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BEGIN:VEVENT
SUMMARY:Relativistic Lagrangian perturbation theory in spherical symmetry.
DTSTART;VALUE=DATE-TIME:20190923T134000Z
DTEND;VALUE=DATE-TIME:20190923T140000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535473@indico.cern.ch
DESCRIPTION:Speakers: Jan Ostrowski (NCBJ)\nPerturbation theories play an
important role in general relativity and cosmology. Depending on the frame
work and the quantities we perturb we can distinguish two main approaches
in perturbation theories: Eulerian and Lagrangian. Like in the Newtonian t
heory\, relativistic Lagrangian perturbations allow us to get insight into
a mildly non-linear stages of structure formation\, substantially exceedi
ng the Eulerian regime. However\, there is an inherent level of ambiguity
when it comes to evaluating certain functionals (e.g. density\, spatial cu
rvature\, expansion) within the Lagrangian framework\, coming from more th
an one definition of these fields in terms of governing equations. One pos
sible work-around is to compare the perturbative expectations with some ex
act relativistic solutions. In my talk I will present such comparison for
spherically symmetric dust solutions\, the Lemaitre-Tolman-Bondi metrics\,
with an emphasis on the evaluation of spatial curvature\, extending previ
ous works focusing mostly on density field.\nhttps://indico.cern.ch/event/
773241/contributions/3535473/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535473/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Top-down approach to the curved spacetime effective field theory (
cEFT) – theory and examples
DTSTART;VALUE=DATE-TIME:20190923T140000Z
DTEND;VALUE=DATE-TIME:20190923T142000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535501@indico.cern.ch
DESCRIPTION:Speakers: Lukasz Nakonieczny (University of Warsaw)\nThe effec
tive field theory (EFT) turns out to be an instrument of an immense value
in all aspects of modern particle physics being theory\, phenomenology or
experiment. In this talk I will show how to extend the systematic top down
approach to construction of the EFT proposed by Hitoshi Murayama (LBL\, B
erkeley) and separately by John Ellis (King’s Coll. London) groups to th
e curved spacetime. To this end\, I will take advantage of the heat kernel
method so far extensively used in obtaining the one-loop effective action
in curved spacetime. After an introduction of the formalism I will discus
s its application to the problem of an influence of gravity on the stabili
ty of the Higgs effective potential. The talk is based on JHEP01(2019)034.
\nhttps://indico.cern.ch/event/773241/contributions/3535501/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535501/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Standing gravitational waves
DTSTART;VALUE=DATE-TIME:20190923T132000Z
DTEND;VALUE=DATE-TIME:20190923T134000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535465@indico.cern.ch
DESCRIPTION:Speakers: Sebastian Szybka\nI will discuss existence\, propert
ies\, and an effective description of standing gravitational waves in gene
ral relativity.\nhttps://indico.cern.ch/event/773241/contributions/3535465
/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535465/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Instability of a RNAdS black hole under perturbations of a scalar
field coupled to the Einstein tensor
DTSTART;VALUE=DATE-TIME:20190923T140000Z
DTEND;VALUE=DATE-TIME:20190923T142000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535474@indico.cern.ch
DESCRIPTION:Speakers: Rodrigo Fontana (Federal University of Fronteira Sul
)\, Elcio Abdalla (University of Sao Paulo)\, Alan Pavan (Federal Universi
ty of Itajuba)\, Bertha Cuadros-Melgar (USP)\, Eleftherios Papantonopoulos
(National Technical University of Athens)\, Jeferson De Oliveira (Federal
University of Mato Grosso)\nWe study the instability of a Reissner-Nordst
röm-AdS (RNAdS) black hole under perturbations of a massive scalar field
coupled to Einstein tensor. Calculating the potential of the scalar pertur
bations we find that as the strength of the coupling of the scalar to Eins
tein tensor is increasing\, the potential develops a\nnegative well outsid
e the black hole horizon\, indicating an instability of the background RNA
dS. We then investigate the effect of this coupling on the quasinormal mod
es. We find that there exists a critical value of the coupling that trigge
rs the instability of the RNAdS. We also find that as the charge of the RN
AdS is increased towards its extremal value\, the critical value of the de
rivative coupling is decreased.\nhttps://indico.cern.ch/event/773241/contr
ibutions/3535474/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535474/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Conserved quantities related to (3+1) decomposition of CYK tensors
DTSTART;VALUE=DATE-TIME:20190923T151000Z
DTEND;VALUE=DATE-TIME:20190923T153000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535476@indico.cern.ch
DESCRIPTION:Speakers: Jacek Jezierski (University of Warsaw)\, Tomasz Smo
łka (University of Warsaw)\nConformal Yano-Killing (CYK) tensor is a gene
ralization of Killing vector to anti-symmetric two-form which describes so
called hidden symmetries. (3+1) decomposition of CYK tensor enables one t
o construct charges from initial data in a new\, simple and geometric way.
I will present the construction and compare it with traditional ADM appro
ach. Joint work with Jacek Jezierski.\nhttps://indico.cern.ch/event/773241
/contributions/3535476/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535476/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Conformally recurrent heavenly spaces
DTSTART;VALUE=DATE-TIME:20190923T153000Z
DTEND;VALUE=DATE-TIME:20190923T155000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535477@indico.cern.ch
DESCRIPTION:Speakers: Chudecki Adam (Lodz University of Technology\, Cente
r of Mathematics and Physics)\nTwo-sided conformally recurrent complex and
real 4-dimensional spaces are considered. It is proved\, that such spaces
are equipped with nonexpanding congruence of totally null and geodesic 2-
dimensional surfaces\, null strings. Two-sided conformally recurrent heave
nly spaces of the Petrov-Penrose type [D] are considered. Also\, some real
slices of type [D] heavenly metric are discussed.\nhttps://indico.cern.ch
/event/773241/contributions/3535477/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535477/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Black-hole mimickers and echos from compact objects
DTSTART;VALUE=DATE-TIME:20190923T130000Z
DTEND;VALUE=DATE-TIME:20190923T132000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535478@indico.cern.ch
DESCRIPTION:Speakers: Roman Konoplya (Silesian University in Opvava)\nHere
we will discuss two questions related to black-hole mimickers: a) whether
echoes from a compact object\, if observed\, should necessarily mean a qu
alitatively non-Einsteinian behavior near its surface or may also indicate
presence of astrophysical environment? b) whether a perfect\, stable blac
k-hole mimicker is possible in the form of a Schwarzschild star.\nhttps://
indico.cern.ch/event/773241/contributions/3535478/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535478/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Magnetized self-gravitating tori around black holes
DTSTART;VALUE=DATE-TIME:20190923T145000Z
DTEND;VALUE=DATE-TIME:20190923T151000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535475@indico.cern.ch
