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Entanglement entropy, which is a measure of quantum correlations between separate parts of a many-body system, has emerged recently as a fundamental quantity in broad areas of theoretical physics, from cosmology and field theory to…

Quantum Physics · Physics 2009-03-09 Israel Klich , Leonid Levitov

An analysis of quantum measurement is presented that relies on an information-theoretic description of quantum entanglement. In a consistent quantum information theory of entanglement, entropies (uncertainties) conditional on measurement…

Quantum Physics · Physics 2008-02-03 N. J. Cerf , C. Adami

All our former experience with application of quantum theory seems to say: {\it what is predicted by quantum formalism must occur in laboratory}. But the essence of quantum formalism - entanglement, recognized by Einstein, Podolsky, Rosen…

Quantum Physics · Physics 2011-03-02 Ryszard Horodecki , Pawel Horodecki , Michal Horodecki , Karol Horodecki

Entanglement is not only the most intriguing feature of quantum mechanics, but also a key resource in quantum information science. The entanglement content of random pure quantum states is almost maximal; such states find applications in…

Quantum Physics · Physics 2009-04-04 Giuliano Benenti

By using finite resolution measurements it is possible to simultaneously obtain noisy information on two non-commuting polarization components of a single photon. This method can be applied to a pair of entangled photons with polarization…

Quantum Physics · Physics 2007-05-23 Holger F. Hofmann

Quantum entanglement, crucial for understanding quantum many-body systems and quantum gravity, is commonly assessed through various measures such as von Neumann entropy, mutual information, and entanglement contour, each with its inherent…

Quantum Physics · Physics 2025-07-08 Liang-Hong Mo , Yao Zhou , Jia-Rui Sun , Peng Ye

Quantum communication schemes widely use dielectric four-port devices as basic elements for constructing optical quantum channels. Since for causality reasons the permittivity is necessarily a complex function of frequency, dielectrics are…

Quantum Physics · Physics 2007-05-23 S. Scheel , L. Knoll , T. Opatrny , D. -G. Welsch

We study the correlations of classical and quantum systems from the information theoretical points of view. We analyze a simple measure of correlations based on entropy (such measure was already investigated as the degree of entanglement by…

Quantum Physics · Physics 2012-09-13 Yuji Hirota , Dariusz Chruściński , Takashi Matsuoka , Masanori Ohya

The role of entanglement and quantum correlations in complex physical systems and quantum information processing devices has become a topic of intense study in the past two decades. In this work we present new tools for learning about…

Quantum Physics · Physics 2017-03-01 Michel Boyer , Aharon Brodutch , Tal Mor

Entropy measures quantify the amount of information and correlation present in a quantum system. In practice, when the quantum state is unknown and only copies thereof are available, one must resort to the estimation of such entropy…

Quantum Physics · Physics 2024-03-27 Ziv Goldfeld , Dhrumil Patel , Sreejith Sreekumar , Mark M. Wilde

Entanglement and coherence are fundamental properties of quantum systems, promising to power near future quantum technologies, such as quantum computation, quantum communication and quantum metrology. Yet, their quantification, rather than…

Entanglement is a quantum resource, in some ways analogous to randomness in classical computation. Inspired by recent work of Gheorghiu and Hoban, we define the notion of "pseudoentanglement'', a property exhibited by ensembles of…

We introduce ways to measure information storage in quantum systems, using a recently introduced computation-theoretic model that accounts for measurement effects. The first, the quantum excess entropy, quantifies the shared information…

Quantum Physics · Physics 2010-04-05 James P. Crutchfield , Karoline Wiesner

Through the generalization of Khinchin's classical axiomatic foundation, a basis is developed for nonadditive information theory. The classical nonadditive conditional entropy indexed by the positive parameter q is introduced and then…

Quantum Physics · Physics 2009-11-07 Sumiyoshi Abe

The unambiguous detection and quantification of entanglement is a hot topic of scientific research, though it is limited to low dimensions or specific classes of states. Here we identify an additional class of quantum states, for which…

Quantum Physics · Physics 2014-12-03 Marco Roncaglia , Arianna Montorsi , Marco Genovese

For quantum states of two subsystems, entanglement measures are related to capacities of communication tasks -- highly entangled states give higher capacity of transmitting classical as well as quantum information. However, we show that…

Quantum Physics · Physics 2010-02-05 Aditi Sen De , Ujjwal Sen

This thesis explores the use of entangled states in quantum computation and quantum information science. Entanglement, a quantum phenomenon with no classical counterpart, has been identified as an important and quantifiable resource in many…

Quantum Physics · Physics 2008-08-12 Hyeyoun Chung

The von Neumann entropy plays a vital role in quantum information theory. The von Neumann entropy determines, e.g., the capacities of quantum channels. Also, entropies of composite quantum systems are important for future quantum networks,…

Quantum Physics · Physics 2018-10-31 Christian Majenz

Dynamical quantum phase transitions (DQPTs) are temporal singularities marked by zeros of the Loschmidt echo, yet their underlying quantum-information structure remains elusive. Here, we introduce a momentum-resolved entanglement entropy as…

Quantum Physics · Physics 2026-01-21 Kaiyuan Cao , Mingzhi Li , Xiang-Ping Jiang , Shu Chen , Jian Wang

Current advancements in communication equipment demand the investigation of classical information transfer over quantum channels, by encompassing realistic scenarios in finite dimensions. To address this issue, we develop a framework for…

Quantum Physics · Physics 2026-01-08 Sudipta Mondal , Pritam Halder , Saptarshi Roy , Aditi Sen De