scholarly journals Experimental quantum conference key agreement

2021 ◽  
Vol 7 (23) ◽  
pp. eabe0395
Author(s):  
Massimiliano Proietti ◽  
Joseph Ho ◽  
Federico Grasselli ◽  
Peter Barrow ◽  
Mehul Malik ◽  
...  
Keyword(s):  
Secure Communication ◽  
Key Agreement ◽  
Quantum Communication ◽  
Quantum Information Processing ◽  
Global Scale ◽  
Low Noise ◽  
Long Distance ◽  
Quantum Networks ◽  
High Brightness ◽  
Ghz States

Quantum networks will provide multinode entanglement enabling secure communication on a global scale. Traditional quantum communication protocols consume pair-wise entanglement, which is suboptimal for distributed tasks involving more than two users. Here, we demonstrate quantum conference key agreement, a cryptography protocol leveraging multipartite entanglement to efficiently create identical keys between N users with up to N-1 rate advantage in constrained networks. We distribute four-photon Greenberger-Horne-Zeilinger (GHZ) states, generated by high-brightness telecom photon-pair sources, over optical fiber with combined lengths of up to 50 km and then perform multiuser error correction and privacy amplification. Under finite-key analysis, we establish 1.5 × 106 bits of secure key, which are used to encrypt and securely share an image between four users in a conference transmission. Our work highlights a previously unexplored protocol tailored for multinode networks leveraging low-noise, long-distance transmission of GHZ states that will pave the way for future multiparty quantum information processing applications.

scholarly journals Parameter regimes for surpassing the PLOB bound with error-corrected qudit repeaters

Quantum ◽  
2019 ◽  
Vol 3 ◽  
pp. 216 ◽  
Author(s):  
Daniel Miller ◽  
Timo Holz ◽  
Hermann Kampermann ◽  
Dagmar Bruß
Keyword(s):  
Secure Communication ◽  
Quantum Communication ◽  
Quantum Repeater ◽  
Long Distance ◽  
Quantum Networks ◽  
Quantum Capacity ◽  
Higher Dimensional ◽  
Quantum Repeaters ◽  
New Applications ◽  
Provably Secure

A potential quantum internet would open up the possibility of realizing numerous new applications, including provably secure communication. Since losses of photons limit long-distance, direct quantum communication and wide-spread quantum networks, quantum repeaters are needed. The so-called PLOB-repeaterless bound [Pirandola et al., Nat. Commun. 8, 15043 (2017)] is a fundamental limit on the quantum capacity of direct quantum communication. Here, we analytically derive the quantum-repeater gain for error-corrected, one-way quantum repeaters based on higher-dimensional qudits for two different physical encodings: Fock and multimode qudits. We identify parameter regimes in which such quantum repeaters can surpass the PLOB-repeaterless bound and systematically analyze how typical parameters manifest themselves in the quantum-repeater gain. This benchmarking provides a guideline for the implementation of error-corrected qudit repeaters.

scholarly journals A low-noise single-photon detector for long-distance free-space quantum communication

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Elena Anisimova ◽  
Dmitri Nikulov ◽  
Simeng Simone Hu ◽  
Mark Bourgon ◽  
Sebastian Philipp Neumann ◽  
...  
Keyword(s):  
Free Space ◽  
Quantum Communication ◽  
Detection Efficiency ◽  
Single Photon ◽  
Avalanche Photodiode ◽  
Low Noise ◽  
Photon Detector ◽  
Single Photon Detector ◽  
Long Distance ◽  
Communication Links

AbstractWe build and test a single-photon detector based on a Si avalanche photodiode Excelitas 30902SH thermoelectrically cooled to −100∘C. Our detector has dark count rate below 1 Hz, $500\ \mu\mathrm{m}$ 500 μ m diameter photosensitive area, photon detection efficiency around 50%, afterpulsing less than 0.35%, and timing jitter under 1 ns. These characteristics make it suitable for long-distance free-space quantum communication links, which we briefly discuss. We also report an improved method that we call long-time afterpulsing analysis, used to determine and visualise long trap lifetimes at different temperatures.

MULTIPARTY CONTROLLED DETERMINISTIC SECURE QUANTUM COMMUNICATION THROUGH ENTANGLEMENT SWAPPING

2008 ◽  
Vol 19 (11) ◽  
pp. 1673-1681 ◽  
Author(s):  
LI DONG ◽  
XIAO-MING XIU ◽  
YA-JUN GAO ◽  
FENG CHI
Keyword(s):  
Quantum Channel ◽  
Secure Communication ◽  
Quantum Communication ◽  
Entanglement Swapping ◽  
Deterministic Secure Quantum Communication ◽  
Classical Information ◽  
Secret Information ◽  
Ghz States ◽  
Quantum Secure Communication ◽  
Communication Scheme

A three-party controlled deterministic secure quantum communication scheme through entanglement swapping is proposed firstly. In the scheme, the sender needs to prepare a class of Greenberger–Horne–Zeilinger (GHZ) states which are used as quantum channel. The two communicators may securely communicate under the control of the controller if the quantum channel is safe. The roles of the sender, the receiver, and the controller can be exchanged owing to the symmetry of the quantum channel. Different from other controlled quantum secure communication schemes, the scheme needs lesser additional classical information for transferring secret information. Finally, it is generalized to a multiparty controlled deterministic secure quantum communication scheme.

scholarly journals Optomechanical interfaces for hybrid quantum networks

2015 ◽  
Vol 2 (4) ◽  
pp. 510-519 ◽  
Author(s):  
Chunhua Dong ◽  
Yingdan Wang ◽  
Hailin Wang
Keyword(s):  
Degrees Of Freedom ◽  
Quantum Communication ◽  
Quantum Information Processing ◽  
Quantum Systems ◽  
Optical Control ◽  
Special Role ◽  
Mechanical Motion ◽  
Optical Fields ◽  
Quantum Networks ◽  
Optical Resonances

