Domenico Frattulillo, Federico II University in Naples
Quantum Euler angles and agency-dependent spacetime
Quantum gravity is expected to introduce quantum aspects into the description of reference frames. Here we set the stage for exploring how quantum gravity induced deformations of classical symmetries could modify the transformation laws among reference frames in an effective regime. We invoke the quantum group SUq(2) as a description of deformed spatial rotations and interpret states of a representation of its algebra as describing the relative orientation between two reference frames. This leads to a quantization of one of the Euler angles and to the new paradigm of agency dependence: space is reconstructed as a collection of fuzzy points, exclusive to each agent, which depends on their choice of reference frame. Each agent can choose only one direction in which points can be sharp, while points in all other directions become fuzzy in a way that depends on this choice. Two agents making different choices will thus observe the same points with different degrees of fuzziness.
Michele Arzano, University of Naples
Entanglement entropy and horizon temperature in conformal quantum mechanics
The generators of radial conformal symmetries in Minkowski space-time can be put in correspondence with generators of time evolution in conformal quantum mechanics. Within this correspondence I show that in conformal quantum mechanics the state corresponding to the inertial vacuum for a conformally invariant field in Minkowski spacetime has the structure of a thermofield double. The latter is built from a bipartite "vacuum state” corresponding to the ground state of the generators of hyperbolic time evolution. These can evolve states only within a portion of the time domain. When such generators correspond to conformal Killing vectors mapping a causal diamond in itself and generators of dilations, the temperature of the thermofield double reproduces, respectively, the diamond temperature and the Milne temperature found for massless fields in Minkowski spacetime. We calculate the entanglement entropy associated to the thermofield double states and obtain a UV divergent logarithmic behaviour analogous to known results in two-dimensional conformal field theory in which the entangling boundary is point-like.
Riccardo Borsato, University of Santiago de Compostela, Galician Institute of High Energy Physics
Deformations of 2D field theories and the light-cone gauge
Recently, there has been a lot of progress in the construction of deformations of 2-dimensional integrable field theories that do not break the original integrity. Often, the motivation is related to the realization of such integrable models in the context of the holographic duality, thus opening the possibility to obtain exact results for gauge and gravity theories and their deformations. At the same time, the study of such deformations has led to some puzzles that force us to better understand already the undeformed models. In particular, in this talk I will explain why it is important to carefully choose the light-cone gauge (necessary to fix the reparametrisation invariance on the worldsheet of the string) in order to have a workable description of the deformed models, and I will show how inequivalent light-cone gauges are related to each other.
Linus Wulff, Mastaryk University, Brno
Stringy corrections to gravity from dualities
As a quantum theory of gravity, string theory predicts specific corrections to Einstein's theory. These corrections are in general difficult to compute. I will describe an approach that uses another characteristic feature of string theory - the existence of dualities - to constrain the form these corrections can take.
Sibylle Driezen (ETH Zurich)
Exploring integrable deformations
Recent years have seen an upsurge of interest in deformations of two-dimensional sigma-models which preserve classical integrability when present in the original model. This property enables powerful techniques for solving these models, even in non-trivial scenarios such as at strong coupling. This talk introduces classical integrability concepts and reviews the construction of a large family of integrable deformed sigma-models. We will focus on the crucial role played by “worldsheet dualities”, which have been naturally developed within the context of string theory. In the second part of the talk, we will explore the interest of applying integrable deformations on the so-called AdS/CFT correspondence, a duality connecting highly symmetrical string theories to gauge theories. Specifically, we will focus on the “Jordanian” subclass of integrable deformations and provide insights into ongoing research in this area.
Aleksander Kozak
Conformally-invariant framework for scalar-tensor theories of gravity in the metric, Palatini, and hybrid approaches
In my talk, I will summarize the research I conducted as a Ph.D. student at the Institute of Theoretical Physics. I will focus on the issue of conformal frames in modified gravity theories. Modified theories of gravity (or extended theories of gravity) introduce ambiguity in the description of gravitational phenomena related to the fact that there exists a multitude of conformal frames yielding - possibly - inequivalent predictions. In the literature, the most common frames are the Einstein and Jordan frames, and the issue of which one is correct remains a topic of debate. However, it was shown recently that it would be possible to construct a conformally-invariant framework for metric scalar-tensor (ST) theories of gravity. I will demonstrate that it is possible to extend the framework of conformal invariants to the case of Palatini ST theories of gravity. The connections between different versions of ST theories will also be explored. Some remarks on choosing the ‘right’ conformal frame will also be made. In the second part of my talk, I will move on to discussing applications of the invariant framework. It will be demonstrated that, in the minisuperspace formalism applied to the cosmological scenarios, the lapse function can be treated as a conformal factor, which will enable us to simplify the considerations and find integrals of motion for different theories. We will also revisit the connections between f(R) theories in different approaches and their ST representations. In the end, the conformally-invariant Tolman-Oppenheimer-Volkoff equation will be discussed.
