Density and Temperature of Bosons from Quantum Fluctuations

TL;DR

The paper introduces a quantum fluctuation-based method to determine the density and temperature of Bosonic systems near the Bose-Einstein condensation point, validated through heavy ion collision simulations.

Contribution

It presents a novel approach using quantum fluctuations to extract thermodynamic parameters of Bosons, applicable to both infinite and finite systems, and compares it with classical methods.

Findings

Quantum temperatures are systematically higher than classical ones.

The method is validated on heavy ion collision models without indicating a Bose condensate.

Differences with classical approximations are highlighted.

Abstract

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 reached temperature T is close to the critical temperature $T_c$ for a Bose condensate at a given density $\rho$. Quadrupole and particle multiplicity fluctuations relations are derived in terms of $\frac{T}{T_c}$. This method is valid for weakly interacting infinite and finite Boson systems. As an example, we apply it to heavy ion collisions using the Constrained Molecular Dynamics (CoMD) approach which includes the Fermi statistics. The model shows some clusterization into deuteron and ${\alpha}$ clusters which could suggest a Bose condensate. However, our approach demonstrates that in the model there is no Bose condensate but it gives useful informations to be tested experimentally. We stress the differences with methods based on classical approximations. The derived 'quantum' temperatures are systematically higher than the corresponding 'classical' ones. The role of the Coulomb charge of fragments is discussed.