DESCRIPTION:Speakers: Patryk Mach\nI will discuss recent models of station
ary\, self-gravitating\, magnetized tori (disks) around black holes. They
are constructed by solving the coupled set of Einstein equations and the e
quations of ideal general-relativistic magnetohydrodynamics. In the first
part of the talk\, I will focus on the impact of the magnetic field on the
properties of such tori. If time permits\, I will also discuss general-re
lativistic effects characteristic for very massive tori: bifurcations in t
he parameter space of solutions\, toroidal ergoregions connected with the
tori\, the appearance of local maxima of the circumferential radius.\nhttp
s://indico.cern.ch/event/773241/contributions/3535475/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535475/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The solution to the Petrov type D equation on the non-trivial bund
le topology and its embeddability
DTSTART;VALUE=DATE-TIME:20190923T132000Z
DTEND;VALUE=DATE-TIME:20190923T134000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535499@indico.cern.ch
DESCRIPTION:Speakers: Denis Dobkowski-Ryłko\, Jerzy Lewandowski (Univers
ity of Warsaw)\, Racz Isvan\nWe consider $3$-dimensional isolated horizo
ns (IHs) generated by null curves that form non-trivial $U(1)$ bundles a
nd the Petrov type D equation. From the $4$-dimensional spacetime point of
view\, solutions to that equation define isolated horizons embeddable in
vacuum spacetimes (with cosmological constant) as Killing horizons to the
second order such that the spacetime Weyl tensor at the horizon is of the
Petrov type D. From the point of view of the $U(1)$-bundle structure\, th
e equation couples a $U(1)$-connection\, a metric tensor defined on the b
ase manifold and the surface gravity in a very non-trivial way. We focus
on the $U(1)$-bundles over $2$-dimensional manifolds diffeomorphic to $2$-
sphere. We have derived all the axisymmetric solutions to the Petrov type
D equation. For a fixed value of the cosmological constant they set a $3$-
dimensional family as one could expect. A surprising result is\, that gene
rically our horizons are not embeddable in the known exact solutions to Ei
nstein's equations. It means that among the exact type D spacetimes there
exists a new family of spacetimes that generalize the properties of the Ke
rr- (anti) de Sitter black holes on one hand and the Taub-NUT spacetimes
on the other hand.\nhttps://indico.cern.ch/event/773241/contributions/3535
499/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535499/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fierz theory vs Linear Gravity
DTSTART;VALUE=DATE-TIME:20190923T134000Z
DTEND;VALUE=DATE-TIME:20190923T140000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535500@indico.cern.ch
DESCRIPTION:Speakers: Marian Wiatr (Universtity of Warsaw)\nOne of the mos
t popular points of view on Linearized Gravity is a Massless Spin-2 Partic
le Theory. This theory often serves as a starting point to formulate a qua
ntum version of gravity theory. The Spin-2 Field has a well defined local
energy density equal to $\\frac12(E^2 + B^2)$ in analogy to Maxwell Electr
odynamics. However\, obtaining this energy formula from Hamiltonian formul
ation is not obvious\, so to clarify it\, I will present a new formulation
of Classical Electrodynamics analogical to Fierz formulation of the Spin-
2 Field Theory. The relations and differences between Linearized Gravity a
nd the Spin-2 Field Theory will be discussed.\nhttps://indico.cern.ch/even
t/773241/contributions/3535500/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535500/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Merger and mass ejection of neutron star binaries (tentative)
DTSTART;VALUE=DATE-TIME:20190923T101500Z
DTEND;VALUE=DATE-TIME:20190923T110000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537320@indico.cern.ch
DESCRIPTION:Speakers: Masaru Shibata (Max Planck Institute for Gravitation
al Physics at Potsdam)\nOn August 17th\, 2017\, merger of binary neutron s
tars was observed \nfor the first time by gravitational-wave and electroma
gnetic telescopes. \nOptical and infrared observations in particular agree
broadly with \nthe prediction by numerical relativity. From this April\,
advanced \nLIGO and VIRGO will start observation again and we expect \na f
ew more observations of neutron-star mergers (including black hole-\nneutr
on star merger). I will review our current understanding for neutron-star
\nmergers and related mass ejection that are obtained by numerical relativ
ity \nsimulations and summarize predicted observational (optical and infra
red) \nfeatures for next events. (Content could be changed if new events a
re observed.)\nhttps://indico.cern.ch/event/773241/contributions/3537320/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537320/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quantum cosmology with compact phase space
DTSTART;VALUE=DATE-TIME:20190925T132000Z
DTEND;VALUE=DATE-TIME:20190925T134000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535503@indico.cern.ch
DESCRIPTION:Speakers: Jakub Mielczarek (Jagiellonian University)\nThe kine
matical phase space of classical gravitational field is flat (affine) and
unbounded. Because of this\, field variables may tend to infinity leading
to appearance of singularities\, which plague Einstein's theory of gravity
. During the talk the idea of generalizing the theory of gravity by compac
tification of the phase space will be discussed. The procedure of compacti
fication of the phase space of a minisuperspace gravitational model with t
wo dimensional phase space will be introduced. The model will be analyzed
at both classical and quantum level.\nhttps://indico.cern.ch/event/773241/
contributions/3535503/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535503/
END:VEVENT
BEGIN:VEVENT
SUMMARY:On the relation between the canonical Hamilton-Jacobi equation a
nd the De Donder-Weyl Hamilton-Jacobi formulation in general relativity
DTSTART;VALUE=DATE-TIME:20190923T151000Z
DTEND;VALUE=DATE-TIME:20190923T153000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535504@indico.cern.ch
DESCRIPTION:Speakers: Natascha Riahi (Universität Wien)\nWe discuss the r
elation between the canonical Hamilton-Jacobi theory and the \nDe Donder-W
eyl Hamilton-Jacobi theory known in the calculus of variations using the \
nexamples of a scalar field on curved space-time background and general re
lativity. \n\nWe show that the canonical Hamilton-Jacobi equation of gener
al relativity which preceded \nthe Wheeler-De Witt formulation of quantum
gravity can be derived from the De Donder-Weyl \nHamilton-Jacobi reformula
tion of the Einstein equations. The timelessness of the canonical \nHamilt
on-Jacobi formulation appears as a consequence of the split into space and
time in \nthe Donder-Weyl Hamilton-Jacobi equation where no space-time de
composition is required. \nThe result is crucial for the understanding of
the relation between various formulations of\ncanonical quantum gravity an
d the results of precanonical quantization of general relativity \n based
on the De Donder-Weyl Hamiltonian theory.\nhttps://indico.cern.ch/event/77
3241/contributions/3535504/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535504/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quantum gravity on a torus - an update
DTSTART;VALUE=DATE-TIME:20190923T153000Z
DTEND;VALUE=DATE-TIME:20190923T155000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535505@indico.cern.ch
