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VERSION:2.0
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BEGIN:VEVENT
SUMMARY:Gravitational Wave Astronomy -- Avant le De'luge
DTSTART;VALUE=DATE-TIME:20220919T070000Z
DTEND;VALUE=DATE-TIME:20220919T080000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-874@events.ncbj.gov.pl
DESCRIPTION:Speakers: Keith Riles ( University of Michigan )\nThe era of g
ravitational-wave (GW) astronomy is now well under way\, with nearly 100 c
ompact binary coalescences (CBCs) confidently detected in the first three
observing runs of LIGO and Virgo. With the fourth observing run of LIGO\,
Virgo and KAGRA starting in early 2023\, it is timely to review what has b
een learned so far\, both from the CBC events and from the absence of othe
r types of GW detections\, including continuous and stochastic radiation.
Prospects for making such new discoveries soon will be discussed\, along w
ith the potential insights to be gained from the deluge of CBC events expe
cted in the coming years and decades.\n\nhttps://events.ncbj.gov.pl/event/
152/contributions/874/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/874/
END:VEVENT
BEGIN:VEVENT
SUMMARY:CANCELLED Compactification of the phase space in the scalar field
cosmology with non-minimal coupling
DTSTART;VALUE=DATE-TIME:20220923T125000Z
DTEND;VALUE=DATE-TIME:20220923T131000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-941@events.ncbj.gov.pl
DESCRIPTION:Speakers: Franciszek Humieja ( Jagiellonian University )\nWe i
nvestigate the FLRW cosmological model with a non-minimally coupled scalar
field generalized according to the methods given by the nonlinear field s
pace theory. In this approach\, one generalizes the phase space of a given
field to a topological space (such as symplectic manifold). We consider t
he compactification of the phase space to a spherical case\, corresponding
to a spin system\, and analyze the evolutionary scenarios of such a model
of the universe. Introduction of the non-minimal coupling in the model pr
ovides interesting outcome in the dynamics of the late time acceleration.\
n\nhttps://events.ncbj.gov.pl/event/152/contributions/941/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/941/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Low scale inflation without (much of) fine-tuning
DTSTART;VALUE=DATE-TIME:20220923T091000Z
DTEND;VALUE=DATE-TIME:20220923T094000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-939@events.ncbj.gov.pl
DESCRIPTION:Speakers: Michał Artymowski (UKSW)\nIn my talk\, I will argue
that the GUT scale is the most natural scale for inflation. I will show w
hy we may actually need to go much lower and why this may cause massive fi
ne-tuning. Finally\, I will present a possible solution - warm inflation w
ith (almost) arbitrarily low energy scale.\n\nhttps://events.ncbj.gov.pl/e
vent/152/contributions/939/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/939/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Opening remarks
DTSTART;VALUE=DATE-TIME:20220919T065000Z
DTEND;VALUE=DATE-TIME:20220919T070000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-951@events.ncbj.gov.pl
DESCRIPTION:https://events.ncbj.gov.pl/event/152/contributions/951/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/951/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Jet structure and variability studies of GRBs with 3D GRMHD simula
tions of magnetically arrested disks
DTSTART;VALUE=DATE-TIME:20220920T145000Z
DTEND;VALUE=DATE-TIME:20220920T151000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-898@events.ncbj.gov.pl
DESCRIPTION:Speakers: Bestin James ( Center for Theoretical Physics PAS )\
nWe study the structure and temporal variabilty properties of the GRB jets
considering a magnetically arrested disk as their central engine. We nume
rically evolve the accretion disk around a Kerr black hole using 3D genera
l relativistic magnetohydrodynamic simulations. We consider two analytical
equillibrium disk configurations\, the Fishbone-Moncrief and Chakrabarti
solutions\, as the initial conditions and impose poloidal magnetic fields
upon them. The disk starts accreting due to the development of the magneto
rotational instability and eventually develops to a magnetically arrested
accretion disk state. We consider these models as central engines of short
and long-GRBs\, based on our initial conditions\, and investigate the pro
perties of the jets launched from these models. Our models self-consistent
ly produce structured jets with a hollow core up to ~ 5 degrees. The jets
from our simulations have an opening angle up to ~ 11 degrees for the long
-GRB model and up to ~ 25 degrees for the short-GRB model. We also do the
time variabilty studies of the jets and provide an estimate of their minim
um variabilty timescales. Our models can be applied to the GRB jets in the
binary neutron star post-merger system or to the ultra-relativistic jets
launched from collapsing stars.\n\nhttps://events.ncbj.gov.pl/event/152/co
ntributions/898/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/898/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Optical distance measures in general relativity
DTSTART;VALUE=DATE-TIME:20220920T140000Z
DTEND;VALUE=DATE-TIME:20220920T143000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-896@events.ncbj.gov.pl
DESCRIPTION:Speakers: Mikołaj Korzyński ( CFT PAN )\nI will discuss
the relation between the angular diameter distance and parallax distance i
n general relativity. This relation involves the curvature tensor along th
e line of sight and the difference between distance measures can be used t
o measure the matter content along the line of sight. Moreover\, it is als
o possible to prove that the parallax distance must be not smaller than th
e angular diameter distance if the null energy condition holds. I will dis
cuss possible astrophysical and cosmological application of these results.
\n\nhttps://events.ncbj.gov.pl/event/152/contributions/896/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/896/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stiffness\, complexity\, cracking and stability of relativistic co
mpacts stars
DTSTART;VALUE=DATE-TIME:20220920T131000Z
DTEND;VALUE=DATE-TIME:20220920T133000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-895@events.ncbj.gov.pl
DESCRIPTION:Speakers: Ranjan Sharma ( Cooch Behar Panchanan Barma Universi
ty )\nCurrent multi-messenger approach has made it possible to get a much
more precise estimation of stellar observables like mass $M$ and radius $R
$ of a neutron star which consequently can help us constrain the neutron s
tar equation of state (EOS) like never before. Theoretical stellar models
are being refined accordingly. Using Chandrasekhar's variational method\,
we examine the dynamical stability of a recently proposed modified Tolman
VII solution that can accommodate a more realistic neutron star EOS consis
tent with observational data. We note that the critical value of compactne
ss ($M/R$) at which instability develops within the configuration decrease
s with the stiffness increase of the assumed EOS. The critical bound remai
ns below the Buchdahl bound throughout. We further invoke the concepts of
'cracking' and 'complexity' in the stability analysis of an anisotropic st
ellar configuration. We show that for a static\, spherically symmetric\, a
nisotropic distribution of matter with radially decreasing energy density
possessing zero 'complexity'\, the tangential pressure must be greater tha
n the radial pressure at all interior points of a potentially stable stell
ar configuration.\n\nhttps://events.ncbj.gov.pl/event/152/contributions/89
5/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/895/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Recovery schemes in numerical GR MHD simulation of the post-merger
system with a composition-dependent equation of state
DTSTART;VALUE=DATE-TIME:20220920T120000Z
DTEND;VALUE=DATE-TIME:20220920T123000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-890@events.ncbj.gov.pl
DESCRIPTION:Speakers: Agnieszka Janiuk ( Center for Theoretical Physics PA
S )\nThe code HARM_COOL\, a conservative scheme for relativistic magnetohy
drodynamics\, is being developed in our group and works with a tabulated e
quation of state of dense matter. This EOS can be chosen and used during d
ynamical simulation\, instead of the simple ideal gas one. In this case\,
the inversion scheme between the conserved and primitive variables is not
a trivial task. In principle\, the code needs to solve numerically five co
upled non-linear equations at every time-step. The 5-D recovery schemes we
re originally implemented in HARM and worked accurately for a simple polyt
ropic EOS which has an analytic form. Our current simulations support the
composition-dependent EOS\, formulated in terms of rest-mass density\, tem
perature and electron fraction. I will discuss and compare several recover
y schemes that have been included in our code. I will present and discuss
their convergence tests. I will also show some preliminary results of a nu
merical simulation\, addressed to the post-merger system formed after the
coalescence of binary neutron stars.\n\nhttps://events.ncbj.gov.pl/event/1
52/contributions/890/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/890/
END:VEVENT
BEGIN:VEVENT
SUMMARY:A new generic and structurally stable cosmological model without s
ingularity
DTSTART;VALUE=DATE-TIME:20220919T145000Z
DTEND;VALUE=DATE-TIME:20220919T151000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-887@events.ncbj.gov.pl
DESCRIPTION:Speakers: Orest Hrycyna (NCBJ)\nDynamical systems methods are
used to investigate a cosmological model with non-minimally coupled scalar
field and asymptotically quadratic potential function. We found that for
values of the non-minimal coupling constant parameter $\\frac{3}{16}\n\nht
tps://events.ncbj.gov.pl/event/152/contributions/887/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/887/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Newtonian regime and topology: consequence for the role of spatial
curvature in cosmology
DTSTART;VALUE=DATE-TIME:20220919T143000Z
DTEND;VALUE=DATE-TIME:20220919T145000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-886@events.ncbj.gov.pl
DESCRIPTION:Speakers: Quentin Vigneron ( Copernicus University\, Torun )\n
The standard model of cosmology currently allows for three types of geomet
ries (or topologies) for our Universe (Euclidean\, spherical or hyperbolic
)\, each of these types corresponding to a set of different (multiconnecte
d)-topologies. Among these geometries\, Newton’s theory of gravity is on
ly defined on the Euclidean one. Still\, extending the validity of this th
eory to the other two cases (called a non-Euclidean Newtonian theory)\, wi
th the aim that this should constitute the limit of a relativistic theory
of gravity\, could provide a strong theoretical tool to probe large scale
effects of global topology. We will see that Einstein's equation is actual
ly incompatible with such a theory. Therefore this equation must be modifi
ed in the hypothesis where we require the relativistic theory describing o
ur Universe to be compatible with the presence of a Newtonian regime in an
y topology. I will present such a modification which is based on Rosen's b
i-metric theory. Its main consequence is that the expansion law of a homog
eneous and isotropic solution no longer features the spatial curvature (i.
