Plenary Sessions 
P.
Lasky
(Melbourne U., Australia)
Title:
What's next in gravitationalwave
astronomy?
Abstract:
The LIGOVirgoKAGRA collaborations
have now observed gravitational
waves from more than 100 mergers of
black holes and neutron stars. I
will give an overview of the physics
and astrophysics we've learned from
the beginning of this new field. I
will discuss what comes next, both
in terms of potential upcoming
discoveries, and the next generation
of observatories planned for the
2030s.
Back 
V.
Vaskonen
(U. of
Padova)
Title:
Primordial black holes.
Abstract:
In this talk, I will review the
formation of primordial black holes
and the constraints on their
abundance. I will also highlight the
potential observational signatures
of primordial black holes. In
particular, I will discuss the
possibility that some of the LIGOVirgo
gravitational wave events originate
from primordial black hole mergers,
the possibility that the
gravitational wave background seen
by PTAs is a signature of primordial
black hole formation in the early
Universe and the possibility that
the JWST observations of highz
galaxies are an imprint of a
primordial black hole population.
Back 
M.
Tortola
(Valencia U., IFIC)
Title:
Neutrino masses and mixings and
beyond
Abstract:
Since the historic discovery of
neutrino oscillations, the study of
their properties has been performed
within a wide variety of
experiments. Thanks to this great
experimental effort, the
determination of neutrino masses and
mixings has entered the precision
era. However, many challenges remain
such as the determination of the
ordering of the neutrino mass
spectrum, the octant of the
atmospheric mixing angle, and a
robust measurement of CP violation
in neutrino oscillation. Several
experiments involving powerful
accelerator neutrino sources and
very large detectors will try to
solve these questions in the near
future and also in the longer term.
Besides neutrino masses and mixings,
the existence of other exotic
neutrino properties, such as new
interactions with matter or neutrino
electromagnetic properties are
searched for in a variety of
experiments. In that respect,
observing neutralcurrent coherent
elastic neutrinonucleus scattering
(CEvNS) at the COHERENT experiment
has opened a new window to search
for new physics beyond the Standard
model. We will discuss the potential
of current and upcoming CEvNS
experiments to investigate neutrino
properties.
Back 
J.R.
Ellis
(CERN
and Kings College)
Title:
What is the source of the
gravitational waves detected by PTA
experiments?
Abstract:
The most conservative interpretation
of the nHz gravitational waves
discovered by NANOGrav and other
Pulsar Timing Array (PTA)
Collaborations is astrophysical,
namely that they arise from
supermassive black hole (SMBH)
binaries. However, alternative
cosmological models have been
proposed, including cosmic strings,
phase transitions, domain walls,
primordial fluctuations and
"audible" axions. We compare how
well these different hypotheses fit
the NANOGrav data, both in isolation
and in combination with SMBH
binaries, and address the questions:
Which interpretations fit the data
best, and which are disfavoured? We
also discuss experimental signatures
that can help discriminate between
different sources of the PTA GW
signal, including fluctuations in
the signal strength between
frequency bins, individual sources
and how the PTA signal extends to
higher frequencies.
Back 
G.
Barnich
(ULB,
Brussels)
Title:
Lessons from DLCQ for physics at
null infinity.
Abstract:
Motivated by issues in the context
of asymptotically flat spacetimes at
null infinity, we clarify in the
simplest example of a massless
scalar field in two dimensions
several subtleties that arise when
setting up the canonical formulation
on a single or on two intersecting
null hypersurfaces with a special
emphasis on the infinitedimensional
global and conformal symmetries, the
free data, a consistent treatment
of zero modes, matching conditions,
implications for quantization of
massless versus massive fields and
on a derivation from first
principles of the socalled modified
bracket.
Back 
P.
Ullio
(SISSA,
Italy)
Title:
An outlook on
particle dark matter phenomenology.
Abstract:
Back 
W.
Buchmuller
(DESY)
Title:
Baryogenesis  a piece of a puzzle.
Abstract:
The ratio of the number density of
baryons to photons in the universe
is a tiny number O(10^9). It must
be explained dynamically and in this
way it connects particle physics
beyond the Standard Model with the
physics of the very early universe.
The implications for Higgs physics,
dark matter, neutrino physics and
gravitational waves are illustrated
with several representative
examples. Baryogenesis significantly
constrains different extrapolations
of the Standard Model to shorter
distances.
