Thermal expansion and Grueneisen parameter in quantum Griffiths phases
英文摘要：
We consider the behavior of the Grüneisen parameter, the ratio between thermal expansion and specific heat, at pressure-tuned infinite-randomness quantum-critical points and in the associated quantum Griffiths phases. We find that the Grüneisen parameter diverges as $\ln(T_0/T)$ with vanishing temperature $T$ in the quantum Griffiths phases. At the infinite-randomness critical point itself, the Grüneisen parameter behaves as $[\ln(T_0/T)]^{1+1/(νψ)}$ where $ν$ and $ψ$ are the correlation length and tunneling exponents. Analogous results hold for the magnetocaloric effect at magnetic-field tuned transitions. We contrast clean and dirty systems, we discuss subtle differences between Ising and Heisenberg symmetries, and we relate our findings to recent experiments on CePd$_{1-x}$Rh$_x$.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