e. $\\Omega = 1\, \\ \\forall \\Omega_k$)\, asking for a reevaluation of t
hat curvature from cosmological data.\n\nhttps://events.ncbj.gov.pl/event/
152/contributions/886/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/886/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Effective banks of templates in detection of almost monochromatic
gravitational waves
DTSTART;VALUE=DATE-TIME:20220919T120000Z
DTEND;VALUE=DATE-TIME:20220919T122000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-880@events.ncbj.gov.pl
DESCRIPTION:Speakers: Andrzej Pisarski ( University of Bialystok )\nProble
m of finding effective banks of templates is very important in match filte
ring method used in detection of almost monochromatic gravitational waves
coming from single rotating neutron stars located in our Galaxy. Construct
ion of effective banks of templates requires finding optimal grid covering
s in the space spanned by unknown parameters of the gravitational-wave sig
nal we are looking for. Such coverings can be generated by the software ''
Grids Generator'' devised by me. In my talk\, I will show some results pro
duced by this software and explain in more detail one of the algorithms us
ed to generate effective grid coverings.\n\nhttps://events.ncbj.gov.pl/eve
nt/152/contributions/880/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/880/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gravitational waves on Riemann-Cartan geometries
DTSTART;VALUE=DATE-TIME:20220919T095000Z
DTEND;VALUE=DATE-TIME:20220919T101000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-878@events.ncbj.gov.pl
DESCRIPTION:Speakers: Fernando Izaurieta ( Department of Physics\, Unive
rsity of Concepcion )\nWe offer a mathematical toolkit for the study of wa
ves propagating on a background manifold with nonvanishing torsion. As an
example\, we briefly analyze the amplitude propagation of gravitational wa
ves in an Einstein-Cartan-Sciamma-Kibble (ECSK) assuming a dark matter spi
n tensor sourcing for spacetime torsion at cosmological scales and assess
whether a future detection by LISA is possible.\n\nhttps://events.ncbj.gov
.pl/event/152/contributions/878/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/878/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Searching for gravitational-wave emission due to r-modes from the
pulsar PSR J0537–6910 in LIGO O3 data.
DTSTART;VALUE=DATE-TIME:20220919T093000Z
DTEND;VALUE=DATE-TIME:20220919T095000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-877@events.ncbj.gov.pl
DESCRIPTION:Speakers: Orest Dorosh (NCBJ)\nI shall present results of the
search for gravitational wave emission due to r-modes for the pulsar PSR J
0537-6910 using data from the LIGO and Virgo ground based detectors in the
O3 observing run. PSR J0537-6910 is a young X-ray pulsar and is currently
the most frequent glitcher known. Its inter-glitch braking index suggests
that gravitational wave emission due to r-modes may play an important rol
e in the spindown of this pulsar. The times of the glitches during the O3
run were known from the timing ephemeris obtained from the NICER mission d
ata. We searched for gravitational wave signals due to r-modes in the epoc
hs between glitches. We do not detect any signals in the theoretically all
owed band of 86-97 Hz\, and report upper limits on the amplitude of the gr
avitational waves. Our upper limits place stringent constraints on theoret
ical models for r-mode driven spin-down in PSR J0537−6910.\n\nhttps://ev
ents.ncbj.gov.pl/event/152/contributions/877/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/877/
END:VEVENT
BEGIN:VEVENT
SUMMARY:BLACK HOLES BINARIES FROM GLOBULAR CLUSTERS as sources of gravitat
ional waves
DTSTART;VALUE=DATE-TIME:20220919T090000Z
DTEND;VALUE=DATE-TIME:20220919T093000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-876@events.ncbj.gov.pl
DESCRIPTION:Speakers: Dorota Rosinska ( OA\, University of Warsaw )\nWe an
alyze about a thousand globular cluster (GC) models simulated using the MO
CCA Monte Carlo code for star cluster evolution to study black hole - blac
k hole interactions in these dense stellar sys- tems that can lead to grav
itational wave emission. We extracted information for all coalescing binar
y black holes (BBHs) that merge via gravitational ra- diation from these G
C models and for those BHs that collide due to 2-body\, 3-body and 4-body
dy- namical interactions. By obtaining results from a substantial number o
f realistic star clusters evolu- tion models\, that cover different initia
l parameters (masses\, metallicities\, densities etc) we have an ex- treme
ly large statistical sample of two black holes which merge or collide with
in a Hubble time. We found that creation of an Intermediate Mass Black Hol
e (IMBH\, defined as a BH with mass above 100 M ) in a GC’s center has l
arge influence on merger and collision rates.\n\nhttps://events.ncbj.gov.p
l/event/152/contributions/876/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/876/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matter bounce and dynamical aspects in nonmetricity gravity
DTSTART;VALUE=DATE-TIME:20220919T131000Z
DTEND;VALUE=DATE-TIME:20220919T134000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-888@events.ncbj.gov.pl
DESCRIPTION:Speakers: Bivudutta Mishra (BITS-Pilani\, Hyderabad Campus)\nI
n the context of the late time cosmic acceleration phenomenon\, many geome
trically modified theories of gravity have been proposed in recent times.
