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BEGIN:VEVENT
SUMMARY:Astrophysical Graviton Squeezing Can Be Hidden in the Far Field
DTSTART;VALUE=DATE-TIME:20261025T075000Z
DTEND;VALUE=DATE-TIME:20261025T081000Z
DTSTAMP;VALUE=DATE-TIME:20261025T024635Z
UID:indico-contribution-655-3064@indico.itp.ac.cn
DESCRIPTION:Speakers: Zi-Zheng Zhou ()\nhttps://indico.itp.ac.cn/event/427
 /contributions/3064/
LOCATION:
URL:https://indico.itp.ac.cn/event/427/contributions/3064/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Cosmological Stasis and Its Phenomenological Implications
DTSTART;VALUE=DATE-TIME:20261024T060000Z
DTEND;VALUE=DATE-TIME:20261024T062000Z
DTSTAMP;VALUE=DATE-TIME:20261025T024635Z
UID:indico-contribution-655-3010@indico.itp.ac.cn
DESCRIPTION:Speakers: Fei Huang (Anhui University of Science and Technolog
 y)\nCosmological stasis is a phenomenon in which multiple energy component
 s with different equation-of-state parameters maintain constant abundances
  for an extended period despite the expansion of the universe. In this tal
 k\, I review how stasis arises and discuss the possible implications of th
 is phenomenon in observations. These include the enhancement in the growth
  of matter density perturbations on small scales\, and characteristic impr
 ints in the stochastic gravitational-wave background.\n\nhttps://indico.it
 p.ac.cn/event/427/contributions/3010/
LOCATION:
URL:https://indico.itp.ac.cn/event/427/contributions/3010/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Shadow of rotating black hole surrounded by dark matter
DTSTART;VALUE=DATE-TIME:20261024T073000Z
DTEND;VALUE=DATE-TIME:20261024T075000Z
DTSTAMP;VALUE=DATE-TIME:20261025T024635Z
UID:indico-contribution-655-3006@indico.itp.ac.cn
DESCRIPTION:Speakers: Haiyuan Feng (Shanxi Normal University)\nDark matter
  (DM)\, a fundamental cosmic component\, motivates the study of its influe
 nce on black hole (BH) shadows\, especially for spinning BHs confirmed by 
 EHT observations. This work generalizes the Schwarzschild BH surrounded by
  DM to an axisymmetric Kerr BH using the Newman–Janis Algorithm (NJA)\, 
 investigating the resulting event horizon and ergosphere structures. Emplo
 ying null geodesics\, we examine the effects of DM mass (\\Delta M) on BH 
 shadow\, including its radius\, distortion\, and the associated energy emi
 ssion rate. Our analysis reveals that DM has a negligible effect below a c
 ritical mass\, once this threshold is surpassed\, all BH structures expand
  significantly. Furthermore\, DM robustly contributes to the shadow mainta
 ining a near circular shape\, even for highly spinning BHs. This pronounce
 d structural expansion under high DM mass may potentially exceed current o
 bservational constraints\, suggesting that DM must either be absent in the
  immediate vicinity of the BH or its localized mass must remain below this
  critical value to be consistent with astrophysical observations.\n\nhttps
 ://indico.itp.ac.cn/event/427/contributions/3006/
LOCATION:
URL:https://indico.itp.ac.cn/event/427/contributions/3006/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Geodesic Focusing Conditions in  f(Q) Gravity
DTSTART;VALUE=DATE-TIME:20261025T060000Z
DTEND;VALUE=DATE-TIME:20261025T062000Z
DTSTAMP;VALUE=DATE-TIME:20261025T024635Z
UID:indico-contribution-655-3002@indico.itp.ac.cn
DESCRIPTION:Speakers: Chunhui Liu (HIAS\,UCAS)\nIn this talk\, I will disc
 uss the focusing of timelike geodesic congruences in $f(Q)$ gravity. I wil
 l first introduce geodesic deviation in symmetric teleparallel geometry an
 d the modified Raychaudhuri equation obtained under a Weyl-type nonmetrici
 ty ansatz and an additional nonmetricity–acceleration condition. I will 
 then present a focusing condition expressed in terms of the matter energy-
 momentum trace and an effective trace\, and discuss the compatibility of t
