We study lower and upper bounds on the parameters for stochastic state vector reduction, focusing on the mass-proportional continuous spontaneous localization (CSL) model. We show that the assumption that the state vector is reduced whan a latent image is formed, in photography or etched track detection, requires a CSL rate parameter
λ that is larger than conventionally assumed by a factor of roughly
2×109±2, for a correlation length
rC of
10−5cm. We reanalyze existing upper bounds on the reduction rate and conclude that all are compatible with such an increase in
λ. The best bounds that we have obtained come from a consideration of heating of the intergalactic medium (IGM), which shows that
λ can be at most
∼108±1 times as large as the standard CSL value, again for
rC=10−5cm. (For both the lower and upper bounds, quoted errors are not purely statistical errors, but rather are estimates reflecting modeling uncertainties.) We discuss modifications in our analysis corresponding to a larger value of
rC. With a substantially enlarged rate parameter, CSL effects may be within range of experimental detection (or refutation) with current technologies. ADDED NOTE: A careful calculation of radiation from atomic systems in the CSL model (Adler and Ramazanoglu, arXiv:0707.3134) has reinstated the bound obtained by Fu as the best upper bound on lambda, with significant implications for CSL model phenomenology.
We calculate the photon emission rate from a general atomic system in the mass- proportional CSL model. For an isolated charged particle emitting kilovolt gamma rays, our results agree with those obtained by Fu. For a neutral atomic system, photon emission is strongly suppressed for photon wavelengths much larger than the atomic radius. However, for kilovolt gamma rays, Fu's result is modified by a structure factor that is of order unity, giving no rate suppression. Our calculation is readily generalized to the case of non-white noise, noise couplings that are not mass-proportional, and general (non-Gaussian) spatial correlation functions, and corresponding results are given. We briefly discuss the implications of our calculation for upper bounds on the CSL model parameters.
We calculate the photon emission rate from a general atomic system in the mass-proportional CSL model. For an isolated charged particle emitting kilovolt gamma rays, our results agree with those obtained by Fu. For a neutral atomic system, photon emission is strongly suppressed for photon wavelengths much larger than the atomic radius. However, for kilovolt gamma rays, Fu’s result is modified by a structure factor that is of order unity, giving no rate suppression. Our calculation is readily generalized to the case of non-white noise, noise couplings that are not mass-proportional, and general (non-Gaussian) spatial correlation functions, and corresponding results are given. We briefly discuss the implications of our calculation for upper bounds on the CSL model parameters. 1