Conferences 


Contact 
Chair of Theory of
Relativity and Gravitation,
Institute of Theoretical Physics,
University of Warsaw
ul. Pasteura 5,
02093 Warsaw, Poland
Phone: (+48 22) 5532245
Fax: (+48 22) 6219475



List of talks given by members of the Department of the Theory of Relativity and Gravitation in a reverse chronological order.
The Fifteenth Marcel Grossmann Meeting on Recent Developments in Theoretical and Experimental General Relativity, Astrophysics and Relativistic Field Theories (MG15), July 17, 2018, Rome, Italy
Gioele Botta
Quantum reduced loop gravity effective dynamics from a statistical regularization scheme
Denis DobkowskiRyłko
Stationary isolated horizons of the Petrov type D
Jerzy Lewandowski
On the Hamiltonian operator in loop quantum gravity
IX International Meeting on Lorentzian Geometry, June 1823, 2018, Warsaw, Poland
Jerzy Lewandowski
Stationary isolated horizons of the Petrov type D
Sixth Tux workshop on Quantum Gravity, February 1923, 2018, Tux, Austria
Mehdi Assanioussi
On the polymer quantization of YangMills theories: new coherent states
Denis DobkowskiRyłko
Geometric characterization of the Kerrde Sitter horizon
Patryk Drobinski
Continuum approach to the BF vacuum
Maciej Kolanowski
Holographic models for 2dimensional black holes
Jerzy Lewandowski
Petrov type D isolated null surfaces
Ilkka Makinen
A coherentstate representation for the LQG intertwiner space
Tomasz Pawlowski
Emergent de Sitter phase of LQC
Piotr Sułkowski
Quantum geometry and string dualities
Yaser Tavakoli
Particle production in a cosmological quantum spacetime
Cong Zhang
Some analytical results of the Hamiltonian (constraint) operator in LQG
Jerzy Lewandowski
Surprising properties of geometric Dirac Observables in General Relativity
Carmen Li
Spacetime near an extremal horizon
Anna Nakonieczna
Black hole initial data within the parabolichyperbolic formulation
Jacek Tafel
TT tensors in flat spaces of any dimension
Jerzy Lewandowski
The issues and results of canonical (loop) quantum gravity
Jerzy Lewandowski
Canonical Loop Quantum Gravity
Jerzy Lewandowski
Canonical Loop Quantum Gravity: issues, framework and results
Partyk Drobiński
The continuum BF vacuum representation
Ilkka Makinen
Spin coherent state representation for intertwiners in loop quantum gravity
Jerzy Lewandowski
Lorentz and deformed Poincare symmetry in curved spacetime
Mehdi Assanioussi
Approximation methods for the dynamics in deparametrized LQG
Jerzy Lewandowski
Canonical Loop Quantum Gravity: available framework
Jacek Tafel (invited speaker)
Covariant description of isothermic surfaces
Jerzy Lewandowski
Nonexpanding horizons including near horizon geometries as related subject
Andrzej Trautman
Gravitational waves: what little I remember of my early work on the subject
Jacek Tafel
Optical geometries and algebraically special spacetimes
Ilkka Makinen
Time evolution in deparametrized models of loop quantum gravity
Jerzy Lewandowski
Canonical Loop Quantum Gravity (lecture course)
Jerzy Lewandowski
When near horizon geometries meet nonexpanding horizons
Canonical Loop Quantum Gravity
Jerzy Lewandowski
Canonical Loop Quantum Gravity  Status Report (plenary talk)
Ilkka Makinen
Scalar field as a physical time variable in loop quantum gravity
Jerzy Lewandowski and ChunYen Lin
From The Quantum Scalar Constraint To The Minkowski Theorem
Ilkka Makinen
The Hamiltonian operator in deparametrized loop quantum gravity
International Loop Quantum Gravity Seminar
Jerzy Lewandowski
New applications for LQG
October 28, 2014
Antonia Zipfel
Linking canonical and covariant LQG
April 15, 2014
Norbert Bodendorfer
Black hole entropy from loop quantum gravity: Generalized theories and higher dimensions
October 1, 2013
Emanuele Alseci
Quantum reduced loop gravity
March 12, 2013
Workshop on Noncommutative Field Theory and Gravity, September 2226
Jerzy Lewandowski
Noncommutative structure of spacetime from classical general relativity
