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BEGIN:VEVENT
SUMMARY:Phase diagram of hadron matter in effective models of QCD
DTSTART;VALUE=DATE-TIME:20170921T203000Z
DTEND;VALUE=DATE-TIME:20170921T204500Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2730765@cern.ch
DESCRIPTION:Speakers: Alexandra Friesen (JINR\, Dubna)\nFor a description
of matter at high temperature and density effective\nmodels of Nambu-Jona
-Lasinio type have proven most useful. The Polyakov\nloop extended NJL (PN
JL) model can reproduce results of lattice QCD at\nzero and imaginary chem
ical potential\, where LQCD has no sign problem. In\nthe contribution we p
resent the dependence of the first-order phase\ntransition line and its cr
itical endpoint in the PNJL model phase diagram\nwhen the following aspect
s are taken into account: the parametrization of\nthe effective potential
U($\\Phi\, \\bar{\\Phi}$\; T )\; including of the quarks\nrepulsion (vecto
r interaction)\;\nan additional interaction between quarks and gluons.\n\n
https://indico.cern.ch/event/597202/contributions/2730765/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2730765/
END:VEVENT
BEGIN:VEVENT
SUMMARY:“Trapped ghost” wormholes and regular black holes. The stabili
ty problem.
DTSTART;VALUE=DATE-TIME:20170922T144000Z
DTEND;VALUE=DATE-TIME:20170922T152000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2714705@cern.ch
DESCRIPTION:Speakers: Kirill Bronnikov (Center of Grav. and Fund. Metrolog
y\, VNIIMS\, Ozyornaya 46\, Moscow 119361\, Russia\;)\nWe briefly review t
he properties of static\, spherically symmetric configurations of general
relativity with a minimally coupled scalar field $\\phi$ whose kinetic ene
rgy is negative in a restricted (strong-field) region of space and positiv
e outside it [1--3]. This ``trapped ghost'' concept may in principle expla
in why no ghosts are observed under usual\, weak-field conditions. The co
nfigurations considered are wormholes and regular black holes without a ce
nter\, in particular\, black universes (black holes with an expanding cosm
ology beyond the event horizon) [4--6]. Spherically symmetric perturbation
s of these objects are considered\, \nand it is stressed that\, due to the
universal shape of the effective potential near a transition surface from
canonical to phantom behavior of the scalar field\, such surfaces restric
t the possible perturbations and play a stabilizing role.\n\n[1] K.A. Bron
nikov and S.V. Sushkov\, “Trapped ghosts: a new class of wormholes\,”
Class. Quantum Grav. 27\, 095022 (2010)\; arXiv: 1001.3511.\n[2] K.A. Bron
nikov and E.V. Donskoy\, “Black universes with trapped ghosts.” Grav.
Cosmol. 17\, 176–180 (2011).\n[3] K.A. Bronnikov\, E.V. Donskoy\, and P.
Korolyov\, “Magnetic wormholes and black universes with trapped ghosts\
,” Vestnik RUDN No. 2\, 139–149 (2013).\n[4] K.A.BronnikovandJ.C.Fabri
s\,“Regularphantomblackholes\,”Phys.Rev.Lett.96\,251101 (2006)\; gr-qc
/0511109.\n[5] S.V. Bolokhov\, K.A. Bronnikov\, and M.V. Skvortsova\, “M
agnetic black universes and worm- holes with a phantom scalar\,” Class.
Quantum Grav. 29\, 245006 (2012)\; arXiv: 1208.4619.\n[6] K. A. Bronnikov
and S. G. Rubin\, Black Holes\, Cosmology\, and Extra Dimensions (World Sc
ientific\, Singapore\, 2012).\n\nhttps://indico.cern.ch/event/597202/contr
ibutions/2714705/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2714705/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal discussion on perspectives in compact stars
DTSTART;VALUE=DATE-TIME:20170919T204000Z
DTEND;VALUE=DATE-TIME:20170919T213000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2712578@cern.ch
DESCRIPTION:https://indico.cern.ch/event/597202/contributions/2712578/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2712578/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Realistic compactification models in Einstein-Gauss-Bonnet gravity
DTSTART;VALUE=DATE-TIME:20170919T201000Z
DTEND;VALUE=DATE-TIME:20170919T204000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2713250@cern.ch
DESCRIPTION:Speakers: Sergey Pavluchenko (Universidade Federal do Maranhao
\, Sao Luis\, Brazil)\nThe abstract: In this talk I give a brief review of
our recent development on the cosmological dynamics in the Einstein-Gauss
-Bonnet gravity. The special attention is paid to the models which allow r
ealistic compactification. We require only for model to be free of future
singularities and has a ``standard'' cosmological singularity af the origi
n. Using such weak requirements\, for the simplest spatially flat model\,
we are able to put constraints on the parameters of the theory and the num
ber of extra dimensions. Consideration of more complex\nmodels (with spati
al curvature and additional anisotropies) allow us to tighten the constrai
nts.\n\nhttps://indico.cern.ch/event/597202/contributions/2713250/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2713250/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Scalar field dark energy reconstruction from the SNe Ia data
DTSTART;VALUE=DATE-TIME:20170921T200000Z
DTEND;VALUE=DATE-TIME:20170921T203000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2713251@cern.ch
DESCRIPTION:Speakers: Arpine Piloyan ()\nI report the results of the scala
r field dark energy reconstruction from the SNe Ia data. In our reconstruc
tion we do not use any ansatz for the dark energy\, which makes our proced
ure quite generic. We describe the reconstruction procedure and test it wi
th mock data. After this\, we apply it to real SNe data. Our results sugge
st that the current SNe Ia data is of insufficient quality for the scalar
field dark energy to be reliably reconstructed.\n\nhttps://indico.cern.ch/
event/597202/contributions/2713251/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2713251/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Informal discussion on gravity problems and cosmology
DTSTART;VALUE=DATE-TIME:20170921T204500Z
DTEND;VALUE=DATE-TIME:20170921T214500Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2712579@cern.ch
DESCRIPTION:https://indico.cern.ch/event/597202/contributions/2712579/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2712579/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Stability and mass defect of hot strange dwarfs
DTSTART;VALUE=DATE-TIME:20170921T184000Z
DTEND;VALUE=DATE-TIME:20170921T191000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2695559@cern.ch
DESCRIPTION:Speakers: Gevorg Hajyan (Yerevan State University)\nThe depend
ences of the mass and the mass defect on the baryonic mass of the isotherm
al (the stars with the same core temperature) and the isentropic (the star
s with the same entropies per one baryonic chargе) series of the hot st
range stars are investigated .The stability of these stars is determined b
