DIPANKAR HOME

Department of Physics, Bose Institute, Calcutta 700 009, India

Email: dhom@bosemain.boseinst.ernet.in

Abstract.

Tripartite entangled states of systems 1, 2 and 3 involving nonorthogonal states are used to reveal two hitherto unexplored quantum effects. The first shows that kinematic entanglement between the states of 1 and 2 can affect the result of dynamical interaction between 2 and 3, though 1 and 2 may be spatially separated so that they no longer interact. The second shows that if a   residual interaction persists between 1 and 2 while 2 interacts with 3 to form an entangled state, the  measurement of observables of 1 can be used to determine whether 2 has interacted with 3. This effect occurs even when the measurement on 1 is made long after the residual interaction between 1 and 2 has ceased to act. Such effects resulting from interplay between unitary dynamics and kinematic entanglement have interesting implications. In particular, we discuss the significance as regards what we call the dynamic version of Einstein locality.

Keywords: Tripartite entanglement; nonorthogonality;   unitarity; residual interaction; Einstein locality.

Pacs No. 03.65.Bz