Heating of trapped ultracold atoms by collapse dynamics

TL;DR

This paper investigates how the collapse dynamics predicted by CSL theory could heat ultracold atoms, using experimental data to set an upper limit on the CSL collapse rate parameter.

Contribution

It provides the first experimental upper limit on CSL collapse rate by analyzing heating effects in ultracold atomic gases, linking theory with observable phenomena.

Findings

Upper limit on CSL parameter λ: approximately 10^{-7} sec^{-1}

Analysis of heating in cesium BECs constrains collapse models

Experimental data on ultracold atoms used to test quantum collapse theories

Abstract

{The Continuous Spontaneous Localization (CSL) theory alters the Schr\"odinger equation. It describes wave function collapse as a dynamical process instead of an ill-defined postulate, thereby providing macroscopic uniqueness and solving the so-called measurement problem of standard quantum theory. CSL contains a parameter $\lambda$ giving the collapse rate of an isolated nucleon in a superposition of two spatially separated states and, more generally, characterizing the collapse time for any physical situation. CSL is experimentally testable, since it predicts some behavior different from that predicted by standard quantum theory. One example is the narrowing of wave functions, which results in energy imparted to particles. Here we consider energy given to trapped ultra-cold atoms. Since these are the coldest samples under experimental investigation, it is worth inquiring how they are affected by the CSL heating mechanism. We examine the CSL heating of a BEC in contact with its thermal cloud. Of course, other mechanisms also provide heat and also particle loss. From varied data on optically trapped cesium BEC's, we present an energy audit for known heating and loss mechanisms. The result provides an upper limit on CSL heating and thereby an upper limit on the parameter $\lambda$. We obtain $\lambda\lesssim 1(\pm1)\times 10^{-7}$sec$^{-1}$.}