XXXV Max Born Symposium, September 712, 2015, Wrocław, Poland
Norbert Bodendorfer
Symmetry reductions in loop quantum gravity based on classical gauge fixings
Ilkka Makinen
A new Hamiltonian operator for loop quantum gravity
Jerzy Lewandowski
Emanuele Alesci
Quantum Reduced Loop Gravity
Mehdi Assanioussi
Recent developments in quantum dynamics of LQG
Jerzy Lewandowski
Canonical LQG
Jędrzej Świeżewski
Quantum Reduction To Spherical Symmetry
Andrea Dapor
Coherent State Operators in Loop Quantum Gravity
Andrea Dapor
Coherent State Operators in Loop Quantum Gravity
Ilkka Mäkinen
Loop Quantum Gravity with a Scalar Field: A Physical Hamiltonian Operator
Emanuele Alesci
Quantum Reduced Loop Gravity
Norbert Bodendorfer
Higher dimensional connection dynamics and applications
Mehdi Assanioussi
New perspectives for canonical LQG dynamics
Jerzy Lewandowski
New applications for canonical LQG
Jędrzej Świeżewski
Using radial gauge to define quantum spherical symmetry
Wojciech Kamiński
Gravity in the radial gauge
Antonia Zipfel
A stability criterion for coherent states
Jerzy Lewandowski
New Results in the Canonical Loop Quantum Gravity
Third EFI winter conference of quantum gravity, February 1620, 2015, Tux, Austria
Mehdi Assanioussi
Deparametrized gravity with a scalar field & Beyond: A new quantum Hamiltonian operator for LQG
Norbert Bodendorfer
A quantum reduction to Bianchi I models in LQG
Andrea Dapor
Rainbows from Quantum Gravity
Marcin Kisielowski
Firstorder Dipole Cosmology
Ilkka Mäkinen
Coherent state operators in loop quantum gravity
Tomasz Pawłowski
Interfacing loop quantum gravity with cosmology
Jedrzej Świeżewski
Radial Gauge  reduced phase space of General Relativity
Conceptual and Technical Challenges for Quantum Gravity, Rome, Italy, September 812, 2014
Jerzy Lewandowski
Conceptual and technical chalanges of LQG
Friday
Emanuele Alesci
Quantum Reduced Loop Gravity
Tuesday
Abstract
Quantum Reduced Loop Gravity is a recently proposed model to address the quantum dynamics of the early Universe. We will review it’s semiclassical limit, a link with LQC and how the QRLG could simplify the analysis of the dynamics in the full theory.
Frontiers of fundamental physics 14, Marseille, France, July 1518, 2014
Jerzy Lewandowski
Background independence of GR and in LQG
July 17
Abstract
The physical meaning of the diffeomorphisms in the general relativistic theories will be discussed, the issues of time evolution in terms of the Dirac observables and physical Hamiltonian will be addressed. New proposals for geometric deparametrization will be presented. The quantum part of the lecture will concern the canonical LQG. New, improved formulations of the quantum Hamiltonian will be proposed. New applications for LQG will be offered. Original results that will be presented in this lecture were obtained in collaboration with: Dapor, Duch, Kaminski, Swiezewski, Alesci, Assanioussi, Dziendzikowski and Sahlmann.
Jerzy Lewandowski
Exact formulation of the quantum scalar constraint in LQG
July 18
Abstract
Several new applications for LQG will be presented. The first one is a new quantum representation of the gravitational scalar constraint. In this representation, for the first time in the literature, the quantum C(N) itself preserves the Hilbert space for every laps function N. Owing to that property, solutions to the quantum constraints of vacuum GR can be well defined by the spectral decomposition and set a physical Hilbert space. Our representation admits also a new proposal of the quantum physical Hamiltonian of the RovelliSmolin model of gravity coupled to the massless KleinGordon time field. The third application we propose, is a new operator for the quantum Hamiltonian of the KleinGordon Scalar field coupled to LQG. Our new framework captures the degrees of freedom of the scalar field lost in the framework in which time is deparametrized by the scalar field.
