arXiv subjects

Vivek Pandey

Publications and source records attributed to Vivek Pandey.

40 records · Page 3Linked to original sources

arXiv2022

Entanglement Meter: Estimation of entanglement with single copy in Interferometer

Efficient certification and quantification of high dimensional entanglement of composite systems are challenging both theoretically as well as experimentally. Here, we demonstrate that several entanglement detection methods can be implemented efficiently in a Mach-Zehnder Interferometric set-up. In particular, we demonstrate how to measure the linear entropy and the negativity of bipartite systems from the visibility of Mach-Zehnder interferometer using single copy of the input state. Our result shows that for any two qubit pure bipartite state, the interference visibility is a direct measure of entanglement. We also propose how to measure the mutual predictability experimentally from the intensity patterns of the interferometric set-up without having to resort to local measurements of mutually unbiased bases. Furthermore, we show that the entanglement witness operator can be measured in a interference setup and the phase shift is sensitive to the separable or entangled nature of the state. Our proposals bring out the power of Interferometric set-up in entanglement detection of pure and several mixed states which paves the way towards design of entanglement meter.

quant-ph↗

arXiv2022

Capacity of Entanglement for Non-local Hamiltonian

The notion of capacity of entanglement is the quantum information theoretic counterpart of the heat capacity which is defined as the second cumulant of the entanglement spectrum. Given any bipartite pure state, we can define the capacity of entanglement as the variance of the modular Hamiltonian in the reduced state of any of the subsystems. Here, we study the dynamics of this quantity under non-local Hamiltonian. Specifically, we address the question: Given an arbitrary non-local Hamiltonian what is the capacity of entanglement that the system can possess? As an useful application, we show that the quantum speed limit for creating the entanglement is not only governed by the fluctuation in the non-local Hamiltonian, but also depends inversely on the time average of square root of the capacity of entanglement. Furthermore, we discuss this quantity for a general self-inverse Hamiltonian and provide a bound on the rate of the capacity of entanglement. Towards the end, we generalise the capacity of entanglement for bipartite mixed states based on the relative entropy of entanglement and show that the above definition reduces to the capacity of entanglement for pure bipartite states. Our results can have several applications in diverse areas of physics.

quant-ph↗

arXiv2021

An ab-initio study of topological and transport properties of YAuPb

In the last few decades, the study of topological materials has been carried out on an extensive scale. Half-Heusler alloys are well known for their topological behaviours. In this work, we present a detailed study of topological properties of a ternary Half-Heusler alloy, YAuPb, using the tight-binding approach. We have calculated some important topological properties which includes$-$ finding nodes and their chiralities, Berry curvature ($\boldsymbolΩ$) and the surface-states. Based on the study of these properties, we categorise the material as non-trivial topological semimetal. Besides the topological behaviours, we present a comparative study of temperature dependent transport properties corresponding to the chemical potential ($μ$) of the Fermi level and the node points. The results obtained from the calculations of electrical conductivity per unit relaxation time ($\boldsymbolσ/τ$) and the electronic part of thermal conductivity per unit relaxation time ($\boldsymbolκ_0$) indicates the conducting nature of the material to both the heat and electricity. Furthermore, the negative value of $S$ obtained, indicates the n-type behaviour of the compound. The calculated value of electronic specific heat (Pauli magnetic susceptibility) corresponding to Fermi level is $\sim 0.03 \hspace{1mm}(0.18) \times 10^{-2}$ $ Jmol^{-1}K^{-1}$ ($\sim 1.21 \hspace{1mm}(1.14) \times 10^{-10}$ $ m^{3}mol^{-1}$) at 50 (300) K. This work suggests that YAuPb is a promising candidate of non-trivial topological semimetals which can be employed in transmission of heat and electricity, and as n-type material within the temperature range of 50-300 K.

cond-mat.mtrl-sci↗

arXiv2005

Leveraging Social-Network Infrastructure to Improve Peer-to-Peer Overlay Performance: Results from Orkut

Application-level peer-to-peer (P2P) network overlays are an emerging paradigm that facilitates decentralization and flexibility in the scalable deployment of applications such as group communication, content delivery, and data sharing. However the construction of the overlay graph topology optimized for low latency, low link and node stress and lookup performance is still an open problem. We present a design of an overlay constructed on top of a social network and show that it gives a sizable improvement in lookups, average round-trip delay and scalability as opposed to other overlay topologies. We build our overlay on top of the topology of a popular real-world social network namely Orkut. We show Orkuts suitability for our purposes by evaluating the clustering behavior of its graph structure and the socializing pattern of its members.

cs.NI↗