Causality in Quantum Theory  

In General > s.a. causality [as emergent]; causality in quantum field theory; locality; quantum effects, locality and measurement; path integrals.
* Idea: In the operator version it is built in via the unitarity of time evolution; Quantum non-locality is causal because it cannot be used to transfer classical information across spacelike intervals, and measurements of entangled systems cannot be used for superluminal signalling (not true in non-linear quantum mechanics); But see barrier transmission.
* Abstract causal structure: A causal structure is a relationship between observed variables that restricts the set of possible correlations between them.
* Rem: Causal reversibility is related to the fact that the observables of a quantum theory form a real C*-algebra; Locality and separability then impose restrictions.
* Relativistic: Versions include Stochastic Einstein Locality, Reichenbach's Principle of Common Cause, and Bell's Local Causality.
* Information causality: A principle that places restrictions on physical processes, used in proposals for deriving quantum theory from information-theoretic considerations.
@ General references: Kraus FPL(89) [no action at a distance]; Stapp AJP(97)apr; Westmoreland & Schumacher qp/98; Mashkevich qp/98, qp/98; Cereceda FPL(00)qp [constraints and EPR]; Srikanth PLA(01) [entangled systems]; Segev PRA(01) [phase-space formulation]; Simon et al PRL(01)qp [axioms]; Grove FP(02) [changing the past]; Belavkin RPP(02)qp [trajectories and information]; Palmer qp/05 [causal incompleteness and non-locality]; Pegg PLA(06) [arrow of time]; Evans et al BJPS(12)-a1001 [and spacelike action at a distance]; Hofmann a1005-proc [weak measurements, statistics and causality]; Zaopo a1110 [relativity of causal strucure]; Gillis FP(11) [measurement and elementary interactions]; Ried et al nPhys(15)-a1406 [causal inference for quantum variables]; Oreshkov & Giarmatzi NJP(16)-a1506 [causality and causal separability, multipartite causal processes]; Diel a1604 [possibility of local causal models]; Eckstein & Miller PRA(17)-a1610 [evolution of wave packets]; Horodecki & Ramanathan a1611 [vs no-signaling constraints].
@ Role of causality in quantum theory: Popescu & Rohrlich qp/97-proc [as axiom]; Wharton qp/03/PRA; Delphenich qp/04-conf; David PRL(11)-a1103 [role of causality and locality]; Kakushadze UJP-a1505 [rules based on causality]; Winter a1705; > s.a. quantum correlations.
@ Bell's local causality: Norsen AJP(11)-a0707; Seevink & Uffink in(11)-a1007 [sharp and clean mathematical formulation]; Ringbauer et al a1602 [test].
@ Information causality: Pawłowski et al Nat(09)oct-a0905; Barnum et al NJP(10)-a0909 [in general probabilistic theories]; Ahanj et al PRA(10) [and Hardy's non-locality]; Cavalcanti et al nComm(10)-a1008 [and local quantum correlations]; Gazi et al JPA(10) [and Hardy's correlations]; Al-Safi & Short PRA(11) [entropic and probabilistic perspective]; Beigi & Gohari a1111; Pawłowski & Scarani a1112 [rev]; Hsu PRA(12) [multipartite]; Yu & Lin a1301 [testing]; Pitalúa-García PRL(13); Zoka & Ahanj a1510 [and quantum correlations].
@ Information-theoretic constraints on correlations: Chaves et al nComm(15)-a1407.
@ Abstract causal structure: Weilenmann & Colbeck a1605 [entropy vector approach]; Kissinger et al a1708 [and process terminality].
@ Models with indefinite causal structure: Hardy gq/05, JPA(07)gq/06-in, a0804-in ["causaloids"]; Oreshkov et al nComm(12)-a1105; Ibnouhsein & Grinbaum PRA(15)-a1408, Ibnouhsein PhD(14)-a1510 [and information-theoretic reconstruction]; Baumeler & Wolf NJP(16)-a1511; Costa & Shrapnel NJP(16)-a1512 [framework for quantum causal modelling]; MacLeanet al a1606 [quantum-coherent mixtures]; Budroni et al PRA(16)-a1607 [distinguishability]; Rubino et al SciAdv(17)-a1608 [experimentally implemented process without a definite causal order]; Araújo et al Quant(17)-a1611; Perinotti a1612 [and higher-order quantum computations]; Kissinger & Uijlen a1701 [categorical semantics]; Silva et al a1701 [and multi-time quantum states]; Ried et al PRA(17)-a1707 [transitions between causal relations]; Abbott et al a1708 [genuinely multipartite non-causal correlations]; > s.a. Causal Model; correlations; entanglement; quantum computation.
@ Causally non-separable processes: Branciard SRep(16)-a1603; Feix et al a1604 [processes admitting a causal model].
@ Related topics: Teufel et al PRA(97) [hidden variables]; Kent PRD(99)gq/97 [time-neutral cosmologies]; Kent PRA(05)qp/02, Pienaar PhD-a1401 [and non-linear quantum mechanics]; Fitzsimons et al a1302 [pseudo-density matrix for spatial and temporal measurements]; Han & Choi a1307 [and probabilities]; Cavalcanti JPCS(16)-a1602 [proposals for a quantum theory of causation]; Allen et al PRX(17)-a1609 & Pienaar Phy(17) [quantum common causes, quantum version of Reichenbach's principle].
> Related topics: see bell's theorem; Contextuality; Lieb-Robinson Bounds; quantum collapse; Retrocausation.

