11 research outputs found
Generalized and Annihilation Potentials for Decay into Two Mesons based on a Simple Quark Model
Within the quark model a generalization is proposed of the commonly used
annihilation potential to describe antiproton-proton annihilation into two
mesons, the so-called and mechanisms. This generalized
potential treats the two mechanisms in a more symmetric way, has additional
angular dependence, and results in an expanded set of selection rules.Comment: LATEX, 8 pages, 1 figure (available upon request), Preprint #RU924
Scalable quantum computation via local control of only two qubits
We apply quantum control techniques to control a large spin chain by only
acting on two qubits at one of its ends, thereby implementing universal quantum
computation by a combination of quantum gates on the latter and swap operations
across the chain. It is shown that the control sequences can be computed and
implemented efficiently. We discuss the application of these ideas to physical
systems such as superconducting qubits in which full control of long chains is
challenging.Comment: 4 pages, 3 figure
Transient Ca2+-channel current characterized by a low-threshold voltage in zona glomerulosa cells of rat adrenal cortex
The CLIC electron and positron polarized sources
The CLIC polarized electron source is based on a DC gun where the photocathode is illuminated by a laser beam. Each micro-bunch has a charge of 6x109 e−, a width of 100 ps and a repetition rate of 2 GHz. A peak current of 10 A in the micro-bunch is a challenge for the surface charge limit of the photo-cathode. Two options are feasible to generate the 2 GHz e− bunch train: 100 ps micro-bunches can be extracted from the photo-cathode either by a 2 GHz laser system or by generating a macro-bunch using a ~200 ns laser pulse and a subsequent RF bunching system to produce the appropriate micro-bunch structure. Recent results obtained by SLAC, for the latter case, are presented. The polarized positron source is based on a positron production scheme in which polarized photons are produced by a laser Compton scattering process. The resulting circularly-polarized gamma photons are sent onto a target, producing pairs of longitudinally polarized electrons and positrons. The Compton backscattering process occurs either in a Compton ring, where a 1 GeV electron beam interacts with circularly-polarized photons in an optical resonator or in a 1.8 GeV Compton Energy Recovery Linac (ERL) or in a 6 GeV Linac with several optical cavities. The undulator scheme is also studied. The nominal CLIC e+ bunch population is 6.7x109 particles per bunch at 200 MeV. The tradeoff between e+ yield and level of polarization is an important topic. The overal l scheme for both polarized electron and positron beams is described