In this paper\, we have investigated the role of a recently proposed exten
sion of symmetric teleparallel gravity dubbed as $f(Q\,T)$ gravity in gett
ing viable cosmological models\, where $Q$ and $T$ respectively denote the
non-metricity and the trace of energy momentum tensor. We stress upon the
mathematical simplification of the formalism in the $f(Q\,T)$ gravity and
derived the dynamical parameters in more general form in terms of the Hub
ble parameter. We considered two different cosmological models mimicking n
on-singular matter bounce scenario. Since energy conditions play a vital r
ole in providing bouncing scenario\, we have analyzed different possible e
nergy conditions to show that strong energy condition and null energy cond
ition be violated in this theory. The models considered in the work are va
lidated through certain cosmographic tests and stability analysis.\n\nhttp
s://events.ncbj.gov.pl/event/152/contributions/888/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/888/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Electromagnetic and Gravitational Hopfion-like solutions in de Sit
ter spacetime
DTSTART;VALUE=DATE-TIME:20220922T072000Z
DTEND;VALUE=DATE-TIME:20220922T074000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-919@events.ncbj.gov.pl
DESCRIPTION:Speakers: Tomasz Smółka (University of Warsaw/AEI Max Planck
)\nHopfions are a family of `solitonary’ field solutions which have non-
trivial topological structure associated with Hopf fibration. I will prese
nt a generalisation of such solutions\, based on conformal transformations
\, to de Sitter spacetime. Two physical applications of Hopfion-like solut
ions: electromagnetism and linear gravitation will be discussed.\n\nhttps:
//events.ncbj.gov.pl/event/152/contributions/919/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/919/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Examining Quasinormal Mode Instability with the Pseudospectrum
DTSTART;VALUE=DATE-TIME:20220922T070000Z
DTEND;VALUE=DATE-TIME:20220922T072000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-918@events.ncbj.gov.pl
DESCRIPTION:Speakers: Brad Cownden (Jagiellonian University)\nQuasinormal
modes (QNMs) are the exponentially damped\, oscillatory solutions to linea
rized wave equations that appear in a variety of physical contexts. Most n
otably\, the gravitational waves emitted during the ringdown phase of the
merger of two compact objects\, such as neutron stars or black holes\, are
characterized by QNMs. The frequencies of the QNMs encode information abo
ut the relic object such as mass and spin\, and -- in the most energetic c
ases -- are sensitive to higher-curvature corrections to general relativit
y. The stability of a QNM depends on how its frequency changes in response
to perturbations\; the pseudospectrum allows us to examine the stability
of all the QNMs to a specific perturbation of the background. In this talk
\, I will review how the pseudospectrum is used to examine the stability o
f the QNMs of Schwarzschild and Kerr black holes. I will then discuss how
these methods can be applied to the stability of QNMs for classical solito
n solutions.\n\nhttps://events.ncbj.gov.pl/event/152/contributions/918/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/918/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quantum dynamics of relativistic systems
DTSTART;VALUE=DATE-TIME:20220922T130000Z
DTEND;VALUE=DATE-TIME:20220922T132000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-925@events.ncbj.gov.pl
DESCRIPTION:Speakers: Przemysław Małkiewicz (NCBJ)\nThe appearance of Ha
miltonian constraint in the canonical formalism for general relativity ref
lects the lack of any preferred notion of time. The dynamics of general re
lativistic systems can be equivalently expressed with respect to various i
nternal degrees of freedom. However\, quantization of general relativistic
systems breaks down the diffeomorphism invariance and different time vari
ables generally yield inequivalent quantum dynamics. We investigate the se
nse in which these inequivalent quantum dynamics could be reconciled. Our
result is illustrated with the dynamics of gravitational waves in a quanti
sed universe.\n\nhttps://events.ncbj.gov.pl/event/152/contributions/925/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/925/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The most massive galaxy clusters
DTSTART;VALUE=DATE-TIME:20220919T141000Z
DTEND;VALUE=DATE-TIME:20220919T143000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-885@events.ncbj.gov.pl
DESCRIPTION:Speakers: Jan Ostrowski (NCBJ)\nExtreme bound objects are impo
rtant probes of the large-scale Universe. The abundance and certain parame
ters of the most massive (super-) clusters of galaxies put constraints on
the cosmological parameters and the background evolution. In my talk I wil
l present two approaches\, one [1] based on the exact solution to Einstein
's equations and a complementary one [2]\, based on the relativistic\, La
grangian perturbation theory. Both allow to derive an observationally-veri
fiable predictions regarding the biggest\, gravitationally bounded struct
ures. Comparison with observations will be summarized and put into perspec
tive.\n \nReferences\n[1] Bolejko K.\, Ostrowski J. J.\, The environm
ent-dependence of the growth of the most massive objects in the Universe\,
Phys. Rev. D 99\, 124036 (2019) [arXiv:1805.11047]\n[2] Ostrowski J.J.\,
Delgado Gaspar I.\, On the maximum volume of collapsing structures\, JCAP\
, 4\, 59 (2022) [arXiv:2112.05245]\n\nhttps://events.ncbj.gov.pl/event/152
/contributions/885/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/885/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Rip Cosmological Models in Extended Symmetric Teleparallel Gravity
.
DTSTART;VALUE=DATE-TIME:20220923T140000Z
DTEND;VALUE=DATE-TIME:20220923T142000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-943@events.ncbj.gov.pl
DESCRIPTION:Speakers: Laxmipriya Pati ( BITS-Pilani\, Hyderabad Campus )\n
In this work\, we have investigated some rip cosmological models in an ext
ended symmetric teleparallel gravity theory. We consider the form f (Q\, T
) = aQ^m+bT in the Einstein–Hilbert action and expressed the field equa
tions and the dynamical parameters in terms of the non-metricity Q. Three
rip models such as Little Rip\, Big Rip\, and Pseudo Rip are presented als
o the energy conditions and the cosmographic parameters are derived and an
alyzed for all these models.\n\nhttps://events.ncbj.gov.pl/event/152/contr
ibutions/943/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/943/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Scalar-tensor cosmology in a minisuperspace formulation with Chapl
ygin Gas
DTSTART;VALUE=DATE-TIME:20220923T134000Z
DTEND;VALUE=DATE-TIME:20220923T140000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-942@events.ncbj.gov.pl
DESCRIPTION:Speakers: Marcin Postolak ( University of Wrocław )\nScalar t
ensor theories (STT) of gravity are one of the most fundamental types of m
odified theories of gravity. By introducing a non-minimally coupled dynami
cal scalar field\, they make it possible to describe gravitational interac
tion to the extent that the purely tensor general theory of relativity fai
ls\, or does not give sufficiently accurate predictions. One of the ideas
strongly developed in recent years regarding the attempt to describe the d
ark sector of the universe is the so-called dark fluid. In its concept\, i
t aims to unify in one physical phenomenon the influence of dark energy an
d dark matter on the evolution of the universe. One example of such a flui
d is the family of models of the so-called Chaplygin gas (CG) [1]\, which
is characterized by a specific equation of state: p(ρ) = − A /ρ^α. By
considering particular CG models as sources of matter in the Universe\, s
pecific FLRW cosmological models in the minisuperspace (MSS) formalism can
be obtained\, which can be presented in specific conformal frames\, such
as the best known Einstein and Jordan frame. Classical mechanical systems
in cosmology in the MSS formulation are proved to be extremely effective i
n studying ST cosmological models [2]. During the talk I will present an a
nalysis on the conservation laws of the energy-momentum tensor in the case
of minimal and non-minimal coupling for metric and metric-hybrid STT\, as
well as a numerical analysis to verify whether the obtained cosmological
models can be an extension of the Λ-CDM model. References [1] M. C. Bento
\, O. Bertolami\, and A. A. Sen\, Generalized Chaplygin gas\, acceler- ate
d expansion\, and dark-energy-matter unification\, Phys. Rev. D 66\, 04350
