Seminar by Dr Prolay K Chanda
Title: Interacting and Dissipative Dark Sectors in Light of DESI
Speaker: Dr Prolay K Chanda, Postdoc at TIFR
Abstract: Recent DESI observations hint that dark energy may be evolving and that its inferred equation of state crosses the phantom divide (w=-1). Such behavior is difficult to realize with canonical quintessence without introducing pathological phantom dynamics. In this talk, I will show that the apparent phantom crossing can instead arise from nontrivial dynamics within the dark sector. I will first discuss a scenario in which quintessence interacts with dark matter, modifying the evolution of the dark matter density and consequently the effective dark-energy equation of state inferred by an observer. I will then present a physically distinct possibility in which dark energy dissipates energy into dark matter, introducing additional friction in the scalar-field dynamics. Even weak, late-time dissipation can reproduce the behavior suggested by DESI.
Venue: Seminar Room (202), Physics Department IIT Bombay, Powai, Mumbai