Wave-Function Collapse as a Dynamical Process| Wave-Function Collapse as a Dynamical Process |
In General
> s.a. wave-function collapse [including some models]; zeno effect.
* Idea: The point of view
according to which wave-function collapse (quantum-state reduction) is a physical
process, as opposed to just being related to our knowledge and description of
the system; In a relativistic scenario the collapse will then happen at a finite
speed, as opposed to the instantaneous collapse of the conventional view.
* Tests: One way to test it is
to look for quantum behaviour in larger and larger objects; If collapse models
are correct, then quantum effects will not be apparent above a certain mass;
2015, Physicists have already carried out double-slit interference experiments
with large molecules; Various groups are planning to search for such a cut-off
using metal clusters and nanoparticles, and hope to see results within a decade;
2018, Work on bulk heating experiments in spontaneous collapse.
* Motivation: Using this
point of view it becomes easier to explain how quantum fluctuations in
the early universe might have become classical.
@ General references: Lewin FP(09) [as an effect of field quantization];
Omnès a1006,
a1601
[derivation of collapse from quantum dynamics];
Carlesso & Donadi a1907-proc [rev];
Carlesso & Bassi a2001-in [rev, tests].
@ Speed / time for collapse:
Squires PLA(90);
Pegg PLA(91);
Zurek qp/03 ["decoherence timescale"];
Ohanian a1311 [atom-interferometer test].
@ State recovery / uncollapse: Katz et al PRL(08)-a0806;
Jordan & Korotkov CP(10)-a0906 [undoing quantum measurements];
news PhysOrg(13)nov.
@ Objective collapse, and retina / mind:
Georgiev qp/02;
Thaheld qp/06/PRA,
BioSys(08)qp/06;
Ghirardi & Romano JPCS-a1401 [collapse models and perceptual processes];
Ghirardi IJTP(15)-a1411 [reply to Elio Conte].
@ Constraints: Jones et al FP(04)qp [SNO experiment];
Curceanu et al JAP(15)-a1502 [from X-ray experiments];
Helou et al PRD(17)-a1606,
Carlesso et al PRD(16)-a1606 [from gravitational-wave detectors].
@ Other phenomenology:
Squires PLA(91),
Pearle et al FP(99)qp/00 [and radiation];
Pearle FP(12)-a1003 [and cosmogenesis];
Donadi et al FP(13)-a1207 [and neutrino oscillations],
FP(13)-a1207 [and flavor oscillations];
Okon & Sudarsky FP(14)-a1309 [advantages for cosmology and quantum gravity];
Donadi & Bassi JPA(15)-a1408 [and electromagnetic radiation];
Toroš & Bassi JPA(18)-a1601 [and matter-wave interferometry];
Simonov & Hiesmayr PRA(16)-a1606 [and neutral meson flavor oscillations];
Adler a1712 [minimum temperature for solid objects],
PRA(18)-a1801 [heating by phonon excitation];
Carlesso & Paternostro a1906-ch [opto-mechanical tests];
Vinante et al PRA(19) [tests with levitated nanoparticles].
@ Collapse over a finite time:
Marchewka & Schuss a1103;
Ignatiev JPCS(13)-a1204;
Moreno et al a1809
[incompatible with non-local correlations and non-signaling].
@ Related topics: Bassi et al JPA(05)qp [and E non-conservation],
JPA(07) [and Hilbert space operator formalism];
Bondoni a1006-wd [measurement as mathematical vs phenomenological.process];
Tumulka a1102 [paradoxes and primitive ontology];
Brouzakis et al PLB(12)-a1109;
Weinberg PRA(12)-a1109;
Rizos & Tetradis JHEP(12)-a1112;
Simpson FP(11);
Melkikh a1311 [and quantum field theory];
McQueen SHPMP(15)-a1501 [four tails problems];
Yun a1606 [entangling-speed threshold];
Bedingham & Maroney PRA(17)-a1607 [and time-reversal symmetry];
Tilloy a2007-FQXi
[can wave-function collapse be heard?].
And Gravity > s.a. models of
decoherence [gravity-related]; semiclassical gravity.