7 (2002). [2] A. Borowiec\, A. Kozak\, Scalar-tensor cosmologies in a mini
superspace formu- lation: A case study\, Phys. Rev. D 105\, 4 (2022).\n\nh
ttps://events.ncbj.gov.pl/event/152/contributions/942/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/942/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Metric-affine gravity effects on terrestrial (exo)planets' profile
s
DTSTART;VALUE=DATE-TIME:20220923T123000Z
DTEND;VALUE=DATE-TIME:20220923T125000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-940@events.ncbj.gov.pl
DESCRIPTION:Speakers: Aleksander Kozak ( University of Wrocław )\nExtende
d gravity theories modify gravitational phenomena at various scales\, rang
ing from cosmological to the scale of our Solar System. Given the multitud
e of possible modifications\, it is essential to test the models at differ
ent energy regimes. Gravity is well-tested here on Earth\; any deviations
from general relativity (GR) should be miniscule\, which imposes some limi
tations on possible extensions. As it turns out\, modified gravity has an
influence on the internal structure of spherically-symmetric bodies\, such
as (exo)planets. In principle\, it should be possible to constrain altern
atives to GR using\, for example\, seismicvdata\, informing us of the size
and composition of layers inside the Earth. In my talk\, I will present t
he way alternative gravity can modify the structure of planets composed of
one and two layers\, obtaining mass-radius relations of homogeneous and d
ifferentiated cold spheres. An additional degeneracy in the (exo)planets'
profiles will be discussed together with their properties concluded from o
ur findings in the framework of Palatini f(R) gravity. Possible generaliza
tions will also be discussed.\n\nhttps://events.ncbj.gov.pl/event/152/cont
ributions/940/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/940/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Challenging ΛCDM with scalar-tensor f(R\,T) gravity and thermodyn
amics of irreversible matter creation
DTSTART;VALUE=DATE-TIME:20220923T121000Z
DTEND;VALUE=DATE-TIME:20220923T123000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-938@events.ncbj.gov.pl
DESCRIPTION:Speakers: Miguel Pinto ( Institute of Astrophysics and Space S
ciences - University of Lisbon )\nWe investigate the possibility of gravit
ationally generated particle production via the mechanism of non-minimal c
urvature-matter coupling. An intriguing feature of this theory is that the
divergence of the matter energy-momentum tensor does not vanish identical
ly. We explore the physical and cosmological implications of the non-conse
rvation of the energy-momentum tensor by using the formalism of irreversib
le thermodynamics of open systems in the presence of matter creation/annih
ilation. The particle creation rates\, pressure\, temperature evolution an
d the expression of the comoving entropy are obtained in a covariant formu
lation and discussed in detail. Applied together with the gravitational fi
eld equations\, the thermodynamics of open systems lead to a generalizatio
n of the standard ΛCDM cosmological paradigm\, in which the particle crea
tion rates and pressures are effectively considered as components of the c
osmological fluid energy-momentum tensor. We also consider specific models
\, and we compare the cosmology with a curvature-matter coupling with the
ΛCDM scenario\, and if it additionally gives rise to particle creation ra
tes\, creation pressures\, and entropy generation through gravitational ma
tter production in both low and high redshift limits.\n\nhttps://events.nc
bj.gov.pl/event/152/contributions/938/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/938/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cosmological perturbations beyond the linear order
DTSTART;VALUE=DATE-TIME:20220923T102000Z
DTEND;VALUE=DATE-TIME:20220923T104000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-936@events.ncbj.gov.pl
DESCRIPTION:Speakers: Szymon Sikora ( Jagiellonian University )\nIn this t
alk I will present the specific solution to the second-order cosmological
perturbation theory. For the background I will consider any Friedmann-Lema
itre-Robertson-Walker model filled with a dust\, and a positive cosmologic
al constant. The presented model is a generalization of the previous resul
ts obtained with Krzysztof Głód where the background was the Einstein-de
Sitter spacetime. Here\, I investigate the case of the spatially non-flat
background and a positive cosmological constant.\n\nhttps://events.ncbj.g
ov.pl/event/152/contributions/936/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/936/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Structure forming plane symmetric dust inhomogeneous cosmological
model
DTSTART;VALUE=DATE-TIME:20220923T100000Z
DTEND;VALUE=DATE-TIME:20220923T102000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-935@events.ncbj.gov.pl
DESCRIPTION:Speakers: Krzysztof Głód ( Jagiellonian University )\nWe pre
sent a special case of the plane symmetric model from the G_3/S_2-symmetri
c space-times solving the Einstein equations for a dust source which exhib
its a controlled form of the growth of the matter density inhomogeneities.
\n\nhttps://events.ncbj.gov.pl/event/152/contributions/935/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/935/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gauge-fixing and spacetime reconstruction in the Hamiltonian theor
y of cosmological perturbations
DTSTART;VALUE=DATE-TIME:20220923T094000Z
DTEND;VALUE=DATE-TIME:20220923T100000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-934@events.ncbj.gov.pl
DESCRIPTION:Speakers: Alice Boldrin (NCBJ)\nWe will present a general form
alism for the Hamiltonian description of any spatially homogeneous spaceti
me in perturbation theory. We will employ and refine the Dirac method for
constrained systems\, which is very well-suited to cosmological perturbati
ons. This approach includes a discussion of the gauge-invariant dynamics o
f perturbations as well as an analysis of gauge transformations\, gauge-fi
xing\, partial gauge-fixing and spacetime reconstruction. We will introduc
e the Kuchař parametrization of the kinematical phase space as a convenie
nt tool for studying the gauge transformations. The key element of this ap
proach is the reconstruction of spacetime based on gauge-fixing conditions
. Some examples for selected gauges will be presented.\n\nhttps://events.n
cbj.gov.pl/event/152/contributions/934/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/934/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The relativistic galaxy bispectrum
DTSTART;VALUE=DATE-TIME:20220923T081000Z
DTEND;VALUE=DATE-TIME:20220923T091000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-932@events.ncbj.gov.pl
DESCRIPTION:Speakers: Chris Clarkson ( University of London )\nThe galaxy
bispectrum will play an important role for future galaxy surveys. On large
scales it will be a key probe for measuring primordial non-Gaussianity\,
and hence help discriminate between different inflationary models and othe
r theories of the early universe. On these scales\, a variety of relativis
tic effects come into play once the galaxy number-count fluctuation is pro
jected onto the past light cone. The Fourier-space galaxy bispectrum is co
mplex\, with the imaginary part arising from leading-order relativistic co
rrections. Detection of the imaginary part is potentially a smoking gun si
gnal of relativistic contributions. We will discuss whether next-generatio
n surveys could make such a detection. Further\, We will discuss the decom
position of the bispectrum into invariant multipoles about the observer’
s line of sight\, and examine in detail how the relativistic effects contr
ibute to these.\n\nhttps://events.ncbj.gov.pl/event/152/contributions/932/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/932/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quantum simulations of loop quantum gravity
DTSTART;VALUE=DATE-TIME:20220923T072000Z
DTEND;VALUE=DATE-TIME:20220923T074000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-931@events.ncbj.gov.pl
DESCRIPTION:Speakers: Grzegorz Czelusta ( Jagiellonian University )\nOne o
f the possible applications of quantum computers in the near future are si
mulations of physics. An example are quantum gravitational systems associa
ted with the Planck scale physics. Such systems are expected to be of the
many-body type\, which justifies utility of quantum computations in the an
alysis of their complex quantum behaviour. In this talk\, simulation of lo
op quantum gravity on quantum computer are considered. A construction of q
uantum circuits which generate states of spin networks will be presented.
