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We study the entanglement detection by using mutually unbiased measurements and provide a quantum separability criterion that can be experimentally implemented for arbitrary $d$-dimensional bipartite systems. We show that this criterion is…

Quantum Physics · Physics 2015-06-22 Bin Chen , Teng Ma , Shao-Ming Fei

We develop a statistical framework, based on a manifold learning embedding, to extract relevant features of multipartite entanglement structures of mixed quantum states from the measurable correlation data of a quantum computer. We show…

Quantum Physics · Physics 2024-07-26 Eric Brunner , Aaron Xie , Gabriel Dufour , Andreas Buchleitner

Device-independent quantum key distribution (QKD) can permit the superior security even with unknown devices. In practice, however, the realization of device-independent QKD is technically challenging because of its low noise tolerance. In…

Quantum Physics · Physics 2022-03-22 Feihu Xu , Yu-Zhe Zhang , Qiang Zhang , Jian-Wei Pan

Entangled quantum states are essential ingredients for many quantum technologies, but they must be validated before they are used. As a full characterization is prohibitively resource-intensive, recent work has focused on developing methods…

The fabrication of quantum key distribution (QKD) systems typically involves several parties, thus providing Eve with multiple opportunities to meddle with the devices. As a consequence, conventional hardware and/or software hacking attacks…

Localizability of entanglement in fully inseparable states is a key ingredient of assisted quantum information protocols as well as measurement-based models of quantum computing. We investigate the existence of fully inseparable states with…

Quantum Physics · Physics 2017-10-31 M. Mičuda , D. Koutný , M. Miková , I. Straka , M. Ježek , L. Mišta

Mode-pairing quantum key distribution (MP-QKD) is advantageous for long-distance secure communication, leveraging its simple implementation and quadratic scaling capacity. The post-measurement pairing in MP-QKD alleviates the…

Measurement-induced entanglement phase transitions in monitored quantum circuits have stimulated activity in a diverse research community. However, the study of measurement-induced dynamics, due to the requirement of exponentially complex…

Quantum Physics · Physics 2025-07-01 Kim Pöyhönen , Ali G. Moghaddam , Moein N. Ivaki , Teemu Ojanen

An optical procedure in the context of continuous variables to verify bipartite entanglement without destroying both systems and their entanglement is proposed. To perform the nondestructive verification of entanglement, the method relies…

Quantum Physics · Physics 2016-07-06 Alencar J. de Faria

Assessing the quality of an ensemble of noisy entangled states is a central task in quantum information processing. Usually this is done by measuring and hence destroying multiple copies, from which state tomography or fidelity estimation…

Quantum Physics · Physics 2023-02-14 Ferran Riera-Sàbat , Jorge Miguel-Ramiro , Wolfgang Dür

We propose a state preparation protocol based on sequential measurements of a central spin coupled with a spin ensemble, and investigate the usefulness of the generated multi-spin states for quantum enhanced metrology. Our protocol is shown…

Quantum Physics · Physics 2025-01-15 T. B. Lantaño , Dayou Yang , K. M. R. Audenaert , S. F. Huelga , M. B. Plenio

We present a finite-size security proof for generic quantum key distribution protocols against independent and identically distributed collective attacks and extend it to coherent attacks using the postselection technique. This work…

Quantum Physics · Physics 2025-02-11 Lars Kamin , Devashish Tupkary , Norbert Lütkenhaus

In this paper, we investigate properties of some multi-particle entangled states and, from the properties applying the secret sharing present a new type of quantum key distribution protocols as generalization of quantum key distribution…

Quantum Physics · Physics 2007-05-23 Sora Choi , Jinsoo Kim , Dong Pyo Chi

The large-scale deployment of quantum secret sharing (QSS) in quantum networks is currently challenging due to the requirements for the generation and distribution of multipartite entanglement states. Here we present an efficient…

Quantum Physics · Physics 2024-07-24 Yi-Ran Xiao , Zhao-Ying Jia , Yu-Chen Song , Yu Bao , Yao Fu , Hua-Lei Yin , Zeng-Bing Chen

Entanglement is an essential ingredient in many quantum communication protocols. In particular, entanglement can be exploited in quantum key distribution (QKD) to generate two correlated random bit strings whose randomness is guaranteed by…

A continuous-variable measurement-device-independent quantum key distribution (CV-MDI QKD) protocol using squeezed states is proposed where the two legitimate partners send Gaussian-modulated squeezed states to an untrusted third party to…

Quantum Physics · Physics 2014-11-20 Yi-Chen Zhang , Zhengyu Li , Song Yu , Wanyi Gu , Xiang Peng , Hong Guo

The precision advantages offered by harnessing the quantum states of sensors can be readily compromised by noise. However, when the noise has a different spatial function than the signal of interest, recent theoretical work shows how the…

A detailled analysis of quantum key distribution employing entangled states is presented. We tested a system based on photon pairs entangled in energy-time optimized for long distance transmission. It is based on a Franson type set-up for…

Quantum Physics · Physics 2009-11-06 Gregoire Ribordy , Juergen Brendel , Jean-Daniel Gautier , Nicolas Gisin , Hugo Zbinden

The idea of post-measurement coincidence pairing simplifies substantially long-distance, repeater-like quantum key distribution (QKD) by eliminating the need for tracking the differential phase of the users' lasers. However, optical…

Quantum Physics · Physics 2024-07-23 Chengfang Ge , Lai Zhou , Jinping Lin , Hua-Lei Yin , Qiang Zeng , Zhiliang Yuan

A key goal of quantum communication is to determine the maximum number of bits shared between two quantum systems. An important example of this is in entanglement based quantum key distribution (QKD) schemes. A realistic treatment of this…

Quantum Physics · Physics 2015-06-04 Thomas Brougham , Stephen M. Barnett