HEAT CAPACITY AND ENTANGLEMENT MEASURE IN A SIMPLE TWO-QUBIT MODEL

A simple two-qubit model showing quantum phase transitions as a consequence of ground-state-level crossings is studied in detail. Using the system’s concurrence as an entanglement measure and heat capacity as a marker of thermodynamical properties, we obtain an analytical expression giving thelatter in terms of the former. A protocol allowing an experimental measure of entanglement is then presented and compared with a related proposal recently reported by Wie´sniak, Vedral, and Brukner.