Heat capacity for systems with excitedstate quantum phase transitions
Abstract
Heat capacities of model systems with finite numbers of effective degrees of freedom are evaluated using canonical and microcanonical thermodynamics. Discrepancies between both approaches, which are observed even in the infinitesize limit, are particularly large in systems that exhibit an excitedstate quantum phase transition. The corresponding irregularity of the spectrum generates a singularity in the microcanonical heat capacity and affects smoothly the canonical heat capacity.
 Publication:

Physics Letters A
 Pub Date:
 March 2017
 DOI:
 10.1016/j.physleta.2017.01.022
 arXiv:
 arXiv:1612.00613
 Bibcode:
 2017PhLA..381..984C
 Keywords:

 Canonical and microcanonical heat capacity;
 Thermodynamic systems with low numbers of degrees of freedom;
 Excitedstate quantum phase transitions;
 Quantum Physics;
 Condensed Matter  Statistical Mechanics
 EPrint:
 12 pages, 6 figures