BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//IAP calendar product//iap.fr//
CALSCALE:GREGORIAN
X-WR-CALNAME:IAP Journal Club: Doctorants
BEGIN:VTIMEZONE
TZID:Europe/Paris
BEGIN:STANDARD
DTSTART:19961027T030000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
TZNAME:CET
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
END:STANDARD
BEGIN:DAYLIGHT
DTSTART:19810329T020000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=3
TZNAME:CEST
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
END:DAYLIGHT
END:VTIMEZONE
BEGIN:VEVENT
SUMMARY:From particles to galaxies: fluctuations\, collisions and large de
 viations 
DTSTART;TZID=Europe/Paris:20260213T160000
DTEND;TZID=Europe/Paris:20260213T170000
DTSTAMP:20260213T155100Z
UID:2026-02-1316:00:00+00:09"Fromparticlestogalaxies:fluctuations\,collisi
 onsandlargedeviations"_HmF8J8As12UwZg759lSs
DESCRIPTION:Anwar El Rhirhayi\nInstitut d'Astrophysique de Paris\, Paris\,
  France\n\n\nAbstract: The long-term evolution of galaxies and stellar sys
 tems relies on collective interactions that\, although tiny at the individ
 ual scale\, produce significant macroscopic effects. In this presentation\
 , we will begin by introducing the Landau equation\, which describes the a
 verage evolution of the velocity distribution under the effect of grazing 
 and frequent collisions. To make these dynamics more tangible\, we will il
 lustrate it through a stochastic formulation inspired by Langevin\, allowi
 ng for the direct simulation of collective noise. Finally\, we will addres
 s the issue of atypical fluctuations via the principle of large deviations
 \, which allows quantifying the occurrence of rare and potentially structu
 ring events in the evolution of galactic systems. \n
LOCATION:Salle des séminaires Évry Schatzman 
END:VEVENT
BEGIN:VEVENT
SUMMARY:De Sitter momentum space 
DTSTART;TZID=Europe/Paris:20260320T160000
DTEND;TZID=Europe/Paris:20260320T170000
DTSTAMP:20260320T155100Z
UID:2026-03-2016:00:00+00:09"DeSittermomentumspace"_vLBhZHev2y6jOmyeh0Xe
DESCRIPTION:Arthur Poisson\nInstitut d'Astrophysique de Paris\, Paris\, Fr
 ance\n\n\nAbstract: In many inflationary scenarios\, primordial correlatio
 n functions are encoded in late-time observables in de Sitter spacetime\, 
 where even the simplest processes already involve highly nontrivial time i
 ntegrals. I will show that this difficulty can be overcome by introducing 
 a new momentum-space representation adapted to de Sitter isometries. This 
 construction is based on diagonalizing the Casimir operator rather than th
 e Hamiltonian\, effectively trading the usual (d+1)-dimensional Fourier sp
 ace for the Kontorovich–Lebedev–Fourier (KLF) space. I will also show 
 practical advantages of this description: quadratic dynamics provide a sim
 ple propagator analogous to flat space\, and the nested time integrals tur
 n into frequency-space integrals over meromorphic functions.\n
LOCATION:Salle des séminaires Évry Schatzman 
END:VEVENT
END:VCALENDAR