Minimum Interior Temperature for Solid Objects Implied by Collapse Models

Heating induced by the noise postulated in wave function collapse models leads to a lower bound to the temperature of solid objects. For the noise parameter values $\lambda ={\rm coupling~strength}\sim 10^{-8} {\rm s}^{-1}$ and $r_C ={\rm correlation~length} \sim 10^{-5} {\rm cm}$, which were suggested \cite{adler1} to make latent image formation an indicator of wave function collapse and which are consistent with the recent experiment of Vinante et al. \cite{vin}, the effect may be observable. For metals, where the heat conductivity is proportional to the temperature at low temperatures, the lower bound (specifically for RRR=30 copper) is $\sim 5\times 10^{-11} (L/r_C)$K, with L the size of the object. For the thermal insulator Torlon 4203, the comparable lower bound is $\sim 3 \times 10^{-6} (L/r_c)^{0.63}$ K. We first give a rough estimate for a cubical metal solid, and then give an exact solution of the heat transfer problem for a sphere.