Yuri Shtanov, Bogolyubov Institute for Theoretical Physics, Kiev, Ukraine
Facets of f(R) gravity: inflation, dark matter, scale symmetry breaking
We discuss several facets of the metric f(R) gravity theory coupled to the Standard Model. The theory contains an extra scalar degree of freedom (the scalaron), which can be employed in several interesting ways. Firstly, if the scalaron is very heavy, it can play the role of an inflaton. In this case, a typical f(R) theory is equivalent to scalar-field models with hilltop or tabletop potentials in the Einstein frame. Inflationary evolution in such models can proceed in two alternative directions: towards the stable point at small scalar curvature describing the observable universe, or towards the asymptotic region at large scalar curvature. A universe evolving towards this asymptotically free gravity region will either run into a "Big-Rip" singularity or inflate eternally. Secondly, the scalaron in metric f(R) gravity can be a dark-matter candidate if its mass lies in the range between around 4 meV and 1.2 MeV. The scalaron manifests itself as an almost sterile cold dark matter, and one of its possible observational verifications consists in measuring specific Yukawa gravitational forces on submillimeter spatial scales. We will discuss initial conditions for the scalaron in the early universe and the role played by the Higgs field and electroweak crossover in the formation of these initial conditions. Thirdly, the scalaron in scale-invariant R^2 gravity theory can play the role of a massless dilaton breaking the scale (and electroweak) symmetry and generating the mass scale in quantum field theory. We briefly discuss this model and its fine-tuning.
Prof. Richard Kerner, Sorbonne University, Paris
Non-linear Electrodynamics derived from the Kaluza-Klein Theory
The Lagrangian of the Kaluza-Klein theory, in its simplest five-dimensional version, should include not only the scalar curvature R, but also the quadratic Gauss-Bonnet invariant. The general Lagrangian is computed and the resulting non-linear equations which generalize Maxwell's system in a quite unique way are investigated. The possibility of the existence of static solutions is presented, and the qualitative behaviour of such solutions is discussed.
Jorge Ovalle (Silesian University in Opava)
Regular black holes without Cauchy horizons? The role of integrable singularities
Although we cannot understand the true nature of singularities in the framework of GR, it is possible to evade them by following a fairly simple strategy: generate regular BHs by filling the spacetime around the central singularity with some physically reasonable source of matter (which could be consequence of some new gravitational sector). This has produced a plethora of new regular BH solutions in recent years, mainly because the matter source used to evade the central singularity can be interpreted in terms of nonlinear electrodynamics. However, all these regular BH solutions contain a Cauchy horizon, a null hyper-surface beyond which predictability breaks down, and also leads to mass inflation at the perturbative level, a pathology which occurs even in loop quantum gravity inspired models. Even though the strong cosmic censorship conjecture establish the impossibility of extending spacetime beyond this region, in this talk we show how far we can go, without invoking this conjecture, in the building of a physically reasonable black hole without a Cauchy hyper-surface. Following this reasoning, we find a black hole lacking of Cauchy horizon, asymptotically flat and satisfying either the strong or dominant energy condition. The above is possible by demanding integrable singularity for the Ricci scalar, whose direct consequence is the appearance of finite tidal forces.
Jerzy Kowalski-Glikman
Why there is (almost) nothing rater than something? The cosmological constant problem
In the talk, I will present a new understanding of the cosmological constant problem, built upon the realization that the vacuum energy density can be expressed in terms of a phase space volume. To this end, a UV-IR regularization is introduced, which implies a relationship between the vacuum energy and entropy. Combining this insight with the holographic bound on entropy then yields a bound on the cosmological constant consistent with observations. It follows that the universe is large, and the cosmological constant is naturally small, because the universe is filled with a large number of degrees of freedom.
Amir Khan, Max Planck Institute, Heidelberg, Germany
General Neutrino Interactions and its Phenomenology
In this talk, I will give an overview of the general neutrino interactions, namely, vector (V), axial-vector (A), scalar (S), pseudoscalar (P), and tensor interactions (T) and their origins. I will discuss the phenomenology of the general neutrino interactions and their importance in the neutrino oscillation and absolute mass experiments, direct detection dark matter experiments and some early universe measurements. I will report recent experimental limits from different experiments. I will also briefly discuss connections between the general neutrino interactions with some simplified models.
