BEGIN:VCALENDAR
VERSION:2.0
CALSCALE:GREGORIAN
PRODID:UW-Madison-Physics-Events
BEGIN:VEVENT
SEQUENCE:1
UID:UW-Physics-Event-8744
DTSTART:20240516T170000Z
DTEND:20240516T190000Z
DTSTAMP:20260413T223343Z
LAST-MODIFIED:20240516T152157Z
LOCATION:5280 Chamberlin Hall
SUMMARY:Large Blue isocurvature from a classical conformal limit\, The
 sis Defense\, Sai Chaitanya Tadepalli\, Physics PhD Graduate Student
DESCRIPTION:When additional degrees of freedom are considered during i
 nflation\, a crucial aspect of early-universe physics emerges: the gen
 eration of isocurvature quantum fluctuations\, akin to independent qua
 ntum perturbations. These fluctuations can offer valuable insights int
 o inflation and the presence of spectator fields and their mass scales
 . Current data tightly constrains the cold dark matter (CDM) isocurvat
 ure amplitude on scales k&lt\;0.1 h/Mpc. However\, blue-tilted (spectr
 al index &gt\;1) isocurvatures can be invisible on large scales and le
 ave a huge imprint on small scales. This thesis explores the generatio
 n and forecast of axionic blue-tilted isocurvature perturbations.<br>

 \n<br>
\nIn the first part of this thesis\, we study the generation of
  CDM uncorrelated blue-tilted isocurvature perturbations for the axion
 s when the axionic sector is far out of equilibrium during inflation t
 hrough an initial Peccei-Quinn symmetry breaking field displacement. W
 e investigate two distinct models\, where these fluctuations originate
  from the dynamical evolution of the radial field through the quadrati
 c and quartic components of the effective potentials. In the quadratic
  case\, we find that there exist parametric regions with a strong reso
 nant spectral behavior that leads to rich isocurvature spectral shapes
 . A consequence of this nonlinearity-driven resonance is the chaotic n
 ature of the map that links the underlying Lagrangian parameters to th
 e isocurvature amplitudes. In the quartic scenario\, we propose a nove
 l method to generate the blue-tilted spectrum over a large range of sc
 ales by utilizing the classical conformal limit.<br>
\n<br>
\nIn the s
 econd part of the thesis\, we present a Fisher forecast for the Euclid
  and MegaMapper experiments in their ability to detect blue isocurvatu
 re perturbations. We construct the theoretical predictions in the EFTo
 fLSS and bias formalisms and report optimistic results highlighting th
 e potential for detecting the CDM blue isocurvature amplitude in forth
 coming surveys.
URL:https://www.physics.wisc.edu/events/?id=8744
END:VEVENT
END:VCALENDAR