Jędrzej Świeżewski
Observers diffeomorphisminvariant description of a general relativistic system
July 18
Abstract
I will present a construction of observables following naturally from an introduction of an observer into a relativistic theory. The observables are invariant under a large class of spatial diffeomorphisms. I will discuss the description of the theory in terms of spatialdiffeomorphisminvariant degrees of freedom. The talk will be based on P. Duch, W. Kaminski, J. Lewandowski and J. Swieżewski, Observables for General Relativity related to geometry, arXiv:1403.8062 [grqc].
Mehdi Assanioussi
Application of the Curvature operator: Matrix Elements and properties of the new Hamiltonian Constraint operator in LQG
July 18
Abstract
This talk is a presentation of an ongoing work based on [1] of the same authors. In this work we study properties of the Lorentzian Hamiltonian constraint operator expressed using the curvature operator introduced in [1] and we evaluate its action.
[1] E. Alesci, M. Assanioussi and J. Lewandowski, A curvature operator for LQG, Submitted for publication in Phys. Rev. D [arxiv: 1403.3190v2].
Andrea Dapor
Coherent State Operators in Cosmology and Gravity
July 18
Abstract
Coherent States (CS) are widely used in physics, and quantum gravity is not an exception. However, the application of CS in the construction of operators is rather unexplored in the areas of quantum gravity and quantum cosmology. In my talk, I will present how CS can be used to define “coherent state operators” via a procedure known as “coherent state quantization” [1]. This procedure produces operators with inbuilt good semiclassical properties, while at the same time preserving typical quantum attributes (e.g., discreteness of spectra). Examples of such coherent state quantization will cover: (1) operators on homogeneous isotropic quantum cosmology [2] (based on the affine group); (2) possible extensions to Bianchi I case; (3) simple operators on L2(SU(2),dμH).
[1] S. Twareque Ali, J.P. Antoine and J.P. Gazeau, Coherent States, Wavelets, and Their Generalizations, SpringerVerlag (2013)
[2]H. Bergeron, A. Dapor, J.P. Gazeau and P. Malkiewicz, Smooth big bounce from affine quantization/, Phys. Rev. D 89, 083522 (2014)
Antonia Zipfel
Plebanski sectors of the Lorentzian 4simplex amplitude
July 15
Abstract
The spin foam model is based on a BFtype action restricted by the simplicity constraint. However, the solutions to the simplicity constraint fall into five different sectors. In [1,2] it was argued that a certain mixing of these sectors and the freedom of choosing a tetrad orientation generates undesired terms in the asymptotic of the Euclidean EPRLmodel and can be cured by an additional constraint. We here show that this is also the case for the Lorentzian model. This is joint work with J. Engle.
[1] J. Engle, A spinfoam vertex amplitude with the correct semiclassical limit, Phys.Lett. B724 (2013) 333337.
[2] J. Engle, A proposed proper EPRL vertex amplitude, Phys.Rev D87 (2012) 084048.
Emanuele Alesci
Quantum Reduced Loop Gravity
July 18
Abstract
We will review the current developments of Quantum Reduced Loop Gravity, a recently proposed model to address the quantum dynamics of the early Universe. In particular we will discuss its semiclassical limit, a link with LQC and will review how the QRLG technique naturally selects states based on coherent intertwiners that could simplify the analysis of the dynamics in the full theory.
XXXIII Max Born Symposium, Wrocław, Poland, July 610, 2014
Norbert Bodendorfer
The Verlinde formula and higherdimensional black hole entropy
July 8
Jerzy Lewandowski
The issues and advances in LQG
July 9
DPGFrühjahrstagung 2014, Berlin, Germany
Norbert Bodendorfer
Loop quantum gravity in higher dimensions and black hole entropy
March 17, 2014, Berlin
4th Central European Relativity Seminar, Vienna, Austria, February 27  March 1, 2014
Norbert Bodendorfer
Loop quantum gravity in higher dimensions and black hole entropy
March 1, 2014, Tux
Jędrzej Świeżewski
Geometrical observables for General Relativity related to distances and angles
February 27, 2014, Tux
Abstract
In my talk, I will present the progress obtained in a certain approach to constructing diffeomorphism invariant observables for General Relativity possessing a direct geometrical interpretation. After introducing the observables I will discuss their Poisson algebra. A possibility of reducing the phase space of General Relativity to diffeomorphism invariant degrees of freedom will be highlighted.