y these dependences. It is shown that isentropic series of the hot strange
stars are also isothermic series of these stars for the surface tempera
tures. It is also shown that the proximity of the points of the maximum ma
ss and the loss of stability on the isothermal series is determined by ver
y weak dependence of the numerical value of the maximum mass of strange st
ars on the value of the central temperature.\n\nhttps://indico.cern.ch/eve
nt/597202/contributions/2695559/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2695559/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Bayesian Analysis of Hybrid EoS Models Using Mass and Radius Data
from Compact Star Observations
DTSTART;VALUE=DATE-TIME:20170921T193000Z
DTEND;VALUE=DATE-TIME:20170921T200000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2711255@cern.ch
DESCRIPTION:Speakers: Alexander Ayriyan (JINR)\nA Bayesian analysis for a
new class of realistic models of hybrid equations of state (EoS) with mixe
d phase is performed. The mixed phase is described by a one parameter simp
le model. The parameter represents the impact of the mixed phase structure
to the pressure. It is demonstrated that the observation of a possible pa
ir of high-mass twin stars would have a sufficient discriminating power to
favour hybrid EoS with a strong first-order phase transition over alterna
tive EoS.\n\nhttps://indico.cern.ch/event/597202/contributions/2711255/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2711255/
END:VEVENT
BEGIN:VEVENT
SUMMARY:A NEW APPROACH TO STUDY OF QUANTUM VACUUM - DARK ENERGY
DTSTART;VALUE=DATE-TIME:20170918T201000Z
DTEND;VALUE=DATE-TIME:20170918T204000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2695577@cern.ch
DESCRIPTION:Speakers: Ashot Gevorkyan (Institute for Informatics and Autom
ation Problems\, NAS of Armenia\, Institute of Chemical Physics\, NAS of A
rmenia)\nAs is well known\, in quantum field theory (QFT) the quantum vacu
um (QV) is\nrepresented as an infinite set of different fluctuating virtua
l particles\nand fields in four-dimensional Minkowski space-time. In this
connection\, a\nnatural question arises: what is the structure of QV\, whe
n the latter is\nin a state of statistical equilibrium and there is no ext
ernal influence\non it? It is obvious that satisfactory answers to these
non-trivial\nquestions we can obtained only within the framework of non-p
erturbative\nquantum field models. In this paper\, we consider the quantum
equation of a\nmassless field in the fluctuating four-dimensional Minkows
ki space-time\,\nwhich is equivalent to an uncountable-dimensional space-t
ime. As the basic\nequation is used the Langevin type stochastic matrix eq
uation\, regardless\nof the formalism of second quantization. It is assume
d that\, on small\nfour-dimensional space-time intervals\, the quantum fie
ld equation\ncoincides with a regular matrix equation analogous to the Wey
l equation\nfor a neutrino. It is proved that in the statistical equilibri
um limit the\ninitial uncountable space-time is reduced to a ten-dimension
al space-time\,\nwhere four dimensions are Minkowski space-time\, and the
remaining six\ndimensions are compact topological subspaces. In detail is
studied\nconditions of quantization of vacuum fields in compact subspaces
and it is\nshown that these quantized states can claim the role of dark en
ergy. It is\nshown that even weak external electromagnetic fields are capa
ble of\ndeforming compact subspaces\, because of which the refractive indi
ces of a\nvacuum can vary measurably. The latter\, in particular\, means t
hat the\ndeveloped representation allows for the existence of a new mechan
ism of\ninteraction between photons through the deformation of compact sub
spaces\,\nwhich is fundamentally differ from the usual mechanisms of phot
on-photon\nscattering\, described by the fourth order Feynman's diagram
s.\n\nhttps://indico.cern.ch/event/597202/contributions/2695577/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2695577/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cooling of massive neutron stars
DTSTART;VALUE=DATE-TIME:20170921T181000Z
DTEND;VALUE=DATE-TIME:20170921T184000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2696145@cern.ch
DESCRIPTION:Speakers: Hovik Grigorian ()\nThe existence of the high mass p
ulsars PSR J1614-2230 and PSR J0348-0432 with masses of about 2 M_sun requ
ires a sufficiently stiff equation of state (EoS) of the stellar matter to
fulfill this constraint. We succeeded to explain the thermal evolution of
compact stars with stiff hadronic EoS in the framework of the ``nuclear m
edium cooling" scenario. We have also investigated the case when due to ph
ase transition to quark matter the third family of compact stars for highe
r densities can exist. In this case high-mass twin stars could show diffe
rent cooling behavior. The cooling scenarios have a discriminating power f
or selection of optimal EoS models for compact stars.\n\nhttps://indico.ce
rn.ch/event/597202/contributions/2696145/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2696145/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Low-Energy Nuclear Interaction Chamber for Experiments in Nuclear
Astrophysics
DTSTART;VALUE=DATE-TIME:20170919T181000Z
DTEND;VALUE=DATE-TIME:20170919T184000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2695578@cern.ch
DESCRIPTION:Speakers: Amur Margaryan (Alikhanyan National Science Laborato
ry)\nA Low-EneRgy Nuclear Interaction Chamber\, LERNIC\, has been develope
d to be used as an active target system for nuclear astrophysics experimen
ts. LERNIC is a position and time sensitive detector system based on the l
ow-pressure MWPC technique. While the astrophysically relevant nuclear rea
ction processes at stellar burning temperatures are dominated by radiative
captures\, in this experimental scheme we will measure the time-reversed
processes. Due to the transformation of phase space\, the photodisintegrat
ion cross-sections are up to two orders of magnitude higher. The main adva
ntage of this new target-detector system is a capability to operate at hig
h intensity photon beams\, high sensitivity to the low-energy\, highly ion
izing particles and insensitivity to the γ-rays and minimum ionizing part
icles\, thus allowing us to detect only the products of the nuclear reacti
on of interest. The main disadvantage of this detector is a density severa
l orders of magnitude lower than conventional gas targets. It can be compe
nsated by using multi-module detector system and highly directed\, intense
\, laser Compton backscattered γ-ray beam. The test results of the protot
ype detector as well as the possibility of measurement of the cross sectio
n of γ + 16O → 12C + α reaction are discussed.\n\nhttps://indico.cern.
