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Somshubhro Bandyopadhyay

Publications and source records attributed to Somshubhro Bandyopadhyay.

63 records · Page 4Linked to original sources
arXiv2000

Qubit and Entanglement assisted Optimal Entanglement Concentration

We present two method for optimal entanglement concentration from pure entangled states by local actions only. However a prior knowledge of the Schmidt coefficients is required. The first method is optimally efficient only when a finite ensemble of pure entangled states are available whereas the second method realizes the single pair optimal concentration probability. We also propose an entanglement assisted method which is again optimally efficient even for a single pair. We also discuss concentrating entanglement from N-partite cat like states.

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arXiv1999

Barrier Perturbation Induced Superarrivals and Nonlocality in a Time-Evolving Wave Packet

We compute the time evolving probability of a Gaussian wave packet to be reflected from a rectangular potential barrier which is perturbed by reducing its height. A time interval is found during which this probability of reflection is enhanced (superarrivals) compared to the unperturbed case. Such a time evolving reflection probability implies that the effect of perturbation propagates across the wave packet faster than its group velocity - a curious form of nonlocality.

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arXiv1999

Broadcasting of entanglement and universal quantum cloners

We study broadcasting of entanglement where we use universal quantum cloners (in general less optimal) to perform local cloning operations. We show that there is a lower bound on the fidelity of the universal quantum cloners that can be used for broadcasting. We prove that an entanglement is optimally broadcast only when optimal quantum cloners are used for local copying. We also show that broadcasting of entanglement into more than two entangled pairs is forbidden using only local operations.

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