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Related papers: On super quantum discord for high-dimensional bipa…

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We discuss the interconnections between basic correlation measures of a bipartite quantum state and basic information characteristics of a quantum channel, focusing on the benefits of these interconnections for solving specific problems…

Quantum Physics · Physics 2025-02-18 M. E. Shirokov

Recent results in quantum information theory characterize quantum coherence in the context of resource theories. Here we study the relation between quantum coherence and quantum discord, a kind of quantum correlation which appears even in…

Quantum Physics · Physics 2016-04-29 Jiajun Ma , Benjamin Yadin , Davide Girolami , Vlatko Vedral , Mile Gu

It is known that quantum discord might experience a sudden transition in its dynamics when calculated for certain Bell-diagonal states (BDS) that are in interaction with their surroundings. We examine this phenomenon known as the sudden…

Quantum Physics · Physics 2013-10-01 João P. G. Pinto , Goktug Karpat , Felipe F. Fanchini

Complex forms of quantum entanglement can arise in two qualitatively different ways; either between many qubits or between two particles with higher-than-qubit dimension. While the many-qubit frontier and the high-dimension frontier both…

Quantum Physics · Physics 2024-09-24 Gabriele Cobucci , Armin Tavakoli

We discuss the problem of characterizing upper bounds on entanglement in a bipartite quantum system when only the reduced density matrices (marginals) are known. In particular, starting from the known two-qubit case, we propose a family of…

Quantum discord is a manifestation of quantum correlations due to non-commutativity rather than entanglement. Two measures of quantum discord by the amount of non-commutativity via the trace norm and the Hilbert-Schmidt norm respectively…

Quantum Physics · Physics 2016-05-03 Yu Guo

The minimal Bures distance of a quantum state of a bipartite system AB to the set of classical states for subsystem A defines a geometric measure of quantum discord. When A is a qubit, we show that this geometric quantum discord is given in…

Quantum Physics · Physics 2013-12-24 Dominique Spehner , Miguel Orszag

We propose a new criterion to judge zero quantum discord for arbitrary bipartite states. A bipartite quantum state has zero quantum discord if and only if all blocks of its density matrix are normal matrices and commute with each other.…

Quantum Physics · Physics 2015-03-19 Jie-Hui Huang , Lei Wang , Shi-Yao Zhu

We investigate the dynamics of quantum discord and entanglement for a class of mixed qubit-qutrit states assuming that only the qutrit is under the action of a dephasing channel. We demonstrate that even though the entanglement in the…

Quantum Physics · Physics 2013-04-02 G. Karpat , Z. Gedik

Quantum discord in a bipartite system can be dynamically revealed and quantified through purely local operations on one of the two subsystems. To achieve this, the local detection method harnesses the influence of initial correlations on…

Quantum Physics · Physics 2017-07-04 Manuel Gessner , Heinz-Peter Breuer , Andreas Buchleitner

We study the relationship between the behavior of global quantum correlations and quantum phase transitions in XY model. We find that the two kinds of phase transitions in the studied model can be characterized by the features of global…

Quantum Physics · Physics 2016-08-18 Si-Yuan Liu , Yu-Ran Zhang , Wen-Li Yang , Heng Fan

We investigate the geometric picture of the level surfaces of quantum entanglement and geometric measure of quantum discord (GMQD) of a class of X-states, respectively. This pictorial approach provides us a direct understanding of the…

Quantum Physics · Physics 2013-12-03 Wei Song , Long-Bao Yu , Ping Dong , Da-Chuang Li , Ming Yang , Zhuo-Liang Cao

One of the defining differences between classical and quantum systems is how measurements affect them. Here, we compare the approaches of contextuality and quantum discord in capturing quantum correlations in special classes of two-qubit…

Quantum Physics · Physics 2022-08-11 Asma Al-Qasimi

The problems of genuine multipartite entanglement detection and classification are challenging. We show that a multipartite quantum state is genuine multipartite entangled if the multipartite concurrence is larger than certain quantities…

Quantum Physics · Physics 2015-12-31 Ming Li , Shao-Ming Fei , Xianqing Li-Jost , Heng Fan

Positivity of quantum discord is shown to be equivalent to the strong sub additivity of the Von-Nuemann entropy. This leads to a connection between the mother protocol of quantum information theory [A. Abeyesinghe, I. Devetak, P. Hayden,…

Quantum Physics · Physics 2011-07-07 Vaibhav Madhok , Animesh Datta

We quantify the usefulness of a bipartite quantum state in the ancilla-assisted channel discrimination of arbitrary quantum channels, formally defining a worst-case-scenario channel discrimination power for bipartite quantum states. We show…

Quantum Physics · Physics 2018-03-28 Matteo Caiaffa , Marco Piani

Discord, originally notable as a signature of bipartite quantum correlation,in fact can be nonzero classically, i.e., arising from noisy measurements by one of the two parties. Here we redefine classical discord to quantify channel…

Quantum Physics · Physics 2021-09-16 Wei-Wei Zhang , Yuval R. Sanders , Barry C. Sanders

The emerging quantum technologies rely on our ability to establish and control quantum systems in nonclassical states, exhibiting entanglement and quantum coherence. It is thus crucial to understand how entanglement and coherence can be…

Quantum Physics · Physics 2022-06-22 Masaya Takahashi , Swapan Rana , Alexander Streltsov

A simple relation is introduced for concurrence to describe how much the entanglement of bipartite system is at least left if either (or both) subsystem undergoes an arbitrary physical process. This provides a lower bound for concurrence of…

Quantum Physics · Physics 2009-11-13 Chang-shui Yu , X X Yi , He-shan Song

We investigate the phenomenon of sudden transition between classical and quantum decoherence in the study of quantum discord for a dissipative cavity QED system, which consists of two noninteracting two-level atoms, each trapped in a…

Quantum Physics · Physics 2015-03-19 Qi-Liang He , Jing-Bo Xu , Dao-Xin Yao , Ye-Qi Zhang