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We show the unconditional security of decoy-state method quantum cryptography with whatever intensity error pattern provided that the error is not too large. Our result immediately applies to the existing experimental data. Our result is…

Quantum Physics · Physics 2013-05-29 Xiang-Bin Wang , Cheng-Zhi Peng , Jun Zhang , Jian-Wei Pan

We Haar uniformly generate random states of various ranks and study their performance in an entanglement-based quantum key distribution (QKD) task. In particular, we analyze the efficacy of random two-qubit states in realizing…

Quantum Physics · Physics 2023-02-14 Subhankar Bera , Shashank Gupta , A. S. Majumdar

Efficiency is a key issue in any real implementation of a cryptographic protocol since the physical resources are not unlimited. We will first show that Quantum Key Distribution is possible with an "Entanglement based" scheme with NPPT…

Quantum Physics · Physics 2015-03-17 Carles Rodó

The one-way distillable entanglement is a central operational measure of bipartite entanglement, quantifying the optimal rate at which maximally entangled pairs can be extracted by one-way LOCC. Despite its importance, it is notoriously…

Quantum Physics · Physics 2026-03-25 Rabsan Galib Ahmed , Graeme Smith , Peixue Wu

High-dimensional photonic entanglement holds significant promise for advancing quantum communication, computation, and metrology. For example, large-alphabet quantum communication protocols are known to benefit from enhanced noise…

We consider discrete-alphabet encoding schemes for coherent-state quantum key distribution. The sender encodes the letters of a finite-size alphabet into coherent states whose amplitudes are symmetrically distributed on a circle centered in…

Quantum Physics · Physics 2018-08-02 Panagiotis Papanastasiou , Cosmo Lupo , Christian Weedbrook , Stefano Pirandola

Preparing and certifying bound entangled states in the laboratory is an intrinsically hard task, due to both the fact that they typically form narrow regions in the state space, and that a certificate requires a tomographic reconstruction…

Quantum Physics · Physics 2018-12-20 Gael Sentís , Johannes N. Greiner , Jiangwei Shang , Jens Siewert , Matthias Kleinmann

Quantum key distribution (QKD) refers to specific quantum strategies which permit the secure distribution of a secret key between two parties that wish to communicate secretly. Quantum cryptography has proven unconditionally secure in ideal…

Quantum Physics · Physics 2008-10-14 C. Rodó , O. Romero-Isart , K. Eckert , A. Sanpera

In this work, we construct small sets of bipartite orthogonal pure states that cannot be perfectly distinguished by local operations and classical communication (LOCC). We mention that not all the states within the constructed sets are…

Quantum Physics · Physics 2026-03-31 Saronath Halder , Suchetana Goswami

The security of quantum key distribution (QKD) has been proven for different protocols, in particular for the BB84 protocol. It has been shown that this scheme is robust against eventual imperfections in the state preparation, and sending…

Quantum Physics · Physics 2018-12-05 Davide Rusca , Alberto Boaron , Marcos Curty , Anthony Martin , Hugo Zbinden

The quantum dense coding (DC) protocol, which has no security feature, deals with the transmission of classical information encoded in a quantum state by using shared entanglement between a single sender and a single receiver. Its…

Quantum Physics · Physics 2024-09-17 Ayan Patra , Rivu Gupta , Tamoghna Das , Aditi Sen De

We present a lower bound of concurrence for arbitrary dimensional bipartite quantum states. This lower bound may be used to improve all the known lower bounds of concurrence. Moreover, the lower bound gives rise to an operational sufficient…

Quantum Physics · Physics 2011-12-26 Ming-Jing Zhao , Xue-Na Zhu , Shao-Ming Fei , Xianqing Li-Jost

In this paper, we present the first experimental demonstration on continuous variable quantum key distribution using determinant Einstein-Podolsky-Rosen entangled states of optical field. By means of the instantaneous measurements of the…

Quantum Physics · Physics 2015-05-30 Xiaolong Su , Wenzhe Wang , Yu Wang , Xiaojun Jia , Changde Xie , Kunchi Peng

By carrying out measurements on entangled states, two parties can generate a secret key which is secure not only against an eavesdropper bound by the laws of quantum mechanics, but also against a hypothetical "post-quantum" eavesdroppers…

Quantum Physics · Physics 2007-10-22 Antonio Acin , Serge Massar , Stefano Pironio

Quantum communication over long distances is integral to information security and has been demonstrated in free space and fibre with two-dimensional polarisation states of light. Although increased bit rates can be achieved using…

We give an entanglement assisted scheme for quantum key distribution. The scheme requires the maximally entangled 2-qubit state but does not require any quantum storage. The scheme is unconditionally secure under whatever Eve's attack.…

Quantum Physics · Physics 2016-09-08 Xiang-Bin Wang

Quantum communication in general helps deter potential eavesdropping in the course of transmission of bits to enable secure communication between two or more parties. In this paper, we propose a novel quasi-deterministic secure quantum…

Quantum Physics · Physics 2021-03-08 Sujan Vijayaraj , S. Balakrishnan , K. Senthilnathan

We prove unconditional security for a quantum key distribution (QKD) protocol based on distilling pbits (twisted ebits) [quant-ph/0309110] from an arbitrary untrusted state that is claimed to contain distillable key. Our main result is that…

Quantum Physics · Physics 2016-11-18 Karol Horodecki , Michal Horodecki , Pawel Horodecki , Debbie Leung , Jonathan Oppenheim

We provide a general formalism to characterize the cryptographic properties of quantum channels in the realistic scenario where the two honest parties employ prepare and measure protocols and the known two-way communication reconciliation…

Quantum Physics · Physics 2010-09-23 Joonwoo Bae , Antonio Acin

We show that non-maximally entangled states can be used to build a quantum key distribution (QKD) scheme whose security and key rate transmission is nearly equivalent to those of standard QKD protocols. These aspects can be controlled by…

Quantum Physics · Physics 2009-11-19 Goren Gordon , Gustavo Rigolin