 April 2024
Wednesday 17 April 2024
Thursday 18 April 2024
Friday 19 April 2024
Saturday 20 April 2024
Sunday 21 April 2024
Monday 22 April 2024
Tuesday 23 April 2024
Wednesday 24 April 2024
Thursday 25 April 2024
Friday 26 April 2024
Saturday 27 April 2024
Sunday 28 April 2024
Monday 29 April 2024
Tuesday 30 April 2024
Wednesday 1 May 2024
Thursday 2 May 2024
Friday 3 May 2024
Saturday 4 May 2024
Sunday 5 May 2024
Monday 6 May 2024
Tuesday 7 May 2024
Wednesday 8 May 2024
Thursday 9 May 2024
Friday 10 May 2024
Saturday 11 May 2024
Sunday 12 May 2024
Monday 13 May 2024
Tuesday 14 May 2024
Wednesday 15 May 2024
Thursday 16 May 2024
Friday 17 May 2024
Saturday 18 May 2024
Sunday 19 May 2024
Monday 20 May 2024
Tuesday 21 May 2024
Wednesday 22 May 2024
Thursday 23 May 2024
Friday 24 May 2024
Saturday 25 May 2024
Sunday 26 May 2024
Monday 27 May 2024
Tuesday 28 May 2024
Wednesday 29 May 2024
Thursday 30 May 2024
Friday 31 May 2024
Saturday 1 June 2024
Sunday 2 June 2024
Monday 3 June 2024
Tuesday 4 June 2024
Wednesday 5 June 2024
Thursday 6 June 2024
Friday 7 June 2024
Saturday 8 June 2024
Sunday 9 June 2024
Monday 10 June 2024
Tuesday 11 June 2024
Wednesday 12 June 2024
Thursday 13 June 2024
Friday 14 June 2024
Saturday 15 June 2024
Sunday 16 June 2024
Monday 17 June 2024
Tuesday 18 June 2024
Wednesday 19 June 2024
Thursday 20 June 2024
Friday 21 June 2024
Saturday 22 June 2024
Sunday 23 June 2024
Monday 24 June 2024
Tuesday 25 June 2024
Wednesday 26 June 2024
Thursday 27 June 2024
Friday 28 June 2024
Saturday 29 June 2024
Sunday 30 June 2024
Monday 1 July 2024