DESCRIPTION:Speakers: Jakub Gizbert-Studnicki (Jagiellonian University)\nD
uring last POTOR's conference I discussed a quantum gravity model defined
by Causal Dynamical Triangulations (CDT) where spatial slices of equal pro
per time have fixed topology of a 3-torus. Identification of phase structu
re and order of the phase transitions constitute first steps in the quest
for a continuum limit of CDT where\, following the asymptotic safety conje
cture\, the resulting theory of quantum gravity becomes nonperturbatively
renormalizable. Initial study of the toroidal model\, presented last year\
, showed that one can identify the same phase structure as earlier observe
d for the spherical spatial topology\, including phase 'C'\, where quantum
fluctuations of spatial volume are well described by mini-superspace like
models. Now I will also discuss the recent study of the order of phase tr
ansitions in the toroidal case\, which is crucial in defining the continuu
m limit of CDT. If time permits I will comment on the possibility of reint
roducing spatial coordinates in the CDT model and on the impact of scalar
fields with non-trivial boundary conditions on the toroidal CDT results.\n
https://indico.cern.ch/event/773241/contributions/3535505/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535505/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Massline and other recent results of CDT quantumgravity
DTSTART;VALUE=DATE-TIME:20190923T155000Z
DTEND;VALUE=DATE-TIME:20190923T161000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535506@indico.cern.ch
DESCRIPTION:Speakers: Dániel Németh (Jagiellonian University)\nCausal Dy
namical Triangulations is a nonperturbative approach to quantum gravity ba
sed on Regge calculus\, which uses lattice regularization in the form of a
triangulation. To describe the theory for dimension higher than 2 only nu
merical simulations are available. It is well known through the numerical
simulations\, that for certain values of bare coupling constants the de-Si
tter Universe emerges as a dynamically created background solution around
which quantum fluctuations are observed\, which agrees with the solutions
of the Minisuperspace model. The effects of including scalar-/vector- fiel
ds or particles in the theory is less understood. In our new research we a
re analyzing the effect of introducing closed timelike loops for point par
ticles of various masses and lattice volumes\, for spherical and toroidal
topologies. The massline is minimally coupled to the geometry through the
action dependent on its mass and length $S_m = m*L$. The next step will b
e to measure the possible behavior of two or more such masslines to see th
eir interaction may produce any noticable gravitational effect. These mass
line measurements and some other new approaches help us understanding the
underlying structure of the generated triangulations.\nhttps://indico.cern
.ch/event/773241/contributions/3535506/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535506/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quantum corrections in rigidly-rotating thermal states on anti-deS
itter space
DTSTART;VALUE=DATE-TIME:20190923T130000Z
DTEND;VALUE=DATE-TIME:20190923T132000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535520@indico.cern.ch
DESCRIPTION:Speakers: Victor Eugen Ambrus (West University of Timisoara)\n
https://indico.cern.ch/event/773241/contributions/3535520/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535520/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Modeling short gamma ray bursts from binary neutron star mergers w
ith general relativistic magnetohydrodynamics
DTSTART;VALUE=DATE-TIME:20190924T103000Z
DTEND;VALUE=DATE-TIME:20190924T110000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535521@indico.cern.ch
DESCRIPTION:Speakers: Agnieszka Janiuk (Center for Theoretical Physics PAS
)\nI will present the recent development of numerical tools for GR MHD mod
eling of the black hole accretion flows.\nThe black hole appears as the re
sult of a binary neutron star merger\, and is surrounded by a remnant debr
is torus.\nThe code named HARM_COOL is our implementation of the existing
algorithm\nfor a conservative GR MHD scheme.\nThe newly added modules cove
r the neutino cooling and the nuclear equation of state for dense matter\,
as relevant for the physics\n of accretion flows in a gamma-ray burst (GR
B) central engine environment. We also implement\n further post-processing
with a nuclear reaction network\, and reproduce the nucleosynthesis of he
avy\, neutron-rich isotopes.\nThese elements are synthesized within the ma
gnetically driven outflow from the remnant torus.\nThese fast wind outflow
s (v/c∼0.11−0.23) appear with a broad range of electron fraction Ye∼
0.1−0.4. \nThe total mass loss from the post-merger disk via unbound out
flows is between 2\\% and 17\\% of the initial disk mass. \nThe results ar
e in agreement with the scenarios that explain the blue and red kilonova c
omponents\, detected in optical lightcurves \nafter the gravitational wave
event GW 170817.\nhttps://indico.cern.ch/event/773241/contributions/35355
21/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535521/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Loop quantum gravity: developments and recent results
DTSTART;VALUE=DATE-TIME:20190924T070000Z
DTEND;VALUE=DATE-TIME:20190924T074500Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535525@indico.cern.ch
DESCRIPTION:Speakers: Jorge Pullin (Jorge)\nWe present a largely non-techn
ical review of loop quantum gravity\, describing its basic principles and
recent results in applications to cosmology and black holes.\nhttps://indi
co.cern.ch/event/773241/contributions/3535525/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535525/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Palatini stars
DTSTART;VALUE=DATE-TIME:20190924T130000Z
DTEND;VALUE=DATE-TIME:20190924T132000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535526@indico.cern.ch
DESCRIPTION:Speakers: Aneta Wojnar (Espirito Santo University)\nI will bri
efly show how low mass stars (\nhttps://indico.cern.ch/event/773241/contri
butions/3535526/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535526/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Solar system analysis of a polynomial class of Palatini f(R) gravi
ty
DTSTART;VALUE=DATE-TIME:20190924T132000Z
DTEND;VALUE=DATE-TIME:20190924T134000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535528@indico.cern.ch
DESCRIPTION:Speakers: Davi Cabral Rodrigues (Federal University of Espirit
o Santo)\, Aneta Wojnar (Federal University of Espirito Santo)\, JUNIOR TO
NIATO (Federal University of Espirito Santo)\nIt is made a post-Newtonian
analysis of a class of Palatini $f(R)$ theories of gravity where the lagra
ngian density is assumed to be a polynomial function of the Ricci scalar.
The resulting metric is not covered by the classical parametrized post-New
tonian formalism (PPN) since new gravitational potentials emerges. I will
then discuss post-Newtonian equations of motion of massive bodies and ligh
t rays to see whether deviations from general relativity can be used to de
termine upper bound limits to Palatini $F(R)$ gravity according to tests p
erformed in the solar system.\nhttps://indico.cern.ch/event/773241/contrib
utions/3535528/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535528/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mass and spin constraint on black holes associated with long GRB
’s in Collapsar model.