 he ansatz with homogeneous and isotropic connections. Finally\, I will con
 sider a shear-free flat FLRW background in the compatible coincident-gauge
  sector\, where the modified Friedmann equations yield $T_\\text{eff} = T$
  for $f_Q>0$. Under these assumptions\, the focusing inequality is saturat
 ed and imposes no additional constraint on the matter content.\n\nhttps://
 indico.itp.ac.cn/event/427/contributions/3002/
LOCATION:
URL:https://indico.itp.ac.cn/event/427/contributions/3002/
END:VEVENT
BEGIN:VEVENT
SUMMARY:SN1987A constraints on the neutrino-dark-fermion interaction from 
 resonant scattering with C$\\nu$B
DTSTART;VALUE=DATE-TIME:20261025T073000Z
DTEND;VALUE=DATE-TIME:20261025T075000Z
DTSTAMP;VALUE=DATE-TIME:20261025T024635Z
UID:indico-contribution-655-3007@indico.itp.ac.cn
DESCRIPTION:Speakers: Rui Zou (Southern University of Science and Technolo
 gy)\nNeutrino self-interactions mediated by a light scalar offer a compell
 ing resolution to cosmological tensions and may naturally arise in neutrin
 o mass generation mechanisms. When the scalar also couples to a light dark
 -sector fermion\, supernova neutrinos can resonantly annihilate with the c
 osmic neutrino background (C$\\nu$B) into invisible dark radiation\, deple
 ting the flux en route to Earth. We use this depletion to constrain the ne
 utrino-scalar coupling from the SN1987A data. Within a Bayesian framework 
 we analyze the data for two supernova neutrino emission models\, a paramet
 erized model and a 2D hydrodynamic simulation\, and for two coupling types
 \, a mass-independent one and a mass-proportional one. Our results show th
 at new-physics limits from SN1987A cannot be quoted independently of the h
 eavy-flavor emission\, the flavor conversion\, or the coupling structure. 
 Finally\, we forecast that a future high-statistics burst recorded by Hype
 r-Kamiokande would restore a meaningful upper bound even when flavor conve
 rsion is included.\n\nhttps://indico.itp.ac.cn/event/427/contributions/300
 7/
LOCATION:
URL:https://indico.itp.ac.cn/event/427/contributions/3007/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Quantum geometry effects in quantum field theory: Hamiltonian cons
 traint generates gravity-matter entanglement in spherically symmetric loop
  quantum gravity
DTSTART;VALUE=DATE-TIME:20261025T064000Z
DTEND;VALUE=DATE-TIME:20261025T070000Z
DTSTAMP;VALUE=DATE-TIME:20261025T024635Z
UID:indico-contribution-655-3009@indico.itp.ac.cn
DESCRIPTION:Speakers: Gaoping Long (Jinan University)\nIn this work\, we a
 ddress a foundational challenge in quantum field theory on curved spacetim
 e by developing a consistent framework in spherically symmetric loop quant
 um gravity. We introduce a methodology for defining meaningful superpositi
 ons of quantum geometry and matter states near the semiclassical apparent 
 horizon. This is achieved by identifying a restricted subspace of the grav
 itational phase space\, which ensures unitary equivalence among Fock repre
 sentations of a scalar field across different quantum geometries. Within t
 he resulting well-defined state space\, we derive weak solutions to the qu
 antum Hamiltonian constraint of general relativity near the semiclassical 
 apparent horizon. Furthermore\, we generalize the Hartle-Hawking vacuum st
 ate to this quantum geometric framework. The resulting state exhibits the 
 inherent entanglement between geometry and matter\, which arises from the 
 quantum Hamiltonian constraint of general relativity. This work establishe
 s a principled framework for studying geometry-matter entanglement and off
 ers new insights into the quantum foundations of the black hole informatio
 n paradox.\n\nhttps://indico.itp.ac.cn/event/427/contributions/3009/
LOCATION:
URL:https://indico.itp.ac.cn/event/427/contributions/3009/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nash Equilibrium from Quantum-Field Entanglement
