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BEGIN:VEVENT
SUMMARY:Force-free electrodynamics near the rotation axis of a Kerr black
hole
DTSTART;VALUE=DATE-TIME:20190910T121500Z
DTEND;VALUE=DATE-TIME:20190910T130000Z
DTSTAMP;VALUE=DATE-TIME:20200712T075444Z
UID:indico-contribution-19413-99211@agenda.infn.it
DESCRIPTION:Speakers: Gianluca Grignani (PG)\nDespite their potential impo
rtance for understanding astrophysical jets\, physically realistic exact s
olutions for magnetospheres around Kerr black holes have not been found\,
even in the force-free approximation. Instead\, approximate analytical sol
utions such as the perturbative solution in the spin parameter proposed by
Blandford and Znajek\, as well as numerical solutions\, have been constru
cted. I will introduce a new approach to the analysis and construction of
such magnetospheres by considering force-free electrodynamics close to the
rotation axis of a magnetosphere surrounding a Kerr black hole assuming a
xisymmetry. This is the region where the force-free approximation should w
ork the best and where the jets are located. I will illustrate a systemati
c study of the asymptotic region with (split-)monopole\, paraboloidal and
vertical asymptotic behaviors. In the (split-)monopole case\, I will show
that by demanding regularity in the asymptotic region\, at the rotation ax
is and the event horizon\, restricts solutions of the stream equation so m
uch that it is not possible for a solution to be continuously connected to
the static (split-)monopole around the Schwarzschild black hole in the li
mit where the rotation goes to zero. This provides independent evidence to
the issues discovered with the asymptotics of the Blandford-Znajek (split
-)monopole from which it follows that its perturbative construction is inc
onsistent.\n\nhttps://agenda.infn.it/event/19413/contributions/99211/
LOCATION:
URL:https://agenda.infn.it/event/19413/contributions/99211/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gravity from worldlines
DTSTART;VALUE=DATE-TIME:20190910T151500Z
DTEND;VALUE=DATE-TIME:20190910T160000Z
DTSTAMP;VALUE=DATE-TIME:20200712T075444Z
UID:indico-contribution-19413-99207@agenda.infn.it
DESCRIPTION:Speakers: Roberto Bonezzi (Humboldt University Berlin)\nIn thi
s talk I will present the first-quantized description of Einstein gravity
in terms of a point particle model with N=4 local worldline supersymmetrie
s. In particular\, I will discuss how the quantum consistency of the under
lying first-quantized system produces fully nonlinear Einstein field equat
ions for the target space metric\, thus showing that this is not a peculia
rity of string theory.\nAs a warmup\, I will first present the simpler cas
e of a worldline model with N=2 supersymmetries\, describing Yang-Mills\,
and then move to the recently found results for gravity.\n\nhttps://agenda
.infn.it/event/19413/contributions/99207/
LOCATION:
URL:https://agenda.infn.it/event/19413/contributions/99207/
END:VEVENT
BEGIN:VEVENT
SUMMARY:A worldline quantization approach to higher spin theories
DTSTART;VALUE=DATE-TIME:20190910T143000Z
DTEND;VALUE=DATE-TIME:20190910T151500Z
DTSTAMP;VALUE=DATE-TIME:20200712T075444Z
UID:indico-contribution-19413-99262@agenda.infn.it
DESCRIPTION:Speakers: Stefano Giaccari (Holon Institute of Technology)\nUs
ing the effective action method\, we investigate the higher spin actions i
n flat spacetime that can be obtained by integrating out a fermion field c
oupled to external higher spin source fields. In particular\, an approach
based on worldline quantization allows to identify the gauge symmetry of t
hese models and to find the L_infinity structure that characterizes many (
classical) field theories\, including closed string field theory. This str