Michele Arzano
Getting hot without accelerating: diamond and Milne temperature from conformal quantum mechanics
The generators of radial conformal symmetries in Minkowski space-time can be put in correspondence with the generators of time evolution in conformal quantum mechanics. Within this correspondence I show that in conformal quantum mechanics the state corresponding to the inertial vacuum for a conformally invariant field in Minkowski spacetime has the structure of a thermofield double. The latter is built from a bipartite "vacuum state” corresponding to the ground state of the generators of hyperbolic time evolution. These can evolve states only within a portion of the time domain. When such generators correspond to conformal Killing vectors mapping a causal diamond in itself and generators of dilations, the temperature of the thermofield double reproduces, respectively, the diamond temperature and the Milne temperature. This result indicates that, for conformally invariant fields, the fundamental ingredient at the basis vacuum thermal effects in flat-space time is the non-eternal nature of the lifetime of observers rather than their acceleration.
dr David Osten
New classically integrable sigma models based on Z(N)-symmetric homogeneous spaces
Typical two dimensional integrable sigma models are those which have group manifolds or Riemannian symmetric spaces, or in other words homogeneous spaces with a Z(2)-grading, as target spaces. This construction can be generalised to homogeneous spaces based on a Z(N)-grading. After a review of these sigma models and their classical integrability, I present new types of sigma models with Z(N)-symmetric homogeneous target spaces and some of their deformations. I comment on the geometric interpretation of the Z(N)-symmetry, the applicability as string sigma models and Hamiltonian integrability
Dr. Amir Khan, Max Planck Institute, Heidelberg, Germany
General Neutrino Interactions and its Phenomenology
In this talk, I will give an overview of the general neutrino interactions, namely, vector (V), axial-vector (A), scalar (S), pseudoscalar (P), and tensor interactions (T) and their origins. I will discuss the phenomenology of the general neutrino interactions and their importance in the neutrino oscillation and absolute mass experiments, direct detection dark matter experiments and some early universe measurements. I will report recent experimental limits from different experiments. I will also briefly discuss connections between the general neutrino interactions with some simplified models.
Michał Bobula
Rainbow Oppenheimer-Snyder collapse and the entanglement entropy production
I derive a new model of black-to-white hole transition - the classical Oppenheimer-Snyder dust ball interior is modified with Loop Quantum Cosmology dynamics. I consider the rainbow metric approach for both pure dust ball collapse and the similar scenario accounting for scalar field perturbations. The collapsing matter bounces and reemerges in a new universe. Exterior geometry is extracted as well as the global causal structure of the process. I study entanglement entropy production to verify whether the black hole information paradox exists within the model.
Eric Lescano, Ruđer Bošković Institut (Zagreb, Croatia)
Statistical matter coupled to the (double) geometry
This talk will be about cosmology and string theory and it will have two parts. In the first one we will review the inclusion of statistical matter in Riemannian geometries. Our starting point will be the Einstein equation and we will focus on energy-momentum tensors that depend on hydrodynamics/thermodynamics variables, such as the perfect fluid. We will derive conservation laws considering relativistic kinetic theory. We will finish this part with a quick introduction to the low energy limit of string theory (supergravity) and its Double Field Theory (DFT) rewriting. In the second part of the talk we will include statistical matter in DFT (based on 2003.09588), we will construct the energy-momentum tensor for the perfect fluid in the double geometry (based on 2111.03682) and finally we will discuss about the relation between string cosmologies, DFT cosmologies and alpha'-corrections (based on 2207.04041).
Prof. Khalil Idiab, Humboldt University, Berlin
Yang-Baxter deformations of the flat space string
Symmetric space sigma models (SSSM) and their Yang-Baxter deformations are integrable, which makes them useful in providing exact results in the AdS/CFT correspondence. Much is known about these integrable models at classical level, but difficulties with quantization makes it hard to make general statements about their quantum integrable structure. By considering deformations of the flat space sigma model, with non semi-simple Poincaré symmetry, it turns out one can find deformed models that can be canonically quantized (plane waves), enabling future investigation of their quantum structure. As a first step, this requires extending Yang-Baxter deformations of SSSMs to cases with non semi-simple symmetry groups, this will be the main objective of the talk.
mgr Arkadiusz Bochniak, prof. Andrzej Sitarz (joint talk) (UJ)
Physics from spectral triples with non-product geometries
We'll briefly review the concept of applying the construction of Connes' spectral triples to the Standard Model and gravity which goes beyond the commonly assumed product of two spectral triples. The application to the SM allows having no fermion doubling, explains naturally CP violation and no strong symmetry breaking while the gravity part leads to interesting models similar to bimetric modifications of gravity.