DTSTART;VALUE=DATE-TIME:20190924T134000Z
DTEND;VALUE=DATE-TIME:20190924T140000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535529@indico.cern.ch
DESCRIPTION:Speakers: Petra Sukova (Instytut Astronomii Czeskiej Akademii
Nauk\,Praga)\, Agnieszka Janiuk (Center for theoretical physics\, PAS)\, I
shika Palit (Center for theoretical Physics \, PAS)\nGamma ray bursts are
highly energetic and brightest explosions that have been observed in EM sp
ectrum. These can last from few seconds to few hours. The progenitors of l
ong GRBs are believed to be massive stars exploding due to the collapse of
their cores. Matter from the star around the core falls down towards the
center forming a gaseous envelope and (for rapidly rotating stars) swirls
into a highly density accretion disk. \nIn my talk\, I will present our re
sults showing how much mass and spin a newly formed black hole should poss
ess during collapsar to launch long GRB. In our model\, We start with a n
ewly formed black hole whose mass and spin are going to evolve depending o
n the rotation of the collapsing cloud. We set a critical angular momentum
of the cloud at certain circular radii and we further study the growth of
black hole in sub critical\, critical and super critical regime. In addi
tion to metric change effects on the evolution\, mini disk formation has a
lso been investigated and have been accounted for variability in accretion
rate. Our results also testify that the massive BH detected by LIGO till
date was never able to launch a powerful GRB because as per our results su
ch massive BH should not have required high spin to support such event.\nh
ttps://indico.cern.ch/event/773241/contributions/3535529/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535529/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Modeling General- relativistic disk in OJ 287
DTSTART;VALUE=DATE-TIME:20190924T140000Z
DTEND;VALUE=DATE-TIME:20190924T142000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535530@indico.cern.ch
DESCRIPTION:Speakers: Patryk Mach\, Wojciech Dyba (Jagiellonian University
)\, Edward Malec\nWe have modelled the accretion disk around the primary b
lack hole in the binary black hole system OJ 287 as a self-gravitating\, s
tationary torus of barotropic matter in Keplerian motion. Using a consiste
ntly general-relativistic approach\, we found solutions that satisfy eithe
r geometric requirements on the disk or the requirements on its mass densi
ty\nfound by Lehto\, Valtonen\, and their co-workers. It seems that the mo
st important observable features of OJ 287 may be consistent with the mode
l based on the Bondi-Hoyle-Lyttleton transit of the secondary black hole t
hrough the disk. This talk is based on paper: W. Dyba\, P. Mach and E. Ma
lec\, MNRAS 486\, 3118-3123 (2019).\nhttps://indico.cern.ch/event/773241/c
ontributions/3535530/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535530/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Simple SUGRA inflation
DTSTART;VALUE=DATE-TIME:20190924T130000Z
DTEND;VALUE=DATE-TIME:20190924T132000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535535@indico.cern.ch
DESCRIPTION:Speakers: Michal Artymowski (Jagiellonian University)\nIn my t
alk I will present a simple idea of Supergravity with flat Kahler geometry
. I will show how it may lead to simple scalar potentials\, which in princ
iple may lead to inflation or dark energy. Furthermore\, I will show how a
simple generalization of a simplest flat Kahler leads to generic inflatio
nary potentials from the simplest\, linear Superpotentials.\nhttps://indic
o.cern.ch/event/773241/contributions/3535535/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535535/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Multidimensional dynamics of the brane - dilaton black hole system
DTSTART;VALUE=DATE-TIME:20190924T134000Z
DTEND;VALUE=DATE-TIME:20190924T140000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535537@indico.cern.ch
DESCRIPTION:Speakers: Marek Rogatko (Maria Curie-Skłodowska University\,
Lublin\, Poland)\, Anna Nakonieczna (University of Warsaw\, Poland)\, Łuk
asz Nakonieczny (University of Warsaw\, Poland)\nInteractions among black
holes and branes could have been relevant in the early stages of the evolu
tion of the Universe. Primordial black holes could have formed out of matt
er density perturbations\, while phase transitions in the cooling Universe
may have resulted in an occurrence of extended topological defects. There
can exist two types of static configurations within the brane - black hol
e system. The first one corresponds to the brane which intersects the even
t horizon\, the second one represents unlinked objects. In the case of an
extremal black hole\, the former does not form. Our research was devoted t
o examining the dynamical behavior of the brane - dilaton black hole syste
m. The evolution of a brane of a nonzero initial velocity was traced with
respect to the position of a black hole. The dynamics was described in mul
tiple dimensions and for various values of parameters of the theoretical s
etup.\nhttps://indico.cern.ch/event/773241/contributions/3535537/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535537/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hopf-algebraic deformations of 3d spacetime symmetries
DTSTART;VALUE=DATE-TIME:20190924T132000Z
DTEND;VALUE=DATE-TIME:20190924T134000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535536@indico.cern.ch
DESCRIPTION:Speakers: Tomasz Trzesniewski (Jagiellonian University)\nIt is
widely argued\, especially in the phenomenological approach to quantum gr
avity\, that at the Planckian scales the geometry of spacetime may become
noncommutative. A closely related effect is the generalization of classica
l spacetime symmetries into quantum-deformed algebras and groups\, which a
re expected to have the structure of Hopf algebras and be characterized by
the (classical) $r$-matrices - solutions of the Yang-Baxter equations. Th
e best known example is the $\\kappa$-Poincare algebra. Such quantum algeb
ras and groups actually arise in the convincing way in 2+1 dimensions\, wh
ere gravity can be described as a Chern-Simons theory with the gauge group
given by the isometry group of spacetime\, the latter depending on the me
tric signature and cosmological constant. For non-vanishing cosmological c
onstant the relevant algebras are $\\mathfrak{o}(4)$\, $\\mathfrak{o}(3\,1
)$ and $\\mathfrak{o}(2\,2)$. They can also be treated as real forms of th
e complex algebra $\\mathfrak{o}(4\;\\mathbb{C})$\, which has recently bee
n applied to classify all of their possible quantum deformations. We have
further expanded this line of inquiry by studying the quantum Inonu-Wigner
contractions\, i.e. calculating the limit of vanishing cosmological const
ant of deformations of the $\\mathfrak{o}(4)$\, $\\mathfrak{o}(3\,1)$ and
$\\mathfrak{o}(2\,2)$ algebras\, which leads to either deformed 3d inhomog
eneous Euclidean algebras or deformed 3d Poincare algebras. The obtained a
lgebras form a subclass in the known classification of quantum 3d inhomoge
neous symmetry algebras and can be compared with e.g. the recent results c
oncerning deformed symmetry algebras that are associated with the Drinfel'
d double structures (the latter are claimed to be a necessary ingredient i
n the quantization of 2+1d gravity).\nhttps://indico.cern.ch/event/773241/
contributions/3535536/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535536/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Discrete scale invarinace in holography revisited
DTSTART;VALUE=DATE-TIME:20190924T140000Z
DTEND;VALUE=DATE-TIME:20190924T142000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3535538@indico.cern.ch
DESCRIPTION:Speakers: Mario Flory (Jagiellonian University)\nhttps://indic
o.cern.ch/event/773241/contributions/3535538/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3535538/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Space-Based Gravitational Wave Observations in the Mid-Band Freque
ncy Region
DTSTART;VALUE=DATE-TIME:20190923T073000Z
DTEND;VALUE=DATE-TIME:20190923T081500Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537321@indico.cern.ch
DESCRIPTION:Speakers: Massimo Tinto (UCSD)\nThe opportunity exists to scie
ntifically explore the intermediate Gravitation Wave (GW) frequency detect
ion band\, a region that is in between those accessible by LISA and LIGO.
