Bounds on quantum collapse models from matter-wave interferometry: calculational details

Toroš, Marko; Bassi, Angelo

doi:10.1088/1751-8121/aaabc6

Cited by 57 publications

(64 citation statements)

References 54 publications

(187 reference statements)

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“…This theoretical bound (see Ref. [21]) is obtained by requiring that a single-layered graphene disk of radius ∼0.01 mm is localized within ∼10 ms (these are the minimum resolution and perception time of the human eye, respectively).…”

Section: Mapping Csl Parameters Spacementioning

confidence: 99%

CSL Collapse Model Mapped with the Spontaneous Radiation

Piscicchia

Bassi

Curceanu

et al. 2017

Entropy

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Abstract:In this paper, new upper limits on the parameters of the Continuous Spontaneous Localization (CSL) collapse model are extracted. To this end, the X-ray emission data collected by the IGEX collaboration are analyzed and compared with the spectrum of the spontaneous photon emission process predicted by collapse models. This study allows the obtainment of the most stringent limits within a relevant range of the CSL model parameters, with respect to any other method. The collapse rate λ and the correlation length r C are mapped, thus allowing the exclusion of a broad range of the parameter space.Keywords: quantum mechanics; the measurement problem; collapse models; X-rays The CSL Collapse ModelCollapse models are phenomenological models introduced to solve the measurement problem of quantum mechanics and explain the quantum-to-classical transition [1][2][3][4][5][6]. According to these models, the linear and unitary evolution given by the Schrödinger equation is modified by adding a non-linear term and the interaction with a stochastic noise field. These modifications have two very important consequences: (i) they lead to the collapse of the wave function of the system in space (localization mechanism) and (ii) the collapse effects get amplified with the mass of the system (amplification mechanism). The combination of these two properties guarantees that macroscopic objects always have well defined positions, explaining why we do not observe quantum behaviour at the macroscopic level. On the other hand, for microscopic systems, the effect of the non-linear interaction with the noise field is very small and their dynamics is dominated by the Schrödinger evolution. Due to the presence of the non-linear interaction with the noise field, collapse models predict slight deviations from the standard quantum mechanics predictions [7].The analysis discussed in this work sets limits on the characteristic parameters of the Continuous Spontaneous Localization (CSL) model [8][9][10], which is one of the most relevant and well-studied collapse models in the literature. In the CSL model, the state vector evolution is described by a modified Schrödinger equation which contains, besides the standard Hamiltonian, non-linear and stochastic terms, characterized by the interaction with a continuous set of independent noises w(x, t) (one for each point of the space, which is why this set is often referred to as "noise field") having zero average and white correlation in time, i.e., E[w(x, t)] = 0 and E[w(x, t)w(y, s)] = δ(x − y)δ(t − s) where E[...] denotes the average over the noises. Two phenomenological parameters (λ and r C ) are introduced in

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Section: Mapping Csl Parameters Spacementioning

confidence: 99%

CSL Collapse Model Mapped with the Spontaneous Radiation

Piscicchia

Bassi

Curceanu

et al. 2017

Entropy

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“…Because the apparatus is massive, the Brownian noise leads to rapid reduction of the state vector to either |A ↑ |B ↓ |apparatus ↑ (16) or |B ↑ |A ↓ |apparatus ↓ ;…”

Section: A the Nonrelativistic Csl Model Does Not Obey Fin And Minmentioning

confidence: 99%

Connecting the Dots: Mott for Emulsions, Collapse Models, Colored Noise, Frame Dependence of Measurements, Evasion of the “Free Will Theorem”

Adler

2018

Found Phys

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We review the argument that latent image formation is a measurement in which the state vector collapses, requiring an enhanced noise parameter in objective reduction models.Tentative observation of a residual noise at this level, plus several experimental bounds, imply that the noise must be colored (i.e., non-white), and hence frame dependent and nonrelativistic. Thus a relativistic objective reduction model, even if achievable in principle, would be incompatible with experiment; the best one can do is the non-relativistic CSL model. This negative conclusion has a positive aspect, in that the non-relativistic CSL reduction model evades the argument leading to the Conway-Kochen "Free Will Theorem". I. THE MOTT SCENARIO APPLIED TO AN EMULSION STACKIn a celebrated paper [1] dating from the early days of quantum theory, Neville Mott answered the question of how a spherically symmetric α decay in a cloud chamber can lead to a linear track.His argument is based on excitation of two or more atoms to form the track, but the core of Mott's calculation can be stated [2] using just one atom. Consider an alpha particle emitted in a spherical wave by a nucleus located at the coordinate origin, and an atom at location a. We want the amplitude for the alpha particle to scatter to a plane wave with wave number k, conditional on the atom being excited from an initial state ψ 0 to an excited state ψ S . For an alpha particle with coordinate R and an atomic electron with coordinate r, and assuming the atom excitation energy is negligible, the Born approximation (dropping overall constants) is proportional towith ψ * final ∝e −i k· R ψ * S ( r) , V ∝1/| R − r| , ψ initial ∝ e ik| R| /| R| ψ 0 ( r) .

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“…The first class includes those experiments, which directly create and detect quantum superpositions of the center of mass of massive systems. Examples of this type are molecular interferometry [8][9][10][11] and entanglement experiment with diamonds [12,13]. Actually, the strongest bounds on the CSL parameters come from the second class of non-interferometric experiments, which are sensitive to small position displacements and detect CSL-induced diffusion in position [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Non-interferometric test of the continuous spontaneous localization model based on rotational optomechanics

et al. 2018

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The continuous spontaneous localization (CSL) model is the best known and studied among collapse models, which modify quantum mechanics and identify the fundamental reasons behind the unobservability of quantum superpositions at the macroscopic scale. Albeit several tests were performed during the last decade, up to date the CSL parameter space still exhibits a vast unexplored region. Here, we study and propose an unattempted non-interferometric test aimed to fill this gap. We show that the angular momentum diffusion predicted by CSL heavily constrains the parametric values of the model when applied to a macroscopic object.

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Bounds on quantum collapse models from matter-wave interferometry: calculational details

Cited by 57 publications

References 54 publications

CSL Collapse Model Mapped with the Spontaneous Radiation

CSL Collapse Model Mapped with the Spontaneous Radiation

Connecting the Dots: Mott for Emulsions, Collapse Models, Colored Noise, Frame Dependence of Measurements, Evasion of the “Free Will Theorem”

Non-interferometric test of the continuous spontaneous localization model based on rotational optomechanics

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