Furthermore\, a quantum algorithms which enable projection of states on ph
ysical subspace of Hilbert space and determination of amplitudes of transi
tions between different states of spin network are proposed. Results of im
plementation of the approach on IBM superconducting quantum computers will
be presented. Obtained results provide building blocks for quantum simula
tions of complex spin networks\, which can give insight into the Planck sc
ale physics in the near future.\n\nhttps://events.ncbj.gov.pl/event/152/co
ntributions/931/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/931/
END:VEVENT
BEGIN:VEVENT
SUMMARY:κ-deformed complex fields\, (discrete) symmetries\, and charges
DTSTART;VALUE=DATE-TIME:20220923T070000Z
DTEND;VALUE=DATE-TIME:20220923T072000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-930@events.ncbj.gov.pl
DESCRIPTION:Speakers: Andrea Bevilacqua (NCBJ)\nIt is commonly expected th
at the usual description of spacetime as a smooth manifold is no longer re
liable as we approach the Planck scale when quantum effects of the geometr
y can no longer be neglected. Noncommutativity of spacetime has been advoc
ated as a possible way to effectively model quantum gravitational effects
in regimes of negligible curvature. A widely studied incarnation of this i
dea suggests that the scale of noncommutativity should be seen as an obser
ver-independent length scale and that\, in order to accommodate such a fun
damental scale\, ordinary relativistic symmetries should be deformed (keep
ing in mind that they should reproduce the usual Poincaré algebra in the
limit of vanishing noncommutativity). The κ-Poincaré algebra is an examp
le of such deformation. In this talk I will briefly describe a constructio
n of a κ-deformed complex scalar field theory\, while at the same time sh
edding light on the behaviour of discrete and continuous symmetries in thi
s formalism. This in turn will open the way to the study of the applicatio
n of this formalism to actual physical processes. I will then conclude wit
h some comments and prospects for the future.\n\nhttps://events.ncbj.gov.p
l/event/152/contributions/930/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/930/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Ascribing quantum system to Schwarzschild spacetime
DTSTART;VALUE=DATE-TIME:20220922T124000Z
DTEND;VALUE=DATE-TIME:20220922T130000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-929@events.ncbj.gov.pl
DESCRIPTION:Speakers: Aleksandra Pędrak (NCBJ)\nI will present the quanti
zation the Schwarzschild black hole using the affine coherent states quant
ization method. The novelty of the approach is quantization of both tempor
al and spatial coordinates. Quantization smears the gravitational singular
ity indicated by the Kretschmann invariant avoiding its localization in th
e configuration space. This way we resolve\, to some extent\, the singular
ity problem of considered black hole. The approach relies on using only th
e metric tensor so that it can be applied to other black holes with the me
trics satisfying Einstein's equation.\n\nhttps://events.ncbj.gov.pl/event/
152/contributions/929/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/929/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Integral quantization and quantum time
DTSTART;VALUE=DATE-TIME:20220922T122000Z
DTEND;VALUE=DATE-TIME:20220922T124000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-928@events.ncbj.gov.pl
DESCRIPTION:Speakers: Andrzej Góźdź ( Institute of Physics UMCS )\nQuan
tization of classical models is a non-unique and heuristic procedure. A se
t of different\, in fact non-equivalent approaches is known. In the talk s
ome principles of the integral quantization method is presented. The simpl
est integral quantization procedure is based on decomposition of unity in
the Hilbert state space. More sophisticated way of thinking in this direct
ion is related to the so called Quantum Motion Algebras. One of the unique
property of the integral quantization is a possibility to treat physical
time on the same footing as the space coordinates. This allows for constru
ction of the covariant quantum spacetime position observable. In this case
\, instead of the unitary time evolution\, other operators\, usually proje
ction or POVM operators which map the space of initial states into the spa
ce of final states at each step of the evolution can be used. The quantum
evolution itself is a stochastic process. This allows to treat time as a q
uantum observable in a~consistent\, observer independent way\, which is a
very important and required feature to resolve some quantum paradoxes and
the time problem in cosmology. Changing ''parameter time'' into ''quantum
observable time'' seems to be a good step to combine relativity and quantu
m mechanics.\n\nhttps://events.ncbj.gov.pl/event/152/contributions/928/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/928/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quantum chaos of the Belinski-Khalatnikov-Lifshitz scenario
DTSTART;VALUE=DATE-TIME:20220922T120000Z
DTEND;VALUE=DATE-TIME:20220922T122000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-927@events.ncbj.gov.pl
DESCRIPTION:Speakers: Włodzimierz Piechocki (NCBJ)\nWe quantize the solut
ion to the Belinski-Khalatnikov-Lifshitz scenario using the affine coheren
t states quantization method. Quantization smears the gravitational singul
arity avoiding its localization in the configuration space. Classical chao
tic behavior of the BKL scenario becomes enhanced at the quantum level. Ou
r results strongly suggest that the generic singularity of general relativ
ity can be avoided at quantum level.\n\nhttps://events.ncbj.gov.pl/event/1
52/contributions/927/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/927/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Universality and scaling in the collapse of spherical scalar field
s in semiclassical loop quantum gravity
DTSTART;VALUE=DATE-TIME:20220922T135000Z
DTEND;VALUE=DATE-TIME:20220922T145000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-924@events.ncbj.gov.pl
DESCRIPTION:Speakers: Jorge Pullin ()\nWe explore the phenomena first desc
ribed by Choptuik\nof universality and scaling in the collapse of minimall
y\ncoupled spherically symmetric scalar fields with the \neffective semicl
assical equations of loop quantum gravity.\nContrary to expectations and s
ome previous analyses\,\nwe find universality and scaling like those seen
in classical\ngeneral relativity.\n\nhttps://events.ncbj.gov.pl/event/152/
contributions/924/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/924/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Mixmaster universe: semiclassical dynamics and inflation from boun
cing
DTSTART;VALUE=DATE-TIME:20220922T101000Z
DTEND;VALUE=DATE-TIME:20220922T103000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-923@events.ncbj.gov.pl
DESCRIPTION:Speakers: Jaime de Cabo Martín (NCBJ)\nIn this work we expl
ore the quantum Bianchi type IX-model\, its semi-classical features\, and
its relevance in early cosmology to tentatively explain inflation and prod
uction of primordial structures. We specially focus on the analytical and
numerical exploration of the dynamical system derived from the phase-space
portraits. Afterwards we investigate the reliability of our results with
regard to inflation and post inflation scenarii commonly accepted nowadays
.\n\nhttps://events.ncbj.gov.pl/event/152/contributions/923/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/923/
END:VEVENT
BEGIN:VEVENT
SUMMARY:3d gravity\, point particles and deformed symmetries
DTSTART;VALUE=DATE-TIME:20220922T095000Z
DTEND;VALUE=DATE-TIME:20220922T101000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-922@events.ncbj.gov.pl
DESCRIPTION:Speakers: Tomasz Trześniewski ( University of Wroclaw )\nt is
well known that gravity in 2+1 dimensions can be recast as the Chern-Simo
ns theory\, with the gauge group given by the local isometry group\, depen
ding on the metric signature and the cosmological constant. Point particle
s are added into spacetime as (spinning) conical defects. Then\, in princi
ple\, one may integrate out the gravitational degrees of freedom to obtain
the effective particle action\; the most interesting consequence is that
the momentum space of a particle turns out to be curved. This is still not
completely understood in the case of non-zero cosmological constant. Mean
while\, quantisation of the theory consists in the Hopf-algebraic deformat
ion of the Poisson structure\, which is determined by a given classical r-
matrix associated with the gauge algebra. All such possible r-matrices hav
e recently been classified. One of the remaining open questions is whether
the widely-studied kappa-Poincare algebra (associated with noncommutative
kappa-Minkowski space) actually plays a physical role here.\n\nhttps://ev
ents.ncbj.gov.pl/event/152/contributions/922/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/922/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Non-extensive Thermodynamics of Black Holes
DTSTART;VALUE=DATE-TIME:20220922T093000Z
DTEND;VALUE=DATE-TIME:20220922T095000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-921@events.ncbj.gov.pl
DESCRIPTION:Speakers: Hussain Gohar ()\nHawking temperature has been widel
y utilized in the literature as the temperature corresponding to various n
onextensive entropies. In this talk\, I will talk about the compatibility
of Hawking temperature with the nonextensive entropies and demonstrate tha
t\, for every nonextensive entropy\, one may define an effective temperatu
re by utilizing the equilibrium condition\, and that there is always an ad
ditive equilibrium entropy associated with this effective temperature.\n\n
https://events.ncbj.gov.pl/event/152/contributions/921/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/921/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Generalized Uncertainty Principle and Nonextensive Entropies
DTSTART;VALUE=DATE-TIME:20220922T091000Z
DTEND;VALUE=DATE-TIME:20220922T093000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-920@events.ncbj.gov.pl
DESCRIPTION:Speakers: Mariusz P. Dąbrowski ( University of Szczecin )\n
I will discuss the extensions of Heisenberg Uncertainty Principle onto the
gravitational interaction both in small (generalized) and large (extended
) scales. Then I will review our results related to the GUP in various non
extensive thermodynamics of black hole and cosmological horizons.\n\nhttps
://events.ncbj.gov.pl/event/152/contributions/920/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/920/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Scalar curvature operator for loop quantum gravity on a cubical gr
aph
DTSTART;VALUE=DATE-TIME:20220922T082000Z
DTEND;VALUE=DATE-TIME:20220922T084000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-917@events.ncbj.gov.pl
DESCRIPTION:Speakers: Ilkka Makinen ( University of Warsaw )\nWe introduce
a new operator representing the three-dimensional scalar curvature in loo
p quantum gravity. The classical starting point of our construction is to
express the Ricci scalar directly as a function of the Ashtekar variables.