A GW mission operating in this part of the GW band will complement and enh
ance the scientific capabilities of both LIGO and LISA. Such a mission ent
ails three drag-free satellites in a geosynchronous trajectory resulting i
n a triangle formation of arm-length equal to 73000 km and an observationa
l frequency band that is “blue-shifted” with respect to that of LISA b
y about a factor 70. Because of the complementarity of the observational b
andwidths and sensitivities of the two missions\, their joint operation wi
ll result in an enhanced scientific return over those obtainable by each o
bservatory operated as stand-alone.\nhttps://indico.cern.ch/event/773241/c
ontributions/3537321/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537321/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Curvature perturbations in quantum cosmological spacetimes
DTSTART;VALUE=DATE-TIME:20190923T145000Z
DTEND;VALUE=DATE-TIME:20190923T151000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537322@indico.cern.ch
DESCRIPTION:Speakers: Przemysław Małkiewicz (National Centre for Nuclear
Research)\nI will present some preliminary results on the evolution of pe
rturbations in quantum cosmological spacetimes. The classical framework i
s derived with the Dirac procedure from the second order ADM formalism. Th
en the framework is quantised covariantly\, i.e.\, respecting the symmetri
es of the phase space. Next\, a semi-classical framework is established an
d the evolution of perturbations in semi-classical spacetimes is investiga
ted for a range of cosmological fluids. A discussion on the final amplitud
e spectra will follow. I will conclude with an outlook for the future inve
stigations in anisotropic cosmological spacetimes.\nhttps://indico.cern.ch
/event/773241/contributions/3537322/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537322/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quantum Big Bounce scenario and primordial gravitational waves
DTSTART;VALUE=DATE-TIME:20190925T104000Z
DTEND;VALUE=DATE-TIME:20190925T110000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537256@indico.cern.ch
DESCRIPTION:Speakers: Przemyslaw Malkiewicz\, Artur Miroszewski (National
Centre for Nuclear Research)\nIn my talk I will present a method to quanti
se and solve the dynamics of gravitational waves in a quantum Friedmann-Le
maitre-Robertson-Walker spacetime filled with radiation.\nThe classical mo
del is formulated in the ADM formalism. The system is then de-parametrised
and reduced phase space is found. With the use of phase space symmetry re
specting quantisation map the perturbed quantum FLRW cosmology is obtained
. As a result of such procedure the initial singularity is replaced with a
quantum bounce\, which can act as a mechanism for generation of primordia
l gravitational waves. The properties of Big Bounce scenario and emitted g
ravitational waves will be presented\, both in the coherent states approxi
mation and using the exact results.\nhttps://indico.cern.ch/event/773241/c
ontributions/3537256/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537256/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Perturbations of the Kerr metric in modified gravity
DTSTART;VALUE=DATE-TIME:20190925T132000Z
DTEND;VALUE=DATE-TIME:20190925T134000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537258@indico.cern.ch
DESCRIPTION:Speakers: Arthur Suvorov (University of Tübingen)\nThe Kerr m
etric\, which describes the geometry surrounding an isolated\, rotating co
mpact object\, is unique in general relativity (GR)\, in the sense that al
l asymptotically flat\, stationary\, vacuum black holes must be locally is
ometric to the Kerr spacetime. As such\, probing the Kerr metric is one of
the best means to test GR. However\, because modified theories of gravity
are often built such that they contain GR in some limit\, the Kerr metric
is also common to many of these theories. This means that\, in the absenc
e of `smoking-gun' type deviations\, a validation of the Kerr metric does
not necessarily favour GR amongst all possibilities. But\, since perturbat
ions are tied to the gravitational action\, disturbances behave differentl
y in different theories. We discuss\, using the Newman-Penrose formalism\,
how the field equation structure manifests in the properties of distorted
black holes in non-Einstein theories of gravity. This paves the way for f
uture precision tests of GR in the strong field regime using\, for example
\, gravitational waves.\nhttps://indico.cern.ch/event/773241/contributions
/3537258/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537258/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Construction of the cosmological model with periodically distribut
ed dust inhomogeneities with growing amplitude.
DTSTART;VALUE=DATE-TIME:20190925T134000Z
DTEND;VALUE=DATE-TIME:20190925T140000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537274@indico.cern.ch
DESCRIPTION:Speakers: Krzysztof Głód (Astronomical Observatory of the Ja
giellonian University)\, Szymon Sikora (Jagiellonian University)\nAnalytic
al models which generalize the Friedmann-Lemaitre-Robertson-Walker space-t
ime are important tools in the analysis of a possible impact of the large-
scale structure inhomogeneities on the cosmological observables (angular d
iameter distance-redshift relation\, local measurements of the Hubble cons
tant\, etc.) \nIn this talk I will present some progress in the constructi
on of the dust-like cosmological model with a periodically distributed inh
omogeneities. The most important idea in this framework is to simplify the
Einstein equations by imposing specific symmetry conditions on the matter
distribution in space.\nhttps://indico.cern.ch/event/773241/contributions
/3537274/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537274/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Spacetime singularities in inflationary universes
DTSTART;VALUE=DATE-TIME:20190925T130000Z
DTEND;VALUE=DATE-TIME:20190925T132000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537282@indico.cern.ch
DESCRIPTION:Speakers: Daisuke Yoshida (Kobe University)\nhttps://indico.ce
rn.ch/event/773241/contributions/3537282/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537282/
END:VEVENT
BEGIN:VEVENT
SUMMARY:1+1+2 covariant formulation of light propagation in cosmological m
odels
DTSTART;VALUE=DATE-TIME:20190925T145000Z
DTEND;VALUE=DATE-TIME:20190925T151000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537276@indico.cern.ch
DESCRIPTION:Speakers: Krzysztof Głód (Astronomical Observatory of the Ja
giellonian University)\nWe present a covariant approach to the problem of
light beam propagation in cosmological models. We develop our consideratio
ns within the framework of classical geometric optics in general relativit
y. Using the concept of screen surface orthogonal to the observer velocity
and to the bundle of geodesics\, we introduce covariant four-dimensional
definitions for Sachs and Jacobi fields and for the area distance. Then we
derive relationships between them and their propagation equations and ini
tial conditions for these equations. Ultimately\, for practical use\, we t
ransform the resulting formulas into a redshift dependent form.\nhttps://i
ndico.cern.ch/event/773241/contributions/3537276/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537276/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cosmography as a tool to discriminate between modified gravity and
dark energy
DTSTART;VALUE=DATE-TIME:20190925T070000Z
DTEND;VALUE=DATE-TIME:20190925T074500Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537250@indico.cern.ch
DESCRIPTION:Speakers: Salvatore Capozziello (INFN - National Institute for
Nuclear Physics)\nCosmography can be considered as a sort of a\nmodel-i
ndependent approach to tackle the dark energy/modified gravity \nproblem
. In this talk\, the success and the shortcomings of the\n$\\Lambda$CDM mo
del\, based on General Relativity and standard model of\nparticles\, are d
iscussed in view of the most recent observational\nconstraints. The motiva
tions for considering extensions and modifications\nof General Relativity
are taken into account\, with particular attention to\n$f(R)$ and $f(T)$
theories of gravity where dynamics is represented by\ncurvature or torsion
field respectively. The features of $f(R)$ models\nare explored in metr
ic and Palatini formalisms. \nCosmological dynamics of $f(R)$ models is i
nvestigated through the\ncorresponding viability criteria. Afterwards\, t
he equivalent formulation\nof General Relativity (Teleparallel Equivalent
General Relativity) in\nterms of torsion and its extension to $f(T)$ gravi
ty is considered.\nFinally\, the cosmographic method is adopted to break t
he degeneracy among\ndark energy models. A novel approach\, built upon rat
ional Pad\\'e and\nChebyshev polynomials\, is proposed to overcome limit
s of standard\ncosmography based on Taylor expansion. The approach prov
ides accurate\nmodel-independent approximations of the Hubble flow. Nume
rical analyses\nare presented to bound coefficients of the cosmographic s
eries. These\ntechniques are thus applied to reconstruct $f(R)$ and $f(T)$
functions \nand to frame the late-time expansion history of the universe
with no\n\\emph{a priori} assumptions on its equation of state. A comparis
on \nbetween the $\\Lambda$CDM cosmological model with $f(R)$ and $f(T)$ m
odels\nis reported.\nhttps://indico.cern.ch/event/773241/contributions/35
37250/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537250/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Static\, spherically symmetric black holes in quadratic gravity
DTSTART;VALUE=DATE-TIME:20190925T134000Z
DTEND;VALUE=DATE-TIME:20190925T140000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537260@indico.cern.ch
DESCRIPTION:Speakers: Robert Svarc\, Jiri Podolsky\, Vojtech Pravda\, Alen
a Pravdova\nIt can be shown that all Robinson-Trautman spacetimes are conf
ormal to Kundt spacetimes. For spacetimes with constant Ricci scalar\, all
quadratic gravity corrections to Einstein gravity can be combined into th
e Bach tensor which is well behaved under conformal transformations.\n\nCo
mbining these results leads to a considerable simplification of the vacuum
field equation of quadratic gravity for static\, spherically symmetric sp
acetimes. \nThis allow us to study non-Schwarzschild static\, spherically
symmetric black holes in four-dimensional quadratic gravity using analytic
al methods.\n\n\nBased on:\n\nV. Pravda\, A. Pravdová\, J. Podolský\, an
d R. Švarc\, Phys. Rev. D 95\, 084025 (2017)\,\nJ. Podolský\, R. Švarc
\, V. Pravda\, and A. Pravdová\, Phys. Rev. D 98\, 021502(R) (2018)\,\nR.
