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Saptarshi Saha

Publications and source records attributed to Saptarshi Saha.

20 records · Page 2Linked to original sources

Retarded resonance Casimir-Polder interaction of a uniformly rotating two-atom system

We consider here, a two-atom system is uniformly moving through a circular ring at an ultra-relativistic speed and weakly interacting with common external fields. The vacuum fluctuations of the quantum fields generate the entanglement between the atoms. Hence an effective energy shift is originated, which depends on the inter-atomic distance. This is commonly known as resonance Casimir-Polder interaction (RCPI). It is well known that, for a linearly accelerated system coupled with a massless scalar field, we get a thermal response when the local inertial approximation is valid. On the contrary, the non-thermality arises in the presence of the centripetal acceleration. We use the quantum master equation formalism to calculate the second-order energy shift of the entangled states in the presence of two kinds of fields. They are the massive free scalar field and the electromagnetic vector field. For both cases, we observe the non-thermal behavior. A unique retarded response is also noticed in comparison to the free massless case, which can be observed via the polarization transfer technique.

gr-qc↗

How the mass of a scalar field influences Resonance Casimir-Polder interaction in Schwarzschild spacetime

\emph{Resonance Casimir-Polder interaction(RCPI)} occurs in nature when one or more atoms are in their excited states and the exchange of real photon is involved between them due to vacuum fluctuations of the quantum fields. In recent times, many attempts have been made to show that the curved spacetime such as the \emph{de-Sitter spacetime} can be separated from a \emph{thermal Minkowski spacetime} using \emph{RCPI}. Motivated from these ideas, here we study the \emph{RCPI} between two atoms that interact with a massive scalar field in Schwarzschild spacetime provided the atoms are placed in the near-horizon region. Subsequently, we use the tool of the \emph{open quantum system} and calculate the Lamb shift of the atomic energy level of the entangled states. We show that the behavior of \emph{RCPI} modifies depending on the mass of the scalar field. In the high mass limit, the interaction becomes short-range and eventually disappears beyond a characteristic length scale of $1/m$, where $m$ is the mass of the scalar field.

gr-qc↗