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We derive a general approximate solution to the problem of minimizing the conditional entropy of a qudit-qubit system resulting from a local projective measurement on the qubit, which is valid for general entropic forms and becomes exact in…

Quantum Physics · Physics 2015-06-22 N. Gigena , R. Rossignoli

Quantum discord was proposed as a measure of the "quantumness" of correlations. There are at least three different discord-like quantities, two of which determine the difference between the efficiencies of a Szilard's engine under different…

Quantum Physics · Physics 2010-06-10 Aharon Brodutch , Daniel R. Terno

An essential quantity in quantum information theory is the von Neumann entropy which depends entirely on the quantum density operator. Once known, the density operator reveals the statistics of observables in a quantum process, and the…

Systems and Control · Electrical Eng. & Systems 2023-09-08 Mark Balas , Vinod P. Gehlot , Tristan D. Griffith

Dissimilar notions of quantum correlations have been established, each being motivated through particular applications in quantum information science and each competing for being recognized as the most relevant measure of quantumness. In…

Quantum Physics · Physics 2021-05-05 S. Köhnke , E. Agudelo , M. Schünemann , O. Schlettwein , W. Vogel , J. Sperling , B. Hage

By carrying out appropriate continuous quantum measurements with a family of projection operators, a unitary channel can be approximated in an arbitrary precision in the trace norm sense. In particular, the quantum Zeno effect is described…

Mathematical Physics · Physics 2013-12-10 Toru Fuda

The Pusey-Barrett-Rudolph theorem has recently provoked a lot of discussion regarding the reality of the quantum state. In this article we focus on a property called antidistinguishability, which is a main component in constructing the…

Quantum Physics · Physics 2018-08-13 Teiko Heinosaari , Oskari Kerppo

Renyi entropy associated with spin tomograms of quantum states is shown to obey to new inequalities containing the dependence on quantum Fourier transform. The limiting inequality for the von Neumann entropy of spin quantum states and a new…

Quantum Physics · Physics 2015-05-13 M. A. Man'ko , V. I. Man'ko

Criteria of measure quantifying quantum coherence, a unique property of quantum system, are proposed recently. In this paper, we first give an uncertainty-like expression relating the coherence and the entropy of quantum system. This…

Quantum Physics · Physics 2015-07-15 Zhengjun Xi , Yongming Li , Heng Fan

The study of quantum correlations in High-dimensional bipartite systems is crucial for the development of quantum computing. We propose relative entropy as a distance measure of correlations may be measured by means of the distance from the…

Quantum Physics · Physics 2016-04-12 M. Mahdian , M. B. Arjmandi

We consider three von Neumann entropy inequalities: subadditivity; Pinsker's inequality for relative entropy; and the monotonicity of relative entropy. For these we state conditions for equality, and we prove some new error bounds away from…

Quantum Physics · Physics 2014-10-21 Eric A. Carlen , Elliott H. Lieb

The requirement of complete positivity is very often regarded as a fundamental consistency condition for the description of open quantum dynamics. We critically examine this requirement and discuss both its physical motivations and its…

Quantum Physics · Physics 2026-05-19 Fabio Benatti , Dariusz Chruściński , Saverio Pascazio

A general state of an $m\otimes n$ system is a classical-quantum state if and only if its associated $A$-correlation matrix (a matrix constructed from the coherence vector of the party $A$, the correlation matrix of the state, and a…

Quantum Physics · Physics 2016-04-19 S. Javad Akhtarshenas , Hamidreza Mohammadi , Saman Karimi , Zahra Azmi

Various measures have been suggested recently for quantifying the coherence of a quantum state with respect to a given basis. We first use two of these, the l_1-norm and relative entropy measures, to investigate tradeoffs between the…

Quantum Physics · Physics 2015-10-08 Shuming Cheng , Michael J. W. Hall

The von Neumann entropy of a quantum state is a central concept in physics and information theory, having a number of compelling physical interpretations. There is a certain perspective that the most fundamental notion in quantum mechanics…

Quantum Physics · Physics 2021-05-12 Gilad Gour , Mark M. Wilde

Two long standing open problems in quantum theory are to characterize the class of initial system-bath states for which quantum dynamics is equivalent to (1) a map between the initial and final system states, and (2) a completely positive…

Quantum Physics · Physics 2009-04-15 A. Shabani , D. A. Lidar

We analyze, for a general concave entropic form, the associated conditional entropy of a quantum system A+B, obtained as a result of a local measurement on one of the systems (B). This quantity is a measure of the average mixedness of A…

Quantum Physics · Physics 2013-12-16 N. Gigena , R. Rossignoli

Quantum discord is the quantitative difference between two alternative expressions for bipartite mutual information, given respectively in terms of two distinct definitions for the conditional entropy. By constructing a stochastic model of…

Quantum Physics · Physics 2015-07-22 Vlad Gheorghiu , Marcos C. de Oliveira , Barry C. Sanders

When a quantum system is divided into two local subsystems, measurements on the two subsystems can exhibit correlations beyond those possible in a classical joint probability distribution; these are partially explained by entanglement, and…

Quantum Physics · Physics 2019-06-17 Aaron Szasz

Due to some ambiguity in defining mutual Tsallis entropy in the classical probability theory, its generalization to quantum theory is discussed and, as a consequence, two types of generalized quantum discord, called $q$-discords, are…

Quantum Physics · Physics 2012-06-04 Jacek Jurkowski

Quantum physics, despite its observables being intrinsically of a probabilistic nature, does not have a quantum entropy assigned to them. We propose a quantum entropy that quantify the randomness of a pure quantum state via a conjugate pair…

Quantum Physics · Physics 2022-10-05 Davi Geiger , Zvi M. Kedem