Locality and Localization in Quantum Mechanics  

Locality > s.a. experiments; foundations and interpretations; locality; locality and localization in quantum field theory.
* Idea: Quantum mechanics and relativistic causality imply non-locality.
* Non-locality: Wave-function collapse, the Aharonov-Bohm effect, and likely effects due to small-scale spacetime structure; Quantum non-locality is usually tied to the celebrated no-go theorems, including the Kochen-Specker and Bell theorems, as well as elegant refinements by Mermin, Peres, Hardy, GHZ, and many others; Typically entanglement or carefully prepared multipartite systems have been considered essential for violations of local realism and for understanding quantum non-locality; However, sharp violations of local realism arise almost everywhere without entanglement.
* And correlations: The set of non-local correlations known as Popescu-Rohrlich box can be seen as a unit of non-locality.
* Implementations of locality: de Broglie-Bohm's pilot wave, or parametrized relativistic quantum theory (> see modified quantum mechanics).
* Ways out: Non-locality is only an artifact of considering quantum objects and classical observers (Tipler); Particles described by the Klein-Gordon or Dirac equation cannot be localized and therefore don't violate causality; See also Marolf + Rovelli model.
@ In general, and non-relativistic: Sorkin pr(83); Groenewold PRP(87); Hoekzema FP(87) [in contextual theories]; Hajra & Bandyopadhyay PLA(91) [and quantization procedure, quantum geometry]; Kar PRA(97) [n spin-1/2]; Healey PhSc(97)mar [Aharonov-Bohm effect]; Strunz et al PRL(99) [stochastic quantum mechanics, high-T environment]; de la Madrid IJTP(07)qp/06 [and rigged Hilbert space]; Ghirardi & Marinatto PRA(06) [Hardy for mixed states]; De Bievre mp/06 [rev]; Laloë in(07)cm/06 [and BEC]; Nikolic qp/07 [algorithmic definition of locality]; Chen & Zhu a0711 [vs realism]; Griffiths a0908 [Einstein locality vs Bell inequalities].
@ Single particle: Björk et al PRA(01); Dunningham & Vedral PRL(07) [realizable experiment]; > s.a particle models and quantum particles.
@ Relativistic: Omnès JMP(97); Zakrzewski JPA(97); Terno qp/02 [and energy density]; Barat & Kimball PLA(03); Slavnov TMP(08); Albert & Galchen SA(09)mar; > s.a. relativistic quantum mechanics, quantum measurement [MR model].
@ Photons: Hardy PLA(91), PRL(94), Drezet FPL(06) [single]; Pryde et al PRL(05)qp/04 [without entanglement].
@ Other systems: Parasuram & Ghosh a0903 [bipartite spin systems]; Bancal et al PRL(09)-a0903 [multipartite]; > s.a. networks; quantum systems; spin models.

Localization
* Idea: Described by the Born localization formalism, which in the relativistic context becomes Newton-Wigner localization), and modular localization in quantum field theory; Related to the concepts of uncertainty, entropy, phase space volume.
* Hegerfeldt theorem: A wave function for a particle whose time evolution is determined by a positive (or bounded from below) Hamiltonian, and initially confined to a finite volume, will instantaneously develop infinite tails and violate causality, even in relativistic quantum mechanics; This paradoxical result arises in relativistic theories from a failure of objectivity of localization – the so-called 'Jericho effect'.
* In solid state: Localization of electrons is a dramatic effect of destructive interference; The phenomenon is usually perceived as arising from extrinsic disorder that breaks the discrete translational invariance of a perfect crystal lattice (e.g., defects or impurities for phonons, disorder for electrons); However, intrinsic localized modes, a.k.a. discrete breathers, are typical excitations in perfectly periodic but strongly non-linear systems.
* In atomic physics: Non-dispersing electron wave packets can be obtained by applying a circularly polarized microwave field.
@ General references: Szabo ht/96 [and path integrals]; Bracken & Melloy JPA(99)qp [of electrons, solution]; Nicrosini & Rimini FP(03)qp/02 [relativistic spontaneous]; Detournay et al PRD(02)ht [generalized commutation relations]; Dunstan qp/05 [interaction with the environment]; Morchio & Strocchi JPA(07)qp/06-in [consequences]; Pinamonti RVMP(07) [intrinsic, from symmetry group]; Schroer a0711 [vs quantum field theory]; Sträng JPA(08)-a0708 [squeezed states]; Pennini et al PLA(08) [and Husimi distributions, Wehrl entropy].
@ Hegerfeldt theorem: Wickramasekara & Bohm JPA(02) [for t-semigroups]; Debs & Redhead SHPMP(03) [relativistic, Jericho effect].
@ Measurement-induced: Irby PRA(03)qp/02 [gamma-rays]; Cable et al PRA(05)qp/04 [relational degrees of freedom].
@ In condensed matter, mesoscopic physics: Janssen 01 [fluctuations and localization]; > s.a. Anderson Localization [random media].
@ In atomic physics: Maeda et al PRL(09) and Stroud Phy(09) [non-dispersing electron wave packets].

