The Design and function of a radiation tolerant silicon tracker for an LHC experiment

We present a description of the RD2 design for a silicon tracking detector and discuss its function as an integrated component of an LHC experiment. An advantage of the design is that considerable flexibility is possible in the granularity and radial position of each plane; these parameters are determined by the physics requirements as well as by the radiation environment, engineering and electronics considerations. The simulated performance of the detector is discussed and our experimental investigations of irradiation effects are summarised. The development of an analogue pipe-line and related front-end electronics for the storage and processing of the signals is described. Our work indicates the suitability of silicon as a detector for LHC experiments. © 1993

Competition between diagonal and off-diagonal coupling gives rise to charge-transfer states in polymeric solar cells

It has long been a puzzle on what drives charge separation in artificial polymeric solar cells as a consensus has yet to emerge among rivaling theories based upon electronic localization and delocalization pictures. Here we propose an alternative using the two-bath spin-boson model with simultaneous diagonal and off-diagonal coupling: the critical phase, which is born out of the competition of the two coupling types, and is neither localized nor delocalized. The decoherence-free feature of the critical phase also helps explain sustained coherence of the charge-transfer state. Exploiting Hamiltonian symmetries in an enhanced algorithm of density-matrix renormalization group, we map out boundaries of the critical phase to a precision previously unattainable, and determine the bath spectral densities inducive to the existence of the charge-transfer state