Quantum Discord  

In General > s.a. correlations in physics; quantum correlations.
* Idea: Discord is the difference between two classically equivalent expressions for bipartite mutual information, one expressed in terms of joint entropy and the other expressed in terms of mutual entropy; It quantifies non-classical correlations in a quantum system, including those not captured by entanglement; States with zero discord exhibit strictly classical correlations; > s.a. quantum phase transitions.
@ General references: Ferraro et al PRA(10)-a0908 [negligibly few states exhibit strictly classical correlations]; Brodutch & Terno a1608-ln; Adesso et al a1611, Vedral a1702 [intros]; Dutta et al QIP(17)-a1702 [graph-theoretic study].
@ Measures: Brodutch & Terno PRA(10)-a1002 [different discord-like quantities]; Dakić et al PRL(10)-a1004; Cavalcanti et al PRA(11)-a1008, Madhok & Datta PRA(11)-a1008 [operational interpretation]; Batle et al a1103; Yao et al PLA(12); Piani PRA(12)-a1206 [problem, and mutual-information-based discord]; Yao et al PLA(12)-a1303 [geometric interpretation]; Spehner & Orszag NJP(13)-a1304; Ali a1912 [local quantum uncertainty].
@ Discord, other: Fanchini et al PRA(10) [dynamics]; Giorda & Paris PRL(10)-a1003 [bipartite Gaussian states]; Adesso & Datta PRL(10)-a1003 [two-mode Gaussian states]; Maziero et al a1004; Al-Qasimi & James a1007 [vs entanglement]; Fanchini et al NJP(12)-a1106 [and entanglement of formation]; Thilagam a1106 [and quantum Zeno effect]; Huang et al NJP(11) [criterion for zero discord]; Jin et al JPA(12)-a1110 [measurement]; Okrasa & Walczak EPL(11)-a1112 [and multipartite correlations]; Arsenijević et al a1201-proc [zero-discord classicality]; Guo & Hou JPA(13)-a1206 [local creation, necessary and sufficient conditions]; Wiseman AP(13)-a1208 [and Bohr's non-mechanical disturbance]; Benedetti et al IJQI(12)-a1209, Gheorghiu et al PRL(15)-a1407 [effects of classical noise]; Modi OSID(14)-a1312 [overview]; Piani PRL(16)-a1501 [computationally efficient lower bounds]; Agrawal et al IJQI(16)-a1502 [local and non-local quantumness]; > s.a. markov processes.

Types of Discord and Systems
@ Types and generalizations: Jebarathinam a1407 [Bell and Mermin discord, and decomposition of quantum correlations for non-signaling theories]; Xu a1506 [oblique discord]; Mazumdar et al a1812 [Sharma-Mittal quantum discord].
@ Two-qubit states: Galve et al PRA(11)-a1007; Girolami et al JPA(11)-a1008; Shi et al NJP(11)-a1102 [geometric picture]; Girolami & Adesso PRA(11)-a1103; Jurkowski a1206 [q-discord, from Tsallis entropy]; Nguyen & Joynt a1310/PRA [topology of the hypersurface of zero discord].
@ Other specific systems: Sarandy PRA(09)-a0905 [critical systems]; Perinotti PRL(12)-a1112 [probabilistic theories]; Rossignoli et al PRA(12)-a1206 [spin-1 systems]; Canosa et al IJMPB(13)-a1206 [XY chains]; Gwozdz & Jakobczyk QIP-a1306 [spontaneous emission can create quantum discord]; Weedbrook et al NJP(16)-a1604 [and the resilience of quantum illumination]; Kanno et al PRD(16)-a1608 [in de Sitter space]; Martin & Vennin PRD(16)-a1609 [and cmb anisotropies]; > s.a. spin models.

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