The construction does not apply to the entire Hilbert space of loop quant
um gravity\; instead\, the operator is defined on the Hilbert space of a f
ixed cubical graph. As such\, the operator is relevant to approaches such
as algebraic quantum gravity\, quantum-reduced loop gravity and models of
effective dynamics. (Jerzy Lewandowski\, Ilkka Mäkinen\, arXiv:2110.10667
)\n\nhttps://events.ncbj.gov.pl/event/152/contributions/917/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/917/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fermion coupling in Loop Quantum gravity
DTSTART;VALUE=DATE-TIME:20220922T080000Z
DTEND;VALUE=DATE-TIME:20220922T082000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-916@events.ncbj.gov.pl
DESCRIPTION:Speakers: Cong Zhang ( University of Warsaw )\nIn the model of
a fermion field coupled to loop quantum gravity\, we consider the Gauss a
nd the Hamiltonian constraints. According to the explicit solutions to the
Gauss constraint\, the fermion spins and the gravitational spin networks
intertwine with each other so that the fermion spins contribute to the vol
ume of the spin network vertices. For the Hamiltonian constraint\, the reg
ularization and quantization procedures are presented in detail. By introd
ucing an adapted vertex Hilbert space to remove the regulator\, we propose
a diffeomorphism covariant graph-changing Hamiltonian constraint operator
of the fermion field. This operator shows how fermions move in the loop q
uantum gravity spacetime and simultaneously influences the background quan
tum geometry. Moreover\, as an innovation of our work\, introducing the ve
rtex Hilbert space also fixes issues so that a densely defined symmetric H
amiltonian constraint operator can be obtained. (Jerzy Lewandowski\, Cong
Zhang\, arXiv:2112.08865)\n\nhttps://events.ncbj.gov.pl/event/152/contribu
tions/916/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/916/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Matter fields in loop quantum gravity
DTSTART;VALUE=DATE-TIME:20220922T074000Z
DTEND;VALUE=DATE-TIME:20220922T080000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-915@events.ncbj.gov.pl
DESCRIPTION:Speakers: Mehdi Assanioussi ( Faculty of Physics\, University
of Warsaw )\nThe talk concerns the current status of matter fields in the
framework of loop quantum gravity\, with an emphasis on the recent develop
ments. The presentation will particularly focus on the r-Fock representati
ons and their relation to the standard loop representations\, in light of
the recent generalization of the construction of r-Fock measures to SU(N)
gauge theories\, and how one could try bridging the gap between quantum fi
eld theory on Minkowski spacetime and the background independent framework
of loop quantum gravity.\n\nhttps://events.ncbj.gov.pl/event/152/contribu
tions/915/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/915/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Scalarization in Einsteinian Cubic Gravity with General Relativity
as a cosmic attractor
DTSTART;VALUE=DATE-TIME:20220921T143000Z
DTEND;VALUE=DATE-TIME:20220921T145000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-914@events.ncbj.gov.pl
DESCRIPTION:Speakers: Cristian Erices ( Universidad Central de Chile )\nWe
address the issue of black hole scalarization and its compatibility with
cosmic inflation and big bang cosmology from an effective field theory (EF
T) point of view. In practice\, using a well-defined and healthy toy model
which (in part) has been broadly considered in the literature\, we consid
er how higher-order theories of gravity\, up to cubic operators in Riemann
curvature\, fit within this context. Interestingly enough\, we find that
already at this minimal level\, there is a non-trivial interplay between t
he Wilson coefficients which are otherwise completely independent\, constr
aining the parameter space where scalarization may actually occur. Conclus
ively\, we claim that the EFT does exhibit black hole scalarization\, rema
ining compatible with the inflationary paradigm\, and admitting General Re
lativity as a cosmological attractor.\n\nhttps://events.ncbj.gov.pl/event/
152/contributions/914/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/914/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Halilsoy spacetime
DTSTART;VALUE=DATE-TIME:20220921T141000Z
DTEND;VALUE=DATE-TIME:20220921T143000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-913@events.ncbj.gov.pl
DESCRIPTION:Speakers: Sebastian Szybka ( Jagiellonian University )\nThe Ha
lilsoy solution corresponds to cross-polarized standing gravitational wave
s in cylindrical symmetry. In my talk\, I will present recent results on t
he structure of this spacetime and particles' orbits.\n\nhttps://events.nc
bj.gov.pl/event/152/contributions/913/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/913/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Existence of potential for linearized Weyl tensor as a generalized
Poincare lemma
DTSTART;VALUE=DATE-TIME:20220921T132000Z
DTEND;VALUE=DATE-TIME:20220921T134000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-912@events.ncbj.gov.pl
DESCRIPTION:Speakers: Marian Wiatr ( University of Warsaw\, Faculty of Phy
sics )\nLinearized gravity could be treated as a linear theory of a field
having symmetries of the Weyl tensor (spin-2 field). To obtain linearized
gravity equations in this formulation from a variational formula\, it is n
ecessary to have a guarantee of the existence of potential for every spin-
2 field. This problem is known as an existence of Lanczos potential\, whic
h has been fully solved by F. Bampi and G. Caviglia in 1983. I will show t
hat behind this problem lies the elegant mathematical structure of the N-c
omplex of traceless tensor fields of given Young symmetry (which is a gene
ralization of the de Rham complex of differential forms). The main result
presented in the talk will be the fact that existence of potential for spi
n-2 field is a strict consequence of the generalized Poincare lemma for so
me N-complex of tensor fields\, analogically to classical electrodynamics.
\n\nhttps://events.ncbj.gov.pl/event/152/contributions/912/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/912/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Spherical and Non-spherical collapse of a finite two-layer body
DTSTART;VALUE=DATE-TIME:20220921T130000Z
DTEND;VALUE=DATE-TIME:20220921T132000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-911@events.ncbj.gov.pl
DESCRIPTION:Speakers: Prakash Sarnobat ( East Surrey Gravity Research )\nW
e study the simplest possible analytical model for spherical collapse that
involves density variations\, that of a homogeneous core surrounded by a
different homogeneous layer\, where both are joined using the Darmois matc
hing conditions. The aim is to obtain an analytical expression for whether
or not a naked singularity forms\, in terms of both mass densities. Altho
ugh there have been several investigations during the last decade about in
homogeneous collapse models (e.g. Joshi\, Bicak)\, the reason that here we
pursue the simplest possible Spherical Model is so that we can then proce
ed to apply it to Non-spherical collapse by using the Price-Cunningham-Mon
crief (1980) slow-rotation framework. This should provide a first indicati
on of how inhomogeneity may lead to the formation of something different t
o the Kerr Black Hole during a rotating collapse.\n\nhttps://events.ncbj.g
ov.pl/event/152/contributions/911/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/911/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Equatorial accretion on the Kerr black hole
DTSTART;VALUE=DATE-TIME:20220921T124000Z
DTEND;VALUE=DATE-TIME:20220921T130000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-910@events.ncbj.gov.pl
DESCRIPTION:Speakers: Andrzej Odrzywolek ( IFT UJ )\nWe investigate statio
nary accretion of the collisionless Vlasov gas onto the Kerr black hole\,
occurring in the equatorial plane. At infinity the gas obeys the Maxwell-J
uttner distribution\, restricted to the equatorial plane. In the vicinity
of the black hole\, the motion of the gas is governed by the spacetime geo
metry. We compute accretion rates of the rest-mass\, the energy\, and the
angular momentum\, as well as the particle number surface density\, focusi
ng on the dependence of these quantities on the asymptotic temperature of
the gas and the black hole spin. The accretion slows down the rotation of
the black hole.\n\nhttps://events.ncbj.gov.pl/event/152/contributions/910/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/910/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Critical relaxation in AdS/CFT
DTSTART;VALUE=DATE-TIME:20220921T122000Z
DTEND;VALUE=DATE-TIME:20220921T124000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-909@events.ncbj.gov.pl
DESCRIPTION:Speakers: Mario Flory ( Jagiellonian University Krakow )\nIt i
s not only known that hairy black holes can exist in asymptotically Anti-d
e Sitter (AdS) spaces\, but also that in the context of the Anti-de Sitter
/Conformal Field Theory (AdS/CFT) correspondence\, such black holes can be
interpreted as holographic duals of superfluids. After a perturbation\, t
hese black holes usually exhibit an exponentially damped ringing down desc
ribed by quasi-normal modes\, however\, I will show that for perturbations
around the exact critical point that characterizes the onset of the forma
tion of scalar hair this relaxation will exhibit a power law behaviour at
late times. I will also explain how this can be interpreted through the le
ns of the AdS/CFT correspondence.\n\nhttps://events.ncbj.gov.pl/event/152/
contributions/909/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/909/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Resonant enlargements of the Poincaré/AdS (super)algebras
DTSTART;VALUE=DATE-TIME:20220921T120000Z
DTEND;VALUE=DATE-TIME:20220921T122000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-908@events.ncbj.gov.pl
DESCRIPTION:Speakers: Remigiusz Durka ( Institute of Theoretical Physics\,
University of Wroclaw )\nUsing an efficient pattern-based computational m
ethod of generating the so-called ‘resonating’ algebraic structures re
sults in a wide class of the new Lie (super)algebras. They are enlargement
s of the Poincaré and Anti-de-Sitter (super)algebras\, which inherit thei
r base (anti)commutation structure. Obtained superalgebras are rooted in t
he semigroup expansion method and Maxwell and Soroka-Soroka algebras\, spa
nned by the Lorentz generator $J_ab$\, translations $P_{a}$ and additional
Lorentz-like generator $Z_{ab}$. Considered configurations include cases
up to two fermionic supercharges $Q^I_{alpha}$ and oﬀer interesting modi
ﬁcations to the gauge (super)gravity theories. Presentation is based on
arxiv:2108.10304 and arxiv:2205.05921.\n\nhttps://events.ncbj.gov.pl/event
/152/contributions/908/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/908/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quasinormal modes of extremal black holes
DTSTART;VALUE=DATE-TIME:20220921T090000Z
DTEND;VALUE=DATE-TIME:20220921T093000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-907@events.ncbj.gov.pl
DESCRIPTION:Speakers: Filip Ficek ( Jagiellonian University )\nIn this sho
rt talk I will discuss the explicitly-solvable toy-model for the problem o
f waves propagating outside of an extremal black hole. After showing some
results regarding quasinormal modes in such setup I will move to the more
complicated case of an extremal Reissner-Nordström-anti-de Sitter black h
ole. This is a joint work with Claude Warnick.\n\nhttps://events.ncbj.gov.
