Showing papers by "Artur F. Izmaylov published in 2010"
TL;DR: This Letter introduces a class of linear N-representability conditions based on exact calculations on a reduced active space of the two-particle reduced density matrix (2-RDM) that yields a significant improvement over traditional 2-positivity constraints with the same computational scaling.
Abstract: The ground-state energy of a system of fermions can be calculated by minimizing a linear functional of the two-particle reduced density matrix (2-RDM) if an accurate set of N-representability conditions is applied. In this Letter we introduce a class of linear N-representability conditions based on exact calculations on a reduced active space. Unlike wave-function-based approaches, the 2-RDM methodology allows us to combine information from calculations on different active spaces. By adding active-space constraints, we can iteratively improve our estimate for the ground-state energy. Applying our methodology to a 1D Hubbard model yields a significant improvement over traditional 2-positivity constraints with the same computational scaling.
46 citations
01 Nov 2010-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: The side muon range detector (SMRD) as mentioned in this paper was designed to help measure the neutrino energy spectrum, to identify background and to calibrate the other detectors, and achieved a high MIP detection efficiency of greater than 99%.
Abstract: The T2K neutrino experiment at J-PARC uses a set of near detectors to measure the properties of an unoscillated neutrino beam and neutrino interaction cross-sections. One of the sub-detectors of the near-detector complex, the side muon range detector (SMRD), is described in the paper. The detector is designed to help measure the neutrino energy spectrum, to identify background and to calibrate the other detectors. The active elements of the SMRD consist of 0.7 cm thick extruded scintillator slabs inserted into air gaps of the UA1 magnet yokes. The readout of each scintillator slab is provided through a single WLS fiber embedded into a serpentine-shaped groove. Two Hamamatsu multi–pixel avalanche photodiodes (MPPC's) are coupled to both ends of the WLS fiber. This design allows us to achieve a high MIP detection efficiency of greater than 99%. A light yield of 25–50 p.e./MIP, a time resolution of about 1 ns and a spatial resolution along the slab better than 10 cm were obtained for the SMRD counters.
15 citations
01 Jan 2010
TL;DR: The Side Muon Range Detector (SMRD) as discussed by the authors is a component of the Off-Axis near detector, which is used for neutrino oscillation measurement.
Abstract: The T2K long-baseline neutrino oscillation experiment is running in Japan. The primary goals of the T2K are measurement of the mixing angle θ13, and precise measurements of the mixing angle θ23 and of the mass difference Δm232. The installation of the near detector complex was completed and first data were already registered. This article presents operation of the Side Muon Range Detector, a component of the Off-Axis near detector. Detector concept and implementation are presented, followed by a description of cosmic muon track reconstruction algorithm and finally current status.
3 citations