scholarly journals Discussions about the landscape of possibilities for treatments of cosmic inflation involving continuous spontaneous localization models

2020 ◽  
Vol 80 (11) ◽  
Author(s):  
Gabriel R. Bengochea ◽  
Gabriel León ◽  
Philip Pearle ◽  
Daniel Sudarsky
Keyword(s):  
General Nature ◽  
Quantum Field ◽  
Microwave Background ◽  
Cosmic Inflation ◽  
Cosmological Context ◽  
Generating Operator ◽  
General Relativistic ◽  
Spontaneous Localization ◽  
Parameter Values ◽  
Continuous Spontaneous Localization

AbstractIn this work we consider a wide variety of alternatives opened when applying the continuous spontaneous localization (CSL) dynamical collapse theory to the inflationary era. The definitive resolution of many of the issues discussed here will have to await, not only for a general relativistic CSL theory, but for a fully workable theory of quantum gravity. Our concern here is to explore these issues, and to warn against premature conclusions. This exploration includes: two different approaches to deal with quantum field theory and gravitation, the identification of the collapse-generating operator and the general nature and values of the parameters of the CSL theory. All the choices connected with these issues have the potential to dramatically alter the conclusions one can draw. We also argue that the incompatibilities found in a recent paper, between the CSL parameter values and the cosmic microwave background observational data, are associated with specific choices made for the extrapolation to the cosmological context of the CSL theory (as it is known to work in non-relativistic laboratory situations) which do not represent the most natural ones.

scholarly journals Enlightening the CSL model landscape in inflation

2021 ◽  
Vol 81 (12) ◽  
Author(s):  
Gabriel León ◽  
Gabriel R. Bengochea
Keyword(s):  
Momentum Tensor ◽  
Scale Invariant ◽  
Cosmological Perturbation ◽  
Cosmological Perturbation Theory ◽  
Spacetime Curvature ◽  
Cosmological Context ◽  
Generating Operator ◽  
Spontaneous Localization ◽  
Continuous Spontaneous Localization ◽  
Covariant Version

AbstractWe propose a novel realization for the natural extrapolation of the continuous spontaneous localization (CSL) model, in order to account for the origin of primordial inhomogeneities during inflation. This particular model is based on three main elements: (i) the semiclassical gravity framework, (ii) a collapse-generating operator associated to a relativistic invariant scalar of the energy-momentum tensor, and (iii) an extension of the CSL parameter(s) as a function of the spacetime curvature. Furthermore, employing standard cosmological perturbation theory at linear order, and for a reasonable range within the parameter space of the model, we obtain a nearly scale invariant power spectrum consistent with recent observational CMB data. This opens a vast landscape of different options for the application of the CSL model to the cosmological context, and possibly sheds light on searches for a full covariant version of the CSL theory.

scholarly journals A response to criticisms on “CMB constraints cast a shadow on CSL model”

2021 ◽  
Vol 81 (1) ◽  
Author(s):  
Jérôme Martin ◽  
Vincent Vennin
Keyword(s):  
Cosmic Microwave Background ◽  
Microwave Background ◽  
Recent Letter ◽  
Link Type ◽  
Spontaneous Localization ◽  
Continuous Spontaneous Localization

AbstractOur recent letter “Cosmic Microwave Background Constraints Cast a Shadow On Continuous Spontaneous Localization Models” (Martin and Vennin Phys Rev Lett 124:080402, 2020, arXiv:1906.04405) has recently been criticised in Ref. (Bengochea et al. Eur Phys J C 80:1021, 2020a) (see also Ref. Bengochea et al. 2020b, arXiv:2006.05313). In this reply, we explain why the arguments presented in those articles are either incorrect or a confirmation of the robustness of our results.

scholarly journals Stochastic Gravity and Ontological Quantum Mechanics

2018 ◽  
Author(s):  
Thomas C Andersen
Keyword(s):  
Quantum Mechanics ◽  
Thermal Noise ◽  
Wave Radiation ◽  
Semiclassical Theory ◽  
Noise Component ◽  
Quantum Theories ◽  
Nuclear Systems ◽  
Spontaneous Localization ◽  
Continuous Spontaneous Localization ◽  
Stochastic Gravity