Prof. Richard Kerner, Sorbonne, Paris
Lorentz covariance from discrete symmetries Z2 and Z3
Our aim is to derive the symmetries of the space-time, i.e. the Lorentz transformations, from symmetries of the interactions between the most fundamental constituents of matter, in particular quarks and leptons. We show how the discrete symmetries Z_2 and Z_3 combined with the superposition principle result in the SL(2, C) and SU(3) symmetries. The role of Pauli's exclusion principle in the derivation of the SL(2, C) symmetry is put forward as the source of the macroscopically observed Lorentz symmetry. Then Pauli's principle is generalized for the case of the Z_3 grading replacing the usual Z_2 grading, leading to ternary commutation relations. We present the cubic and ternary algebras which are a direct generalization of fermionic algebras with Z_3-grading replacing the usual Z_2-grading. Elementary properties and structures of such algebras are discussed, with special interest in the low-dimensional ones, with two generators only. Invariant cubic forms on Z_3-graded algebra with two generators are introduced, a possible description of the isospin. It is shown how a Z_3-graded generalization of the SL(2,C) group arises naturally as the symmetry group preserving the Z_3-graded ternary isospin algebra. Vectorial and spinorial representations of the generalized Z_3-graded. Lorentz algebra are briefly discussed.
mgr Aleksander Kozak
Inflationary potentials from F(R) gravity in a unified hybrid metric-Palatini approach
A class of scalar-tensor theories that unify metric, Palatini and hybrid metric-Palatini gravitational actions with nonminimal interaction is investigated from the point of view of their consistency with generalized conformal transformations. It is known that such theory can be represented on shell by a purely metric scalar-tensor theory. This extends the formalism previously introduced in our last paper [1]. Exploiting properties of the Legendre transformation, we relate some viable inflationary potentials with F(R)-gravitational Lagrangians by solving corresponding Clairaut's equation. Then for given potential function various gravitational scenarios are discussed within a metric, Palatini, as well as a hybrid metric-Palatini formulations. [1] A. Kozak and A. Borowiec, "Palatini frames in scalar-tensor theories of gravity", Eur.Phys.J. C79 (2019) no.4, 335
prof. Michele Arzano
Horizon temperature without space-time
I will show how the characteristic thermal effects that observers experience in space-times possessing an event horizon, emerge already in a simple quantum system with affine symmetry living on the real line. The derivation I will present is essentially group theoretic in nature: a thermal state emerges naturally when comparing different representations of the group of affine transformations of the real line. The freedom in the choice of different notions of translation generators is the key to the Unruh effect on the real line which I will describe.
dr Anna Pachoł, Queen Mary University of London
Digital quantum geometries
Noncommutative geometry, as the generalised notion of geometry, allows us to model the quantum gravity effects in an effective description without full knowledge of quantum gravity itself. On a curved space one must use the methods of Riemannian geometry - but in their quantum version, including quantum differentials, quantum metrics and quantum connections. The brief introduction to the general framework involving noncommutative differential graded algebra and construction of quantum Riemannian geometry elements will be provided. This framework has been applied to classification of all possible noncommutative Riemannian geometries in small dimensions (including finding explicit forms for quantum Levi-Civita connections and Riemann, Ricci and Einstein tensors), working over the field F_2 of 2 elements and with coordinate algebras up to dimension n<=3. We have found a rich moduli of examples for n=3 and top form degree 2 (providing a landscape of all reasonable up to 2D quantum geometries), including many which are not flat. Their coordinate algebras are commutative but their differentials are not. The choice of the finite field in this framework proposes a new kind of 'discretisation scheme', which we called the 'digital geometry'.
prof. L. Dąbrowski, SISSA, Trieste, Italy
Almost commutative geometry of the Standard Model
By functions on a noncommutative (or `quantum') space one usually means a suitable algebra of operators. Then the smooth and metric structures can be described in terms of a spectral triple which involves an analogue of the Dirac operator. The Standard Model of fundamental particles in physics can be understood as the almost commutative geometry, the exterior part of which is the canonical spectral triple on a spin manifold and the finite inner part a quantum analogue of the de-Rham-Hodge spectral triple.
prof. Zbigniew Haba
Conformally flat travelling plane wave solutions of Einstein equations
Einstein equations with a conformally flat metric and ideal fluid source are discussed. It is shown that these equations have plane wave solutions. Scalar fields, electromagnetic plane waves and relativistic particles can be considered as the source of such an energy-momentum.
