Probabilistic collapse model of QM
9 S L. Adler and A Bassi Is Quantum Theory Exact?
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*introduction to the continuous spontaneous localization (CSL) model (4) as Q phenomenology (7).
Its Ingredients:
(i) Rare modifications, or hits, acting on a system by localizing its wave function, do not alter coherent superpositions for microscopic systems, but when accumulated over a macroscopic apparatus can lead to definite outcomes that differ from run to run ( 2).
(ii) A probabilistic explanation of the Born rule ( 3).
*A Brownian motion noise term coupled nonlinearly to the local mass density is added to the Schrodinger equation. This noise is responsible for the spontaneous collapse of the wave function. At the same time, the standard form of this model has a linear evolution equation for the noise-averaged density matrix (other proposals 5.6)
*The CSL model has two intrinsic parameters; noise strength and its spatial correlation length. The paper gives the upper and the lower bounds of these parameters that may be experimentally detected.