Other References > s.a. particle statistics; quantum technology; realism; time in quantum theory; wave-function collapse.
@ I, II: Nadeau & Kafatos 00; Jacobs & Wiseman AJP(05)oct [short story].
@ Non-locality: Bohm & Hiley FP(75); Brody & de la Peña-Auerbach NCB(79); Stapp AJP(85)apr, FP(88); Ne'eman FP(86)-in(88) [and gauge theory]; Clifton FPL(89); Aerts & Reignier HPA(91); Elitzur et al PLA(92); Popescu PRL(94); Rosen AJP(94)feb; Rohrlich & Popescu qp/95; Nogueira et al PS(96); Popescu & Rohrlich qp/97-in; Stapp AJP(97)apr, comment Finkelstein qp/98, Mashkevich qp/98, Shimony & Stein AJP(01)aug; Mermin AJP(98)oct-qp/97, qp/97; Tittel et al EPL(97)qp [experiment with photons]; Unruh PRA(99)qp/97, comment Stapp qp/98, PRA(99)qp/98; Hegerfeldt qp/98-in, AdP(98)qp-in; Pati qp/98-in; Sidharth qp/98; Choy & Ziegeler qp/99/AJP; Stapp qp/00; Dieks PRA(02)qp [inequalities]; Jones et al PRA(05)qp/04 [multi-particle]; Wiseman CP(06)qp/05 [history, Einstein]; Ghirardi & Marinatto JOB-qp/05-in [without inequalities]; Unruh IJQI(06); Scarani PRA(08)-a0712 [Elitzur-Popescu-Rohrlich approach]; Dukaric & Wolf a0808 [non-locality distillation]; Almeida et al a0911 [multipartite].
@ Proof: Hardy PRL(93) [two particles]; Boschi et al PRL(97); Hardy in(97) [spin-1/2]; Cabello PRA(98) [ladder, spin-1].
@ And correlations: Clifton et al BJPS(90); Tittel et al PRA(98)qp/97 [> 10 km]; Mermin FP(99)qp/98; Unnikrishnan qp/00; Barrett & Pironio PRL(05)qp [as non-locality units]; Buchholz & Summers PLA(05); Suarez a0902 [why not maximally non-local?]; > s.a. EPR correlations.
@ And entanglement: Bennett et al PRA(99)qp/98; Unnikrishnan qp/00-in; Brunner et al NJP(05)qp/04; Malley & Fine PLA(05)qp.
@ And information processing: Forster et al PRL(09) [distilling nonlocality in generalized non-signaling theories].
@ And causality: Ruijsenaars AP(81), Bruß et al PRA(00)qp [superluminal propagation]; Mashkevich qp/98; Busch JPA(99) [unsharp localization]; Buscemi & Compagno JPB(06)qp.
@ And Bell's inequality: Jarrett Noûs(84); Stapp qp/99; Pitowsky & Svozil PRA(01); Socolovsky PLA(03)qp; Rizzi qp/03; Hemmick qp/04 [hidden variables]; Cavalcanti a0911.
@ Quantum mechanics is local: de Muynck et al FP(94), comment Stapp FP(94); De Baere et al FP(99); Bene qp/00-in; Tommasini JHEP(02)ht; Unnikrishnan FPL(02)qp, qp/02-in [wave-function collapse]; Clover qp/03; De Baere FP(05)qp; Filk IJTP(06)qp; Weinstein FP(09)-a0812 [model].
@ In many-worlds interpretation: Sakaguchi qp/96; Tipler qp/00; Rubin FP(02)qp.
@ And hidden-variable interpretations: Teufel et al PRA(97); > s.a. pilot-wave theory.
@ Recovery of locality in classical limit: Pagonis et al PLA(91); Gisin et al qp/96-in; 't Hooft ht/00-in.
@ Related topics: Aharonov & Vaidman qp/99 [fermions vs bosons]; Sant'Anna qp/00 [and quasi-set theory]; Melloy FP(02) [formalism]; Kafatos et al qp/02 [and sheaf cohomology]; van Dam et al IEEE(05)qp/03 [strength of proofs]; Assar & Putz mp/05 [massless, momentum]; Slavnov a0903.


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