New trends in Teichmuller theory and mapping class groups, Oberwolfach (MFO), Germany, February 917, 2014
Piotr Sułkowski
Chord diagrams, random matrices, and topological recursion
Second EFI winter conference on canonical and covariant LQG, Tux, Austria, February 1014, 2014
Jerzy Lewandowski
Deparametrising GR with distances and angles and interpreting it geometrically
February 14, 2014, Tux
Jędrzej Świeżewski
Deparametrising GR with distances and angles
February 14, 2014, Tux
Antonia Zipfel
Plebanski sectors of the Lorentzian 4simplex amplitude
February 14, 2014, Tux
Norbert Bodendorfer
Some comments and open questions on black hole entropy from LQG
February 13, 2014, Tux
Wojciech Kaminski
Surprises in the asymptotic analysis of the spinfoam vertex
February 10, 2014, Tux
Symposium of the Institute for Theoretical Physics, Warsaw, Poland, December 1314, 2013
Piotr Sułkowski
On dualities in string theory
II Konwencja Badań i Innowacji, Warsaw, Poland, November 29, 2013
Piotr Sułkowski
Quantum Fields and Knot Homologies
Nobember 29, 2013, Warsaw
Sympozjum KRAB, Warsaw, Poland, November 28, 2013
Piotr Sułkowski
Quantum Fields and Knot Homologies
Nobember 28, 2013, Warsaw
Loops 13, Perimeter Institute, Waterloo, Canada, July 2226, 2013
Marcin Kisielowski
On firstorder contributions to the Dipole Cosmology transition amplitude
July 26, 2013, Waterloo
Abstract
We discuss some firstorder contributions to the (Euclidean) Dipole Cosmology transition amplitude. These amplitudes correspond to spin foams having the boundary graph of Dipole Cosmology, one internal vertex and no edges connecting this vertex with itself. We expect that the amplidutes are dominated by the BianchiRovelliVidotto transition amplitude in a limit of large volume of the universe, and the transition amplitude including contributions from all these spin foams gives the correct Friedmann dynamics in the classical limit.
Antonia Zipfel
On the relation between canonical and covariant Quantum Gravity
July 26, 2013, Waterloo
Abstract
Heuristically, spin foams can be understood as the Feynman graphs of Quantum Gravity. Yet, summing over all histories would lead to a projector on the physical Hilbert space of the canonical theory rather than to a true propagator due to the constraint nature of GR. Following this idea we construct a spinfoam operator acting on the kinematical Hilbert space and analyze its properties.
Jerzy Lewandowski
Exact solutions of canonical LQG
July 23, 2013, Waterloo
Abstract
In the case of LQG coupled to the massless scalar field (the RovelliSmolin model) the form of the quantum scalar constraint drastically simplifies in comparison to other cases. The properties of the physical Hamitonian will be discussed.
Jędrzej Świeżewski
Geometrical observables for General Relativity coupled to dust
July 23, 2013, Waterloo
Abstract
In my talk I will present a proposal for the construction of Dirac observables for General Relativity. The construction relies on the use of geometrically defined coordinates with a clear physical interpretation. I will discuss some problems of the construction and turn to a similar construction of observables for a simplified theory of General Relativity coupled to a dust field.
Mehdi Assanioussi
A Quantum Curvature Operator for LQG
July 23, 2013, Waterloo
Abstract
We introduce a new operator in Loop Quantum Gravity  the 3D curvature operator  related to the 3dimensional Ricci scalar. The construction is based on the concepts of Regge. We define this operator starting from the classical expression of Regge curvature then we derive some of its properties and discuss some explicit checks of the semiclassical limit.
Norbert Bodendorfer
Black hole entropy in LQG and the Wald formula
July 23, 2013, Waterloo
Emanuele Alesci
Quantum Reduced Loop Gravity
July 22, 2013, Waterloo
Abstract
We present a new framework to study symmetric sectors of loop quantum gravity. The reduction is performed at a quantum level using projected spin networks coherent states and spinfoam techniques that allow us to project the Hilbert space of the full canonical theory. As a first application we present an inhomogeneous extension of the Bianchi I model and discuss the semiclassical limit of the theory.