ucture is also found to be consistent with a Yang-Mills-like model\, where
a limited amount of non-locality plays a crucial role in granting the abs
ence of ghosts at perturbative level.\n\nhttps://agenda.infn.it/event/1941
3/contributions/99262/
LOCATION:
URL:https://agenda.infn.it/event/19413/contributions/99262/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Thermal field theory with acceleration\, entropy current and Unruh
effect
DTSTART;VALUE=DATE-TIME:20190909T091500Z
DTEND;VALUE=DATE-TIME:20190909T100000Z
DTSTAMP;VALUE=DATE-TIME:20200712T075444Z
UID:indico-contribution-19413-99375@agenda.infn.it
DESCRIPTION:Speakers: Davide Rindori (University of Florence and INFN)\nWe
evaluate the thermal expectation values in a free quantum field theory at
global thermodynamic equilibrium with acceleration in Minkowski space- ti
me. It is found that Unruh temperature TU = A/2π is an absolute lower bou
nd for the comoving temperature along the hyperbolic flow lines. We also p
resent a method to determine the entropy current\, and we find that at the
Unruh temperature the integral of the entropy current yields the en- tang
lement entropy of the right Rindler wedge in the Minkowski vacuum state.\n
\nhttps://agenda.infn.it/event/19413/contributions/99375/
LOCATION:
URL:https://agenda.infn.it/event/19413/contributions/99375/
END:VEVENT
BEGIN:VEVENT
SUMMARY:One-loop effective action of quantum gravity with fakeons and its
phenomenology
DTSTART;VALUE=DATE-TIME:20190909T143000Z
DTEND;VALUE=DATE-TIME:20190909T151500Z
DTSTAMP;VALUE=DATE-TIME:20200712T075444Z
UID:indico-contribution-19413-99260@agenda.infn.it
DESCRIPTION:Speakers: Marco Piva (Penn State University)\nIn this talk I w
ill expose the features of a new local higher-derivative theory of quantum
gravity. The model is based on the concept of “fakeons” or “fake de
grees of freedom”\, which solves the problem of ghosts and leads to a un
itary\, renormalizable theory. In particular\, I will show the absorptive
part of the graviton self-energy at one loop and its contributions to the
effective action\, both in pure gravity and in the theory coupled with any
type of matter field. I will point out the differences with respect to th
e usual treatment of higher-derivative gravity and some phenomenological i
mplications. Finally\, possible applications in cosmological pertrubation
theory will be addressed.\n\nhttps://agenda.infn.it/event/19413/contributi
ons/99260/
LOCATION:
URL:https://agenda.infn.it/event/19413/contributions/99260/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Lagrangian Formalism for (Super)fluids and (Super)Solids
DTSTART;VALUE=DATE-TIME:20190909T130000Z
DTEND;VALUE=DATE-TIME:20190909T134500Z
DTSTAMP;VALUE=DATE-TIME:20200712T075444Z
UID:indico-contribution-19413-99205@agenda.infn.it
DESCRIPTION:Speakers: Denis Comelli (FE)\nAn effective field theory lagran
gian formalism of four scalar DoF allows to describe both self gravitating
non dissipative fluids and generic massive gravity models as identical sy
stems. We elaborate on the stability of massive gravity models with six Do
F and on the behaviour of cosmological perturbations.\n\nhttps://agenda.in
fn.it/event/19413/contributions/99205/
LOCATION:
URL:https://agenda.infn.it/event/19413/contributions/99205/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Fakeons\, microcausality and quantum gravity: the FLRW metric
DTSTART;VALUE=DATE-TIME:20190909T151500Z
DTEND;VALUE=DATE-TIME:20190909T160000Z
DTSTAMP;VALUE=DATE-TIME:20200712T075444Z
UID:indico-contribution-19413-99206@agenda.infn.it
DESCRIPTION:Speakers: Damiano Anselmi (PI)\nUnder certain assumptions\, it
is possible to make sense of higher derivative theories by quantizing the
unwanted degrees of freedom as fakeons\, which are later projected away.
