The quantum phase transition in the isotropic XY chain with three-site interaction has been studied by calculating the quantum discord, classicai correlation, and concurrence measuring entanglement. It is found that t...The quantum phase transition in the isotropic XY chain with three-site interaction has been studied by calculating the quantum discord, classicai correlation, and concurrence measuring entanglement. It is found that the quantum discord is a better choice than concurrence to signal the presence of the quantum phase transition in this model, since that for next-nearest neighbor spins the derivative of the quantum discord still exhibits singularity at the critical point while there is no more entanglement.展开更多
Ferromagnetic quantum critical points were predicted to be prohibited in clean itinerant ferromagnetic systems,yet such a phenomenon was recently revealed in CeRh_(6)Ge_(4),where the Curie temperature can be continuou...Ferromagnetic quantum critical points were predicted to be prohibited in clean itinerant ferromagnetic systems,yet such a phenomenon was recently revealed in CeRh_(6)Ge_(4),where the Curie temperature can be continuously suppressed to zero under a moderate hydrostatic pressure.Here we report the observation of quantum oscillations in CeRh_(6)Ge_(4)from measurements using the cantilever and tunnel-diode oscillator methods in fields up to 45 T,clearly demonstrating that the ferromagnetic quantum criticality occurs in a clean system.In order to map the Fermi surface of CeRh_(6)Ge_(4),we performed angle-dependent measurements of quantum oscillations at ambient pressure,and compared the results to density functional theory calculations.The results are consistent with the Ce 4f electrons remaining localized and not contributing to the Fermi surface,suggesting that localized ferromagnetism is a key factor for the occurrence of a ferromagnetic quantum critical point in CeRh_(6)Ge_(4).展开更多
基金Supported by National Natural Science Foundation of China under Grant Nos. 11075013 and 10974016
文摘The quantum phase transition in the isotropic XY chain with three-site interaction has been studied by calculating the quantum discord, classicai correlation, and concurrence measuring entanglement. It is found that the quantum discord is a better choice than concurrence to signal the presence of the quantum phase transition in this model, since that for next-nearest neighbor spins the derivative of the quantum discord still exhibits singularity at the critical point while there is no more entanglement.
基金the National Key R&D Program of China(2017YFA0303100,and 2016YFA0300202)the National Natural Science Foundation of China(12034017,U1632275,and 11974306)+2 种基金the Science Challenge Project of China(TZ2016004)the Key R&D Program of Zhejiang Province(2021C01002)supported by the National Science Foundation Cooperative Agreement No.DMR-1644779 and the State of Florida。
文摘Ferromagnetic quantum critical points were predicted to be prohibited in clean itinerant ferromagnetic systems,yet such a phenomenon was recently revealed in CeRh_(6)Ge_(4),where the Curie temperature can be continuously suppressed to zero under a moderate hydrostatic pressure.Here we report the observation of quantum oscillations in CeRh_(6)Ge_(4)from measurements using the cantilever and tunnel-diode oscillator methods in fields up to 45 T,clearly demonstrating that the ferromagnetic quantum criticality occurs in a clean system.In order to map the Fermi surface of CeRh_(6)Ge_(4),we performed angle-dependent measurements of quantum oscillations at ambient pressure,and compared the results to density functional theory calculations.The results are consistent with the Ce 4f electrons remaining localized and not contributing to the Fermi surface,suggesting that localized ferromagnetism is a key factor for the occurrence of a ferromagnetic quantum critical point in CeRh_(6)Ge_(4).