ch/event/597202/contributions/2695578/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2695578/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Charged $\\rho$-meson condensate in neutron stars within RMF model
s
DTSTART;VALUE=DATE-TIME:20170918T182000Z
DTEND;VALUE=DATE-TIME:20170918T185000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2710148@cern.ch
DESCRIPTION:Speakers: Konstantin Maslov (MEPhI)\nKnowledge of the equation
of state (EoS) of cold and dense baryonic matter is essential to describe
the properties of neutron stars (NSs). With an increase of the density ne
w baryon species can appear in NS matter\, as well as various meson conden
sates. In previous works we developed relativistic mean-field (RMF) models
with hyperons and $\\Delta$-isobars\, which passed the majority of known
experimental constraints\, including the existence of a $2 \\\, M_\\odot$
neutron star. In this contribution we present results of inclusion of $\\r
ho^-$-meson condensation into these models. We have shown that in one clas
s of the models\, where the additional stiffening mechanism is incorporate
d in the isospin-symmetric sector (KVOR-based models) the condensation giv
es only a small contribution to the EoS. In other class\, where the stiffe
ning is reached by modifying the isospin-asymmetric part of the model (MKV
OR-based models)\, the condensation can lead to a first-order phase transi
tion and a substantial decrease of the NS mass. Nevertheless\, in all resu
lting models the condensation does not spoil the description of the experi
mental constraints.\n\nhttps://indico.cern.ch/event/597202/contributions/2
710148/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2710148/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Impact of the MIT bag model parameters values on the maximum mass
of neutron star with a quark core
DTSTART;VALUE=DATE-TIME:20170922T152000Z
DTEND;VALUE=DATE-TIME:20170922T160000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2695563@cern.ch
DESCRIPTION:Speakers: Grigor Alaverdyan (Yerevan State University)\nThe ef
fect of model parameters of quark matter equation of state on the magnitud
e of the maximum mass of a hybrid star is investigated. The quark matter i
s described within the framework of the extended MIT bag model with one-gl
uon exchange corrections taken into account. For nucleon matter within the
density region\, corresponding to a phase transition\, the relativistic e
quation of state is used and calculated with consideration of two-particle
correlations\, based on the Bonn meson-exchange potential. Using Maxwell'
s construction\, the characteristics of a first-order phase transition are
calculated\, and it is shown that for a fixed value of the strong interac
tion constant $\\alpha_s$\, the baryon concentrations of the coexisting ph
ases grow monotonically with increasing bag constant $B$. It is shown that
for a fixed value of the strong interaction constant $\\alpha_s$\, the ma
ximum mass of a hybrid star increases with decreasing bag constant $B$. Fo
r a given value of the bag parameter $B$\, the maximum mass increases with
increasing strong interaction constant $\\alpha_s$. It is shown that the
hybrid star configurations\, with maximal mass equal to or exceeding the m
ass of the currently known most massive pulsar\, are possible for the valu
es of the strong interaction constant $\\alpha_s>0.6$\, also for sufficien
tly small values of the bag constant $B$.\n\nhttps://indico.cern.ch/event/
597202/contributions/2695563/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2695563/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Magnetic field generation in hybrid neutron stars
DTSTART;VALUE=DATE-TIME:20170922T134000Z
DTEND;VALUE=DATE-TIME:20170922T142000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2707551@cern.ch
DESCRIPTION:Speakers: David Sedrakian (Yerevan State University)\nThe mech
anism of magnetic field generation in hybrid neutron stars (consisting of
“npe”\nhadronic\, “2SC” and “CFL” quark phases) is considered.
We assume that rotational vortices in “npe”\nand “CFL” phases wit
h quantum of circulation 𝜋ℏ/𝑚 are continued in “2SC” phase as
well. Since\nsuperconducting matter in “npe” and “2SC” phases is c
harged\, rotation induced entrainment currents\narise around vortices\, wh
ich generate magnetic field. Mean value of generated magnetic field is abo
ut\n1016Gs and exceeds one in “npe” phase by 3-4 orders of magnitude.
The magnetic field enters the\nvicicnity of rotational vortices forming th
e clusters of magnetic vortices with quantum of magnetic\nflux Φ0 in “n
pe” phase and 2Φ0 in “2SC” phase. The radii of clusters are 0.1𝑏
and0.3𝑏\, respectively\,\nin “npe” and “2SC” phases\, where
𝑏 is a radius of rotational vortex. Magnetic field penetrates in “CFL
”\nphase via magnteic vortices with magnetic flux2Φ0. In “npe” phas
e this magnetic field can destroy\nproton superconductivity. Magnetic fiel
d on the surface of a star reaches the value of 10\n15Gs\, which is\ncompa
rable with magnetic field of magnetars. Therefore magnetars are candidates
of compact objects\ncontaining quark matter.\nDue to high density of magn
etic energy of vortices\, vortex-free zone appears at the bound of\n“2SC
” phase with width about several hundred meters. An outward motion of vo
rtices during spindown\nof a star leads to energy release when vortices re
ach to the boundary of vortex-free zone.\nMagnetic energy of annihilated v
ortices may become the source of high-frequency radiation of\nobjects like
SGR and AXP.\n\nhttps://indico.cern.ch/event/597202/contributions/2707551
/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2707551/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Equations of state of relativistic mean-field models with differen
t parametrisations of density-dependend couplings
DTSTART;VALUE=DATE-TIME:20170921T134000Z
DTEND;VALUE=DATE-TIME:20170921T142000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2695572@cern.ch
DESCRIPTION:Speakers: Stefan Typel (Technische Universität Darmstadt)\nRe
lativistic mean-field (RMF) models with density dependent (DD) couplings h
ave been used successfully to describe nuclear matter and finite nuclei. T
hey usually assume a dependence of the nucleon-meson couplings on the so-c
alled vector density that is derived from the baryon current. A dependence
on other densities\, in particular the scalar density\, was not really ex
plored although suggested in early introductions of the DD-RMF approach. I
n this contribution\, DD-RMF models\, the corresponding equations of state
(EoS)\, and symmetry energies are compared using DD couplings of differen
t functional form and dependence on vector and scalar densities. They are
obtained by fitting the same set of nuclear observables. The choice of the
dependence changes the EoS and the characteristic nuclear matter paramete
rs. Problems of some of the models are identified.\n\nhttps://indico.cern.