Then the true classical limit is obtained by classicizing the quantum theo
ry. Since quantum field theory is formulated perturbatively\, the classici
zation is also perturbative. After deriving a number of properties in a ge
neral setting\, we consider the theory of quantum gravity that emerges fro
m the \nfakeon idea and study its classicization\, focusing on the FLRW me
tric. We point out cases where the fakeon projection can be handled exactl
y\, which include radiation\, the vacuum energy density and the combinatio
n of the two\, and cases where it cannot\, which include dust. Generically
\, the classical limit shares many features with the quantum theory it com
es from\, including the impossibility to write down complete\, “exact”
field equations\, to the extent that asymptotic series and \nnonperturbat
ive effects come into play.\n\nhttps://agenda.infn.it/event/19413/contribu
tions/99206/
LOCATION:
URL:https://agenda.infn.it/event/19413/contributions/99206/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Infrared dynamics in asymptotically FLRW spacetime
DTSTART;VALUE=DATE-TIME:20190909T121500Z
DTEND;VALUE=DATE-TIME:20190909T130000Z
DTSTAMP;VALUE=DATE-TIME:20200712T075444Z
UID:indico-contribution-19413-99280@agenda.infn.it
DESCRIPTION:Speakers: Yuko Urakawa (Bielefeld University)\nIn various cosm
ological models\, the curvature perturbation $\\zeta$ has a constant solut
ion in the infrared (IR) limit and $\\zeta$ fulfills the soft theorem\, a.
k.a\, the consistency relation. However\, it has not been very clear what
ensures these properties. We show the existence of the constant solution a
nd the soft theorem\, assuming the asymptotically FLRW geometry and the in
variance under the large gauge transformation. In this regard\, the situat
ion is quite similar to gauge theories in asymptotically flat spacetimes (
Strominger et al.\, 13). Based on this\, we propose a general classificati
on of cosmological models according to different IR behaviors.\n\nhttps://
agenda.infn.it/event/19413/contributions/99280/
LOCATION:
URL:https://agenda.infn.it/event/19413/contributions/99280/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Gauging 1-form center symmetries\, Mixed anomalies and Infrared dy
namics in SU(N) gauge theories
DTSTART;VALUE=DATE-TIME:20190910T100000Z
DTEND;VALUE=DATE-TIME:20190910T104500Z
DTSTAMP;VALUE=DATE-TIME:20200712T075444Z
UID:indico-contribution-19413-99261@agenda.infn.it
DESCRIPTION:Speakers: Kenichi Konishi (Univ. Pisa and INFN\, Pisa)\nConseq
uence of gauging 1-form discrete center symmetries are studied in some sim
ple SU(N) gauge theories. In particular\, we discuss how the dynamics of s
trongly coupled chiral gauge theories is constrained by the mixed anomalie
s involving the new\, 1-form symmetries and conventional 0-form symmetries
.\n\nhttps://agenda.infn.it/event/19413/contributions/99261/
LOCATION:
URL:https://agenda.infn.it/event/19413/contributions/99261/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Superlines and Integration on Supermanifolds
DTSTART;VALUE=DATE-TIME:20190910T091500Z
DTEND;VALUE=DATE-TIME:20190910T100000Z
DTSTAMP;VALUE=DATE-TIME:20200712T075444Z
UID:indico-contribution-19413-99213@agenda.infn.it
DESCRIPTION:Speakers: Pietro Grassi (Universita' del Piemonte Orientale)\n
https://agenda.infn.it/event/19413/contributions/99213/
LOCATION:
URL:https://agenda.infn.it/event/19413/contributions/99213/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Towards a Worldline Monte Carlo approach in curved space
DTSTART;VALUE=DATE-TIME:20190910T070000Z
DTEND;VALUE=DATE-TIME:20190910T074500Z
DTSTAMP;VALUE=DATE-TIME:20200712T075444Z
UID:indico-contribution-19413-99212@agenda.infn.it
DESCRIPTION:Speakers: Maurizio Muratori (Università di Modena e Reggio Em
ilia)\nNumerical Worldline MonteCarlo techniques in flat spacetime have be