DTSTART;VALUE=DATE-TIME:20261025T062000Z
DTEND;VALUE=DATE-TIME:20261025T064000Z
DTSTAMP;VALUE=DATE-TIME:20261025T024635Z
UID:indico-contribution-655-3004@indico.itp.ac.cn
DESCRIPTION:Speakers: Hao Xu (Yangzhou University)\nEntanglement harvestin
 g transfers quantum field correlations to localized probes\, yet whether t
 hese correlations can alter stable strategic behavior has remained unclear
 . We formulate a quantum-input game in which two Unruh–DeWitt detectors 
 harvest vacuum entanglement from a free massless scalar field in $(3+1)$-d
 imensional Minkowski spacetime. A referee converts this state into payoffs
  using independent question qubits and phase-calibrated local Bell measure
 ments. To leading perturbative order\, the mean reward is proportional to 
 the signed entanglement margin $\\sqrt{\\mathcal H^2+\\mathcal Q^2}-\\math
 cal P$\, where $\\mathcal H$ is the Hadamard correlation contribution\, $\
 \mathcal Q$ is the Pauli--Jordan causal contribution\, and $\\mathcal P$ i
 s the local excitation noise. Away from payoff degeneracies\, allowing eac
 h player to exit or to choose an early or late interaction yields $1+2n_+$
  trembling-hand perfect equilibria\, where $n_+$ counts the positive-rewar
 d timing equilibria. For one fixed protocol\, five analytically certified 
 settings realize the sequence $7\\to3\\to1\\to7\\to1$. They represent the 
 spacelike region\, the first commutator lobe\, central carrier cancellatio
 n\, the second lobe\, and the post-wavefront Huygens regime. Thus\, within
  this fixed quantum-input verification protocol\, distinct field-correlati
 on regimes generate different stable strategic structures.\n\nhttps://indi
 co.itp.ac.cn/event/427/contributions/3004/
LOCATION:
URL:https://indico.itp.ac.cn/event/427/contributions/3004/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Nonlinear gauge maps and the structure of Goldstone loops in canon
 ical inflation
DTSTART;VALUE=DATE-TIME:20261024T081000Z
DTEND;VALUE=DATE-TIME:20261024T083000Z
DTSTAMP;VALUE=DATE-TIME:20261025T024635Z
UID:indico-contribution-655-3011@indico.itp.ac.cn
DESCRIPTION:Speakers: ChengJun Fang (ITP-CAS)\nNon-attractor inflation has
  drawn significant attention as a class of inflationary models due to its 
 potential to generate primordial black holes (PBHs). However\, calculating
  the one-loop corrections to curvature perturbations in these models has s
 parked considerable theoretical controversy. We find that symmetry serves 
 as a crucial clue in such loop calculations\, and the Ward identity is pre
 cisely the standard manifestation of symmetry in quantum field theory. In 
 this presentation\, we will demonstrate how to apply Ward identities to th
 ese loop calculations.\n\nhttps://indico.itp.ac.cn/event/427/contributions
 /3011/
LOCATION:
URL:https://indico.itp.ac.cn/event/427/contributions/3011/
END:VEVENT
BEGIN:VEVENT
SUMMARY:How to bootstrap a Dark Photon
DTSTART;VALUE=DATE-TIME:20261024T075000Z
DTEND;VALUE=DATE-TIME:20261024T081000Z
DTSTAMP;VALUE=DATE-TIME:20261025T024635Z
UID:indico-contribution-655-3001@indico.itp.ac.cn
DESCRIPTION:Speakers: Álvaro Diaz Carmona (ICTP-AP)\nBootstrapping provid
 es theoretical constraints of the parameter space allowed by the S-matrix 
 properties: analyticity\, unitarity\, crossing symmetry. It has been appli
 ed to constrain different theories without making assumptions about their 
 ultraviolet completions. However\, its application in the forward limit of
  the scattering amplitudes is problematic when considering graviton exchan
 ge.\nIn this talk\, I will review the different approaches for gravity boo
 tstrap\, in the particular case of a Dark Photon model. We will focus on t
 he smearing method\, which replaces the forward limit by a weighted integr