ch/event/597202/contributions/2695572/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2695572/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cosmological scenarios in Horndeski theory
DTSTART;VALUE=DATE-TIME:20170921T130000Z
DTEND;VALUE=DATE-TIME:20170921T134000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2695575@cern.ch
DESCRIPTION:Speakers: Sergey Sushkov (Kazan Federal University)\nWe presen
t a systematic analysis of homogeneous and isotropic cosmologies in Hornde
ski model which is the most general scalar-tensor theory of gravity with s
econd-order field equations. \nA special attention is paid to the particu
lar subclass of Horndeski theory\, namely\, the model with the scalar fiel
d $\\phi$ possessing the nonminimal kinetic coupling to curvature given as
$\\eta G^{\\mu\\nu}\\phi_{\,\\mu}\\phi_{\,\\nu}$.\nA very interesting and
important feature of the model is that it provides an essentially new inf
lationary mechanism without any fine-tuned scalar potential. \nNamely\, at
early cosmological times the domination of coupling terms in the field eq
uations guarantees the quasi-De Sitter behavior of the scale factor: $a(t)
\\propto e^{H_\\eta t}$ with $H_\\eta =1/\\sqrt{9\\eta}$. \nGenerally\, th
e model admits a rich spectrum of solutions. \nSome of them describe the s
tandard late time cosmological dynamic dominated by the $\\Lambda$-term an
d matter\, while at the early times the universe expands with a constant H
ubble rate determined by the value of the scalar kinetic coupling. For oth
er solutions the $\\Lambda$-term and matter are screened at all times but
there are nevertheless the early and late accelerating phases. The model a
lso admits bounces\, as well as peculiar solutions describing "the emergen
ce of time".\nWe find that the universe could transit from one de Sitter s
olution to another\, determined by the coupling parameter. Furthermore\, a
ccording to the parameter choices and without the need for matter\, we can
obtain a Big Bang\, an expanding universe with no beginning\, a cosmologi
cal turnaround\, an eternally contracting universe\, a Big Crunch\, a Big
Rip avoidance and a cosmological bounce. This variety of behaviors reveals
the capabilities of the present scenario.\n\nhttps://indico.cern.ch/event
/597202/contributions/2695575/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2695575/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Astrophysical and Cosmological Tests of Gravity
DTSTART;VALUE=DATE-TIME:20170920T144000Z
DTEND;VALUE=DATE-TIME:20170920T152000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2695573@cern.ch
DESCRIPTION:Speakers: Levon Pogosian (Simon Fraser University)\nThe unknow
n nature of dark matter and dark energy\, as well as rapid improvements in
the accuracy of the astronomical data\, inspired studies of extensions of
Einstein's theory of General Relativity and ways of testing them against
observations. I will review the current state of the very active field of
Testing Gravity\, and what we can expect to learn about Gravity from the n
ext generation of cosmological surveys.\n\nhttps://indico.cern.ch/event/59
7202/contributions/2695573/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2695573/
END:VEVENT
BEGIN:VEVENT
SUMMARY:$f(R)$ relativistic gravity and inflationary models based on it
DTSTART;VALUE=DATE-TIME:20170919T152000Z
DTEND;VALUE=DATE-TIME:20170919T160000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2710354@cern.ch
DESCRIPTION:Speakers: Alexei Starobinsky (Landau Institute of RAS)\nThe $f
(R)$ gravity represents the simplest purely geometrical generalization of\
nthe Einstein general theory of relativity without undesirable ghosts. The
\npioneer $R+R^2$ model of inflation (1980) contains only one adjustable\n
parameter taken from observations\, has a graceful exit from inflation and
\na natural mechanism for creation and heating of matter after its end. It
\nproduces a very good fit to existing observational data on the power\nsp
ectrum of primordial scalar (adiabatic density) perturbations. Due to\nthe
structure of this model\, small quantum-gravitational loop corrections\nt
o it from quantum matter fields and gravity itself are important for its\n
dynamics both during and after inflation and can lead to observable\neffec
ts. I present solution of the inverse problem of reconstruction of\nslow-r
oll inflationary models in f(R) gravity using information on the\npower sp
ectrum of scalar perturbations only and show how ambiguity in this\nproced
ure due to the absence of data for small scales can be fixed using\nsimpli
fying and aesthetic assumptions on the absence of new physical\nscales dur
ing and after inflation. Also discussed is the problem on\nformation of in
flation in f(R) gravity from generic classical curvature\nsingularity prec
eding it\, and which conditions are needed for this.\n\nhttps://indico.cer
n.ch/event/597202/contributions/2710354/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2710354/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Modification of Compact Star Observables due to Quantum Fluctuatio
ns
DTSTART;VALUE=DATE-TIME:20170920T152000Z
DTEND;VALUE=DATE-TIME:20170920T160000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2695571@cern.ch
DESCRIPTION:Speakers: Gergely Gabor Barnafoldi (Wigner RCP Hungarian Acade
my of Sciences (HU))\nWe present the application of our technique to obtai
n equation of state (EoS) by the Functional Renormalization Group (FRG) me
thod presented earlier. Using the expansion of the effective potential in
a base of harmonic functions at finite chemical potential we can provide a
general framework for the calculation of the EoS. Within this theoretical
framework we determined the equation of state and the phase diagram of a
simple model -- as a proof-of-concept. To illustrate this we used the simp
lest\, non-trivial case\, where massless fermions coupled to scalars throu
gh Yukawa-coupling at the zero-temperature limit. \n\nWe compared our res
ults to the 1-loop and the mean field approximation of the same model and
other high-density nuclear matter equation of states. We found a $10-20\\%
$ difference between these approximations. As an application\, we used our
FRG-based equation of states to test the effect of the quantum fluctuatio
ns in superdense nuclear matter of a compact astrophysical object. To illu
strate the magnitude of this effect\, we calculated the mass-radius relati
on for a compact star using the Tolmann-Oppenheimer-Volkov equation and ob
served a 5% effect in compact star observables due to quantum fluctuations
.\n\nhttps://indico.cern.ch/event/597202/contributions/2695571/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2695571/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quark-Nuclear Hybrid Star EoS with Excluded Volume Effects
DTSTART;VALUE=DATE-TIME:20170919T134000Z
DTEND;VALUE=DATE-TIME:20170919T142000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2710149@cern.ch
DESCRIPTION:Speakers: David Blaschke (University of Wroclaw)\nA two-phase
description of the quark-nuclear matter hybrid equation of state that take
s into account the effect of excluded volume in both the hadronic and the
quark-matter phases is introduced. The nuclear phase manifests a reduction
of the available volume as density increases\, leading to a stiffening of
the matter. The quark-matter phase displays a reduction of the effective
string-tension in the confining density-functional from available volume c
ontributions. The nuclear equation of state is based upon the relativistic
density functional model DD2 with excluded volume. The quark-matter EoS i
s based upon a quasiparticle model derived from a relativistic density-fun
ctional approach and will be discussed in greater detail. The interactions
are decomposed into mean scalar and vector components. The scalar interac
tion is motivated by a string potential between quarks\, whereas the vecto
r interaction potential is motivated by higher-order interactions of quark
