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SUMMARY:Can Distance Duality Violation Save Late-time Solutions to the Hub
 ble Tension?
DTSTART;VALUE=DATE-TIME:20261107T070000Z
DTEND;VALUE=DATE-TIME:20261107T073000Z
DTSTAMP;VALUE=DATE-TIME:20261023T141859Z
UID:indico-contribution-2960@indico.itp.ac.cn
DESCRIPTION:Speakers: Yashi Tiwari (Institute of Theoretical Physics\, Chi
 nese Academy of Sciences)\nThe discrepancy between early- and late-Univers
 e determinations of the Hubble constant may point to physics beyond ΛCDM 
 or to unaccounted-for systematics. Numerous late-time modifications to the
  expansion history have been proposed to alleviate this discrepancy\, with
  limited success. Recent works have shown that\, when the sound-horizon an
 d supernova calibrations are held fixed\,any purely late-time resolution r
 equires a violation of the cosmic distance duality relation (CDDR). Recast
 ing the tension in the $r_d–M_B$ plane\, we show explicitly that distanc
 e duality\, together with BAO and uncalibrated supernova data and a fixed 
 sound-horizon calibration\, determines $H_0$ independently of the late-tim
 e expansion history. We then test the viability of the required CDDR viola
 tion by separately constraining reciprocity violation and photon number no
 n-conservation\, deriving a new constraint on reciprocity-violating distor
 tions of angular-diameter distances from BAO and cosmic-chronometer data. 
 Combining this result with existing photon-number-conservation constraints
 \, we find that the level of distance-duality violation needed to resolve 
 the tension is strongly disfavoured by current data. We therefore conclude
  that\, for fixed sound-horizon and supernova calibrations\, no modificati
 on confined to the late-time expansion history—even one violating distan
 ce duality—can resolve the Hubble tension\, pointing instead toward earl
 y-Universe physics or unresolved local systematics.\n\nhttps://indico.itp.
 ac.cn/event/417/contributions/2960/
LOCATION:
URL:https://indico.itp.ac.cn/event/417/contributions/2960/
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