Josua Unger
Asymptotic Symmetries and Quantum Groups
In this talk I will discuss the BMS analysis of asymptotically flat spacetime, their algebraic properties and important consequences for black hole physics. The deformation by twisting of the BMS (Hopf-)algebra is presented and motivated in the context of the information loss paradox.
prof. Jerzy Kowalski-Glikman
Gravity as a constrained BF theory
In my talk I will present the construction of gravity Lagrangian as a sum of the topological term, the BF theory with (anti-) de Sitter gauge group and a 'constraint' term, explicitly breaking the symmetry down to local Lorentz symmetry. I will then comment on several properties of such defined theory: perturbative expansion around topological vacuum, particle(s) coupling, canonical analysis, and calculation of black hole entropy.
dr Remigiusz Durka
Nuts approach to the Taub-NUT space-time (Pokręcone podejście do czasoprzestrzeni Tauba-NUT)
I offer new approach to the subject of Taub-NUT space-time supposedly possessing gravitational analog of the magnetic monopole. Starting from realizing that the source of many inconsistencies lies in neglecting the effects of the wire singularities present in that solution, I am able to explain existence of the NUT parameter by the means of quite peculiar rotation. Among many things, this leads to the consistent description of the black hole thermodynamics for the Lorentzian Taub-NUT spacetime with the essential contribution to the angular momentum and the total entropy.
prof. Jerzy Lukierski
Celebration of prof. Jerzy Lukierski birthday
Our next group seminar on May 21st is going to be devoted to the celebration of prof. Jerzy Lukierski birthday. We are offering short speeches, a bit of wine, some sweets, and a good deal of friendly chats. Everybody is cordially invited.
mgr Lennart Brocki
BMS Group at Spatial Infinity
In this talk I present a recent publication by Henneaux and Troessaert in which they propose new boundary conditions for asymptotically flat spacetimes at spatial infinity and find that the conserved charges close according to the BMS algebra. Their analysis relies on the Hamiltonian formalism of general relativity and is an extension of the work done by Regge and Teitelboim in 1974, which will therefore also be summarized, and mainly differs in the choice of parity conditions. For a more complete understanding the talk will also cover some basics about the BMS Group.
mgr Lennart Brocki
BMS Group at Spatial Infinity
In this talk I present a recent publication by Henneaux and Troessaert in which they propose new boundary conditions for asymptotically flat spacetimes at spatial infinity and find that the conserved charges close according to the BMS algebra. Their analysis relies on the Hamiltonian formalism of general relativity and is an extension of the work done by Regge and Teitelboim in 1974, which will therefore also be summarized, and mainly differs in the choice of parity conditions. For a more complete understanding the talk will also cover some basics about the BMS Group.
mgr Aleksander Kozak
Palatini frames in scalar-tensor theories of gravity
Conformal transformations play an important role in the scalar-tensor theories of gravity, as they allow one to carry out calculations in a more convenient frame, simplifying the field equations. In the Palatini approach, however, the metric structure of space-time is decoupled from its affine structure, so that a transformation of the metric does not entail a corresponding change in the connection. One needs to define independent transformation for the connection, reducing to the standard formula in case the connection is Levi-Civita with respect to the metric. In my presentation, I shall introduce a scalar-tensor theory taking into account such transformation and discuss properties of the solution to the field equation for the connection. I will also introduce invariant quantities, whose functional form remains the same in every conformal frame, and show how they can be applied to analysis of possible equivalence between F(R) and scalar-tensor theories of gravity in the Palatini approach. The main part of the talk will be preceded by a short introduction to metric scalar-tensor theories and conformal transformations.
dr Tomasz Pawłowski
Introduction to Loop Quantum Cosmology
dr Jakub Bilski
Fenomenology of quantum general relativity: idea, difficoulties and possible predictions
During the seminar I will briefly introduce my idea of a canonical quantization under restrictions of general relativity. First I will show how a proper choice of canonical variables leads to the manifestly diffeomorphism invariant description of a quantum field. Next I will present a list of assumptions and simplifications that I will use in direct calculations. Then I will sketch the main steps in the derivation of quantum corrections coming from the gravitational degrees of freedom on the example of the scalar field. Discussing phenomenological applications of my result, I will consider possibilities of proving the assumptions and generalizing the simplifications from the first part of my talk.
