Continuous-spontaneous-reduction model involving gravity

Ghirardi, GianCarlo; Grassi, R.; Rimini, A.

doi:10.1103/physreva.42.1057

Cited by 288 publications

(253 citation statements)

References 20 publications

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“…Although the existence of environmentally induced decoherence does explain why we never experience bizarre macrosuperpositions, and thus makes dynamic reduction mechanisms (DRMs) such as those proposed by GRW and [18,35,36] unnecessary for that purpose, it does no more than that. In other words, despite decoherence, macrosuperpositions still do exist -decoherence merely explains why we cannot experience them.…”

Section: Decoherence and The Interpretation Of Quantum Mechanicsmentioning

confidence: 99%

Apparent wave function collapse caused by scattering

1993

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Some experimental implications of the recent progress on wave function collapse are calculated. Exact results are derived for the center-of-mass wave function collapse caused by random scatterings and applied to a range of specific examples. The results show that recently proposed experiments to measure the GRW effect are likely to fail, since the effect of naturally occurring scatterings is of the same form as the GRW effect but generally much stronger. The same goes for attempts to measure the collapse caused by quantum gravity as suggested by Hawking and others. The results also indicate that macroscopic systems tend to be found in states with ∆x∆p =h/ √ 2, but microscopic systems in highly tiltedly squeezed states with ∆x∆p ≫h.

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Section: Decoherence and The Interpretation Of Quantum Mechanicsmentioning

confidence: 99%

Apparent wave function collapse caused by scattering

1993

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“…In general, this gives rise to a statistical outcome of the reduction process (just like the instabilities of the singlet state gave rise to a statistical, random selection of the orientation of its order parameter under equilibrium conditions). The resulting dynamic process could be somewhat reminiscent of the evolutions considered in the GRW and CSL models for quantum state reduction [39,40], and consist of a random sequence of amplifying one or the other ordered state until one of them completely dominates.…”

Section: : Macroscopic Superpositions and Born's Rulementioning

confidence: 99%

Quantum dynamics in the thermodynamic limit

Wezel

2008

Phys. Rev. B

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The description of spontaneous symmetry breaking that underlies the connection between classically ordered objects in the thermodynamic limit and their individual quantum mechanical building blocks is one of the cornerstones of modern condensed matter theory and has found applications in many different areas of physics. The theory of spontaneous symmetry breaking however, is inherently an equilibrium theory, which does not address the dynamics of quantum systems in the thermodynamic limit. Here, we will use the example of a particular antiferromagnetic model system to show that the presence of a so-called thin spectrum of collective excitations with vanishing energy -one of the well-known characteristic properties shared by all symmetry-breaking objects-can allow these objects to also spontaneously break time-translation symmetry in the thermodynamic limit. As a result, that limit is found to be able, not only to reduce quantum mechanical equilibrium averages to their classical counterparts, but also to turn individual-state quantum dynamics into classical physics. In the process, we find that the dynamical description of spontaneous symmetry breaking can also be used to shed some light on the possible origins of Born's rule. We conclude by describing an experiment on a condensate of exciton polaritons which could potentially be used to experimentally test the proposed mechanism. 1: IntroductionCombining many elementary particles into a single interacting system may result in collective behaviour that qualitatively differs from the properties allowed by the physical theory governing the individual building blocks. This realisation -immortalised by P.W. Anderson in his famous phrase 'More is Different' [1]-not only forms the basis of much of the research being done in condensed matter physics today, but has also found applications in areas ranging from string theory to cosmology. The theory of Spontaneous Symmetry Breaking which formalises these ideas first took shape over fifty years ago [2,3,4,5,6,7], and was completed in the context of quantum magnetism only two decades ago by the detailed description of the classical state as a combination of thin spectrum states, emerging as N → ∞ because of the singular nature of the thermodynamic limit [8,9,10]. The same description of the classical state emerging from the thin spectrum has since been shown to also directly apply to the cases of quantum crystals, antiferromagnets, Bose-Einstein condensates and superconductors [11,12,13,14,15].The connection between the quantum mechanical properties of microscopic particles and the classical behaviour of symmetry broken macroscopic objects has now again come to the forefront of modern science because of our technological capability to create ever larger and heavier quantum superpositions in the laboratory. Superconducting flux qubits harbour counterrotating streams of supercurrent consisting of up to 10 11 Cooper pairs [16,17,18], while Bose Einstein condensates of the order of 10 5 Rubidium atoms can be routinely brought i...

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“…It was then proposed to raise this cut-off to a much higher value r c , the length scale of the CSL model [71].…”

Section: A Brief Review Of the D-model And Comparison With The mentioning

confidence: 99%

A Comparison Between Models of Gravity Induced Decoherence

et al. 2015

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It has been suggested in the literature that spatial coherence of the wave function can be dynamically suppressed by fluctuations in the spacetime geometry. These fluctuations represent the minimal uncertainty that is present when one probes spacetime geometry with a quantum probe. on the mass and size of the quantum object. In the present article we compare and contrast the two models from three aspects: (i) comparison of the spacetime bounds, (ii) method of calculating decoherence time, (iii) comparison of noise correlation. We show that under certain conditions the minimal spacetime bounds in the two models can be derived one from the other. We argue that the methods of calculating the decoherence time are equivalent. We re-derive the two-point correlation for the fluctuation potential in the K-model, and confirm the earlier result of Diósi and Lukács that it is non-white noise, unlike in the D-model, where the corresponding correlation is white noise in time. This seems to be the origin of the different results in the two models. We derive the non-Markovian master equation for the K-model. We argue that the minimal spacetime bound cannot predict the noise correlation uniquely, and additional criteria are necessary to accurately determine the effects of gravitationally induced decoherence.

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Continuous-spontaneous-reduction model involving gravity

Cited by 288 publications

References 20 publications

Apparent wave function collapse caused by scattering

Apparent wave function collapse caused by scattering

Quantum dynamics in the thermodynamic limit

A Comparison Between Models of Gravity Induced Decoherence

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