Back 
Sanjib Kumar Agarwalla (Institute
of Physics, Bhubaneswar, India and
University of WisconsinMadison, WI,
USA)
Title:
Imaging the Earth with Atmospheric
Neutrinos
Abstract:
Neutrinos produced in cosmic ray
interactions in the atmosphere
provide a unique and independent
probe to explore the internal
structure and composition of the
deep Earth, which is complementary
to traditional seismic
and gravitational measurements and
pave the way for multimessenger
tomography of Earth. I will discuss
the two different approaches to
perform Earth tomography with
neutrinos: (i) neutrino absorption
tomography, based on partial
absorption of a highenergy TeVPeV
neutrino flux as it propagates
through Earth and (ii) neutrino
oscillation tomography, based on
Earth matter effects due to the
coherent forward scattering of
multiGeV neutrinos with the ambient
electrons modifying neutrino
oscillation patterns. I will
subsequently show how well the
DeepCore detector, a
densely instrumented subarray of
the IceCube neutrino observatory at
the South Pole, can observe these
Earth matter effects in atmospheric
neutrino oscillations using 9.3
years of data. We
will further demonstrate that these
matter effects in oscillations of
atmospheric neutrinos can be used to
establish the layered structure
inside Earth and measure the mass of
Earth and mass of core. I will
conclude my talk discussing the
remarkable physics reach of a new
extension of DeepCore to be deployed
in the Antarctic summer of 2025/26,
called the IceCube Upgrade.
Back 
S.
Parameswaran
(U.
of Liverpool)
Title:
String Cosmology: from the Early
Universe to Today.
Abstract:
I'll give some taste of applications
of string theory to cosmology, from
primordial times to the presentday
accelerated expansion. Time
permitting, I'll discuss the main
challenges of moduli stabilisation,
inflation in string theory, the
impact of string theory on
postinflationary dynamics, dark
matter and dark energy, drawing
connections with swampland
conjectures, and emphasise
possibilities for novel particles,
excitations, and opportunities for
observations.
Back 
C.
Herdeiro
(U.
Aveiro, Portugal)
Title:
Testing the Kerr hypothesis:
universality, imitators and
dynamical signatures.
Abstract:
To what extent are all
astrophysical, dark, compact objects
both black holes (BHs) and described
by the Kerr geometry? We embark on
the exercise of defying the
universality of this remarkable
idea, often called the "Kerr
hypothesis". After establishing its
rationale and timeliness, we define
a minimal set of reasonability
criteria for alternative models of
dark compact objects. Then, as proof
of principle, we discuss concrete,
dynamically robust nonKerr BHs and
horizonless imitators, that 1) pass
the basic theoretical, and in
particular dynamical, tests, 2)
match (some of the) state of the art
astrophysical observables and 3)
only emerge at some (macroscopic)
scales. These examples illustrate
how the universality (at all
macroscopic scales) of the Kerr
hypothesis can be challenged
Back 
E. O
Colgain
(ATU,
Sligo, Ireland)
Title:
Is H0 a constant in LambdaCDM
cosmology?
Abstract:
I will outline a natural diagnosis
of the Hubble and S8 tension
problems in terms of redshift
dependent cosmological parameters.
If true, this is not a resolution to
the problem, but it simply provides
confirmation that the model has
broken down. I comment on
the difficulties processing these
ideas in the traditional Bayesian
framework.
Back 
Parallel Sessions 
Hepph 
M.
Bustamante
(Bohr Inst.)
Title:
Neutrino physics at the cosmic and energy frontiers.
Abstract:
Highenergy (TeVPeV) and
ultrahighenergy (> 100 PeV)
neutrinos of cosmic origin have
a vast potential to probe
neutrino physics in regimes of
energy and distance otherwise
unreachable. Notable examples
include measuring the
neutrinomatter cross section
beyond accelerator energies,
precision tests using the flavor
composition of the neutrino
flux, testing whether neutrinos
are unstable, and whether they
interact secretly with one
another. Today, we are already
tapping into this potential at
high energies, thanks to recent
discoveries by the IceCube
neutrino telescope. In the
coming decade, we will enter a
regime of higher statistics and
may extend our reach to
ultrahigh energies, thanks to
an ambitious experimental
program currently under
planning. By means of
illustration, I will briefly
survey the rich landscape of
highenergy physics with cosmic
neutrinos, from the perspectives
of theory and experiment. Along
the way, I will point out
manifest instances of the
natural synergy between
lowenergy and highenergy
neutrino experiments, and the
need to account for
astrophysical unknowns.