Prof. Evgeny Ivanov
Deformed supersymmetric quantum mechanics with spin variables
A model of the SU(2|1) supersymmetric quantum mechanics with additional semi-dynamical spin degrees of freedom is studid. The energy spectrum and the full set of physical states are found as functions of the deformation parameter m and SU(2) spin q. The states at the fixed energy levels form irreducible multiplets of the supergroup SU(2|1). The hidden superconformal symmetry OSp(4|2) of the model is revealed and shown to play a role of the spectrum-generating algebra. Some further generalizations are sketched. Based on arXiv:1710.02130 [hep-th] (in collaboration with Sergey Fedoruk and Stepan Sidorov).
Remigiusz Durka
Topological insulators from the Maxwell algebra
The subject of the talk will concern a recent work of D. Palumbo https://arxiv.org/abs/1610.04734. It introduces interesting model of three dimensional topological insulators in the presence of the electromagnetic field, which results from the Chern-Simons theory with the gauge connection that takes values in the Maxwell algebra. The final action written in terms of the dreibein, spin connection and electromagnetic gauge potential leads to a description of the Hall conductance, the torsional Hall viscosity, and novel non-minimal coupling between the abelian gauge field and curved background, which resemble the relativistic version of the Wen-Zee term.
Prof. David Blaschke (Rostock University)
Nonlocal chiral quark model for color superconductivity
We show that within a recently developed nonlocal chiral quark model the critical density for a phase transition to color superconducting quark matter under neutron star conditions can be low enough for these phases to occur in compact star configurations with masses below 1.3M_sun. We study the cooling of these objects in isolation for different values of the gravitational mass and argue that, if the quark matter phase would allow unpaired quarks, the corresponding hybrid stars would cool too fast. The comparison with observational data puts tight constraints on possible color superconductiong quark matter phases. Possible candidates with diquark gaps of the order 10keV - 1MeV such as the "2SC+X" and the color spin locking (CSL) phase are presented.
mgr Artur Pietrykowski
Problem grawitacyjnych poprawek do biegnącej stałej sprzężenia w teoriach z cechowaniem
Powszechnie wiadomo, iż kwantowa Ogólna Teoria Względności jest teorią perturbacyjnie nierenormalizowalną. Uwzględnienie pól materii w procesie kwantyzacji nie zmienia tego rezultatu. Nadto wykazano brak istnienia poprawek grawitacyjnych do stałych sprzężenia w teoriach z cechowaniem na poziomie jednopętlowym. Niemniej podejście do grawitacji Einsteinowskiej jako do niskoenergetycznej teorii efektywnej pozwoliło odkryć, iż jest ona teorią nieperturbacyjnie renormalizowalną. Ów kontekst motywuje ponowne rozpatrzenie wpływu fluktuacji grawitacyjnych na stałe sprzężenia w teoriach z cechowaniem, którym to zagadnieniem zajęli się P.S. Robinson i F. Wilczek. Wyniki ich badań wskazują na obeceność takich poprawek, których uwzględnienie w konsekwencji prowadzi do obniżenia skali unifikacji oddziaływań oraz do asymptotycznej swobody dla stałych sprzężenia. Jednakże istnienie poprawek, jak wynika z rachunków przeprowadzonych przez prelegenta, okazuje się być zależne od wyboru cechowania. Omówienie zarysowanych zagadnień stanowić będzie treść wystąpienia.
prof. Piotr Małecki IFJ w Krakowie
Eksperyment ATLAS (A Toroidal LHC ApparatuS) przy LHC (Large Hadron Collider)
Prof. Bernd Schroers
Boundary terms and symplectic structure in the Chern-Simons formulation of 2+1 dimensional gravity
In 2+1 dimensions Eintein's theory of gravity can be formulated as a gauge group with the Poincare group as the gauge group. In my talk I will explain how to introduce point particles and how to model universes with boundaries in the Chern-Simons formulation. I will also sketch how the (finite dimensional) phase space of the theory can be parametrised and how its symplectic structure can be computed. I will end with remarks about the quantisation of the theory, in particular the role played by quantum groups.
dr Cezary Juszczak
Wrocławski generator oddziaływań neutrin na tle konkurencji
We Wrocławskiej grupie neutrinowej powstaje od kilku lat generator oddziaływań neutrin z jądrami atomowymi. Omówię jego obecny status, zadania na najbliższą przyszłość - w szczególności projekt implementacji kaskady jądrowej, oraz porównam z konkurencyjnymi generatorami.