* History: In the first lecture
of his 1962 course on gravitation Feynman speculated that gravity would enforce
classical behavior for masses larger than the Planck mass; The idea is related to
work on the quantum-classical divide and attempts at building and experimenting
with hybrid quantum-classical devices.
* Gravity produces wave function collapse:
A wave function collapses under the influence of gravity in a region where the
matter density reaches a certain value (masses and lengths of the order of bacterial
scales); Gravity provides a decoherence mechanism; Penrose's proposal is motivated
by a fundamental conflict between the superposition principle of quantum mechanics
and the principle of general covariance.
* Wave function collapse produces gravity:
2017, An idea proposed by Antoine Tilloy is that when a GRW-type flash collapses a wave
function and causes a particle to be localized in one place, it creates a gravitational
field at that event; Gravity remains classical.
@ General references:
Károlyházy NC(66);
Diósi PLA(84)-a1412;
Károlyházy in(85),
et al in(86);
Diósi PRA(89);
Ellis et al PLB(89);
Fivel qp/97;
Anandan FP(99)gq/98;
Christian gq/98-ch;
De Filippo qp/00,
qp/01;
De Filippo et al PhyA(03)qp [simulation];
Mureika PRD(06) [and large extra dimensions];
Adler JPA(07)qp/06;
Salart et al PRL(08)-a0803 [and Bell inequalities];
Diósi JPCS(09)-a0902 [collapse causes gravity];
Diósi JPCS(13)-a1302;
Sharma & Singh GRG(14)-a1403 [Ricci identities and Dirac equations];
Diósi FP(14),
NJP(14)-a1404 [in bulk matter];
Singh JPCS-a1503 [survey];
Banerjee et al IJMPD(15)-a1505-GRF [and the cosmological constant and time].
@ Relativistic models: Quandt-Wiese a0912;
Stoica Quanta(16)-a1601 [continuous evolution];
Quandt-Wiese a1701,
a1701 [from semiclassical gravity,
wave function evolution in a dynamically expanding spacetime];
Gasbarri et al PRD(17)-a1701 [mechanism];
Okon & Sudarsky a1701 [in cosmology and quantum gravity].
@ In pilot-wave theory: Vachaspati a1912,
Rahmani et al a2001,
a2001 [geometric];
Rahmani & Golshani a2012 [dynamical interpretation].
@ Other models: Melko & Mann gq/00 [d-dimensional Schrödinger-Newton equations];
Gao IJTP(10)-a1001 [and spacetime discreteness];
Adler a1401-ch
[state vector reduction as driven by spacetime foam];
Bera et al FP(17)-a1608 [stochastic modification of the Schrödinger-Newton equation];
Brody & Hughston a1611-in [energy-driven stochastic master equation for the density matrix];
Korbicz & Tuziemski a1612;
Tilloy PRD(18)-a1709 [GRW with massive flashes];
Laloë EPJD(20)-a1905 [small imaginary component in the gravitational coupling];
Bruschi & Wilhelm a2006 [self gravity and quantum coherence].
@ Penrose's proposal: Penrose in(81),
in(86);
Penrose GRG(96);
Penrose in(00);
Gao SHPMP(13)-a1305 [critique];
Oosterkamp & Zaanen a1401-conf [thought experiment];
Penrose FP(14);
Bahrami et al PRA(14)-a1408 [cutoff, and dissipative generalization].
@ Gravitational self-interaction: Colin et al CQG(14)-a1403 [approximate dynamics and experimental setting].
@ Tests: Christian PRL(05)qp [with cosmic neutrinos];
van Wezel et al PhilM(08)-a0706 [towards an experimental test];
Quandt-Wiese a1701 [proposal].
> Phenomenology:
see matter phenomenology in quantum gravity;
models of dark energy;
quantum cosmological perturbations.
Continuous Spontaneous Localization
* Idea: CSL models of
spontaneous wave function collapse modify the linear Schrödinger
equation by adding stochastic non-linear terms to it, which leads to
non-conservation of energy for the system under consideration; The larger
a system is, the faster a state superposition will collpase; > s.a.
schrödinger equation.
