BEGIN:VCALENDAR VERSION:2.0 PRODID:-//CERN//INDICO//EN BEGIN:VEVENT SUMMARY:Probing dark energy evolution with Quaia quasars through the integ rated Sachs-Wolfe effect DTSTART;VALUE=DATE-TIME:20260916T150000Z DTEND;VALUE=DATE-TIME:20260916T152500Z DTSTAMP;VALUE=DATE-TIME:20260922T181758Z UID:indico-contribution-5703-31293@indico.ific.uv.es DESCRIPTION:Speakers: Mina Ghodsi Yengejeh (Konkoly Observatory)\nThe Inte grated Sachs--Wolfe (ISW) effect probes the late-time evolution of gravita tional potentials and provides a complementary test of the nature of dark energy. We investigate whether the redshift evolution of the ISW effect ca n provide new constraints on the time evolution of dark energy. We conside r theoretical predictions for the standard ΛCDM cosmology and alternative w0waCDM models favoured by recent DESI BAO and DES Y6 constraints. We per form a tomographic cross-correlation analysis of the Quaia quasar catalogu e and \\textit{Planck} CMB temperature maps to measure the ISW signal over a broad redshift range\, spanning about (10h−1 Gpc)3 comoving volume. W e assess the robustness of the inferred ISW amplitude against variations i n sky coverage\, multipole range\, and tomographic binning. We detect the ISW effect at a significance of 2.8σ\, corresponding to an amplitude of A ISW≃1.69±0.61 relative to the Planck ΛCDM prediction. The inferred sig nal remains stable against various analysis choices\, including various CM B maps (SMICA\, NILC\, SEVEM)\, different choices of ℓmax and the number of multipole bins\, and an alternative quasar bias model. The measured IS W amplitude is moderately stronger than predicted by the fiducial ΛCDM co smology\, and the alternative w0waCDM models do not account for this discr epancy. Future tomographic ISW measurements with improved quasar catalogue s from Gaia and forthcoming wide-area galaxy surveys such as Euclid and DE SI will help clarify the origin of this difference.\n\nhttps://indico.ific .uv.es/event/8160/contributions/31293/ LOCATION: URL:https://indico.ific.uv.es/event/8160/contributions/31293/ END:VEVENT BEGIN:VEVENT SUMMARY:Pseudo-scalar dark energy and cosmic birefringence DTSTART;VALUE=DATE-TIME:20260916T141000Z DTEND;VALUE=DATE-TIME:20260916T143500Z DTSTAMP;VALUE=DATE-TIME:20260922T181758Z UID:indico-contribution-5703-31294@indico.ific.uv.es DESCRIPTION:Speakers: Marco Regis (University of Torino and INFN)\nA cosmo logical pseudo-scalar field provides a compelling realization of dynamical \ndark energy (DE). If its coupling to photons is non-negligible\, the cos mic microwave background acquires a rotation of its polarization plane\, k nown as cosmic birefringence. We discuss pseudo-scalar models that can sim ultaneously account for the recent hints of evolution in the equation of s tate of DE and of the presence of cosmic birefringence.\n\nhttps://indico. ific.uv.es/event/8160/contributions/31294/ LOCATION: URL:https://indico.ific.uv.es/event/8160/contributions/31294/ END:VEVENT BEGIN:VEVENT SUMMARY:The Universal Rotation Curve of disk galaxies: probing dark matter and the local expansion rate DTSTART;VALUE=DATE-TIME:20260916T143500Z DTEND;VALUE=DATE-TIME:20260916T150000Z DTSTAMP;VALUE=DATE-TIME:20260922T181758Z UID:indico-contribution-5703-31297@indico.ific.uv.es DESCRIPTION:Speakers: Tiziano Schiavone (SISSA\, Trieste)\nThe Universal R otation Curve provides a powerful empirical framework to investigate the d istribution of luminous and dark matter in disk galaxies. By adopting norm alized radial and velocity coordinates\, we investigate the emergence of u niversal kinematic properties across galaxies with different masses and lu minosities. The resulting co-added rotation curves will be analyzed throug h different dark matter mass models to constrain the halo density profiles . Finally\, we discuss the use of the radial Tully–Fisher relation to ob tain an independent estimate of the Hubble constant in the local Universe. This work represents a first step toward a unified analysis of galaxy rot ation curves and their cosmological applications.