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Katarzyna Imiłkowska
Teorie z dwoma skalami-motywacje
W referacie zostaną przedstawione główne postulaty teorii z dwoma niezależnymi od obserwatora skalami. Podane zostaną najważniejsze motywacje doświadczalne i teoretyczne skłaniające do zajmowania się taką teorią, m.in. zostanie omówiony paradoks GZK oraz przedstawiona zostanie kontrakcja grupy SO_q(3,1) w granicy płaskiej czasoprzestrzeni.
prof. Jakub Rembieliński
Korelacje EPR dla pary kaonów traktowanych jako kwantowy układ
Referat dotyczy opisu zmodyfikowanego doświadczenia Einsteina-Podolskiego-Rosena-Bohma (korelacje dziwności zamiast korelacji spinu). Do liczenia korelacji itp. wykorzystuję opis cząstek niestabilnych jako kwantowych układów otwartych.
dr Dariusz Prorok
Globalne obserwable w zderzeniach ciężkich jonów - przewidywania w ramach modelu statystycznego
Globalne obserwable to obserwable charakteryzujące całość produkcji cząstek w danym zderzeniu. Są to tzw. energia poprzeczna i całkowita ilość cząstek naładowanych. W pierwszej części referatu przedstawię jak "dopasowuje" się pewien model statystyczny (czyli wartości jego parametrów) do danych doświadczalnych dotyczących zidentyfikowanych cząstek, głównie pionów, kaonów oraz protonów/antyprotonów. W drugiej części zaprezentuję przewidywania na energię poprzeczną i całkowitą ilości cząstek naładowanych uzyskane w tak "dopasowanym" modelu dla konkretnych eksperymentów w RHIC-u.
mgr Paulina Suchanek
Teoria Liouvilla jako konforemna teoria pola - podejście operatorowe
Teoria Liouville może być skwantowana jako 2 wymiarowa konforemna teoria pola. Dzięki własności konforemnej niezmienniczości teorie tego typu można całkowicie scharakteryzować za pomocą spektrum tzw. pól pierwotnych oraz ich trójpunktowych funkcji korelacji. Na seminarium przedstawię sposób konstrukcji trójpunktowej funkcji korelacji w teorii Liouville w ramach podejścia operatorowego.
mgr Dariusz Tryniecki
Czarne dziury w teoriach z wyższymi członami krzywiznowymi
Zgodnie z rozpowszechnioną obecnie opinią , teoria grawitacji oparta na działaniu Hilberta-Einsteina powinna być traktowana jako pierwszy wyraz rozwinięcia efektywnej teorii grawitacji. O wyrazach wyższego rzędu wiemy, iż powinny być zbudowane z odpowiednich członów krzywiznowych, na które (w każdym rzędzie rozwinięcia) składać się mają wyrazy określonego typu, R^{0}_{\mu\nu}. Zadaniem o podstawowym znaczeniu jest zatem próba przeanalizowania wpływu wyższych członów krzywiznowych na charakterystyki fizyki czarnych dziur. W moim wystąpieniu skoncentruję się na trzech konkretnych zagadnieniach: 1) iteracyjnym rozwiązaniu opisującym elektrycznie naładowaną i statyczną czarną dziurę w kwadratowej grawitacji, kładąc szczególny nacisk na przypadek ekstremalny. Można pokazać , że położenie horyzontu zdarzeń jest wówczas dane przez r+=|e|. 2) Obliczeniu poprawki pierwszego rzędu dla rozwiązania sprzężonych równań kwadratowej grawitacji i nieliniowej elektrodynamiki, z rozwiązaniem zerowego rzędu podanym przez Ayona-Beato i Garci i przez Bronnikowa. Pokażę, iż rozwiązanie pierwszego rzędu jest również regularne. 3) Konstrukcji i (perturbacyjnym) rozwiązaniu równań z wyższymi członami krzywiznowymi w D-wymiarowej czasoprzestrzeni.
dr hab. Paweł Rudawy (Instytut Astronomii)
Oddziaływanie plazmy z polem magnetycznym w atmosferze Słońca
Rozbłyski słoneczne, protuberancje, koronalne wyrzuty materii i wiele innych zjawisk i procesów obserwowanych w atmosferze Słońca (od chromosfery do korony), powstaje w wyniku oddziaływania plazmy z polem magnetycznym. Słońce jest jedynym obiektem, w którym - w pewnym zakresie - możemy bezpośrednio obserwować oddziaływania plazma-pole w warunkach niemożliwych do odtworzenia w laboratorium a typowych dla innych obiektów astronomicznych. Dane uzyskiwane z takich obserwacji mają ogromne znaczenie dla badań procesów fizyki wysokich energii (np. generacji energii w wyniku kontrolowanej syntezy termonuklearnej). W ramach referatu zostaną przedstawione: a) standardowy model Słońca wraz z zagadnieniem generacji pola magnetycznego w procesie a-d dynama; b) ogólna charakterystyka zjawisk oddziaływania plazmy z polem magnetycznym w atmosferze Słońca wraz z cyklicznością występowania tych zjawisk; c) charakterystyka rozblysków słonecznych wraz ze standardowym modelem rozbłysku; d) wybrane wyniki badań rozbłysków słonecznych z wykorzystaniem spektrografu MSDP oraz Maszyny Pulsarowej.
