  Continuous spontaneous localisation (CSL) is a model that captures the
effects of a class of extensions to quantum theory which are expected to result
from quantum gravity, and is such that wavefunction collapse is a physical
process. The rate of such a process could be very much lower than the upper
bounds set by searches to date, and yet still modify greatly the interpretation
of quantum mechanics and solve the quantum measurement problem. Consequently
experiments are sought to explore this. We describe an experiment that has the
potential to extend sensitivity to CSL by many orders of magnitude. The method
is to detect heating of the motion of charged macroscopic objects confined in a
Paul trap. We discuss the detection and the chief noise sources. We find that
CSL with standard parameters could be observed using a vibration-isolated ion
trap of size 1 cm at ultra-low pressure, with optical interferometric
detection.