pl/event/152/contributions/907/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/907/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Evolving black hole with scalar field accretion
DTSTART;VALUE=DATE-TIME:20220921T101000Z
DTEND;VALUE=DATE-TIME:20220921T103000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-906@events.ncbj.gov.pl
DESCRIPTION:Speakers: Marco de Cesare ( University of Naples "Federico I
I" )\nI will present recent results on evolving black holes in general rel
ativity. Approximate analytical solutions are obtained by expanding the Ei
nstein field equations close to the trapping horizon for a dynamical spher
ically symmetric black hole in the presence of a minimally coupled self-in
teracting scalar field. This is made possible by a new parametrization of
the metric\, in which the displacement from the horizon as well as its exp
ansion rate feature explicitly. Our results are valid in a neighbourhood o
f the horizon and hold for any scalar field potential and spacetime asympt
otics. An exact equation for the accretion rate is also obtained\, which g
eneralizes the standard Bondi formula. We also develop a dynamical system
approach to study near-equilibrium black holes\; using this formalism\, we
focus on a simple model to show that the near-equilibrium dynamics is cha
racterized by simple scaling relations among dynamical variables. Moreover
\, we show that solutions with purely ingoing energy-momentum flux never r
each equilibrium. [based on arXiv:2205.01712]\n\nhttps://events.ncbj.gov.p
l/event/152/contributions/906/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/906/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Revisiting timelike geodesics in the Schwarzschild spacetime: gene
ral expressions in terms of Weierstrass elliptic functions
DTSTART;VALUE=DATE-TIME:20220921T095000Z
DTEND;VALUE=DATE-TIME:20220921T101000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-905@events.ncbj.gov.pl
DESCRIPTION:Speakers: Adam Cieślik ( Jagiellonian University )\nThe theor
y of Schwarzschild timelike geodesics is revisited. Based on Weierstrass a
nd Biermann's result\, a formula describing all non radial\, timelike traj
ectories in terms of Weierstrass elliptic functions is derived. A single f
ormula works for an entire geodesic trajectory\, even if it passes through
turning points. Additionally\, with this formula's help\, expressions for
the proper and coordinate time along the geodesic are derived.\n\nhttps:/
/events.ncbj.gov.pl/event/152/contributions/905/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/905/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hyperheavenly spaces and their application in para-Kähler geometr
ies
DTSTART;VALUE=DATE-TIME:20220921T093000Z
DTEND;VALUE=DATE-TIME:20220921T095000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-904@events.ncbj.gov.pl
DESCRIPTION:Speakers: Adam Chudecki ( Center of Mathematics and Physics\,
Lodz University of Technology )\nThe talk is devoted to the neutral 4-dime
nsional spaces. As a basic structure we consider weak\, expanding hyperhea
venly space\, i.e.\, a space equipped with (at least one) integrable\, tot
ally null\, 2-dimensional distribution which is not parallely propagated.
It is assumed that this distribution is self-dual (SD). If a space is addi
tionally equipped with two anti-self-dual (ASD)\, parallely propagated dis
tributions\, it becomes para-Kähler space. The metric of such a space is
analyzed. Some new examples of para-Kähler and Einstein metrics are prese
nted.\n\nhttps://events.ncbj.gov.pl/event/152/contributions/904/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/904/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Conformal geodesics can not spiral
DTSTART;VALUE=DATE-TIME:20220921T080000Z
DTEND;VALUE=DATE-TIME:20220921T083000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-902@events.ncbj.gov.pl
DESCRIPTION:Speakers: Maciej Dunajski ( University of Cambridge )\nWe show
that conformal geodesics on a Riemannian manifold cannot spiral: there do
es not exist a conformal geodesic which becomes trapped in every neighbour
hood of a point. This settles an outstanding open problem in General Relat
ivity posed by Friedrich. This is joint work with Peter Cameron and Paul T
od.\n\nhttps://events.ncbj.gov.pl/event/152/contributions/902/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/902/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Coadjoint representation of the BMS group
DTSTART;VALUE=DATE-TIME:20220921T070000Z
DTEND;VALUE=DATE-TIME:20220921T080000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-901@events.ncbj.gov.pl
DESCRIPTION:Speakers: Glenn Barnich ( Université libre de Bruxelles )\nTh
e coadjoint representation of the BMS group is worked out from purely grou
p theoretic considerations. It is then identified in the non-radiative gra
vitational data at null infinity.\n\nhttps://events.ncbj.gov.pl/event/152/
contributions/901/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/901/
END:VEVENT
BEGIN:VEVENT
SUMMARY:POTOR meeting
DTSTART;VALUE=DATE-TIME:20220921T153000Z
DTEND;VALUE=DATE-TIME:20220921T173000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-900@events.ncbj.gov.pl
DESCRIPTION:https://events.ncbj.gov.pl/event/152/contributions/900/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/900/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stability of differentially rotating compact objects against a pro
mpt collapse
DTSTART;VALUE=DATE-TIME:20220920T151000Z
DTEND;VALUE=DATE-TIME:20220920T153000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-899@events.ncbj.gov.pl
DESCRIPTION:Speakers: Paweł Szewczyk ( University of Warsaw\, Astronomica
l Observatory )\nNumerical simulations have been an important method for s
tudying complex astrophysical scenarios\, such as supernova explosions\, s
howing that the remnant of core-collapse supernova rotates differentially
at the initial phase of evolution. For neutron stars\, differential rotati
on allows for significantly larger masses than rigid rotation. In our work
\, we study the stability of those objects and look for the most massive s
table neutron stars that can be produced in core-collapse supernova. I wil
l present the results of our studies. For a polytropic equation of state\,
we have estimated the limit of stability against radial oscillations for
a selected sample of configurations. We considered a wide range of paramet
ers and found stable configurations even twice as massive as the most mass
ive non-rotating configuration.\n\nhttps://events.ncbj.gov.pl/event/152/co
ntributions/899/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/899/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Early evolution of fully convective stars in scalar-tensor gravity
DTSTART;VALUE=DATE-TIME:20220920T143000Z
DTEND;VALUE=DATE-TIME:20220920T145000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-897@events.ncbj.gov.pl
DESCRIPTION:Speakers: Dèbora Aguiar Gomes ()\nhttps://events.ncbj.gov.p
l/event/152/contributions/897/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/897/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Observational properties of bosonic stars at the galactic centre
DTSTART;VALUE=DATE-TIME:20220920T125000Z
DTEND;VALUE=DATE-TIME:20220920T131000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-894@events.ncbj.gov.pl
DESCRIPTION:Speakers: João Rosa ( University of Tartu )\nPushed by a numb
er of advances\, electromagnetic observatories have now reached the horizo
n scale of supermassive black holes. The existence and properties of horiz
ons in our universe is one of the outstanding fundamental issues that can
now be addressed. Here we investigate the ability to discriminate between
black holes and compact\, horizonless objects\, focusing on the lensing of
hot spots and accretion disks around compact objects. We work in particul
