Grüneisen parameter as an entanglement compass and the breakdown of the Hellmann-Feynman theorem

Lucas Squillante, Luciano S. Ricco, Aniekan Magnus Ukpong +3

The Grüneisen ratio $\Gamma$, i.e., the singular part of the ratio of thermal expansion to the specific heat, has been broadly employed to explore both finite-$T$ and quantum critical p…