 al over the transfer momentum. This approach has already been applied to t
 he scattering of scalar particles mediated by graviton exchange. The pione
 ering contribution of this work is the implementation into scattering of v
 ector particles\, extending the existing forward-limit bootstrap of spin-1
  particles.\nFrom the phenomenological point of view\, finding bounds for 
 graviton mass and coupling in this setup would help probing models of grav
 itational particle production with vector particles as Dark Matter\, as we
 ll as giving constraints for the quantum gravity swampland.\n\nhttps://ind
 ico.itp.ac.cn/event/427/contributions/3001/
LOCATION:
URL:https://indico.itp.ac.cn/event/427/contributions/3001/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Local Cosmography from Causal Set Pixies
DTSTART;VALUE=DATE-TIME:20261024T062000Z
DTEND;VALUE=DATE-TIME:20261024T064000Z
DTSTAMP;VALUE=DATE-TIME:20261025T024635Z
UID:indico-contribution-655-3005@indico.itp.ac.cn
DESCRIPTION:Speakers: He Liu (Tsinghua University)\nIn causal set theory\,
  spacetime is represented by a locally finite partially ordered set. The a
 bundances of small combinatorial structures can be used to recover informa
 tion about its continuum geometry. We study how chains and 2-pixies can be
  used to recover local cosmological quantities in four-dimensional\, spati
 ally flat FLRW spacetimes. For causal diamonds centered on a comoving obse
 rver\, we calculate the symmetric abundances through fourth order in the p
 roper duration and the difference between upward and downward 2-pixies thr
 ough third order. Riemann normal expansions identify the geometric terms\,
  and exact integration in conformal coordinates gives their coefficients. 
 The symmetric counts determine combinations of the Hubble and deceleration
  parameters. The difference between upward and downward 2-pixies probes cu
 rvature evolution and gives access to the dimensionless third derivative o
 f the scale factor\, known as the cosmological jerk. We test the calculati
 on with independent continuum integration and simulated causal sets\, and 
 study the inference using the full covariance of the counts. The tests sep
 arate geometric truncation error from sampling uncertainty and show the co
 st of including higher-order terms. The construction uses calibrated inter
 val durations. Applying it within one causal set requires an intrinsic clo
 ck and a treatment of correlations between overlapping intervals.\n\nhttps
 ://indico.itp.ac.cn/event/427/contributions/3005/
LOCATION:
URL:https://indico.itp.ac.cn/event/427/contributions/3005/
END:VEVENT
BEGIN:VEVENT
SUMMARY:Relational Scales and Hamiltonian Renormalization in Quantum Gravi
 ty
DTSTART;VALUE=DATE-TIME:20261024T064000Z
DTEND;VALUE=DATE-TIME:20261024T070000Z
DTSTAMP;VALUE=DATE-TIME:20261025T024635Z
UID:indico-contribution-655-3008@indico.itp.ac.cn
DESCRIPTION:Speakers: Hongguang Liu (Westlake University)\nHow should one 
 define a renormalization scale when spacetime geometry itself is quantum a
 nd dynamical? I will discuss a relational formulation of coarse graining i
 n which physical resolution and mode ordering are defined by dynamical geo
 metric observables\, while RG flow remains distinct from physical clock ev
 olution.\nI will then present a Hamiltonian implementation using the non-p
 erturbative functional renormalization group\, where quantum fluctuations 
 can modify the full momentum–velocity relation and the symplectic struct
 ure. Requiring consistent local evolution further constrains the effective
  Hamiltonian and provides a route from quantum-gravity dynamics to cosmolo
 gical backgrounds\, perturbations and observables.\n\nhttps://indico.itp.a
 c.cn/event/427/contributions/3008/
LOCATION:
URL:https://indico.itp.ac.cn/event/427/contributions/3008/
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