Cosmic Microwave Background Constraints Cast a Shadow On Continuous Spontaneous Localization Models

Area of Science:

• Quantum mechanics
• Cosmology
• General relativity

Background:

• The continuous spontaneous localization (CSL) model offers a solution to the measurement problem in quantum mechanics.
• CSL couples the mass density of a quantum system to a stochastic white-noise field.
• Ambiguity arises in applying CSL to cosmology because mass density is not uniquely defined in general relativity.

Purpose of the Study:

• To investigate the implications of the continuous spontaneous localization model in a cosmological context.
• To explore the compatibility of CSL with observational data from the cosmic microwave background and laboratory experiments.

Main Methods:

• Analyzing the definition of mass density contrast within the framework of general relativity.
• Comparing predictions derived from the CSL model, using various natural choices for density contrast, with existing cosmological and laboratory data.

Main Results:

• The study reveals that the CSL model, when applied to cosmology, encounters significant ambiguity due to the ill-defined nature of mass density.
• Most common choices for the density contrast in the CSL model lead to a contradiction between cosmic microwave background measurements and results from laboratory experiments.
• This incompatibility suggests limitations of the CSL model in its current form for describing both quantum phenomena and cosmological observations.

Conclusions:

• The continuous spontaneous localization model, while promising for quantum measurement, presents challenges when integrated with general relativity and cosmological observations.
• The observed discrepancy between cosmic microwave background data and laboratory experiments under CSL highlights the need for refinement or alternative approaches.
• Further theoretical and experimental work is required to reconcile quantum mechanics and cosmology, potentially necessitating modifications to the CSL framework or exploring alternative theories.