Back

S.
Ansarifard
(IPM)
Title:
The light pseudoscalar lepton
interaction inside the Sun
Abstract:
The longrange force mediated by
a light scalar coupled to SM
fermions is a vastly studied
example of finding new physics.
In this talk, after a brief
review, I explain the physics of
such a longrange force inside
the Sun.
In this regard, I assume a
derivative coupling to electron
neutrino, considering the Sun medium
I find appropriate potential
sourced by electron density. I
examine the adiabatic
approximation for this potential
and I show the effect of this
new physics on the survival
probability of electron
neutrinos. In the end, I
discuss the constraints received
from recent experiments.
Back 
J.
Turner
(Durham
U)
Title:
Primordial Black Holes and the early
universe.
Abstract:
Primordial black holes, which could
have potentially formed after cosmic
inflation, can have significant
implications for the early
Universe's development. These black
holes, which may have differing mass
and spin, undergo evaporation due to
Hawking radiation at different
points in cosmic history. In this
presentation will explore the
potential impact of this evaporation
on various cosmological observables,
including the creation of
matterantimatter asymmetry, dark
radiation, and dark matter.
Back 
J.
HerreroGarcia
(Valencia U. (IFIC))
Title:
An EFT
approach to lepton and baryon number
violation.
Abstract:
In this presentation, I will discuss
lepton and baryon number violation
using an Effective Field Theory (EFT)
approach. In particular, in the
first part of the talk, I will
analyse the generation of treelevel
Majorana neutrino masses by
the introduction of new scalar
multiplets at the electroweak scale,
which acquire vacuum expectation
values (VEVs). We will elucidate the
underlying UV completions for these
effective operators, specifically
the new seesaw models, and
investigate their impact on neutrino
masses, including contributions at
the loop level. We will discuss the
phenomenology of these scenarios,
including constraints from
Electroweak Precision Tests, Lepton
Flavor Violation, and colliders. In
the second part of the talk, I will
explore nucleon decays using SMEFT
operators up to dimension 9. We will
present estimates for the rates of
various nucleon decay channels and
use these to extract
modelindependent lower limits on
the energy scale associated with
these processes. Additionally, we
will investigate potential
correlations among processes.
Back 
A. Ahmed
(MPIK Heidelberg)
Title:
Light hidden sectors,
neutrino masses and dark matter.
Abstract:
We present a class of
models in which the hidden sector is
conformal in the ultraviolet, and
the compositeness scale lies at or
below the weak scale. The hidden
sector interacts with the standard
model through the neutrino portal.
In this framework, dark matter is
the lightest stable composite state
of the hidden sector. When the
hidden sector is in thermal
equilibrium with the Standard Model,
the dark matter relic abundance is
determined by annihilation into
final states containing neutrinos
through freezeout mechanism.
However, when the hidden sector is
out of equilibrium with the Standard
Model, dark matter is produced
through the freezein mechanism. The
neutrino portal also leads to the
generation of neutrino masses
through the inverse seesaw
mechanism, with composite hidden
sector states playing the role of
the singlet neutrinos. We construct
a holographic realization of this
framework based on a
fivedimensional warped geometry and
study its phenomenology.
Back 
N.
Bozorgnia
(Alberta
U.)
Title:
The Influence of the LMC on dark
matter direct detection.
Abstract:
The Large Magellanic Cloud (LMC) can
significantly impact the dark matter
halo of the Milky Way, and boost the
dark matter velocity distribution in
the Solar neighborhood. Cosmological
simulations that sample potential
Milky Way formation histories are
powerful tools, which can be used to
characterize the signatures of the
LMC’s interaction with the Milky
Way, and can provide crucial insight
on the LMC’s effect on the local
dark matter distribution. I will
discuss the influence of the LMC on
the local dark matter distribution
in stateoftheart cosmological
simulations, and its implications
for dark matter direct detection.
Back 
Hepth 
R.
Casadio
(Bologna
Uni)
Title:/b>
Quantum integrable black
holes.
Abstract:
It is common to assume that
quantum gravity belongs at
the Planck scale, but a
possibly much larger width
for the ground state emerges
in the (nonperturbative)
quantisation of the
OppenheimerSnyder model of
dust collapse that naturally
recovers Bekenstein’s area
law. The effective geometry
for such quantum black holes
can then be obtained from
coherent states which
describe integrable
singularities without inner
horizons. The extension to
quantum (differentially)
rotating black holes with
similar properties is also
described.