\n\nhttps://indico.ific.u v.es/event/8160/contributions/31297/ LOCATION: URL:https://indico.ific.uv.es/event/8160/contributions/31297/ END:VEVENT BEGIN:VEVENT SUMMARY:Safe Phantom Divide Crossing from Unscreened Non-Minimal Coupling to Gravity DTSTART;VALUE=DATE-TIME:20260916T134500Z DTEND;VALUE=DATE-TIME:20260916T141000Z DTSTAMP;VALUE=DATE-TIME:20260922T181758Z UID:indico-contribution-5703-31299@indico.ific.uv.es DESCRIPTION:Speakers: Adrià Gómez-Valent (Institut de Ciències del Cosm os\, Universitat de Barcelona)\nRecent hints of dynamical dark energy\, in cluding a possible crossing of the phantom divide inferred from the latest cosmological data\, have motivated the search for viable theoretical expl anations. Scalar fields non-minimally coupled to gravity with a coupling o f the form $F(\\varphi)=1+\\alpha\\varphi^2$ are physically motivated and have emerged as promising candidates\, providing a significantly improved fit to the data compared to $\\Lambda$CDM and even outperforming the $w_0w _a$CDM parametrization. However\, in the absence of a screening mechanism\ , the regions of parameter space examined exhaustively so far in the liter ature (with $\\alpha0$) that realizes a crossing of the phantom divide whi le remaining consistent with Cassini–Huygens bounds and the most recent (and tightest) Lunar Laser Ranging measurements\, without introducing high er-derivative terms in the action. This setup\, which admittedly is subjec t to some degree of fine-tuning\, fully respects the BBN constraints and l eads only to mildly larger values of the effective gravitational coupling in the past\, peaking at the onset of dark energy domination at approximat ely 0.5\\% above Newton's constant. We review the background and linear pe rturbation dynamics of the model\, deriving illustrative analytical result s that provide physical insight into its behavior\, and update the constra ints on the model using the latest cosmological data\, including the DES-D ovekie supernova sample. We perform for the first time a full-fledged Mont e Carlo analysis with $\\alpha>0$\, studying also the impact of the variat ion of $G$ on the supernovae likelihood\, and compare the results obtained with $\\alpha\n\nhttps://indico.ific.uv.es/event/8160/contributions/31299 / LOCATION: URL:https://indico.ific.uv.es/event/8160/contributions/31299/ END:VEVENT BEGIN:VEVENT SUMMARY:Coffee Break DTSTART;VALUE=DATE-TIME:20260916T131500Z DTEND;VALUE=DATE-TIME:20260916T134500Z DTSTAMP;VALUE=DATE-TIME:20260922T181758Z UID:indico-contribution-5703-31300@indico.ific.uv.es DESCRIPTION:https://indico.ific.uv.es/event/8160/contributions/31300/ LOCATION: URL:https://indico.ific.uv.es/event/8160/contributions/31300/ END:VEVENT BEGIN:VEVENT SUMMARY:Addressing the DESI DR2 Phantom-Crossing Anomaly and Enhanced $H_0 $ Tension with Reconstructed Scalar-Tensor Gravity DTSTART;VALUE=DATE-TIME:20260916T125000Z DTEND;VALUE=DATE-TIME:20260916T131500Z DTSTAMP;VALUE=DATE-TIME:20260922T181758Z UID:indico-contribution-5703-31295@indico.ific.uv.es DESCRIPTION:Speakers: Leandros Perivolaropoulos ()\nRecent cosmological da ta\, including DESI DR2\, highlight significant tensions within the $\\Lam bda$CDM paradigm. When analyzed in the context of General Relativity (GR)\ , the latest DESI data favor a dynamical dark energy (DDE) equation of sta te\, $w(z)$\, that crosses the phantom divide line $w=-1$. However\, this framework prefers a lower Hubble constant\, $H_0$\, than Planck 2018\, the reby worsening the tension with local measurements. This phantom crossing is a key feature that cannot be achieved by minimally coupled scalar field s (quintessence) within GR. This suggests the need for a new degree of fre edom that can simultaneously: (A) increase the best-fit value of $H_0$ in the context of the DESI DR2 data\, and (B) allow the crossing of the $w=-1 $ line within a new theoretical approach. In this talk I will demonstrate that both of these goals may be achieved in the context of Modified Gravit y (MG)\, and in particular\, Scalar-Tensor (ST) theories\, where phantom c rossing is a natural and viable feature.\n\nhttps://indico.ific.uv.es/even t/8160/contributions/31295/ LOCATION: URL:https://indico.ific.uv.es/event/8160/contributions/31295/ END:VEVENT BEGIN:VEVENT SUMMARY:Reconstructing the Type Ia Supernova Absolute Magnitude with Two-P robe Physics-Informed Neural Networks DTSTART;VALUE=DATE-TIME:20260916T120000Z DTEND;VALUE=DATE-TIME:20260916T122500Z DTSTAMP;VALUE=DATE-TIME:20260922T181758Z UID:indico-contribution-5703-31296@indico.ific.uv.es DESCRIPTION:Speakers: Denitsa Staicova (Institute for Nuclear Research and Nuclear Energy)\nWe apply two variants of Physics-Informed Neural Network s (PINNs) to reconstruct the Type Ia supernova absolute magnitude M_B(z) f rom joint BAO