Švarc\, J. Podolský\, V. Pravda\, and A. Pravdová\, Phys. Rev. Lett. 1
21\, 231104 (2018)\,\nand papers in preparation.\nhttps://indico.cern.ch/e
vent/773241/contributions/3537260/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537260/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Riemannian geometry imposed on Friedmann and more general spacetim
es
DTSTART;VALUE=DATE-TIME:20190925T145000Z
DTEND;VALUE=DATE-TIME:20190925T151000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537263@indico.cern.ch
DESCRIPTION:Speakers: Janusz Garecki (University of Szczecin)\nAt first we
define Riemannian geometry in general relativity (GR) as geometry determi
ned by Riemannian\, Finsler-like metric\n\\begin{equation}\nh_{ab}(x\;v) :
=2V_a V_b - g_{ab}(x).\n\\end{equation}\nHere $g_{ab}$ is the Lorentzian m
etric of a spacetime and ${\\vec v}$ is an unit timelike vector field: $v
= \\sqrt{g_{ab}v^a v^b} =1$. Then\, we compare this Riemannian geometry wi
th original\, Lorentzian geometry in the case of Friedmann and more genera
l spacetimes\nhttps://indico.cern.ch/event/773241/contributions/3537263/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537263/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Universal black holes
DTSTART;VALUE=DATE-TIME:20190925T151000Z
DTEND;VALUE=DATE-TIME:20190925T153000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537264@indico.cern.ch
DESCRIPTION:Speakers: Marcello Ortaggio\nWe consider a generalized Schwarz
schild-like ansatz and prove that it can be consistently employed to const
ruct $d$-dimensional static vacuum black hole solutions in any metric theo
ry of gravity for which the Lagrangian is a scalar invariant constructed f
rom the Riemann tensor and its covariant derivatives of arbitrary order. A
fter describing the ansatz and the corresponding (reduced) field equations
\, we exemplify it in particular theories such as Gauss-Bonnet\, quadratic
and $F(R)$ gravity\, and certain conformal gravities.\nhttps://indico.cer
n.ch/event/773241/contributions/3537264/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537264/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Anti-evaporation of Schwarzschild-deSitter black hole revisited
DTSTART;VALUE=DATE-TIME:20190926T104000Z
DTEND;VALUE=DATE-TIME:20190926T110000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537299@indico.cern.ch
DESCRIPTION:Speakers: Maciej Kolanowski (University of Warsaw)\nhttps://in
dico.cern.ch/event/773241/contributions/3537299/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537299/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Antisymmetric Tensors in Friedmann Cosmology
DTSTART;VALUE=DATE-TIME:20190926T102000Z
DTEND;VALUE=DATE-TIME:20190926T104000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537296@indico.cern.ch
DESCRIPTION:Speakers: Nils A. Nilsson (National Centre for Nuclear Researc
h)\nAntisymmetric tensor fields arise naturally in superstring theory as w
ell as in some theories with broken Lorentz invariance. However\, models c
ontaining antisymmetric tensor fields often include anisotropic pressure.
I will present a general prescription for constructing ansäzte for antisy
mmetric tensor fields for use in cosmology. With a series of coordinate-de
pendent constraints I will show that these models can fit Friedmann-type g
eometry.\nhttps://indico.cern.ch/event/773241/contributions/3537296/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537296/
END:VEVENT
BEGIN:VEVENT
SUMMARY:On the precanonical structure of the Schroedinger wave functional
in curved space-time
DTSTART;VALUE=DATE-TIME:20190926T094000Z
DTEND;VALUE=DATE-TIME:20190926T102000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537291@indico.cern.ch
DESCRIPTION:Speakers: Igor Kanatchikov (U St. Andrews & KCIK)\nI outline t
he approach of precanonical quantization applied to a scalar field on curv
ed space-time. It leads to the description of quantum fields as sections o
f the Clifford bundle over the bundle of field variables over space-time.
The approach does not require 3+1 decomposition and the corresponding desc
ription of quantum fields is a hypercomplex rather than an infinite-dimens
ional generalization of quantum mechanics. I show how the classical field
equations are obtained from the precanonical analogue of the Schroedinger
equation as the equations for expectation values of the corresponding ope
rators. I discuss the relationship between the precanonical description an
d the standard formulation of quantum scalar fields on a curved space-time
background in the functional Schroedinger representation. The canonical d
escription is shown to emerge from the precanonical one in a singular limi
ting case in which\, after the 3+1 decomposition\, the canonical functiona
l derivative Schroedinger equation is derived from the partial derivative
precanonical Schroedinger equation and an explicit formula is obtained whi
ch relates the Schroedinger wave functional with the trace of the product
integral of precanonical wave functions taken along the surface of initial
data.\nhttps://indico.cern.ch/event/773241/contributions/3537291/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537291/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quantum creation of a universe-antiuniverse pair
DTSTART;VALUE=DATE-TIME:20190926T124000Z
DTEND;VALUE=DATE-TIME:20190926T132000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537302@indico.cern.ch
DESCRIPTION:Speakers: Salvador Robles-Perez (EEBM)\nIf one analyses the qu
antum creation of the universe\, it turns out that the most natural way in
which the universes can be created is in pairs of universes whose time fl
ow is reversely related. It means that the matter that propagates in one o
f the universes can be seen\, from the point of view of the other universe
\, as antimatter\, and viceversa. They thus form a universe-antiuniverse p
air. From a global point of view\, i.e. from the point of view of the whol
e multiverse ensemble\, the creation of universes in universe-antiuniverse
pairs restores the matter-antimatter asymmetry observed in each individua
l universe and it might provide us with an explanation for the baryon asym
metry of our universe.\nhttps://indico.cern.ch/event/773241/contributions/
3537302/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537302/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mass\, density and circumferential radius in general-relativistic
Keplerian disks around black holes
DTSTART;VALUE=DATE-TIME:20190925T153000Z
DTEND;VALUE=DATE-TIME:20190925T155000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3538307@indico.cern.ch
DESCRIPTION:Speakers: Wojciech Kulczycki\nIn my talk I consider self-gravi
tating toroidal disks around black holes that rotate according to the gene
ral-relativistic Keplerian rotation law. During our research on the proble
m of mass estimation in such systems new effects have been discovered. The
y concern density and circumferential radius and appear\, when disks are m
assive enough. In my talk I would like to present these effects.\nhttps://
indico.cern.ch/event/773241/contributions/3538307/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3538307/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Holographic SQUID and detection of dark matter
DTSTART;VALUE=DATE-TIME:20190925T090000Z
DTEND;VALUE=DATE-TIME:20190925T092000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537251@indico.cern.ch
DESCRIPTION:Speakers: Marek Rogatko (Maria Curie-Skłodowska University\,
Lublin\, Poland)\, Bartłomiej Kiczek\, Karol Wysokinski (Maria Curie Sklo
dowska University)\nThe gauge/gravity duality has constituted as a powerfu
l tool for analysis of strongly coupled condensed matter systems on a wea
kly coupled gravitational side in AdS spacetime.\nIt has been shown that t
he holographic theory reproduces several properties of superconducting/sup
erfluid state known from conventional quantum mechanical considerations an
d experiments.\nThis has been extended by possibilities of modeling Joseph