Andrea Dapor
QFT in Quantum Spacetime
July 22, 2013, Waterloo
Abstract
We develop a systematic classical framework to accommodate canonical quantization of both geometric and matter perturbations on a quantum homogeneous isotropic flat spacetime. It is shown that the existing approach of standard cosmological perturbations is good only (i) up to first order in the inhomogeneities and (ii) if the background is treated classically. A new set of classical phase space variables is proposed which in a natural gauge define a complete and canonical algebra of relational Dirac observables. We compute the physical Hamiltonian that generates the dynamics of such observables (with respect to the homogeneous mode of a KleinGordon clock field) and offer a proposal for quantization: what we obtain is a theory of quantum perturbations on a quantum (cosmological) spacetime.
Wojciech Kaminski
Curvature constraints in the spin foam models
July 22, 2013, Waterloo
Abstract
I will present surprising constraints for internal holonomies in the asymptotic (semiclassical) limit in the EPRL model.
GR20 & Amaldi 10, Warsaw, Poland, July 713, 2013
Marcin Kisielowski
The Dipole Cosmology transition amplitude: firstorder contributions
July 12, 2013, Warsaw
Abstract
Bianchi, Rovelli and Vidotto introduced Dipole Cosmology, a quantum cosmological model that opens a new theory which can be called Spin Foam Cosmology. In the original formulation they use a specific 2complex. Its introduction was judged a posteriori by a correct semiclassical limit of the transition amplitude. The 2complex chosen has one internal vertex, and the calculation of a transition amplitude may be thought to be firstorder calculations. We found other possible firstorder contributions. We expect, that those contributions are dominated by the BRV transition amplitude in a limit of large volume of the universe, and a Spin Foam Cosmology model taking into acount those contributions has a proper semiclassical limit.
Andrea Dapor
QFT in Quantum Spacetime
July 11, 2013, Warsaw
Piotr Sułkowski
SuperApolynomials and 3dimensional theories
July 11, 2013, Warsaw
Jacek Tafel
Generalization of initial data for the Kerr metric
July 10, 2013, Warsaw
Abstract
We find new classes of exact solutions of the initial momentum constraint for vacuum Einsteins equations. They are either axially symmetric or the exterior curvature tensor has a simple algebraic structure. In general the mean curvature $H$ is nonconstant and initial metric is not conformally flat. Solutions depend on several free functions. The conformal method of Lichnerowicz, ChoquetBruhat and York is used to prove solvability of the Hamiltonian constraint if $H$ vanishes. The existence of marginally outer trapped surfaces in initial manifold is discussed.
Jędrzej Świeżewski
Construction of Dirac observables for General Relativity with the use of geometry
July 9, 2013, Warsaw
Abstract
In my talk I will present results obtained jointly with Paweł Duch, Wojciech Kamiński and Jerzy Lewandowski. They consist of a proposal for the construction of Dirac observables for General Relativity. The construction relies on the use of geometrically defined coordinates with a clear physical interpretation. I will discuss some problems of the construction and turn to a similar construction of observables for a simplified theory of General Relativity coupled to a dust field.
Jacek Tafel
Static spherical black holes with scalar field
July 9, 2013, Warsaw
Abstract
Static spherically symmetric black holes and particle like solutions with self interacting minimally coupled scalar field $varphi$ are analyzed. They are asymptotically flat or antide Sitter (AdS). We express them in terms of a single function $ ho$ which undergoes simple conditions. If $varphi$ is nontrivial the ADM mass $M$ has to be positive. Nohair theorems are generalized to the AdS asymptotic. For both asymptotics the Killing horizon is nondegenerate and its radius cannot be bigger than $2M$. Derivatives of $ ho$ at singularity determine properties of admissible potentials $V(varphi)$ as regularity, boundedness and behaviour for maximal values of $varphi$. Several classes of solutions with singular or nonsingular potentials are obtained. Their examples are presented in a form of plots.