Back 
A.
Mollabashi
(IPM)
Title:
Timelike Entanglement Entropy.
Abstract:
Motivated by the geometrical
understanding of quantum information
measures in AdS/CFT, I will
introduce a twostate generalization
of von Neumann entropy known as
pseudoentanglement entropy as well
as a novel quantity corresponding to
timelike regions on the CFT side
which we call "timelike entanglement
entropy" (TEE). It turns out that
TEE is a special case of
pseudoentanglement entropy.
Concrete definitions on the CFT side
together with a prescription to
calculate TEE in 2d free quantum
field theories will be introduced,
which contains some clues about how
to understand TEE in quantum
information theory. I will also
introduce our first version of a
holographic prescription to
calculate TEE in AdS3/CFT2 and
address how TEE in AdS3/CFT2 is
related to EE in dS3/CFT2.
Back 
A.
Seraj
(IPM)
Title:
The Infrared triangle in Fracton
gauge theory
Abstract:
In theories with conserved
dipole moment, isolated charged
particles (fractons) are
immobile, but dipoles can move.
We couple these dipoles to the
fracton gauge theory and analyze
the universal infrared
structure. This uncovers an
observable memory effect which
we relate to a novel dipole soft
theorem. Together with their
asymptotic symmetries, this
constitutes the first
realization of an infrared
triangle beyond Lorentz
symmetry, which demonstrates
their robustness and paves the
way for their investigation in
condensed matter systems and
beyond.
Back 
A.A.
Parvizi
(IPM)
Title:
Hydrodynamics at Causal Boundaries.
Abstract:
In many physical scenarios, it is
necessary to describe physics in the
presence of a boundary. In such
cases we should account for the
degrees of freedom (d.o.f.) that
reside on the boundary and study
their dynamics. This talk focuses on
the boundary d.o.f. and their
dynamics in a gravitational theories
on a spacetime with timelike and
null boundaries. We study
3dimensional gravity and explore
the solution phase space, boundary
charges and their algebra. Three of
these charges generalize the
BrownYork charges to any causal
boundary, and are related to the
boundary metric components. They
also lead to a fluid description of
the causal boundary. When the causal
boundary is the asymptotic boundary
of the 3d AdS or flat space, we
recover the conformal or conformalCarrollian
asymptotic hydrodynamics,
respectively.
Back 
V.
Taghiloo
(IPM)
Title:
Shallow Water Memory.
Abstract:
As the name
shallow water suggests, a
shallow water system refers to a
fluid system where the depth is
significantly smaller than its
horizontal extent. The
atmosphere and oceans are prime
examples of such systems. In
this talk, we will explore the
fascinating connection between
gauge theory and shallow water
systems. After reviewing the
gauge theory description of
shallow water systems, we will
introduce an intriguing
phenomenon known as the shallow
water memory effect. This is the
fluid analog of the displacement
memory effect in gravitational
theories.
It is important
to point out that the accuracy
of current detectors of
gravitational waves is not
enough to detect this
phenomenon. For this reason,
revealing the shallow water
memory can be promising for
revealing the gravitational
memory effects.
Back

C.
Zwikel
(Perimeter Inst.)
Title: The
partial Bondi gauge: asymptotic
charges and gauge fixing.
Abstract:
In this talk, I will discuss the
future null boundary of
asymptotically flat spacetimes in
four dimensions. I will introduce
the partial Bondi gauge that include
as particular cases both the usual
Bondi gauge and the NewmanUnti
gauge. The partial Bondi gauge
exhibits additional symmetries. I
will show that two of them possess
nonvanishing charges, rendering
them physically relevant.
Back 
Cosmology 
E. Di
Valentino
(Uni. of
Sheffield)
Title:
Unresolved Anomalies and Tensions in
the Standard Cosmological Model.
Abstract:
The standard Lambda Cold Dark Matter
cosmological model has been
incredibly successful in explaining
a wide range of observational data,
from the cosmic microwave background
radiation to the largescale
structure of the universe. However,
recent observations have revealed a
number of inconsistencies among the
model's key cosmological parameters,
which have different levels of
statistical significance. These
include discrepancies in
measurements of the Hubble constant,
the S8 tension, and the CMB tension.
