Bell violation in the Sky
  In this work, we have studied the possibility of setting up Bell's inequality
violating experiment in the context of cosmology, based on the basic principles
of quantum mechanics. First we start with the physical motivation of
implementing the Bell's inequality violation in the context of cosmology. Then
to set up the cosmological Bell violating test experiment we introduce a model
independent theoretical framework using which we have studied the creation of
new massive particles by implementing the WKB approximation method for the
scalar fluctuations in presence of additional time dependent mass contribution.
Next using the background scalar fluctuation in presence of new time dependent
mass contribution, we explicitly compute the expression for the one point and
two point correlation functions. Furthermore, using the results for one point
function we introduce a new theoretical cosmological parameter which can be
expressed in terms of the other known inflationary observables and can also be
treated as a future theoretical probe to break the degeneracy amongst various
models of inflation. Additionally, we also fix the scale of inflation in a
model independent way without any prior knowledge of primordial gravitational
waves. Next, we also comment on the technicalities of measurements from isospin
breaking interactions and the future prospects of newly introduced massive
particles in cosmological Bell violating test experiment. Further, we cite a
precise example of this set up applicable in the context of string theory
motivated axion monodromy model. Then we comment on the explicit role of
decoherence effect and high spin on cosmological Bell violating test
experiment. In fine, we provide a theoretical bound on the heavy particle mass
parameter for scalar fields, graviton and other high spin fields from our
proposed setup.