* GRW mechanism: It gives
a quantum theory without observers; In fact, two different ones by using
either the matter density ontology (GRWm) or the flash ontology (GRWf);
Testable deviations from quantum mechanics are known for both theories,
but the difference is so small that no decisive experiment has been
performed (2007).
@ General references:
Pearle IJTP(79),
PRA(89) [randomly fluctuating interaction];
Pearle & Soucek FPL(89) [path integral];
Ghirardi & Pearle in(90);
Nicrosini & Rimini FP(90) [stochastic processes in \(\cal H\)];
Squires PLA(91) [without stochastic field];
Pearle in(97)qp/98,
in(97)qp/98,
LNP(99)qp,
PRA(99)qp,
FP(00)qp [and conservation laws],
PRA(04)qp/03 [energy-driven];
Santos & Escobar qp/98 [beable interpretation];
Hansson qp/00 [from non-abelian non-linearity];
Bassi & Ghirardi PRP(03)qp;
Dowker & Herbauts FPL(05)qp/04 [without wave function];
Lewis SHPMP(05) [interpretation];
Morikawa & Nakamichi PTP(06)qp/05 [as spontaneous symmetry breaking];
Pearle JPA(07)qp/06,
qp/06 [overview];
Bassi JPCS(07)qp [rev];
Bassi et al RMP(13)-a1204 [rev, and tests],
a1212/RMP [stochastic methods];
Bassi & Ulbricht JPCS(14)-a1401 [rev];
Bhatt et al a1808 [quantum to classical transition].
@ GRW mechanism:
Ghirardi et al PRA(90),
PRA(90);
Tessieri et al PRA(95);
Clifton & Monton BJPS(99),
Bassi & Ghirardi BJPS(99),
BJPS(99) [and enumeration principle];
Monton SHPMP(04) [interpretation];
Allori et al BJPS(08)qp/06 [and pilot-wave theory];
Vacchini JPA(07) [GRW master equation and decoherence];
Frigg & Hoefer SHPMP(07) [and probabilities];
Goldstein et al JSP(12)-a0710 [testable predictions];
Tumulka RVMP(09)-a0711 [flash ontology];
Bedingham JPA(11) [hidden-variable interpretation];
Esfeld & Gisin a1310 [John Bell's GRW flash theory];
Wallace a1407 [tails of the GRW wave function];
de Stefano a2103 [conceptual].
@ GRW mechanism, variations: Smirne et al PRA(14)-a1408 [dissipative extension];
Egg & Esfeld a1410 [GRW matter density theory (GRWm)];
Jones et al PRA(21)-a1907,
JPA(21)-a2012 [relativistic, no-go results].
@ For quantum field theory: Tumulka PRS(06)qp/05 [GRW];
Diósi AIP(06)qp [QED];
Derakhshani PLA(13)-a1304 [Newtonian theory of semiclassical gravity];
Pearle a1404-wd,
PRD(15)-a1412 [scalar field, relativistic model];
Pearle a1610-in [for photons].
@ Cosmology: Das et al a1302-MG13;
Martin & Vennin a1906,
a1912-in,
comment Bengochea et al a2006 [and the cmb];
Martin & Vennin a2103 [collapse operator].
@ Astrophysics:
Tilloy & Stace a1901,
comment Adler et al PRD(19)-a1901 [test with neutron stars];
> s.a. black-hole information.
@ Other types of systems: Bassi JPA(05)qp/04 [single free particle];
Pearle PRA(05)qp [quasirelativistic quasilocal model];
Laloë et al PRA(14)-a1409 [trapped ultra-cold atoms];
Diósi PRL(15)-a1411 [classical mechanical oscillators];
Tilloy a1910-ch [on finite-dimensional Hilbert spaces].
@ Other phenomenology: Nimmrichter et al PRA(11) [tests with matter-wave interferometry];
Lochan et al PRD(12) [constraints from cmb spectral distortions];
Carlesso et al NJP(18)-a1708 [non-interferometric test];
Mishra et al a1807 [estimates for bulk heating experiments];
Singh ZfN-a1806 [and emergence of spacetime].
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