s leading to an increased stiffening at high densities. As an application\
, we consider matter under compact star constraints of electric neutrality
and beta-equilibrium. We obtain mass-radius relations for hybrid stars th
at form a third family\, disconnected from the purely hadronic star branch
\, and fulfill the 2M_sun constraint.\n\nhttps://indico.cern.ch/event/5972
02/contributions/2710149/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2710149/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cooling of neutron stars within ‘’nuclear medium cooling scena
rio”
DTSTART;VALUE=DATE-TIME:20170919T130000Z
DTEND;VALUE=DATE-TIME:20170919T134000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2695576@cern.ch
DESCRIPTION:Speakers: Dmitry Voskresensky (National Research Nuclear Unive
rsity (NRNU MEPhI))\nNeutrino emission from neutron stars is subject of st
rong modifications due to collective effects in nuclear matter like the pi
on polarization effect and the Cooper pairing of nucleons. The larger is
the star mass (central density) the stronger is the pion polarization. Th
e ``nuclear medium cooling scenario” relates slow and rapid neutron star
cooling to the neutron star masses (interior densities). Recent measurem
ents of the masses of the pulsars PSR J1616-2230\, PSR J0348-0432 and J007
37-3039B and the companion of J1756-2251 provide independent proof for exi
stence of compact stars with masses in a broad range from 1.2 to 2 solar m
ass. The hadronic equation of state should be rather stiff to explain exi
stence of heavy neutron stars. The data on the cooling of neutron stars ca
n be comfortably explained in the nuclear medium cooling scenario exploiti
ng a stiff equation of state.\n\nhttps://indico.cern.ch/event/597202/contr
ibutions/2695576/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2695576/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Accelerating cosmology in modified gravity and neutron stars
DTSTART;VALUE=DATE-TIME:20170918T160000Z
DTEND;VALUE=DATE-TIME:20170918T164000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2695566@cern.ch
DESCRIPTION:Speakers: Sergey Odentsov (ICREA and ICE(CSIC-IEEC)\, Barcelon
a)\nWe give the review of modified gravity as applied to Universe evolutio
n. It is shown that number of modified gravities may provide the consisten
t unification of the early-time inflation with late-time acceleration. Spe
cial attention is paid to F(R) gravity which represents the most developed
class of such theories. Specific features of possible evolution in such t
heories are indicated: singular inflation\, bounces\, etc. We also show th
e possible modification of TOV equations for relativistic stars in modifie
d gravities. As a result the mass-radius relation may change qualitatively
giving the window for the increase of mass for relativistic stars with sm
all radii.\nThe results are based on the following works:\n1. S. Nojiri an
d S.D. Odintsov\, Unified cosmic history in modified gravity: from F(R) th
eory to Lorentz non-invariant models. Phys. Rept. 505\, 2011\, 59\, doi:10
.1016/j.physrep.2011.04.001\, arXiv:1011.0544 [gr-qc].\n 2. A.V. Astasheno
k\, S. Capozziello and S.D. Odintsov\, Extreme neutron stars from Extended
Theories of Gravity\, JCAP 1501\, 2015\, no.01\, 001\, doi:10.1088/1475-
7516/2015/01/001\, arXiv:1408.3856 [gr-qc].\n 3. A. V. Astashenok\, A. de
la Cruz-Dombriz and S.D. Odintsov\, The realistic models of relativistic s
tars in f(R) = R + alpha R^2 gravity\, arXiv:1704.08311 [gr-qc].\n\nhttps
://indico.cern.ch/event/597202/contributions/2695566/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2695566/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hadron-Quark Transition in High Density Nuclear Matter
DTSTART;VALUE=DATE-TIME:20170918T152000Z
DTEND;VALUE=DATE-TIME:20170918T160000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2695567@cern.ch
DESCRIPTION:Speakers: Misak Sargsian ()\nThe talk will focus on the dynam
ics of nucleon-nucleon repulsive core and \nthe mechanisms of quark-hadro
n transition in high density nuclear matter.\nThe strength of the nuclea
r repulsion plays an important role in the equation of state of \nthe nuc
lear matter and its mechanism is largely unknown.\nThere are several issue
s such as hidden-color degrees of freedom\, supefast quarks as well as in
elastic excitations in nucleon-nucleon systems that currently considere
d as \npossible mechanisms in generating nuclear repulsion. These mec
hanisms will\nbe discussed in detail considering their implication in the
dynamics of the superdense \nnuclear matter. Also the brief overview will
be given on the possibilities of experimental \nverification of the nucle
ar core dynamics in fixed target and collider experiments.\n\nhttps://ind
ico.cern.ch/event/597202/contributions/2695567/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2695567/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Pulsar glitch dynamics in general relativity
DTSTART;VALUE=DATE-TIME:20170922T130000Z
DTEND;VALUE=DATE-TIME:20170922T134000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2695561@cern.ch
DESCRIPTION:Speakers: Jerome Novak (CNRS - Observatoire de Paris)\nPulsar
glitches are commonly interpreted as angular momentum transfers occurring
between two fluids present in the stellar interior\, triggered by the rapi
d motion of superfluid vortex lines at large scales. We consider for the f
irst time all general relativistic effects in a numerical model for glitch
es. First\, we show numerical calculation of stationary configurations of
neutron stars composed of a neutron superfluid and a fluid made of charged
particles\, spinning with different rotation rates. These general relativ
istic calculations are based on realistic equations of state accounting fo
r entrainment effects between the fluids. These configurations are then us
ed to build a numerical model for pulsar glitches in full general relativi
ty. In particular\, we study in details the characteristic time scale asso
ciated with the spin-up stage\, during which the stellar dynamics are gove
rned by a mutual friction force arising from the interactions between the
superfluid vortices and the surrounding fluids. Taking general relativity
into account leads to an additional coupling between the fluids through fr
ame-dragging effects and is shown to affect significantly the actual value
of the spin-up time scale.\n\nhttps://indico.cern.ch/event/597202/contrib
utions/2695561/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2695561/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Supporting the existence of the QCD critical point by compact star
observations
DTSTART;VALUE=DATE-TIME:20170918T185000Z
DTEND;VALUE=DATE-TIME:20170918T192000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2710146@cern.ch
DESCRIPTION:Speakers: David Edwin Alvarez Castillo (JINR)\nIn order to pro
ve the existence of a critical end point (CEP) in the QCD phase diagram it
is sufficient to demonstrate that at zero temperature $T=0$ a first order
phase transition exists as a function of the baryochemical potential $\\
mu$\, since it is established knowledge from ab-initio lattice QCD simulat
ions that at $\\mu=0$ the transition on the temperature axis is a crossove
r.\n\nWe present the argument that the observation of a gap in the mass-ra
dius relationship for compact stars which proves the existence of a so-cal
led third family (aka "mass twins") will imply that the $T=0$ equation of
state of compact star matter exhibits a strong first order transition wit
h a latent heat that satisfies $\\Delta\\epsilon/\\epsilon_c > 0.6$. Since
such a strong first order transition under compact star conditions will r
emain first order when going to symmetric matter\, the observation of a di
sconnected branch (third family) of compact stars in the mass-radius diagr
am proves the existence of a CEP in QCD. Modeling of such compact star twi
ns is based on a QCD motivated NJL quark model with high order interaction
s together with the hadronic DD2-MEV model fulfilling nuclear observables.