Some physicists surmise that gravity lies outside of quantum mechanics. Thus theories like the standard semiclassical theory of quantum to gravity coupling (that of Rosenfeld and Møller) are possible real models of interaction, rather than a mere approximation of a theory of quantum gravity. Unfortunately, semiclassical gravity creates inconsistencies such as superluminal communication. Alternatives by authors such as Diósi, Martin, Penrose, and Wang often use the term 'stochastic' to set themselves apart from the standard semiclassical theory. These theories couple to fluctuations caused by for instance continuous spontaneous localization, hence the term 'stochastic'. This paper looks at stochastic gravity in the framework of a class of emergent or ontological quantum theories, such as those by Bohm, Cetto, and de Broglie. It is found that much or all of the trouble in connecting gravity with a microscopic system falls away, as Einstein's general relativity is free to react directly with the microscopic beables. The resulting continuous gravitational wave radiation by atomic and nuclear systems does not, in contrast to Einstein's speculation, cause catastrophic problems. The small amount of energy exchanged by gravitational waves may have measurable experimental consequences. A very recent experiment by Vinante et al. performed on a small cantilever at mK temperatures shows a surprising non-thermal noise component, the magnitude of which is consistent with the stochastic gravity coupling explored here.

scholarly journals Axion experiments to algebraic geometry: Testing quantum gravity via the Weak Gravity Conjecture

2016 ◽  
Vol 25 (12) ◽  
pp. 1643005 ◽  
Author(s):  
Ben Heidenreich ◽  
Matthew Reece ◽  
Tom Rudelius
Keyword(s):  
Field Theory ◽  
Algebraic Geometry ◽  
Quantum Gravity ◽  
General Nature ◽  
Quantum Field ◽  
Gauge Groups ◽  
Common Features ◽  
Conformal Field ◽  
Pure Mathematics ◽  
Weak Gravity

Common features of known quantum gravity theories may hint at the general nature of quantum gravity. The absence of continuous global symmetries is one such feature. This inspired the Weak Gravity Conjecture, which bounds masses of charged particles. We propose the Lattice Weak Gravity Conjecture, which further requires the existence of an infinite tower of particles of all possible charges under both abelian and nonabelian gauge groups and directly implies a cutoff for quantum field theory. It holds in a wide variety of string theory examples and has testable consequences for the real world and for pure mathematics. We sketch some implications of these ideas for models of inflation, for the QCD axion (and LIGO), for conformal field theory, and for algebraic geometry.

scholarly journals REVISITING ROTATIONAL PERTURBATIONS AND THE MICROWAVE BACKGROUND

2007 ◽  
Vol 16 (11) ◽  
pp. 1715-1723 ◽  
Author(s):  
VIKTOR G. CZINNER ◽  
MÁTYÁS VASÚTH
Keyword(s):  
Background Radiation ◽  
Field Equations ◽  
Microwave Background ◽  
Rotation Tensor ◽  
Microwave Background Radiation ◽  
Order Of Magnitude ◽  
Frw Model ◽  
General Relativistic ◽  
Frw Models ◽  
The Given

We consider general-relativistic rotational perturbations in homogeneous and isotropic Friedmann–Robertson–Walker (FRW) cosmologies. Taking linear perturbations of FRW models, the general solution to the field equations contains tensorial, vectorial and scalar functions. The vectorial terms are in connection with rotations in the given model and due to the Sachs–Wolfe effect they produce contributions to the temperature fluctuations of the cosmic microwave background radiation (CMBR). In this paper we obtain the analytic time dependence of these contributions in a spatially flat FRW model with pressureless ideal fluid, in the presence and the absence of a cosmological constant Λ. We find that the solution can be separated into an integrable and a nonintegrable part, as in the case of scalar perturbations. Analyzing the solutions and using the results of recent observations, we estimate the order of magnitude of the angular velocity corresponding to the rotation tensor at the time of decoupling and today.

scholarly journals INFLATION, QUANTUM FIELDS, AND CMB ANISOTROPIES

2009 ◽  
Vol 18 (14) ◽  
pp. 2329-2335 ◽  
Author(s):  
IVÁN AGULLÓ ◽  
JOSÉ NAVARRO-SALAS ◽  
GONZALO J. OLMO ◽  
LEONARD PARKER
Keyword(s):  
Cosmic Microwave Background ◽  
Gravitational Waves ◽  
Early Universe ◽  
Inflationary Cosmology ◽  
Quantum Field ◽  
Quantum Fields ◽  
Microwave Background ◽  
Cosmological Inflation ◽  
Near Future ◽  
Field Renormalization

Inflationary cosmology has proven to be the most successful at predicting the properties of the anisotropies observed in the cosmic microwave background (CMB). In this essay we show that quantum field renormalization significantly influences the generation of primordial perturbations and hence the expected measurable imprint of cosmological inflation on the CMB. However, the new predictions remain in agreement with observation, and in fact favor the simplest forms of inflation. In the near future, observations of the influence of gravitational waves from the early universe on the CMB will test our new predictions.

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