arXiv subjects

Radha Pyari Sandhir

Publications and source records attributed to Radha Pyari Sandhir.

4 recordsLinked to original sources

arXiv2020

State-Independent Quantum Key Distribution with Two-Way Classical Communication

A quantum key distribution protocol is proposed that is a variation of BB84 that provides raw key generation from correlations that violate a Bell-type inequality for single qubit systems and not entangled pairs. Additionally, it 1) is state-independent, 2) involves two-way classical communication, and 3) does not require basis matching between the two parties. The Brukner-Taylor-Cheung-Vedral (BTCV) time-like form of the Bell-CHSH inequality [C. Brukner, S. Taylor, S. Cheung, V. Vedral arXiv:quant-ph/0402127] is employed as an eavesdropping check; sequential measurements lead to an inequality identical in form to the Bell-CHSH inequality, which relies only on the measurements performed with no regard for the qubit states. We show that this form manifests naturally from the non-commutativity of observables.

quant-ph↗

arXiv2019

Weak Classicality in Coupled N-Level Quantum Systems

The notion of `weak classical limit' for coupled N-level quantum systems as N -> infinity is introduced to understand the precise sense in which one attains classicality. There exist proofs that a system becomes classical at large N. On the other hand, it is known that non-locality and entanglement, the two hallmarks of non-classicality, thrive even as N -> infinity. We reconcile these results in this paper by showing that so called classicality is not so much an inherent property of the system, as it is a consequence of limited experimental resources. Our focus is largely on non-locality, for which we study the Bell-CHSH and CGLMP inequalities for N-level systems.

quant-ph↗

arXiv2016

Is non-locality stronger in higher dimensions?

A critique of a prescription of non-locality in [Phys. Rev. Lett. 85, 4418 (2000)], [Phys. Rev. Lett. 88, 040404 (2002)], [Phys. Rev. Lett. 92, 130404 (2004)] that appears to be stronger and more general than the Bell-CHSH formulation is presented. It is shown that, contrary to expectations, this prescription fails to correctly identify a large family of maximally non-local Bell states.

quant-ph↗

arXiv2012

Dynamic Fuzzy c-Means (dFCM) Clustering and its Application to Calorimetric Data Reconstruction in High Energy Physics

In high energy physics experiments, calorimetric data reconstruction requires a suitable clustering technique in order to obtain accurate information about the shower characteristics such as position of the shower and energy deposition. Fuzzy clustering techniques have high potential in this regard, as they assign data points to more than one cluster,thereby acting as a tool to distinguish between overlapping clusters. Fuzzy c-means (FCM) is one such clustering technique that can be applied to calorimetric data reconstruction. However, it has a drawback: it cannot easily identify and distinguish clusters that are not uniformly spread. A version of the FCM algorithm called dynamic fuzzy c-means (dFCM) allows clusters to be generated and eliminated as required, with the ability to resolve non-uniformly distributed clusters. Both the FCM and dFCM algorithms have been studied and successfully applied to simulated data of a sampling tungsten-silicon calorimeter. It is seen that the FCM technique works reasonably well, and at the same time, the use of the dFCM technique improves the performance.

nucl-ex↗