and supernova data under four cosmological models (\\LambdaC DM\, CPL\, GEDE\, \\Lambda_sCDM) and two DESI DR2 fiducial sets. A heteros cedastic single-network method tested across four constraint configuration s establishes that the Etherington distance duality relation is more funda mental constraint than cosmological model priors\, with DDR violations of 30--52 mmag under physical constraints versus 85--2330 mmag without. Under full constraints all models recover M_B \\approx -19.3 mag with biases be low 0.05 mag. A Fisher information-weighted two-network variant trains ind ependent networks on BAO and SN data\, providing clean probe separation an d finding no significant M_B evolution in z \\in [0.3\, 1.5]. The heterosc edastic method identifies a persistent 2-3\\sigma residual at z \\sim 0.4- 0.5 that is consistent across all four models and both fiducials\; the Fis her method finds no significant pointwise deviation in z\\in[0.3\,1.5] but shows a systematic separation of redshift-binned M_B distributions consis tent with the same underlying tension. While the origin of this feature re mains ambiguous\, its model-independence and cross-method consistency warr ant further investigation with forthcoming data.\n\nhttps://indico.ific.uv .es/event/8160/contributions/31296/ LOCATION: URL:https://indico.ific.uv.es/event/8160/contributions/31296/ END:VEVENT BEGIN:VEVENT SUMMARY:Defocusing dark energy: Raychaudhuri diagnostics beyond $w<-1/3$ a nd the phantom divide DTSTART;VALUE=DATE-TIME:20260916T122500Z DTEND;VALUE=DATE-TIME:20260916T125000Z DTSTAMP;VALUE=DATE-TIME:20260922T181758Z UID:indico-contribution-5703-31298@indico.ific.uv.es DESCRIPTION:Speakers: Ozgur Akarsu (Istanbul Technical University (ITU))\n In general relativity\, cosmic acceleration is a statement about geometry- --the timelike defocusing of the comoving congruence---and the field equat ions source it with mass--energy combinations\, not with any equation-of-s tate ratio. Evolving dark energy is now back at the center of cosmology\, and several scenarios under active discussion---sign-switching $\\Lambda_{ \\rm s}$CDM and AdS-to-dS transitions\, which simultaneously ease the $H_0 $ and $S_8$ tensions and restore $\\sum m_\\nu$ to physical values\, as we ll as modified-gravity backgrounds recast in GR-like form---feature an eff ective dark-energy density that is negative in the past and crosses zero a t some redshift $z_\\dagger$. Our standard language quietly assumes this n ever happens: $w_{\\rm de}0$ and the inequality reverses on the negative b ranch\; the phantom divide $w_{\\rm de}=-1$ stops separating anything once the density changes sign\; at $\\rho_{\\rm de}=0$ the ratio $w_{\\rm de}$ does not exist\, though nothing physical is singular there\; and sign-pre serving parametrizations such as $w_0$--$w_a$ cannot represent the crossin g at all. In this talk\, based on arXiv:2607.18008\, we ask what defines d ark energy when $w$ cannot\, and answer with the two combinations the fiel d equations actually use: the active gravitational mass density $\\mathcal {M}=\\rho+3p$\, which drives Raychaudhuri defocusing\, and the inertial ma ss density $\\mathcal{I}=\\rho+p$\, whose zero---the null energy condition (NEC) boundary---replaces the phantom divide as the regular separator. Sh arp results follow: any smooth sign switch is phantom-like and repulsive a t the crossing\, with the total NEC intact\; the pole in $w_{\\rm de}$ is purely kinematic\, with universal residue $n(1+z_\\dagger)/3$\, so $w_{\\r m de}=-1$ is never attained and the two sides of the divide connect only t hrough the pole\; repulsion begins strictly before the switch\, at $z_{\\r m rep}>z_\\dagger$\; an exact window in $\\rho_{\\rm de}'(z_\\dagger)$ per mits acceleration at the crossing itself\; and the deceleration parameter admits exactly one or three sign-changing zeros. An analytic $\\Lambda_{\\ rm s}$CDM profile\, exponential infrared $f(T)$ gravity\, and the minimal phantom brane realize the pattern. The practical moral for reconstructions : across $\\rho_{\\rm de}=0$ the regular targets are $(\\rho_{\\rm de}\,p_ {\\rm de}\,\\mathcal{I}_{\\rm de}\,\\mathcal{M}_{\\rm de})$---kinematic to tals need no dark-sector split---and parametrizations should be allowed to change sign.\n\nhttps://indico.ific.uv.es/event/8160/contributions/31298/ LOCATION: URL:https://indico.ific.uv.es/event/8160/contributions/31298/ END:VEVENT END:VCALENDAR