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Related papers: Kirkwood-Dirac classical pure states

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With the emergence of an information society, the idea of protecting sensitive data is steadily gaining importance. Conventional encryption methods may not be sufficient to guarantee data protection in the future. Quantum key distribution…

Quantum Physics · Physics 2016-09-20 Nitin Jain , Birgit Stiller , Imran Khan , Dominique Elser , Christoph Marquardt , Gerd Leuchs

We prove that most quasi-distributions can be written in a form similar to that of the de Broglie-Bohm distribution, except that ordinary products are replaced by some suitable non-commutative star product. In doing so, we show that the…

Quantum Physics · Physics 2009-11-07 Nuno Costa Dias , Joao Nuno Prata

Quantum key distribution (QKD) is the first quantum information task to reach the level of mature technology, already fit for commercialization. It aims at the creation of a secret key between authorized partners connected by a quantum…

It is widely believed that quantum key distribution (QKD) has been proved unconditionally secure for realistic models applicable to various current experimental schemes. Here we summarize briefly why this is not the case, from both the…

Quantum Physics · Physics 2015-05-30 Horace P. Yuen

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

The security issues facing quantum key distribution (QKD) are explained, herein focusing on those issues that are cryptographic and information theoretic in nature and not those based on physics. The problem of security criteria is…

Quantum Physics · Physics 2016-02-25 Horace Yuen

A pure state of $N$ parties with local dimension $d$ is called a $k$-uniform state if all the reductions to $k$ parties are maximally mixed. Based on the connections among $k$-uniform states, orthogonal arrays and linear codes, we give…

Quantum Physics · Physics 2021-09-15 Fei Shi , Mao-Sheng Li , Lin Chen , Xiande Zhang

$k$-Uniform states are fundamental to quantum information and computing, with applications in multipartite entanglement and quantum error-correcting codes (QECCs). Prior work has primarily focused on constructing exact $k$-uniform states or…

Quantum Physics · Physics 2025-08-13 Kaiyi Guo , Fei Shi , You Zhou , Qi Zhao

Quantum key distribution (QKD) provides secure keys resistant to code-breaking quantum computers. As headed towards commercial application, it is crucial to guarantee the practical security of QKD systems. However, the difficulty of…

Quantum Physics · Physics 2018-05-14 Zhengyu Li , Yi-Chen Zhang , Hong Guo

We present a new measure of non-Markovianity based on the property of nonincreasing quantum coherence via Kirkwood-Dirac (KD) quasiprobability under incoherent completely positive trace-preserving maps. Quantum coherence via the KD…

Quantum Physics · Physics 2025-06-30 Yassine Dakir , Abdallah Slaoui , Rachid Ahl Laamara

It is shown on a simple classical model of a quantum particle at rest that information contained into the quantum state (quantum information) can be obtained by integrating the corresponding probability distribution on phase space, i.e. by…

Quantum Physics · Physics 2007-05-23 B. A. Nikolov

We introduce $k$-local quasi-quantum states: a superset of the regular quantum states, defined by relaxing the positivity constraint. We show that a $k$-local quasi-quantum state on $n$ qubits can be 1-1 mapped to a distribution of…

Quantum Physics · Physics 2025-01-27 Itai Arad , Miklos Santha

Quantum Darwinism (QD) proposes that classical objectivity emerges from the broadcast of information about a microscopic degree of freedom into multiple fractions of a many-body environment. Such a broadcast of information is in sharp…

Quantum Physics · Physics 2024-04-01 Benoît Ferté , Xiangyu Cao

Quantum chaos in many-body systems provides a bridge between statistical and quantum physics with strong predictive power. This framework is valuable for analyzing properties of complex quantum systems such as energy spectra and the…

We consider the properties of a specific distribution of mixed quantum states of arbitrary dimension that can be biased towards a specific mean purity. In particular, we analyze mixtures of Haar-random pure states with Dirichlet-distributed…

We introduce a general method for the construction of quasiprobability representations for arbitrary notions of quantum coherence. Our technique yields a nonnegative probability distribution for the decomposition of any classical state.…

Quantum Physics · Physics 2018-06-22 J. Sperling , I. A. Walmsley

A possible way for the consistent probability interpretation of the Klein-Gordon equation is proposed. It is assumed that some states of a scalar charged particle cannot be physically realized. The rest of quantum states are proven to have…

High Energy Physics - Theory · Physics 2008-11-26 A. A. Semenov , C. V. Usenko , B. I. Lev

There is no doubt that quantum key distribution is an excellent result as a science. However, this paper presents a view on quantum key distribution (QKD) wherein QKD may have a difficulty to provide a sufficient security and good…

Quantum Physics · Physics 2014-09-23 Osamu Hirota

Quantum key distribution (QKD) allows two users to exchange a provably secure key for cryptographic applications. In prepare-and-measure QKD protocols, the states must be indistinguishable to prevent information leakage to an eavesdropper…

Most quantum key distribution (QKD) protocols can be classified as either a discrete-variable (DV) protocol or continuous-variable (CV) protocol, based on how classical information is being encoded. We propose a protocol that combines the…