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Paper 1

Quantum election scheme based on anonymous quantum key distribution

Rui-Rui Zhou, Li Yang

Year

2011

Journal

arXiv preprint

DOI

arXiv:1112.1212

arXiv

1112.1212

An unconditionally secure authority-certified anonymous quantum key distribution scheme using conjugate coding is presented, base on which we construct a quantum election scheme without the help of entanglement state. We show that this election scheme ensures the completeness, soundness, privacy, eligibility, unreusability, fairness and verifiability of a large-scale election in which the administrator and counter are semi-honest. This election scheme can work even if there exist loss and errors in quantum channels. In addition, any irregularity in this scheme is sensible.

Open paper

Paper 2

Preservation of entanglement in local noisy channels

Priya Ghosh, Kornikar Sen, Ujjwal Sen

Year

2022

Journal

arXiv preprint

DOI

arXiv:2209.04422

arXiv

2209.04422

Entanglement subject to noise can not be shielded against decaying. But, in case of many noisy channels, the degradation can be partially prevented by using local unitary operations. We consider the effect of local noise on shared quantum states and evaluate the amount of entanglement that can be preserved from deterioration. The amount of saved entanglement not only depends on the strength of the channel but also on the type of the channel, and in particular, it always vanishes for the depolarizing channel. The main motive of this work is to analyze the reason behind this dependency of saved entanglement by inspecting properties of the corresponding channels. In this context, we quantify and explore the biasnesses of channels towards the different states on which they act. We postulate that all biasness measures must vanish for depolarizing channels, and subsequently introduce a few measures of biasness. We also consider the entanglement capacities of channels. We observe that the joint behaviour of the biasness quantifiers and the entanglement capacity explains the nature of saved entanglement. Furthermore, we find a pair of upper bounds on saved entanglement which are noticed to imitate the graphical nature of the latter.

Open paper