dr Artur Duda
Ewolucja hydrodynamiczna w pobli u krytycznego punktu ko cowego na diagramie fazowym QCD
Zostanie przedstawiona przeprowadzona przez Nonakę i Osakawę (Ch. Nonaka, M. Asakawa, Physical Review C, vol. 71, 044904). analiza ewolucji hydrodynamicznej w pobliżu punktu krytycznego na diagramie fazowym QCD. W oparciu o założenie, że krytyczny punkt końcowy (CEP) występujący na diagramie QCD należy do tej samej klasy uniwersalności co występujący w trójwymiarowym modelu Isinga przeanalizowane będzie zachowanie takich parametrów jak gęstość entropii oraz gęstość liczby barionowej. Przedstawione zostaną dla tego modelu trajektorie izentropowe oraz obserwowany dla nich efekt ogniskowania, porównam je też z przewidywaniami modelu "bag-plus-excluded". Będzie dokonana analiza zachowania prędkości dźwięku dla trajektorii izentropowych dla różnych wartości parametrów. Przedstawię porównanie z danymi eksperymentalnymi.
dr hab. Marek Mozrzymas
Algebraiczne własności operatorów tensorowych
Znaczenie w fizyce operatorów tensorowych związanych z grupami i algebrami Liego skłania do rozważenia koncepcji operatorów tensorowych dla algebr kwantowych i ogólnie algebr Hopfa. W niniejszym wykładzie podana zostanie ogólna definicja operatora tensorowego w reprezentacjach dowolnej algebry Hopfa. Definicja ta opiera się na podstawowy w algebrze pojęciu homomorfizmu i jakkolwiek wydaje się być abstakcyjna to w przypadku klasycznych struktur grup i algebr Liego so(3) staje się klasyczną definicją Wignera i Racaha. W ramach tej definicji można, przy pewnych założeniach udowodnić twierdzenie Wignera-Eckarta dla operatorów tensorowych dowolnej algebry Hopfa. W tym ogólnym podejściu dowód twierdzenia Wignera-Eckarta opiera się na klasycznym lemacie Schura. Jako przykład omówione zostaną operatory tensorowe dla kwantowej algebry Uq[su(2)], które można traktować jako deformację klasycznych operatorów tensorowych pojawiającyh się np. w mechanice kwantowej.
prof. dr hab. Ludwik Turko
Modelowanie struktury fazowej materii hadronowej
Symulacje sieciowe chromodynamiki kwantowej pozwoliły w ostatnich trzech latach na uzyskanie wyników, które dają ilościowy opis struktury fazowej materii hadronowej. Dotyczy to rodzaju przejścia fazowego oraz wyznaczania parametrów krytycznych. Przedmiotem seminarium jest omówienie metodologii sieciowej oraz porównanie wyników otrzymanych na sieci z przewidywaniami statystycznego bootstrapu oraz modelu termicznego.
mgr Artur Ankowski
Funkcja spektralna argonu
Jednym z podejść do opisu jądra w oddziaływaniach neutrin jest formalizm funkcji spektralnej. Przybliżę na czym on polega, pokażę najprostszą metodę liczenia funkcji spektralnej. Uzasadnię dlaczego istotne znaczenie w fizyce neutrin ma argon i pokażę że przekroje czynne otrzymywane w tym podejściu różnią się od przekrojów gazu Fermiego.
mgr Izabella Próchnicka
Grawitacja na branie de-Sittera - problem bezmasowych grawitonów
Po wstępie dotyczącym opisu grawitacji w modelu wszechświata na branie ("brane world scenario") zostanie omówiony model 5-wymiarowej grawitacji Einsteina sprzężonej kowariantnie z 3-braną. Na 3-branie zostanie wprowadzone także indukowane działanie Einsteina-Hilberta. W przybliżeniu biliniowym do działania zostanie przebadany problem bezmasowości pola grawitacyjnego na branie.
Seminarium organizacyjne