  Motivated by recent photoemission and pump-probe experiments, we report
determinant Quantum Monte Carlo simulations of hybridization fluctuations in
the half-filled periodic Anderson model. A tentative phase diagram is
constructed based solely on hybridization fluctuation spectra and reveals a
crossover regime between an unhybridized selective Mott state and a fully
hybridized Kondo insulating state. This intermediate phase exhibits nonlocal
hybridization fluctuations and consequentially the so-called "band bending" and
a direct hybridization gap as observed in angle-resolved photoemission
spectroscopy and optical conductivity. This connects the band bending with the
nonlocal hybridization fluctuations as proposed in latest ultrafast optical
pump-probe experiment. The Kondo insulating state is only established at lower
temperatures with the development of sufficiently strong inter-site
hybridization correlations. Our work suggests a unified picture for
interpreting recent photoemission, pump-probe, and optical observations and
provides numerical evidences for the importance of hybridization fluctuations
in heavy fermion physics.