son junctions in a holographic approach in various scenarios -- different
pairing types or in modified gravity\, which opened a new branch of resear
ch that can be named as Applied AdS/CFT.\nTreating these efforts as an ins
piration we propose bringing the superconducting devices into the field of
the detection of specific kind of dark matter (DM)\, namely the dark phot
on. \nIn our model we construct a holographic SQUID (superconducting quant
um interference device) whose one of Josephson junctions is affected by th
e dark sector. This interaction is realized by kinetic mixing term resulti
ng a photon-dark photon coupling.\nWe have shown that mixing has an impact
on properties of Josephson junction such as current-phase relation.\nOur
results show that proposed SQUID remains trivial with zero signal when the
DM is not affecting it\, however if DM is present in the system an interf
erence occurs and possible signal is created.\nFurthermore we have investi
gated the dependence of the DM wavepacket length on the critical current s
erving as a sensitivity of SQUID for particular mass of a dark particle.\n
We find that the analyzed properties of the device may be used in the futu
re experiments aimed at the detection of the dark sector of our Universe.\
nhttps://indico.cern.ch/event/773241/contributions/3537251/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537251/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Decaying Massive Scalar in the Early Universe
DTSTART;VALUE=DATE-TIME:20190925T100000Z
DTEND;VALUE=DATE-TIME:20190925T102000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537254@indico.cern.ch
DESCRIPTION:Speakers: Juho Lankinen (University of Turku)\nThe presence of
a gravitational field modifies significantly particle decay rates compare
d to the usual Minkowski space results. Because of the lack of energy cons
ervation\, new particle processes\, forbidden in Minkowski space\, are to
be considered leading to new Feynman diagrams even at first order. I will
give a brief introduction to the problems one encounters when trying to ca
lculate decay rates using quantum field theory in curved spacetime in FLRW
-spacetimes. I will focus on conceptual issues\, show methods of calculati
on to overcome some of these issues and present few explicit results of mo
dified decay rates which show that in the early Universe a massive scalar
particle tends to decay into fermionic rather than to scalar channel.\n\nB
ased on: \narXiv:1805.09620\narXiv:1904.05084\nhttps://indico.cern.ch/even
t/773241/contributions/3537254/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537254/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Extended quantum uncertainty in the presence of horizons
DTSTART;VALUE=DATE-TIME:20190925T102000Z
DTEND;VALUE=DATE-TIME:20190925T104000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537255@indico.cern.ch
DESCRIPTION:Speakers: Fabian Wagner (Universytet Szczecinski)\, Mariusz Da
browski (University of Szczecin)\nSpace-time curvature affects quantum unc
ertainty. This effect is commonly known as the Extended Uncertainty princi
ple. In this talk I briefly present a method to calculate the influence of
curvature on the uncertainty relation. Moreover I apply it to cosmologica
l and Rindler horizons and interpret the results in the context of horizon
thermodynamics.\nhttps://indico.cern.ch/event/773241/contributions/353725
5/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537255/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Canonical Quantization of Massive Symmetric Rank-Two Tensor in Str
ing Theory
DTSTART;VALUE=DATE-TIME:20190926T090000Z
DTEND;VALUE=DATE-TIME:20190926T094000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537288@indico.cern.ch
DESCRIPTION:Speakers: Taejin Lee (Department of Physics\, Kangwon National
University)\nCanonical quantization of massive symmetric rank-two tensor
in string theory has been studied. \nThe Lagrangian describing symmetric r
ank-two tensor\, containing two Stueckelberg fields\,\nwas obtained by Sie
gel and Zwiebach from string field theory. Performing canonical analysis\,
\nwe found that the Lagrangian possesses first class constraints only\, wh
ich generate a local gauge transformation. By an explicit calculation\, we
show that the constraints form a closed algebra \nonly in the critical di
mension of string\, $d=26$. It reminds us that the origin of local symmetr
y \nis nilpotency of BRST operator\, which is valid only in the critical d
imension. \nIn a particular gauge\, imposed on the Stueckelberg fields\,
the gauge invariant \nLagrangian of Siegel and Zwiebach reduces to the Fie
rz-Pauli Lagrangian proposed for \na massive spin-two particle. Thus\, the
Fierz-Pauli Lagrangian is a gauged fixed version \nof the gauge invariant
Lagrangian for massive symmetric rank-two tensor. In comparison to \nthe
Fierz-Pauli Lagrangian\, which contains second class constraints\, it is m
uch simpler to \nquantize the gauge invariant Lagrangian. We also construc
ted a covariant \npropogator which may be useful to develop a perturbation
theory for massive spin-two particle.\nhttps://indico.cern.ch/event/77324
1/contributions/3537288/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537288/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Topologically Supported Cosmological Constant
DTSTART;VALUE=DATE-TIME:20190925T094000Z
DTEND;VALUE=DATE-TIME:20190925T100000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537303@indico.cern.ch
DESCRIPTION:Speakers: Paweł Klimasara (Institute of Physics\, University
of Silesia in Katowice)\, Krzysztof Bielas (University of Information Tech
nology and Management)\, Torsten Asselmeyer-Maluga (German Aerospace Cente
r (DLR))\, Jerzy Król (University of Information Technology and Managemen
t)\nWe present a cosmological model where the cosmological constant is a t
opological invariant. The cosmological constant is derived from the curvat
ure of exotic $R^4$ embedded in $K3\\# \\overline{\\mathbb{C}P^2}$. Both o
f the manifolds are perfectly smooth however the 3-diemnsional slices they
generate contain topological changes. Then the value of cosmological cons
tant is expressed via Chern-Simons\, volume\, and Euler invariants of the
3-submanifolds. Moreover\, this cosmological model predicts realistically
the neutrino masses and inflation parameters\, including Starobinsky poten
tial and the number of e-folds.\n\nReferences:\n\n[1] Król\, J.\, Asselme
yer-Maluga\, T.\, Bielas\, K.\, & Klimasara\, P. (2017). From Quantum to C
osmological Regime. The Role of Forcing and Exotic 4-Smoothness. Universe\
, 3(2)\, 31.\n[2] Asselmeyer-Maluga\, T.\, & Król\, J. (2018). How to obt
ain a cosmological constant from small exotic R4. Physics of the dark univ
erse\, 19\, 66-77.\nhttps://indico.cern.ch/event/773241/contributions/3537
303/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537303/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Solutions in Teleparallel Gravity: Gravitomagnetism and Rotational
Effects
DTSTART;VALUE=DATE-TIME:20190925T140000Z
DTEND;VALUE=DATE-TIME:20190925T142000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3556998@indico.cern.ch
DESCRIPTION:Speakers: Andrew Finch (Institute of Space Sciences and Astron
omy\, University of Malta)\, Gabriel Farrugia (University of Malta)\, Jack
son Levi Said (University of Malta-Unknown-Unknown)\nThe theory of $f(T)$
gravity shall be discussed in the context of gravitoelectromagnetism (GEM)
where the modified GEM equations are discussed and derived. Through use o
f linearisation and perturbation techniques\, specific metric solutions ar
e obtained which are then used to investigate specific GEM effects such as
the de Sitter and Lense-Thirring precessions. Following observations from
Gravity Probe B\, the $f(T)$ models are constrained and compared against
cosmological constraints.\nhttps://indico.cern.ch/event/773241/contributio
ns/3556998/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3556998/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Strength of singularities in varying constants theories.