ar with boson and Proca stars as central objects\, and show that the absen
ce of a horizon gives rise to a characteristic feature -- photons that plo
ugh through the central object and produce an extra image. This feature sh
ould be universal for central objects made of matter weakly coupled to the
standard model.\n\nhttps://events.ncbj.gov.pl/event/152/contributions/894
/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/894/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Studying Post-merger Outflows from Magnetized Neutrino-cooled Accr
etion Disk Simulations
DTSTART;VALUE=DATE-TIME:20220920T123000Z
DTEND;VALUE=DATE-TIME:20220920T125000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-893@events.ncbj.gov.pl
DESCRIPTION:Speakers: Fatemeh Hossein-Nouri ( CFT PAN )\nNeutrino-cooled
accretion flow around a spinning black hole\, produced by a compact binar
y merger is a promising scenario for jet formation and launching magnetica
lly and neutrino-driven outflows. Based on GW170817 gravitational wave det
ection by LIGO and Virgo observatories followed by electromagnetic counter
parts\, this model can explain the central engine of the short duration ga
mma ray bursts (GRB) and kilonova radiations. Using the open-source GRMHD
HARM_COOL code\, we evolved several 2D magnetized accretion disk-black hol
e models with realistic equation of state in the fixed curved space-time b
ackground. The disk and black hole’s initial parameters are chosen in a
way to represent different possible post-merger scenarios of the merging c
ompact objects. Our simulations show a strong correlation between black ho
le’s spin and ejected mass. Generally\, mergers producing massive disks
and rapidly spinning black holes launch more wind outflows. We applied par
ticle tracer technique to measure the properties of the outflows\, and Sky
net r-process nucleosynthesis code to measure the abundances for the eject
ed matter. We observed our models generate winds with moderate velocity (v
/c ~ 0.1-2.0)\, and broad range of electron fraction. We use these results
to estimate the luminosity and light curves of possible radioactively pow
ered transients emitted by such systems. We found the luminosity peaks wit
hin the range of 10^40-10^41 erg/s which agrees with previous studies for
disk wind outflows.\n\nhttps://events.ncbj.gov.pl/event/152/contributions/
893/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/893/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Event Horizon Telescope Imaging of Sagittarius A* and M87 black ho
les in unpolarized and polarized light
DTSTART;VALUE=DATE-TIME:20220920T093000Z
DTEND;VALUE=DATE-TIME:20220920T103000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-892@events.ncbj.gov.pl
DESCRIPTION:Speakers: Monika Moscibrodzka ( Radboud University )\nI will t
alk about images of black holes in Saggittarius A* and M87 obtained with t
he Event Horizon Telescope. Both images have a ring-like morphologies cons
isstent with predictions of magnetohydrodynamical simulations of gas dynam
ics in Kerr metric. EHT results provide new window for future tests of gra
vitational physics and unique way to observe physics of accretion and jet
formation around supermassive black holes.\n\nhttps://events.ncbj.gov.pl/e
vent/152/contributions/892/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/892/
END:VEVENT
BEGIN:VEVENT
SUMMARY:The general relativistic two-body problem at 5PN
DTSTART;VALUE=DATE-TIME:20220920T080000Z
DTEND;VALUE=DATE-TIME:20220920T090000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-889@events.ncbj.gov.pl
DESCRIPTION:Speakers: Gerhard Schaefer ( Friedrich Schiller University Jen
a\, Institute of Theoretical Physics )\nThe talk will deliver insight into
the general relativistic conservative binary dynamics through the fifth p
ost-Newonian (5PN) order. Through the 4PN order\, the well established met
hods and results get summarized. At the 5PN order\, a recently completed c
omputation is presented including comparisons with the literature. Partial
results through the 6PN order get reported.\n\nhttps://events.ncbj.gov.pl
/event/152/contributions/889/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/889/
END:VEVENT
BEGIN:VEVENT
SUMMARY:CANCELLED! New perspectives onto the Universe in the era of multi-
messenger astronomy
DTSTART;VALUE=DATE-TIME:20220920T070000Z
DTEND;VALUE=DATE-TIME:20220920T080000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-891@events.ncbj.gov.pl
DESCRIPTION:Speakers: Samaya Nissanke ()\nhttps://events.ncbj.gov.pl/event
/152/contributions/891/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/891/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Canonical structure of f(T) and f(Q) gravity
DTSTART;VALUE=DATE-TIME:20220919T124000Z
DTEND;VALUE=DATE-TIME:20220919T131000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-882@events.ncbj.gov.pl
DESCRIPTION:Speakers: Maria Jose Guzman ( University of Tartu )\nhttps:/
/events.ncbj.gov.pl/event/152/contributions/882/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/882/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lensing of gravitational waves in Palatini f(R) gravity
DTSTART;VALUE=DATE-TIME:20220919T122000Z
DTEND;VALUE=DATE-TIME:20220919T124000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-881@events.ncbj.gov.pl
DESCRIPTION:Speakers: Sreekanth Harikumar (NCBJ)\nhttps://events.ncbj.gov.
pl/event/152/contributions/881/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/881/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Searches for Gravitational Waves from Known Pulsars at Two Harmoni
cs in the Second and Third LIGO-Virgo Observing Runs
DTSTART;VALUE=DATE-TIME:20220919T101000Z
DTEND;VALUE=DATE-TIME:20220919T103000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-879@events.ncbj.gov.pl
DESCRIPTION:Speakers: Paritosh Verma (NCBJ)\nI shall present the results o
f the recent LIGO-Virgo-KAGRA paper on the targeted search from 236 pulsar
s. When the angular momentum of the pulsar is not perfectly aligned with i
ts symmetry axis\, the gravitational wave (GW) signal can originate at bot
h once and twice the spin frequency of the pulsar due to the time-varying
quadrupole moment. There has also been a quest to search for the dipole ra
diation at once the spin frequency predicted by Brans- Dicke (BD) theory.
The methods implemented to search for the signals are Bayesian analysis\,
5n-vector method and F/G/D-statistics.\n\nhttps://events.ncbj.gov.pl/event
/152/contributions/879/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/879/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Strong lensing of gravitational waves - new opportunity of multime
ssenger astronomy
DTSTART;VALUE=DATE-TIME:20220919T080000Z
DTEND;VALUE=DATE-TIME:20220919T083000Z
DTSTAMP;VALUE=DATE-TIME:20230206T202506Z
UID:indico-contribution-152-875@events.ncbj.gov.pl
DESCRIPTION:Speakers: Marek Biesiada ( National Centre for Nuclear Researc
h )\nWe have entered the era of gravitational wave (GW) astronomy with rou
tine detections of GW signals by LIGO-Virgo-KAGRA interferometric detector
s. Future perspectives are bright with new generations of GW detectors: Ea
rth based - Einstein Telescope and Cosmic Explorer or space borne - LISA\,
DECIGO\, BBO. Gravitaional waves traveling along null geodesics can under
go strong gravitational lensing like the electromagnetic waves do. Hence\,
strong lensing of GW is becoming a popular research topic. In my talk I w
ill review the state of the art in this subject\, including contributions
of our group. I will also present new opportunities opening for the multim
essenger astronomy from detections of lensed GW signals.\n\nhttps://events
.ncbj.gov.pl/event/152/contributions/875/
LOCATION:Banach Center IMPAN 321
URL:https://events.ncbj.gov.pl/event/152/contributions/875/
END:VEVENT
END:VCALENDAR