Physics

Dr. Sabyasachi Ghosh
Calcutta University

It is believed that at a few microseconds after the Big Bang, the universe was in the state of
deconfined quarks and gluons, whose temperature was much larger than the
temperature of Sun. The experiments of heavy ion collisions like RHIC at BNL, USA and LHC at
CERN, Switzerland have successfully produced this kind of Little Bang, having a temperature of the
order of trillion degree Kelvin, which is considered as highest man-made temperature till now. Our
studies are focus on this early universe state by investigating its in-medium spectral and transport
responses, where quantum field theory at finite temperature is used as a main mathematical tool.
The investigation on spectral responses is aimed to explain the so called “low mass dilepton
enhancement”, as a signature of the medium, whereas the studies of transport responses have tried
to probe the (nearly) perfect fluid nature of such medium.