Further approaches include multipolytrope EoS description and constant sp
eed of sound for the quark matter EoS. Moreover\, astrophysical applicatio
ns of high mass twins phenomenon are presented.\n\nhttps://indico.cern.ch/
event/597202/contributions/2710146/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2710146/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Electromagnetic vacuum densities induced by a cosmic string in de
Sitter space
DTSTART;VALUE=DATE-TIME:20170921T144000Z
DTEND;VALUE=DATE-TIME:20170921T152000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2707550@cern.ch
DESCRIPTION:Speakers: Vardan Manukyan (Shirak State University)\nWe invest
igate the influence of a cosmic string on the vacuum fluctuations of the e
lectromagnetic field in background of (D+1)-dimensional de Sitter spacetim
e.\nThe expectation values (VEVs) of physical characteristics for the Bunc
h-Davies vacuum state are evaluated. The VEVs are presented in a decompose
d form where\nthe topological parts induced by the cosmic string are expli
citly extracted. The asymptotic behavior of the VEVs at large and small di
stances from the string is discussed.\n\nhttps://indico.cern.ch/event/5972
02/contributions/2707550/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2707550/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Transport coefficients of two-flavor quark matter from the Kubo fo
rmalism
DTSTART;VALUE=DATE-TIME:20170918T192000Z
DTEND;VALUE=DATE-TIME:20170918T195000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2707549@cern.ch
DESCRIPTION:Speakers: Arus Harutyunyan (ITP\, Goethe University\, Frankfur
t am Main )\nWe compute the transport coefficients of quark matter in the
strong coupling regime within the two-flavor Nambu--Jona-Lasinio model. We
apply the Kubo formalism to obtain the thermal ($\\kappa$) and the electr
ical ($\\sigma$) conductivities as well as the shear ($\\eta$) and the bul
k viscosities ($\\zeta$) at leading order in the $1/N_c$ power counting sc
heme. In this approximation the conductivities and the shear viscosity are
given by single-loop skeleton diagrams\, whereas the bulk viscosity inclu
des an infinite geometrical series of multi-loop diagrams. The dispersive
effects that lead to nonzero transport coefficients arise from quark-meson
fluctuations above the Mott transition temperature $T_M$\, where meson de
cay into two on-mass-shell quarks is kinematically allowed. \n \n We fin
d that the conductivities and the shear viscosity are decreasing functions
of temperature and density above $T_M$. We also show\, that the Wiedemann
-Franz law for the ratio $\\sigma/\\kappa$ does not hold. The ratio of the
shear viscosity to the entropy density is larger than unity close to the
Mott temperature and approaches the AdS/CFT bound $1/4\\pi$ at higher temp
eratures. We conjecture on the basis of the uncertainty principle that the
ratio $\\kappa T/c_V$\, where $c_V$ is the heat capacity per unit volume\
, is bounded from below by 1/18. \n \n The case of the bulk viscosity tur
ns out to be special\, because the multi-loop contributions dominate the s
ingle-loop contribution close to the Mott line in the case where the chira
l symmetry is explicitly broken. The resulting bulk viscosity exceeds the
shear viscosity close to the Mott line by factors 5-20. In the high-temper
ature domain the bulk viscosity is negligible compared to the shear viscos
ity. For practical applications we provide simple\, but accurate fits to t
he transport coefficients which can facilitate the implementation of our r
esults in hydrodynamics codes.\n\nhttps://indico.cern.ch/event/597202/cont
ributions/2707549/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2707549/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Hot neutron stars with hyperons
DTSTART;VALUE=DATE-TIME:20170919T144000Z
DTEND;VALUE=DATE-TIME:20170919T152000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2698394@cern.ch
DESCRIPTION:Speakers: Micaela Oertel (Meudon Observatory)\nIn this talk I
will present a temperature dependent equation of\n state (EoS) including
the entire baryon octet\, being compatible with\n the main constraints fr
om nuclear physics and\, in particular\, with a\n maximum mass for cold $
\\beta$-equilibrated neutron stars of \n$2M_\\odot$ in agreement with rece
nt observations. As an application\,\n numerical stationary models for ra
pidly (rigidly) rotating hot\n neutron stars have been computed. I will d
iscuss their maximum\n masses and the universality of $I$-$Q$-relations a
t nonzero\n temperature for fast rotating models.\n\nhttps://indico.cern.