en deeply developed in order to extract physical information from QFT syst
ems. We study a possible way to extend such procedures to the case of (Euc
lidean) curved spaces\, where the proper-time discretization of a bosonic
worldline point-particle is treated similarly to a time-slicing regulariza
tion for the associated quantum path integral. In particular\, it induces
a well-known counterterm in the theory which\, together with curvature eff
ects arising directly from the curved metric tensor\, plays the role of a
potential. To test the setup\, we focus on the calculation of the free hea
t kernel of a bosonic point-particle on a D-sphere\, for which the express
ions of the effective potential and of the metric tensor were provided in
closed form. Here\, the curved space problem was turned into a flat space
one\, making the verification of our numerical method quite straightforwar
d.\n\nhttps://agenda.infn.it/event/19413/contributions/99212/
LOCATION:
URL:https://agenda.infn.it/event/19413/contributions/99212/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Contact quantization: from the harmonic oscillator to the anharmon
ic one\, and back
DTSTART;VALUE=DATE-TIME:20190910T130000Z
DTEND;VALUE=DATE-TIME:20190910T134500Z
DTSTAMP;VALUE=DATE-TIME:20200712T075444Z
UID:indico-contribution-19413-99209@agenda.infn.it
DESCRIPTION:Speakers: Emanuele Latini (University of Bologna and INFN Bolo
gna)\nWe will show how quantization together with quantum dynamics can be
simultaneously formulated as the problem of finding an appropriate flat co
nnection (named contact connection) on a Hilbert bundle over a contact man
ifold. In this setting we will discuss the local\, formal gauge equivalenc
e for a broad class of quantum dynamical systems\; just as classical dynam
ics depends on choices of clocks\, local quantum dynamics can be reduced t
o a problem of studying gauge transformations. As an example and applicati
on of this new approach to the quantization procedure\, we discuss the gau
ge tranformation relating the contact connection for the HO to the AHO one
\, and possibly discuss the space of solutions of the parallel section pro
blem.\n\nhttps://agenda.infn.it/event/19413/contributions/99209/
LOCATION:
URL:https://agenda.infn.it/event/19413/contributions/99209/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Aspects of scale invariant gravity
DTSTART;VALUE=DATE-TIME:20190910T074500Z
DTEND;VALUE=DATE-TIME:20190910T083000Z
DTSTAMP;VALUE=DATE-TIME:20200712T075444Z
UID:indico-contribution-19413-99208@agenda.infn.it
DESCRIPTION:Speakers: Massimiliano Rinaldi (TIFP)\nIn this talk we discuss
the possibility that tensor-scalar gravity is naturally scale-invariant\,
at least at the classical level. This assumption has a number of phenomen
ological consequences on the physics of the Universe at large scale and of
black holes. We consider some of these to assess whether scale-invariance
is a viable and fundamental symmetry.\n\nhttps://agenda.infn.it/event/194
13/contributions/99208/
LOCATION:
URL:https://agenda.infn.it/event/19413/contributions/99208/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Chiral fermions and trace anomalies
DTSTART;VALUE=DATE-TIME:20190909T100000Z
DTEND;VALUE=DATE-TIME:20190909T104500Z
DTSTAMP;VALUE=DATE-TIME:20200712T075444Z
UID:indico-contribution-19413-99204@agenda.infn.it
DESCRIPTION:Speakers: Fiorenzo Bastianelli (BO)\nWe discuss chiral fermion
s in gauge (and gravitational) backgrounds\,\nand focus on the structure o
f their trace anomalies.\nWe regulate the quantum theory with Pauli-Villar
s fields\nand do not find party-odd terms in the trace anomalies.\nThe lat
ter have been the object of recent analyses.\n\nhttps://agenda.infn.it/eve
nt/19413/contributions/99204/
LOCATION:
URL:https://agenda.infn.it/event/19413/contributions/99204/
END:VEVENT
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