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We present a protocol for growing graph states, the resource for one-way quantum computing, when the available entanglement mechanism is highly imperfect. The distillation protocol is frugal in its use of ancilla qubits, requiring only a…

Quantum Physics · Physics 2009-06-09 Earl T. Campbell

It is known that he bipartite quantum states, with rank strictly smaller than the maximum of the ranks of its two reduced states, are distillable by local operations and classical communication. Our first main result is that this is also…

Quantum Physics · Physics 2015-05-27 Lin Chen , Dragomir Z. Djokovic

Measurement-based quantum repeaters employ entanglement distillation and swapping across links using locally prepared resource states of minimal size and local Bell measurements. In this Letter, we introduce a systematic protocol for…

Quantum Physics · Physics 2025-09-30 Yu Shi , Ashlesha Patil , Saikat Guha

We study compression strategies for multipartite entanglement distribution under uncertainty in the partitioning of the quantum state. When the partition is not known at the time of state preparation, we show that a joint design of the…

Device-independent quantum key distribution (DIQKD) allows two distant parties to establish a secret key, based only on the observed Bell nonlocal distribution. It remains however, unclear what the minimal resources for enabling DIQKD are…

Quantum Physics · Physics 2026-01-05 Bora Ulu , Nicolas Brunner , Mirjam Weilenmann

Entanglement distillation is a basic task in quantum information, and the distillable entanglement of three bipartite reduced density matrices from a tripartite pure state has been studied in [Phys. Rev. A 84, 012325 (2011)]. We extend this…

Quantum Physics · Physics 2019-09-09 Yize Sun , Lin Chen

Quantum key distribution(QKD) might be the most famous application of quantum information theory. The idea of QKD is not difficult to understand but in practical implementations, many problems are needed to be solved, for example, the noise…

Quantum Physics · Physics 2023-08-01 Hao Shu , Chang-Yue Zhang , Yue-Qiu Chen , Zhu-Jun Zheng , Shao-Ming Fei

The decoy state protocol has been considered to be one of the most important methods to protect the security of quantum key distribution (QKD) with a weak coherent source. Here we test two experimental approaches to generating the decoy…

Quantum Physics · Physics 2018-09-18 Anqi Huang , Shi-Hai Sun , Zhihong Liu , Vadim Makarov

Entanglement distillation refers to the task of transforming a collection of weakly entangled pairs into fewer highly entangled ones. It is a core ingredient in quantum repeater protocols, needed to transmit entanglement over arbitrary…

Quantum Physics · Physics 2016-01-20 Stephan Waeldchen , Janina Gertis , Earl T. Campbell , Jens Eisert

We propose a measurement-based method to produce a maximally-entangled state from a partially-entangled pure state. Our goal can be thought of as entanglement distillation from a single copy of a partially-entangled state. The present…

Quantum Physics · Physics 2012-10-17 Yukihiro Ota , Sahel Ashhab , Franco Nori

Addition of single photons to two-mode-squeezed-vacuum states has the effect of distilling quantum entanglement, and, when deployed in quantum key distribution, should lead also to an increase in the secret key rate. However, the extraction…

Quantum Physics · Physics 2025-07-25 Hao Jeng , Ping Koy Lam , Syed M. Assad

We study the measurement device independent quantum key distribution (MDI-QKD) in practice with limited resource, when there are only 3 different states in implementing the decoy-state method. We present a more tightened explicit formula to…

Quantum Physics · Physics 2014-01-08 Z. -W. Yu , Y. -H. Zhou , X. -B. Wang

We analyze the set of two-qubit states from which a secret key can be extracted by single-copy measurements plus classical processing of the outcomes. We introduce a key distillation protocol and give the corresponding necessary and…

Quantum Physics · Physics 2016-08-16 A. Acín , J. Bae , E. Bagan , M. Baig , Ll. Masanes , R. Muñoz-Tapia

Quantum key distribution (QKD) offers the promise of absolutely secure communications. However, proofs of absolute security often assume perfect implementation from theory to experiment. Thus, existing systems may be prone to insidious…

Quantum Physics · Physics 2014-06-23 Samuel L. Braunstein , Stefano Pirandola

We derive general upper bounds on the distillable entanglement of a mixed state under one-way and two-way LOCC. In both cases, the upper bound is based on a convex decomposition of the state into 'useful' and 'useless' quantum states. By…

Quantum Physics · Physics 2018-07-11 Felix Leditzky , Nilanjana Datta , Graeme Smith

Quantum key distribution (QKD) allows two remote users to establish a secret key in the presence of an eavesdropper. The users share quantum states prepared in two mutually-unbiased bases: one to generate the key while the other monitors…

Quantum Physics · Physics 2018-05-03 Nurul T. Islam , Charles Ci Wen Lim , Clinton Cahall , Jungsang Kim , Daniel J. Gauthier

With the rise of quantum technologies, data security increasingly relies on quantum cryptography and its most notable application, quantum key distribution (QKD). Yet, current technological limitations, in particular, the unavailability of…

Quantum technologies rely on high-quality resource states, such as maximally entangled or private states, which are indispensable for quantum communication and cryptography. In practice, however, these states are inevitably degraded by…

Quantum Physics · Physics 2026-03-05 Christopher Popp , Tobias C. Sutter , Beatrix C. Hiesmayr

It is known that advantage distillation (that is, information reconciliation using two-way communication) improves noise tolerances for quantum key distribution (QKD) setups. Two-way communication is hence also of interest in the…

Quantum Physics · Physics 2023-03-27 Thomas A. Hahn , Ernest Y. -Z. Tan

We investigate one-way communication scenarios where Bob manipulating on his parts can transfer some sub-system to the environment. We define reduced versions of quantum communication rates and further, prove new upper bounds on one-way…

Quantum Physics · Physics 2013-05-29 Marcin L. Nowakowski , Pawel Horodecki