96 citations · 668 across the 25 of their papers we have counts for
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Open system dynamics in interacting quantum field theories
Brenden Bowen, Nishant Agarwal, Archana Kamal
A quantum system that interacts with an environment generally undergoes nonunitary evolution described by a non-Markovian or Markovian master equation. In this paper, we construct…
Initial value formulation of a quantum damped harmonic oscillator
Nishant Agarwal, Yi-Zen Chu
The in-in formalism and its influence functional generalization are widely used to describe the out-of-equilibrium dynamics of unitary and open quantum systems, respectively. In th…
Loop corrections in Minkowski spacetime away from equilibrium. Part II. Finite-time results
Spasen Chaykov, Nishant Agarwal, Sina Bahrami +1
Loop corrections to finite-time correlation functions in quantum field theories away from equilibrium can be calculated using the in-in path integral approach. In this paper, we ca…
Loop corrections in Minkowski spacetime away from equilibrium. Part I. Late-time resummations
Spasen Chaykov, Nishant Agarwal, Sina Bahrami +1
Loop corrections to unequal-time correlation functions in Minkowski spacetime exhibit secular growth due to a breakdown of time-dependent perturbation theory. This is analogous to…
A cosmological open quantum system
Sarah Shandera, Nishant Agarwal, Archana Kamal
We derive the evolution equation for the density matrix of a UV- and IR- limited band of comoving momentum modes of the canonically normalized scalar degree of freedom in two examp…
Why does the effective field theory of inflation work?
Nishant Agarwal, Raquel H. Ribeiro, R. Holman
The effective field theory (EFT) of inflation has become the preferred method for computing cosmological correlation functions of the curvature fluctuation, . It makes explicit…