Hall 123

Open quantum dynamics and steering of a finite-dimensional system coupled to a controllable, infinite-dimensional environment

Athulya K. P.

IISER--Thiruvananthapuram

When a quantum system interacts with an environment, it
undergoes a non-unitary evolution that could lead to the loss of quantum
features like coherence, entanglement, etc. Understanding, describing, and
characterising the effects of the environment on quantum systems become
especially important if these systems are to be used in technological
applications. Applications of quantum technologies are based on the control
and utilisation of one or more uniquely quantum resources that are not
present in classical systems. In this talk, I will present the work
included in my thesis. The thesis is broadly on the effect and role of
uniquely quantum phenomena like entanglement, steering, non-classical
correlations, etc., on open quantum dynamics. In my talk, I particularly
focus on open dynamics and steerability of finite-dimensional quantum
systems coupled to continuous variable - or equivalently -
infinite-dimensional environments. In the first part of the talk, we
consider a versatile two-photon system to explore open quantum dynamics.
Two important aspects, namely the role of initial correlation within the
bipartite environment (frequency degrees of freedom of each photon) on the
system dynamics and the role of system-environment correlation, in addition
to correlations within the environment on the dynamics of the system are
explored. We also address the correct form of the master to use when there
is a singularity in the open dynamics. In the second half of the talk, we
consider a qubit coupled to a single-mode radiation field and study the
steerability of the qubit in terms of quantum steering ellipsoids. These
ellipsoids represent the set of states of the qubit on to which it can be
steered by performing measurements on the field mode. We also study the
steering ellipsoid corresponding to the joint evolution of the qubit and
field under the Jaynes -Cummings Hamiltonian.