While some of these inconsistencies
could be due to systematic errors,
the persistence of such tensions
across various probes suggests a
potential failure of the canonical
LCDM model. I will examine these
inconsistencies and discuss possible
explanations, including
modifications to the standard model,
that could potentially alleviate
them. However, I will also discuss
the limitations of these proposed
solutions and note that none of them
have successfully resolved the
discrepancies.
Back 
E.
Ebrahimian
(ICTP)
Title:
What does a Dipole universe look
like?
Abstract:
There are various tensions in
cosmology, but there is also
mounting evidence for a cosmic
dipole that cannot be explained
by local peculiar motion alone.
This suggests that the dipole
may not be solely kinematic in
nature and maybe this is why we
faced these tensions. In this
talk, we explore the
observational implications of
Dipole Cosmology, which is a
simplest model that incorporates
anisotropic geometry and
energymomentum tensor. As such,
it can account for a nonkinematic
dipole. Some dynamical aspects
of Dipole Cosmology were
investigated in C. Krishnan et
al. 2023, A. Allahyari et al.
2023, and E. Ebrahimian et
al. 2023.
Back 
G.
Geshnizjani
(Uni. of
Waterloo)
Title:
On the initial singularity and
extendibility of flat quaside
Sitter spacetimes.
Abstract:
Inflationary spacetimes have been
argued to be past geodesically
incomplete in many situations.
However, whether the geodesic
incompleteness implies the existence
of an initial spacetime curvature
singularity or whether the spacetime
may be extended (potentially into
another phase of the universe) is
generally unknown. Both questions
have important physical
implications. In this talk, we take
a closer look at the geometrical
structure of inflationary spacetimes
and investigate these very
questions. I will first discuss
classifying which past inflationary
histories have a scalar curvature
singularity and which might be
extendible and/or nonsingular in
homogeneous and isotropic cosmology
with flat spatial sections. Then,
briefly go over derivation of a
rigorous extendibility criteria of
various regularity classes for
quaside Sitter spacetimes that
evolve from infinite proper time in
the past. Finally, I will argue that
beyond homogeneity and isotropy,
special continuous extensions
respecting the Einstein field
equations with a perfect fluid must
have the equation of state of a de
Sitter universe asymptotically. An
interpretation of these results is
that pasteternal inflationary
scenarios are most likely physically
singular, except in situations with
very special initial conditions.
Back 
M.H.
Namjoo
(IPM)
Title:
Tail diversity from inflation.
Abstact:
The tail of the distribution of
cosmological primordial fluctuations
is of interest, from both
theoretical and observational
perspectives. In particular, it is
relevant for accurately evaluating
the primordial black hole (PBH)
abundance, which is sensitive to the
likelihood of realization of large
fluctuations. In this talk, I will
first advocate the nonperturbative
form of the socalled \delta N
formalism as a method to estimate
the probability distribution
function (PDF) of primordial
fluctuations and discuss several
subtleties that may arise due to the
consideration of large fluctuations.
Next, I will show that there is a
diverse zoo of possible tails from
inflation so that, generally, a
modeldependent and nonperturbative
study of the PDF of the primordial
fluctuations seems inevitable
concerning PBH abundance.
Back 
V. De
Luca
(Pennsylvania U.)
Title:
Superfluid dark matter around black
holes.
Abstract:
The theory of superfluid dark matter
is based on subeV,
selfinteracting, bosons which may
undergo BoseEinstein condensation
at the center of galaxies, thus
creating a superfluid homogeneous
core. We show how the superfluid
density profile changes when massive
black holes sit within these
environments, giving rise to dark
matter spikes whose slopes depend on
the bosons selfinteractions.
Finally, we discuss the role of
dynamical friction in the evolution
of black hole binaries moving within
the superfluid.
Back 
S. Jazayeri
(TBC)
Title:
Cosmological Phonon Collider.
Abstract:
The expansion of the universe
spontaneously breaks time
translation by selecting a
preferred reference frame. As a
consequence, very much like a
superfluid at zero
temperature, the lowenergy
description of single field
inflation can be organised in
terms of the associated
Goldstone mode of the broken
symmetry (aka the phonon).
Similar to particle colliders,
if we were to scatter sound
waves, the presence of
additional heavy fields coupled
to the medium would manifest as
distinct peaks
in the crosssection
of the phonons. In this talk, I
introduce a cosmological version
of this idea, in
which the imprints of additional
heavy particles during inflation
are encoded in the late time
boundary correlators
of the Goldstone boson. I
discuss various phenomenological
consequences of this setup
for the primordial bispectrum
and trispectrum.
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