ch/event/597202/contributions/2698394/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2698394/
END:VEVENT
BEGIN:VEVENT
SUMMARY:MAGIC - MAtter phase transitions at high baryon density\, Gravitat
ional waves and relativistic neutron star - and Ion- Collisions
DTSTART;VALUE=DATE-TIME:20170920T134000Z
DTEND;VALUE=DATE-TIME:20170920T142000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2696050@cern.ch
DESCRIPTION:Speakers: Horst Stoecker (GSI)\nGravitational waves\, Electrom
agnetic radiation and emission of High Energy Particles probe the phase st
ructure of the EoS of dense matter produced at the crossroad of the closel
y related relativistic collisions of heavy ions and of binary neutron star
s. \n3+1 dimensional special- and general relativistic hydrodynamic model
studies reveal a unique window of opportunity to observe phase transiti
ons in compressed baryon matter in statu nascendi by multimessenger obser
vations. The FAiR facility at GSI allows to study the universe in the Labo
ratory.\n\nhttps://indico.cern.ch/event/597202/contributions/2696050/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2696050/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Spectral Analysis of the Vela Pulsar and its Neutrino Cooling Rate
DTSTART;VALUE=DATE-TIME:20170921T174000Z
DTEND;VALUE=DATE-TIME:20170921T181000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2696048@cern.ch
DESCRIPTION:Speakers: Dmitry Ofengeim (Ioffe Institute)\nThe PSR B0833-45
(the Vela pulsar) is the famous neutron star. Its age is about $11$ kyr an
d it cools mainly via neutrino emission from its superdense core. Its surf
ace temperature of $\\sim 0.7$ MK was obtained from the analysis of its X-
ray spectrum assuming that the star's mass is $1.4$ $M_\\odot$ and the rad
ius is $10$ km (Pavlov et al. 2001\, ApJ 552\, L129). The Vela pulsar appe
ars to be one of the coldest middle-aged neutron stars with measured surfa
ce temperature.\n\nWe have reanalyzed the Vela's X-ray spectrum inferred f
rom archival *Chandra* observations (ObsID 127\, 131 and 1852). We have em
ployed a magnetic hydrogen (*nsmax*) atmosphere model from *Sherpa* packag
e\, considering a wide range of possible masses and radii. Our results sho
w that\, while the Vela's surface temperature is very close to that derive
d by Pavlov et al. (2001)\, the star has likely either large mass ($\\ge 1
.7$ $M_\\odot$) or large radius ($\\ge 13$ km).\n\nUsing the results of sp
ectral analysis\, we have considered the cooling of the Vela pulsar. We ha
ve assumed that the star has a nucleon core with strong triplet neutron su
perfluidity\, prohibited (or suppressed) direct Urca process and a partial
ly accreted outer envelope (the so-called minimal cooling paradigm\, Page
et al. 2004\, ApJSS 155\, 623). Neutron pairing produces a sufficient enha
ncement of neutrino emission from the core (compared to the standard neutr
ino cooling via modified Urca process) so that the neutrino cooling can be
responsible for the Vela's low temperature. Employing nuclear physics res
trictions on neutron triplet pairing models\, we can constrain the mass of
the accreted matter (containing light elements) in the Vela's outer envel
ope.\n\nhttps://indico.cern.ch/event/597202/contributions/2696048/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2696048/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Anisotropic Self-gravitating Objects
DTSTART;VALUE=DATE-TIME:20170918T204000Z
DTEND;VALUE=DATE-TIME:20170918T211000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2696047@cern.ch
DESCRIPTION:Speakers: Arman Stepanian (Yerevan Physics Institute)\nWe stud
y the anisotropic self-gravitating objects with polytropic equation of sta
te in both contexts of Newtonian gravity and General Relativity.\nFirst we
discuss Newtonian case\, where we start with hydrostatic equilibrium equa
tion. By arriving at Lane--Emden equation we study the effects of an aniso
tropic pressure on the boundary conditions of the anisotropic Lane–Emden
equation and the homology theorem.\nThen we go to the relativistic case a
nd by using the anisotropic Tolman–Oppenheimer–Volkov (TOV) equations\
, we explore the relativistic anisotropic Lane–Emden equations. After th
at we find how the anisotropic pressure affects the boundary conditions of
these equations.\nFor both cases some new physically well-defined solutio
ns are derived.\n\nhttps://indico.cern.ch/event/597202/contributions/26960
47/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2696047/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Turbulence in Core-Collapse Supernovae
DTSTART;VALUE=DATE-TIME:20170918T134000Z
DTEND;VALUE=DATE-TIME:20170918T142000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2695579@cern.ch
DESCRIPTION:Speakers: Ernazar Abdikamalov (Nazarbayev University)\nCore-co
llapse supernovae are the powerful explosions of massive stars that occur
at the end of their lives. They play a crucial role in the evolution of th
e Universe\, producing most elements heavier than iron and leading to the
formation of neutron stars and black holes. Despite their importance\, the
details of how they explode are still unclear. In this talk\, I will revi
ew the recent progress in our understanding of the explosion mechanism\, w
ith an emphasis on the role of turbulence in facilitating an explosion.\n\
nhttps://indico.cern.ch/event/597202/contributions/2695579/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2695579/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Null congruences crossing generic shells
DTSTART;VALUE=DATE-TIME:20170919T184000Z
DTEND;VALUE=DATE-TIME:20170919T191000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2695574@cern.ch
DESCRIPTION:Speakers: Hovhannes Demirchian (Byurakan Astrophysical Observa
tory)\nWe present a new technique for describing geodesic congruences (for
example the trajectory of a gas of photons or particles) crossing a gener
ic light-like shell in vacuum. In particular the change in the direction o
f the vector field of the congruence has been derived and shown to be in a
greement with the results of Barrabes and Hogan thus demonstrating the val
idity of this technique. For the case of null shells generated by infinite
simal BMS supertranslation type soldering\, the expansion and shear tensor
s of the congruence have also been calculated. We derived the surface equa
tion\, for relative motion orthogonal to the congruence after it crosses t
he shell\, proving also that the congruence is always hypersurface orthogo
nal and the rotation tensor is always zero. This means that the Eikonal ap
proximation can be applied to describe it as a wave on the future\, and th
is has been carried out for a special BMS type soldering. The conditions f
or focusing\, defocusing and formation caustics have been studied.\n\nhttp
s://indico.cern.ch/event/597202/contributions/2695574/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2695574/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Induced fermionic current by a magnetic tube in the cosmic spaceti
me
DTSTART;VALUE=DATE-TIME:20170920T130000Z
DTEND;VALUE=DATE-TIME:20170920T134000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2695569@cern.ch
DESCRIPTION:Speakers: Eugenio Bezerra de Mello (Universidade Federal da Pa
raíba)\nIn this talk we examine the vacuum fermionic current induced by a
magnetic field confined in a cylindrical tube of finite radius a in cosmi
c string spacetime. Three distinct configurations of magnetic fields are t
aken into account:\n\n ∙ a cylindrical shell of radius a\, \n ∙ a
magnetic field proportional to 1/r\, \n ∙ a constant magnetic field.\n
\n In these three cases\, the axis of the infinitely long tube coincide
s with the cosmic string. Our main objective is to analyze the induced azi
muthal fermionic current density outside the tube. We show that this curre
nt can be decomposed into a part corresponding to a zero-thickness magneti
c flux running along the string in addition to a core-induced contribution
. The latter explicitly depends on the specific magnetic fields configurat
ions considered.\n\nhttps://indico.cern.ch/event/597202/contributions/2695
569/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2695569/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Calculation of symmetry energy using Argonne family potentials wi
th three nucleon interaction
DTSTART;VALUE=DATE-TIME:20170919T174000Z
DTEND;VALUE=DATE-TIME:20170919T181000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2695568@cern.ch
DESCRIPTION:Speakers: Zahra Asadi Aghbolaghi (Zanjan University )\nCalcula
tion of symmetry energy using Argonne family potentials \nwith three nucle
on interaction \n\n\n*Z. Asadi and M. Bigdeli*\n\nDepartment of Physics\,
University of Zanjan\, Zanjan\, Iran\n\n The symmetry energy has bee
n given attention in recent years because of its fundamental important rol
e in both astrophysics and nuclear physics. The symmetry energy S is the d
ifference of the energy per particle in symmetric nuclear matter and pure
neutron matter\, which represents the energy cost of preserving an isospin
-symmetry in the homogeneous nucleonic matter [1]. The study of the equati
on of state EOS of asymmetric matter gives clearance for the understanding
of the behavior of the isospin asymmetry energy\, i.e.\, the "symmetry en
ergy".\n In this work\, we intend to apply lowest order constraine
d variational (LOCV) approach [2] to analyze the EOS of asymmetric nuclear
matter using Argonne family potentials with three nucleon interaction TNI
contribution. We have used AV18+TNI\, AV8′+TNI and AV6′+TNI potential
s to calculated symmetry energy and the saturation properties of symmetri
c nuclear matter and nuclear. AV8' [3] and AV6' [4] are built by eliminati
ng operatorial components of the AV18 [5] interaction\, while the remainin
g terms are re-projected to preserve as many properties of the original in
teraction as possible. The TNI model is a three body force approximation\,
which is added to the Hamiltonian that includes the two-body realistic in
teraction [6]. The inclusion of TNI modifies the agreement with the experi
ment. The density behavior of the symmetry energy for NN potential with TN
I contribution and without TNI contribution is moderately different\, espe
cially at low density [7]. \n\n[1] S. Gandol \, J. Carlson\, S. Reddy\, A.
