High-quality variational wave functions for small 4He clusters

We report a variational calculation of ground state energies and radii for 4He_N droplets (3 \leq N \leq 40), using the atom-atom interaction HFD-B(HE). The trial wave function has a simple structure, combining two- and three-body correlation functions coming from a translationally invariant configuration-interaction description, and Jastrow-type short-range correlations. The calculated ground state energies differ by around 2% from the diffusion Monte Carlo results.Comment: 5 pages, 1 ps figure, REVTeX, submitted to Phys. Rev.

The helium trimer with soft-core potentials

The helium trimer is studied using two- and three-body soft-core potentials. Realistic helium-helium potentials present an extremely strong short-range repulsion and support a single, very shallow, bound state. The description of systems with more than two helium atoms is difficult due to the very large cancellation between kinetic and potential energy. We analyze the possibility of describing the three helium system in the ultracold regime using a gaussian representation of a widely used realistic potential, the LM2M2 interaction. However, in order to describe correctly the trimer ground state a three-body force has to be added to the gaussian interaction. With this potential model the two bound states of the trimer and the low energy scattering helium-dimer phase shifts obtained with the LM2M2 potential are well reproduced.Comment: 15 pages, 3 figures, submitted to Few-Body System

Design of a self-checking microprocessor for real-time applications

ISBN: 0080334385Concerns the design of a microprocessor dedicated to safety applications and more particularly to automatic train control. This microprocessor is self-checking i.e. able to detect its own errors. Its name is COBRA (controller with built-in selfchecking for real-time applications). In the design of this circuit, low-level fault hypotheses for the N-MOS technology are considered. In this case redundant faults, i.e. undetectable faults, generally exist in any design and thus fault detecting capabilities must be provided for sequences of faults. The functional circuits will process with coded data and will be checked by strongly code-disjoint checkers. COBRA's data path processes independently 19 different signals, and supervises 14 level inputs (binary values). 7 independent outputs could be binary values, and 3 could be clocks. The data path communicates with an external PROM, used as program storage for COBRA. This PROM is addressed with 14 bits, multiplexed over the 8-bit address/data internal bus of the data path. It also contains one serial I/O, a 64 byte RAM, and 3 independent 14 bits counters. An 8 bit ALU could be used for arithmetical or logical operations. A set of 42 instructions processes all these operations

New design adaptated planar double gate process for performant low standby power application

International audienc

Design for Millimeter-wave Applications in Silicon Technologies

International audienc