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Related papers: Kirkwood-Dirac classical pure states

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Kirkwood-Dirac representations of quantum states are increasingly finding use in many areas within quantum theory. Usually, representations of this sort are only applied to provide a representation of quantum states (as complex functions…

Quantum Physics · Physics 2025-08-15 David Schmid , Roberto D. Baldijão , Yìlè Yīng , Rafael Wagner , John H. Selby

Among the many quasiprobability representations of quantum mechanics, the family of Kirkwood-Dirac (KD) representations has come to the foreground in recent years. Each such KD representation is determined by the choice of two complementary…

Quantum Physics · Physics 2026-05-29 Matéo Spriet , Christopher Langrenez , Raymond Brummelhuis , Stephan De Bièvre

The question of when the Kirkwood-Dirac quasiprobability serves as the most appropriate description for quantum measurements has remained unresolved, particularly across different measurement strengths. While known to generate anomalous…

Quantum Physics · Physics 2026-01-27 Bo Zhang , Yusuf Turek

Recent work has revealed the central role played by the Kirkwood-Dirac quasiprobability (KDQ) as a tool to properly account for non-classical features in the context of condensed matter physics (scrambling, dynamical phase transitions)…

The Scrooge distribution is a probability distribution over the set of pure states of a quantum system. Specifically, it is the distribution that, upon measurement, gives up the least information about the identity of the pure state,…

Quantum Physics · Physics 2018-10-17 William K Wootters

We propose a characterization and a quantification of general quantum correlation which is exhibited even by a separable (unentangled) mixed bipartite state in terms of the nonclassical values of the associated Kirkwood-Dirac (KD)…

Quantum Physics · Physics 2024-05-15 Agung Budiyono , Bobby E. Gunara , Bagus E. B. Nurhandoko , Hermawan K. Dipojono

We define the Kirkwood-Dirac quasiprobability representation of quantum mechanics associated with the Fourier transform over second countable locally compact abelian groups. We discuss its link with the Kohn-Nirenberg quantization of the…

Quantum Physics · Physics 2026-02-23 Matéo Spriet

The Kirkwood-Dirac distribution, serving as an informationally complete representation of a quantum state, has recently garnered increasing attention. We investigate the Kirkwood-Dirac classicality with respect to mutually unbiased bases.…

Quantum Physics · Physics 2025-06-11 Yan Liu , Zhihua Guo , Zhihao Ma , Shao-Ming Fei

The study of measurements in quantum mechanics exposes many of the ways in which the quantum world is different. For example, one of the hallmarks of quantum mechanics is that observables may be incompatible, implying among other things…

Quantum Physics · Physics 2025-10-15 Emery Doucet , Sebastian Deffner

We address a problem of identifying a given pure state with one of two reference pure states, when no classical knowledge on the reference states is given, but a certain number of copies of them are available. We assume the input state is…

Quantum Physics · Physics 2009-11-11 A. Hayashi , M. Horibe , T. Hashimoto

We determine the Kirkwood-Dirac quasiprobability (KDQ) distribution associated to the stochastic instances of internal energy variations for the quantum system and environment particles in coherent Markovian collision models. In the case…

Quantum Physics · Physics 2025-07-23 Marco Pezzutto , Gabriele De Chiara , Stefano Gherardini

The dramatic increase in the efficiency of a quantum computer over a classical computer, raises a natural question asking, how much of this success could be attributed to its quantum nature and how much to its probabilistic content. To…

Statistical Mechanics · Physics 2007-05-23 Anjan Kundu

Quantum key distribution (QKD) promises secure key agreement by using quantum mechanical systems. We argue that QKD will be an important part of future cryptographic infrastructures. It can provide long-term confidentiality for encrypted…

Quantum Physics · Physics 2010-01-25 Douglas Stebila , Michele Mosca , Norbert Lütkenhaus

In quantum physics, the density operator completely describes the state. Instead, in classical physics the mean value of every physical quantity is evaluated by means of a probability distribution. We study the possibility to describe pure…

Quantum Physics · Physics 2011-11-09 Alberto Montina

We use spin coherent states to compare classical and quantum evolution of a simple paradigmatic, discrete-time quantum dynamical system exhibiting chaotic behavior in the classical limit. The spin coherent states are employed to define a…

Quantum Physics · Physics 2020-10-29 Marek Kuś , Robert Przybycień

We show that a quantum state may be represented as the sum of a joint probability and a complex quantum modification term. The joint probability and the modification term can both be observed in successive projective measurements. The…

Quantum Physics · Physics 2007-11-21 Lars M. Johansen

In 1945, Dirac attempted to develop a "formal probability" distribution to describe quantum operators in terms of two non-commuting variables, such as position x and momentum p [Rev. Mod. Phys. 17, 195 (1945)]. The resulting…

Quantum Physics · Physics 2014-03-06 Jeff S. Lundeen , Charles Bamber

Quantum Key Distribution (QKD) is a technology that ensures secure communication by leveraging the principles of quantum mechanics, such as the no-cloning theorem and quantum uncertainty. This chapter provides an overview of this quantum…

Quantum Physics · Physics 2026-02-27 Sebastian Kish , Josef Pieprzyk , Seyit Camtepe

Data centers are nowadays referred to as the digital world's cornerstone. Quantum key distribution (QKD) is a method that solves the problem of distributing cryptographic keys between two entities, with the security rooted in the laws of…

Quantum Physics · Physics 2023-07-26 Nitin Jain , Ulrich Hoff , Marco Gambetta , Jesper Rodenberg , Tobias Gehring

The laws of physics play a crucial role in the security of quantum key distribution (QKD). This fact has often been misunderstood as if the security of QKD would be based only on the laws of physics. As the experts know well, things are…

Quantum Physics · Physics 2014-12-03 Valerio Scarani , Christian Kurtsiefer