Anomalous Femtosecond Quasiparticle Dynamics of Hidden Order State in URu${}_2$Si${}_2$

Georgi L. Dakovski, Yinwan Li, Steve M. Gilbertson +12

At T${}_0$ = 17.5 K an exotic phase emerges from a heavy fermion state in {\ur}. The nature of this hidden order (HO) phase has so far evaded explanation. Formation of an unknown qua…