DTSTART;VALUE=DATE-TIME:20190925T151000Z
DTEND;VALUE=DATE-TIME:20190925T153000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3557135@indico.cern.ch
DESCRIPTION:Speakers: Konrad Marosek\nWe consider a specific type of the b
imetric theory of gravitation with the two different metrics introduced in
the cosmological frame. Both metrics respect all the symmetries of the st
andard FLRW solution and contain conformally related spatial parts. One of
the metric is assumed to describe the causal structure for the matter. An
other metric defines the causal structure for the gravitational interactio
ns. A crucial point is that the spatial part of the metric describing grav
ity is given by the spatial part of the matter metric conformally rescaled
by a time-dependent factor α which\, as it turns out\, can be linked to
the effective gravitational constant and the effective speed of light. In
the context of such a bimetric framework we examine the strength of some s
ingular cosmological scenarios in the sense of the criteria introduced by
Tipler and Królak. In particular\, we show that for the nonsingular scale
factor associated with the matter metric\, both the vanishing or blowing
up of the factor α for some particular moment of the cosmic expansion may
lead to a strong singularity with infinite value of the energy density an
d infinite value of the pressure.\nhttps://indico.cern.ch/event/773241/con
tributions/3557135/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3557135/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gravitational Waves Observations by LIGO and Virgo
DTSTART;VALUE=DATE-TIME:20190926T070000Z
DTEND;VALUE=DATE-TIME:20190926T074500Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3561574@indico.cern.ch
DESCRIPTION:Speakers: Vivien Raymond (Cardiff University)\nOn September 14
th\, 2015 the LIGO-Virgo collaboration made the first direct detection of
gravitational waves\, nearly one hundred years after Einstein first predic
ted them. Since\, several gravitational waves have been detected\, and we
have been able to study new black holes and analyse the collision of two n
eutron stars. Now the Advanced LIGO and Advanced Virgo observatories are o
n their third science run. Many more gravitational-wave candidates have be
en announced since its start in April 2019.\nIn this talk\, I will review
the detections and their physical and astrophysical implications as of the
end of the second science run\, and I'll give and update on the progress
of current observations.\nhttps://indico.cern.ch/event/773241/contribution
s/3561574/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3561574/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Searching for non-Riemannian signatures in cosmological data
DTSTART;VALUE=DATE-TIME:20190926T120000Z
DTEND;VALUE=DATE-TIME:20190926T123000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3565228@indico.cern.ch
DESCRIPTION:Speakers: Krzysztof Bolejko (University of Tasmania)\nThe Eins
tein's theory of gravity\, General Relativity was build on the theory of S
pecial Relativity. This generalisation required utilising the full general
ity of the Riemannian geometry. Many of the present-day cosmological tests
of GR are still based on the assumption of the Riemannian geometry. Howev
er\, in order to fully study and test various extensions of GR one is also
required to move beyond the Riemannian geometry. In my talk I will focuse
s on light propagation and discuss what signatures in cosmological observa
tional data could point to non-Riemannian effects. This talk will not be a
comprehensive review of the issue - it will only focus on the distance an
d redshift relations. I will discuss observational constraints and talk ho
w future surveys could provide a better insight into the underlying geomet
ry of our Universe.\nhttps://indico.cern.ch/event/773241/contributions/356
5228/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3565228/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Breaking the Vainshtein Screening in Clusters of Galaxies
DTSTART;VALUE=DATE-TIME:20190925T130000Z
DTEND;VALUE=DATE-TIME:20190925T132000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3568914@indico.cern.ch
DESCRIPTION:Speakers: Vincenzo Salzano (University of Szczecin)\nAfter a (
necessarily) short introduction about why and how General Relativity\, ass
umed as the established consensus gravity theory\, should be modified/exte
nded\, we will discuss the constraints we obtained for a particular class
of Extended Theory of Gravity (technically defined as “Beyond Horndeski
” and “Vainshtein-breaking” theory)\, using data from clusters of ga
laxies\, both from X-ray observations and from gravitational lensing event
s.\nhttps://indico.cern.ch/event/773241/contributions/3568914/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3568914/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gravitational wave Memory Effect
DTSTART;VALUE=DATE-TIME:20190925T092000Z
DTEND;VALUE=DATE-TIME:20190925T094000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3574055@indico.cern.ch
DESCRIPTION:Speakers: Syed Naqvi (Astronomical Observatory\,Jagiellonian U
niversity)\nGravitational waves offer a unique window to study the strong-
field regime of general relativity. In 1916-18\, Einstein showed their exi
stence in linearized approximation which was followed by a period of confu
sion. Finally cemented theoretically by Bondi\, Sachs\, Trautman gravitati
onal waves are an important tool to discover new information about fundame
ntal gravity effects.\n\nOne of the persistent gravitational wave effect c
alled memory effect forms an interesting proposition theoretically and ast
rophysically. It is essentially a permanent displacement between particles
after GW passes. It's linear and non-linear form will be important for th
e future GW detections from compact binary sources. This effect gives info
rmation about the asymptotic nature of spacetime and is relevant for a lar
ge number of detections by LIGO/VIRGO. The linear part discovered by Zel'd
ovich & Polnarev and the nonlinear part discovered by Christodoulou help u
s understand the nature of spacetime and explore further the nonlinear par
t of general relativity.\n\nWe plan to study the linear memory effect for
different wave profiles under the exact plane wave solution of Einstein's
vacuum equations and then look for other solutions. The displacement and v
elocity memory effects are studied by analyzing the geodesic equation for
test masses under exact plane wave spacetime. The aim is to look for diffe
rent gravitational spacetimes and study the memory effect within them.\nht
tps://indico.cern.ch/event/773241/contributions/3574055/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3574055/
END:VEVENT
BEGIN:VEVENT
SUMMARY:New insight into the Taub-NUT space-time
DTSTART;VALUE=DATE-TIME:20190925T140000Z
DTEND;VALUE=DATE-TIME:20190925T142000Z
DTSTAMP;VALUE=DATE-TIME:20210803T102200Z
UID:indico-contribution-3537275@indico.cern.ch
DESCRIPTION:Speakers: Remigiusz Durka (Univesrity of Wrocław)\nThe Taub-N
UT metric represents quite intriguing space-time configuration supposedly
possessing gravitational analog of the magnetic monopole. We will deal wit
h the new approach to this subject. Starting from realizing that the sourc
e of many inconsistencies lies in neglecting the effects of the wire singu
larities present in that solution\, we are able to explain the existence o
f the NUT parameter by the means of quite peculiar rotation. Among many th
ings\, this leads to the consistent description of the black hole thermody
namics for the Lorentzian Taub-NUT space-time with the essential contribut
ion to the angular momentum and the total entropy.\nhttps://indico.cern.ch
/event/773241/contributions/3537275/
LOCATION:Other Institutes
URL:https://indico.cern.ch/event/773241/contributions/3537275/
END:VEVENT
END:VCALENDAR