Density and temperature of bosons from quantum fluctuations

A method to determine the density and temperature of a system is proposed based on quantum fluctuations typical of bosons in the limit where the temperature T is close to the critical temperature Tc for a Bose–Einstein condensate (BEC) at a given density ρ. Quadrupole and particle multiplicity fluctuations using Landauʼs theory of fluctuations near the critical point are derived. As an example, we apply our approach to heavy ion collisions using the Constrained Molecular Dynamics model (CoMD) which includes the Fermi statistics. The model shows some clusterization into deuteron (d) and alpha (α) clusters but it is not enough to reproduce available experimental data. We propose a modification of the collision term in the approach to include the possibility of α–α collisions. The relevant Bose–Einstein factor in the collision term is properly taken into account. This approach increases the yields of bosons relative to fermions closer to data. Boson fluctuations become larger than 1 as expected. If they are confirmed a new field of research could open up for a mixture of strongly interacting fermions and bosons which requires novel techniques both theoretically and experimentally.