Causality Violations in Quantum Mechanics > s.a. hidden variables; locality; measurements [non-local]; quantum computation; quantum effects.
* Superluminal communication: A number of proposals use quantum non-locality and the reduction process.
* Quantum mechanics with CTCs: A widely accepted theory was proposed by Deutsch; An alternative one was proposed by Lloyd et al.
@ Superluminal communication: Michalski qp/99-wd; Kuzmich et al PRL(01) [and quantum noise]; Yang qp/01; Griffiths PRA(02)qp [no problem]; Ferrero et al PRA(04) [and non-linearity]; Malikotsinas qp/04 [and entanglement]; Ferrero et al IJQI(05)qp [and non-linear evolution]; Panković et al qp/05 [Griffiths' bug shadow]; Bassi & Ghirardi IJTP(08)-a0711 [not possible with wave-function collapse]; Ghirardi & Romano JPA(12), a1305-wd [why some of the most challenging recent proposals cannot work]; Ghirardi in(13)-a1305 [exhaustive review of proposals to send faster-than-light signals]; Sokolovski & Akhmatskaya AP(13)-a1309 [rev]; Bassi & Hejazi EJP(15)-a1411 [no-superluminal-signaling implies linear evolutions].
@ Superluminal tunneling: Aharonov et al PRL(98)qp [and unstable states]; Chiao AIP(99)qp/98; Ghose & Samal PRE(01)qp/00 [and special relativity]; Muga et al PRA(02)qp [Hartman effect]; Sokolovski PRS(04)qp/03, PRA(10); > s.a. tunneling.
@ Causality violations: Bennett PRA(87), PRA(87) [evidence in Compton scattering]; Valentini PRL(88); Vaidman FP(91); Gray qp/98-wd [time machine]; Pegg in(01)qp/05 [and self-consistency]; Greenberger & Svozil in(02)qp/05 [beam-splitter model, paradox resolution], comment Wykes qp/05; Svetlichny IJTP(11)-a0902 [effective time travel]; > s.a. experiments [superluminal].
@ And unitarity: Anderson PRD(95)gq/94; Antonsen & Bormann IJTP(98)qp; Everett PRD(04)gq [many-worlds]; Cornalba & Costa PRD(06).
@ Quantum mechanics with closed timelike curves: Hartle PRD(94)gq/93 [and unitarity]; Fewster & Wells PRD(95)ht/94; Politzer PRD(94)gq; Rosenberg PRD(98)ht/97; Brun et al PRL(09)-a0811 [state distinguishability, cryptography]; DeJonghe et al PRD(10)-a0908 [discontinuous evolution]; Lloyd et al PRL(11)-a1005 + news sn(10)jul [time travel through post-selected teleportation]; Wallman & Bartlett FP(12)-a1005; Lloyd et al PRD(11)-a1007; Lee a1101 [finite state model]; Gedik a1201; Allen PRA(14)-a1401; Dunlap a1510 [metaphysics of Deutsch's approach].
@ Phenomenology: Ringbauer et al nComm(14)-a1501 + news pw(15)feb [experimental simulation with photons]; Cocciaro et al a1701-conf [entanglement over kms].
> Related topics: see phenomenology of entanglement [delayed-choice entanglement swapping]; quantum correlations; wave-function collapse.


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