Abstract Recent advances on optical control of mechanical motion in an optomechanical resonator have stimulated strong interests in exploring quantum behaviors of otherwise classical, macroscopic mechanical systems and especially in exploiting mechanical degrees of freedom for applications in quantum information processing. In an optomechanical resonator, an optically- active mechanical mode can couple to any of the optical resonances supported by the resonator via radiation pressure. This unique property leads to a remarkable phenomenon: mechanically-mediated conversion of optical fields between vastly different wavelengths. The resulting optomechanical interfaces can play a special role in a hybrid quantum network, enabling quantum communication between disparate quantum systems. In this review, we introduce the basic concepts of optomechanical interactions and discuss recent theoretical and experimental progresses in this field. A particular emphasis is on taking advantage of mechanical degrees of freedom, while avoiding detrimental effects of thermal mechanical motion.

scholarly journals Entangling single atoms over 33 km telecom fibre

2022 ◽  
Author(s):  
Tim van Leent ◽  
Matthias Bock ◽  
Florian Fertig ◽  
Robert Garthoff ◽  
Sebastian Eppelt ◽  
...  
Keyword(s):  
Large Scale ◽  
Quantum Communication ◽  
Frequency Conversion ◽  
Single Atom ◽  
Quantum Network ◽  
Low Loss ◽  
Quantum Repeater ◽  
Long Distance ◽  
Quantum Networks ◽  
Network Links

Abstract Heralded entanglement between distant quantum memories is the key resource for quantum networks. Based on quantum repeater protocols, these networks will facilitate efficient large-scale quantum communication and distributed quantum computing. However, despite vast efforts, long-distance fibre based network links have not been realized yet. Here we present results demonstrating heralded entanglement between two independent, remote single-atom quantum memories generated over fibre links with a total length up to 33 km. To overcome the attenuation losses in the long optical fibres of photons initially emitted by the Rubidium quantum memories, we employ polarization-preserving quantum frequency conversion to the low loss telecom band. The presented work represents a milestone towards the realization of efficient quantum network links.

scholarly journals Quantum dot technology for quantum repeaters: from entangled photon generation towards the integration with quantum memories

2021 ◽  
Author(s):  
Julia Neuwirth ◽  
Francesco Basso Basset ◽  
Michele B. Rota ◽  
Emanuele Roccia ◽  
Christian Schimpf ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Quantum Communication ◽  
Special Focus ◽  
Quantum Repeater ◽  
Long Distance ◽  
Quantum Networks ◽  
Pair Generation ◽  
The One ◽  
Photon Generation ◽  
High Degree

Abstract The realization of a functional quantum repeater is one of the major research goals in long-distance quantum communication. Among the different approaches that are being followed, the one relying on quantum memories interfaced with deterministic quantum emitters is considered as one of the most promising solutions. In this work, we focus on the hardware to implement memory-based quantum-repeater schemes that rely on semiconductor quantum dots for the generation of polarization entangled photons. Going through the most relevant figures of merit related to efficiency of the photon source, we select significant developments in fabrication, processing and tuning techniques aimed at combining high degree of entanglement with on-demand pair generation, with a special focus on the progress achieved in the representative case of the GaAs system. We proceed to offer a perspective on integration with quantum memories, both highlighting preliminary works on natural-artificial atomic interfaces and commenting a wide choice of currently available and potentially viable memory solutions in terms of wavelength, bandwidth and noise-requirements. To complete the overview, we also present recent implementations of entanglement-based quantum communication protocols with quantum dots and highlight the next challenges ahead for the implementation of practical quantum networks.

scholarly journals Efficient Key Agreement Algorithm for Wireless Body Area Networks Using Reusable ECG-Based Features

Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 404
Author(s):  
Yasmeen Al-Saeed ◽  
Eman Eldaydamony ◽  
Ahmed Atwan ◽  
Mohammed Elmogy ◽  
Osama Ouda
Keyword(s):  
Secure Communication ◽  
Key Agreement ◽  
Body Area Networks ◽  
Wireless Body Area Networks ◽  
Sensor Nodes ◽  
Security And Privacy ◽  
Physiological Data ◽  
Computer Assisted ◽  
Body Area ◽  
Key Agreement Protocol

Wireless Body Area Networks (WBANs) are increasingly employed in different medical applications, such as remote health monitoring, early detection of medical conditions, and computer-assisted rehabilitation. A WBAN connects a number of sensor nodes implanted in and/or fixed on the human body for monitoring his/her physiological characteristics. Although medical healthcare systems could significantly benefit from the advancement of WBAN technology, collecting and transmitting private physiological data in such an open environment raises serious security and privacy concerns. In this paper, we propose a novel key-agreement protocol to secure communications among sensor nodes of WBANs. The proposed protocol is based on measuring and verifying common physiological features at both sender and recipient sensors prior to communicating. Unlike existing protocols, the proposed protocol enables communicating sensors to use their previous session pre-knowledge for secure communication within a specific period of time. This will reduce the time required for establishing the shared key as well as avoid retransmitting extracted features in the medium and hence thwarting eavesdropping attacks while maintaining randomness of the key. Experimental results illustrate the superiority of the proposed key agreement protocol in terms of both feature extraction and key agreement phases with an accuracy of 99.50% and an error rate of 0.005%. The efficacy of the proposed protocol with respect to energy and memory utilization is demonstrated compared with existing key agreement protocols.

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