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Pahulpreet Singh

Publications and source records attributed to Pahulpreet Singh.

2 recordsLinked to original sources

Maximal Secret Reconstruction, Teleportation and Bell's Inequality

A tripartite state is said to be a potential resource for secret sharing if the state imposes restrictions on the teleportation fidelity of the bipartite dealer--reconstructor and dealer--assistant channels in addition of being useful for the state reconstruction. Given a secret shareable state in a pure three-qubit system, we are able to characterize the set of states with maximum possible reconstruction fidelity (abbreviated as MSR states) for a fixed value of the maximum teleportation fidelity that can be obtained out of both the dealer--receiver channels. Similarly for a value giving the maximum of Bell-CHSH value of both dealer--reconstructor and dealer--assistant channels, we are able to find the maximum achievable reconstruction fidelity. Interestingly, we find that all secret shareable states satisfy Bell's inequality in both dealer--reconstructor and dealer--assistant partitions. This brings out a new mutual exclusivity between secret shareable state and Bell's inequality violations. Our result paves the way in identifying the best candidate among the secret sharing resource states in achieving the maximum reconstruction fidelity thus by setting the practical information transfer limit in a possible resource theoretic extension of secret sharing. It also brings out a new kind of mutual exclusiveness between the bipartite correlation and in the ability of secret sharing in a tripartite setting.

quant-ph

Controlled State Reconstruction and Quantum Secret Sharing

In this article, we present a benchmark for resource characterization in the process of controlled quantum state reconstruction and secret sharing for general three-qubit states. This is achieved by providing a closed expression for the reconstruction fidelity, which relies on the genuine tripartite correlation and the bipartite channel between the dealer and the reconstructor characterized by the respective correlation parameters. We formulate the idea of quantum advantage in approximate state reconstruction as surpassing the classical limit set at 2/3. This article brings out new interoperability between teleportation and state reconstruction. This is detailed through a case-by-case analysis of relevant correlation matrices. We are reformulating the idea of quantum secret sharing by setting up additional constraints on the teleportation capacity of the bipartite channels between the dealer and shareholders by ensuring that, individually, the shareholders cannot reconstruct the secret. We believe that this will give us the ideal picture of how quantum secret sharing should be.

quant-ph