Date:

Location:
CP171
Speaker(s) / Presenter(s):
Diptarka Das (UK)
One of the most important results emerging from string theory is the gauge gravity
duality (AdS/CFT correspondence) which tells us that certain problems in particular
gravitational backgrounds can be exactly mapped to a particular dual gauge theory
a quantum theory very similar to the one explaining the interactions between funda
mental subatomic particles. The chief merit of the duality is that a diﬃcult problem
in one theory can be mapped to a simpler and solvable problem in the other theory.
The duality can be used both ways.
Most of the current theoretical framework is suited to study equilibrium systems,
or systems where time dependence is at most adiabatic. However in the real world,
systems are almost always out of equilibrium. Generically these scenarios are de
scribed by quenches, where a parameter of the theory is made time dependent. In
this dissertation I describe some of the work done in the context of studying quantum
quench using the AdS/CFT correspondence. We recover certain universal scaling
type of behavior as the quenching is done through a quantum critical point. Another
question that has been explored in the dissertation is time dependence of the gravity
theory. Present cosmological observations indicate that our universe is accelerating
and is described by a spacetime called deSitter(dS). In 2011 there had been a spec
ulation over a possible duality between deSitter gravity and a particular ﬁeld theory
(Euclidean SP(N) CFT). However a concrete realization of this proposition was still
lacking. Here we explicitly derive the dS/CFT duality using well known methods in
ﬁeld theory. We discovered that the time dimension emerges naturally in the deriva
tion. We also describe further applications and extensions of dS/CFT.
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