XXXII Workshop on Geometric Methods in Physics, Białowieża, Poland, June 30  July 5, 2013
Piotr Sułkowski
On knots, superApolynomial, and BPS states
Mathematics and physics of knot homologies, Montreal, Canada, June 24  July 5, 2013
Piotr Sułkowski
SuperApolynomials
June 26, 2013, Montreal
String Math 2013 conference, Simons Center, Stony Brook University, USA, June 1721, 2013
Piotr Sułkowski
Matrix model for moduli spaces and chord diagrams
June 19, 2013, Stony Brook
Moduli spaces and macromolecules, IHES, BuressurYvette, France, May 1418, 2013
Piotr Sułkowski
Random matrices, topological recursion, and RNA enumeration
May 15, 2013, BuressurYvette
Stringtheory.pl/2013, Kraków, Poland, April 57, 2013
Piotr Sułkowski
Whats new in mathematical aspects of string theory?
April 6, 2013, Kraków
EFI winter conference on canonical and covariant LQG, Tux, Austria, February 25  March 01, 2013
Andrea Dapor
QFT in Quantum Spacetime: a compatible classical framework
February 28, 2013, Tux
Marcin Kisielowski
On firstorder contributions to the Dipole Cosmology transition amplitude
February 27, 2013, Tux
Abstract
We present some results of an investigation of the amplitudes contributing to the (Euclidean) Dipole Cosmology transition amplitude at the first order. These amplitudes correspond to spin foams having the boundary graph of Dipole Cosmology, one internal vertex and no edges connecting this vertex with itself. We expect the transition amplitude including contributions from all these spin foams gives the correct Friedmann dynamics in the classical limit.
Jędrzej Świeżewski
Constructing geometrical Dirac observables for GR
February 26, 2013, Tux
Third Latin Congress on Symmetries in Geometry and Physics, Sao Luis, Brasil, February 110, 2013
Piotr Sułkowski
Series of lectures on Knots, quantization and superApolynomials
February 68, 2013, Sao Luis
Topological recursion and quantum algebraic geometry, Aarhus, Denmark, January 28  February 1, 2013
Piotr Sułkowski
Quantization and superApolynomials
January 29, 2013, Aarhus
The XXIX International Colloquium on Group Theoretical Methods in Physics, August 2026, 2012, Tianjin, China
Marcin Kisielowski
Spin Foams contributing in first order of vertex expansion to the Dipole Cosmology transition amplitude
August, 22, 2012, Tianjin
Abstract
In this talk we will present a general method for finding all foams with given boundary and given number of internal vertices. We will apply the method to the Dipole Cosmology model and find all spin foams contributing to the transition amplitude in first order of vertex expansion.
Thirteenth Marcel Grossmann Meeting, Stockholm, July 17, 2012
Andrea Dapor
Quantum Field Theory on LQC Bianchi Spacetimes
6th July 2012, Shtockholm
Abstract
We develop the quantum theory of a scalar field on LQC Bianchi I geometry. In particular, we focus on single modes of the field: the evolution equation is derived from the quantum scalar constraint, and it is shown that the same equation can be obtained from QFT on an "classical" effective geometry. We investigate the dependence of this effective spacetime on the wavevector of the mode (which could in principle generate a deformation in local Lorentzsymmetry), focusing our attention on the dispersion relation. We prove that at first order no Lorentzviolation is present  despite the effective metric being different than the classical Bianchi I one. A preliminary analysis of the correction due to inclusion of backreaction is briefly discussed in the context of BornOppenheimer approximation.
Andrea Dapor
Loop Quantum Cosmology for nonminimally coupled Scalar Field
6th July 2012, Shtockholm
Abstract
We conduct a LQCquantization of the FRW cosmological model with nonminimally coupled scalar field. (This model is interesting from the classical point of view because it allows heavy fields (such as the Higgs) to produce inflation.) Making use of a canonical transformation (between Jordan variables and Einstein variables), we recast the theory in a minimally coupled one, for which standard LQC techniques can be applied to find the physical Hilbert space and the dynamics. Though the analysis of the genuine quantum system can be performed, we focus on the semiclassical sector  obtaining a "classical" effective Hamiltonian. At this level, we can transform back to the Jordan frame, and study the dynamics. It turns out that the initial singularity is replaced by a "mexican hat"shaped bounce, joining the contracting and expanding branches.
