The effects of magnetic field on the d-density wave order in the cuprates

We consider the effects of a perpendicular magnetic field on the d-density wave order and conclude that if the pseudogap phase in the cuprates is due to this order, then it is highly insensitive to the magnetic field in the underdoped regime, while its sensitivity increases as the gap vanishes in the overdoped regime. This appears to be consistent with the available experiments and can be tested further in neutron scattering experiments. We also investigate the nature of the de Haas- van Alphen effect in the ordered state and discuss the possibility of observing it.Comment: 5 pages, 4 eps figures, RevTex4. Corrected a silly but important typo in the abstrac

ATLAS Data Challenge 2: A massive Monte Carlo production on the GRID

The study and validation of the ATLAS Computing Model started three years ago and will continue for few years in the context of the so-called Data Chal-lenges (DC). DC1 was conducted during 2002-03; the main goals achieved were to set up the simulation data production infrastructure in a real worldwide collaborative effort and to gain experience in exercising an ATLAS wide production model. DC2 (from May until December 2004) is divided into three phases: (i) generate Monte Carlo data using GEANT4 on three different Grid projects: LCG, GRID3 and NorduGrid; (ii) simulate the first pass recon-struction of real data expected in 2007, and (iii) test the Distributed Analysis model. Experience with the use of the system in world-wide DC2 production of ten million events will be presented. We also present how the three Grid fla-vours are operated. Finally we discuss the first prototypes of Distributed Analy-sis systems