We investigate the sensitivity of pionic bounce{oo and squeeze{out on the density and momentum dependence of the real part of the nucleon optical potential. For the in{plane pion bounce{oo we nd a strong sensitivity on both the density and momentum dependence whereas the out{of{plane pion squeeze{out shows a strong sensitivity only towards the momentum dependence but little sensitivity towards ...

Scattering of energetic F atoms on a fluorinated Si surface is studied by molecular beam methods. The energy transfer closely follows hard-sphere collision kinematics. Energy and angular distributions of unreacted F atoms suggest significant multiple-bounce scattering in addition to single-bounce scattering and trapping desorption. An empirical model of the atom-surface interaction dynamics is ...

When quantum gravity is used to discuss the big bang singularity, the most important, though rarely addressed, question is what role genuine quantum degrees of freedom play. Here, complete effective equations are derived for isotropic models with an interacting scalar to all orders in the expansions involved. The resulting coupling terms show that quantum fluctuations do not affect the bounce m...

We discuss Minkowski space interpretations of euclidean solutions which provide semiclassical approximations to quantum processes. In particular, we consider wormhole and euclidean bounce solutions. We argue that the semiclassical description involves an instantaneous discontinuity in the Minkowski signature classical evolution and that the euclidean solutions provide final and initial value da...

Abstract In loop quantum cosmology (LQC) the big bang singularity is generically resolved by a bounce. This feature holds even when modified quantization prescriptions of Hamiltonian constraint are used such as in mLQC-I and mLQC-II. While later describes an effective description qualitatively similar to that standard LQC, former asymmetric evolution with emergent Planckian de-Sitter pre-bounce...