Andrea Dapor
Nonminimally coupled Scalar Field in Loop Quantum Cosmology
6th July 2012, Shtockholm
Abstract
FRW model with nonminimally coupled scalar field is considered. It is classically known that for a specific form of the coupling the scalar field produces inflation: of particular interest these days is the observation that this model allows for Higgsdriven inflation, avoiding introduction of new particle physics. We consider the LQC corrections to the equations of motion in the framework of "effective dynamics", finding the dynamics of the model at early times. It is found that the initial singularity is replaced by a peculiar "mexican hat" bounce: the universe collapses, at Planck scales it undergoes two consecutive bounces between which it rapidly expands and recollaplses, and finally it reaches inflation. For physical values of the coupling constant the count of efoldings and the computation of cosmological parameters show that the model is in agreement with observations  providing a nonsingular cosmology where inflation can be generated by standard model fields (such as the Higgs).
Jędrzej Świeżewski
Between General Relativity and Electrodynamics  hamiltonian description of a field theory
6th July 2012, Shtockholm
Abstract
In the talk I will present a hamiltonian analysis of a simplified teleparallel theory. The analysis consists of a derivation of the hamiltonian and calculation of the Poisson brackets of the constraints that will apear in the process. The theory I will consider has the same kinematics as the full teleparallel theory in its cotetrad formulation, however, the dynamics is considerably simplified. The simplification consists of choosing a lagrangian which resembles the electrodynamics lagrangian, hence the theory no longer describes gravitational phenomena. Inspite of that, a close resemblance to the teleparallel theory is kept. Firstly, the hamiltonian consists of scalar and vector constraints which form the usual Dirac algebra under Poisson bracket. Secondly, the form of the constraints is very similar to the form of constraints of the full teleparallel theory, which have been derived by the coauthor.
Marek Demiański
High redshift cosmography: new results and implications for dark energy
6th July 2012, Shtockholm
Abstract
We use all the available date on high redshift objects (Union2 Type Ia supernovae, GRBs and BAO) to derive constrains on the parameters of FRWL cosmological model without imposing any a priori assumptions about on the dynamical equations for gravity. These data sets allow us to put constrains on the cosmographic expansion up to the fifth order. To perform our analysis we use the Markov Chain Monte Carlo Method. To investigate the dark energy component we use different parametrizations of its equation of state. We show that the deceleration parameter clearly confirms the present acceleration phase of the Universe, there are hints that the dark energy equation of state is evolving and there are possible deviations from the LCDM model.
Tomasz Pawłowski
Geometric time in quantum cosmology
6th July 2012, Shtockholm
Abstract
In quantum cosmology a physically meaningful description of a models dynamical evolution requires selection of a suitable function of its degrees of freedom as an internal clock. Requirement of independence of this choice on the matter content restricts it to the geometry degrees of freedom. In Loop Quantum Cosmology (LQC) the phenomenon of the bounce further excludes scale factor/volume variables leaving out only their momenta. We test the latter possibility on the model of FRW universe with massive scalar field quantized within framework of geometrodynamics. The results are compared against known description using the scale factor time. We discuss the consequences of both treatments for formalisms featuring infinite number of massive fields. Further application within LQC to describe scalar inflaton is also discussed.
Tomasz Pawlowski
Computable framework of Loop Quantum Gravity
3rd July 2012, Shtockholm
Abstract
We present a framework of a nonperturbative quantization of general relativity coupled to dust and other matter fields. The irrotational dust provides a natural time variable, leading to a physical Hamiltonian with spatial diffeomorphism symmetry. The surprising feature is that the Hamiltonian is not a square root. This property, together with the kinematical structure of loop quantum gravity, provides a complete theory of quantum gravity with strict control over the physical Hilbert space, action of the Hamiltonian on it and the construction of physical observables. This puts in technical reach applications to cosmology, quantum gravitational collapse and Hawking radiation.
Jacek Puchta
Operator Spinnetwork Diagrams in calculations of higher order amplitudes in dipole cosmology
3rd July 2012, Shtockholm
Abstract
The Operator Spinnetwork Diagrams is a new framework that enables to express Spinfoam amplitudes in a clear graphical way. Within this framework it is easy to find and characterise all the spinfoams with a given fixed boundary graph. We used this technique to characterise transition amplitudes in Dipole Cosmology in higher order in the vertex expansion.
Andrzej Okołów
ADMlike Hamiltonian formulation of gravity in the teleparallel geometry
3rd July 2012, Shtockholm
Abstract
The Teleparallel Equivalent of General Relativity is considered as a theo