W. Steiner\, R. B. Wiringa\, Eur. Phys. J. A50\, 10 (2014).\n\n[2] R.F. B
ishop\, C. Howes\, J. M. Irvine and M. Modarres\, J. Phys. G: Nucl. Phys.
4\, 1709 (1978).\n\n[3] B. S. Pudlineret al.\, Phys. Rev. C56\, 1720 (1997
).\n\n[4] R. B. Wiringa and S. C. Pieper\, Phys. Rev. Lett. 89\, 182501 (2
002).\n\n[5] R. B. Wiringa\, V. G. J. Stoks\, and R. Schiavilla\, Phys. Re
v. C 51\, 38 (1995).\n\n[6] I.E. Lagaris\, V.R. Pandharipande\, Nucl. Phys
. A 359\, 349(1981).\n\n[7] Z. Asadi\, M. Bigdeli\, Submitted to PRC.\n\nh
ttps://indico.cern.ch/event/597202/contributions/2695568/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2695568/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Is it possible to determine whether the EG 50 is a white or stran
ge dwarf by the nature of its cooling?
DTSTART;VALUE=DATE-TIME:20170919T194000Z
DTEND;VALUE=DATE-TIME:20170919T201000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2695565@cern.ch
DESCRIPTION:Speakers: Gevorg Hajyan (Yerevan State University)\nTaking int
o account the neutrino energy losses the time dependences of the luminosit
ies of a white dwarf and four strange dwarfs with masses of $0.5 M_\\odot$
(the mass of white dwarf EG 50 with the surface temperature $2.1\\cdot
10^4 K$) has been determined. It was assumed that these configurations r
adiate only at the expense of thermal energy reserves. It has been shown t
hat the sources of thermal energy due to nonequilibrium $\\beta$ -processe
s and the phenomenon of crystallization of the electron-nuclear matter in
determining the cooling time of white and strange dwarfs with a mass of $0
.5 M_\\odot$ are insignificant . It has been shown that in the considered
approximation\, the time dependences of the luminosities of the white and
strange dwarfs with a mass of $0.5 M_\\odot$ differ noticeable only at su
rface temperatures $T_R>7\\cdot 10^4 K$. So it is impossible to determine
the whether EG 50 belongs to white or strange dwarfs.\n\nhttps://indico.ce
rn.ch/event/597202/contributions/2695565/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2695565/
END:VEVENT
BEGIN:VEVENT
SUMMARY:An empirical nuclear Equation of State constrained by nuclear obse
rvables
DTSTART;VALUE=DATE-TIME:20170918T142000Z
DTEND;VALUE=DATE-TIME:20170918T150000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2695562@cern.ch
DESCRIPTION:Speakers: Debarati Chatterjee (LPC/ENSICAEN)\nOne of the chall
enges in nuclear physics is to describe finite nuclei and neutron stars wi
thin the same theoretical framework. A crucial entity is the nuclear Equat
ion of State (EoS)\, which can be defined in terms of a set of empirical p
arameters (saturation density\, compressibility\, symmetry energy and its
derivatives etc). In turn\, these quantities are constrained using experim
ental data on ground state nuclear properties. The phenomenological models
that are extensively employed in nuclear calculations have parameters tha
t are fit to well-determined empirical nuclear observables\, which must be
updated with the rapidly improving experimental data. Further\, they may
contain spurious correlations with the empirical quantities. In this work\
, we develop a model-independent unified description of nuclear matter\, t
hat can be related directly to empirical quantities specifically sensitive
to the EoS. We then apply this model to predict experimental observables
such as charge radii and the neutron skin.\n\nhttps://indico.cern.ch/event
/597202/contributions/2695562/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2695562/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Some theoretical aspects of magnetars
DTSTART;VALUE=DATE-TIME:20170921T152000Z
DTEND;VALUE=DATE-TIME:20170921T160000Z
DTSTAMP;VALUE=DATE-TIME:20170926T091949Z
UID:indico-contribution-597202-2695560@cern.ch
DESCRIPTION:Speakers: Monika Sinha (Indian Institute of Technology Jodhpur
)\nMagnetars have been observationally determined to have surface magnetic
fields of order of $10^{14} –10^{15}$ G\, the implied internal field st
rength being several orders larger. We discuss the effect of strong field
on the dense matter expected to be inside neutron stars. We describe the m
icrophysics\, phenomenology\, and astrophysical implication of strong fiel
d induced unpairing effect that may occur in magnetars\, if the local magn
etic field in the core of a magnetar exceeds a critical value. The density
dependence of pairing of proton condensate implies that the critical valu
e required for unpairing effect to occur is maximal at the crust-core inte
rface and decreases towards the center of the star. As a consequence\, mag
netar cores with homogenous constant fields will be partially superconduct
ing for “medium-field” magnetars whereas “strong-field” magnetars
will be void of superconductivity. We also discuss its effect on some obse
rvational effect which depend the nature and composition of matter inside
neutron stars.\n\nhttps://indico.cern.ch/event/597202/contributions/269556
0/
LOCATION:Yerevan\, Armenia
URL:https://indico.cern.ch/event/597202/contributions/2695560/
END:VEVENT
END:VCALENDAR