935 research outputs found
Overlap/Domain-wall reweighting
We investigate the eigenvalues of nearly chiral lattice Dirac operators
constructed with five-dimensional implementations. Allowing small violation of
the Ginsparg-Wilson relation, the HMC simulation is made much faster while the
eigenvalues are not significantly affected. We discuss the possibility of
reweighting the gauge configurations generated with domain-wall fermions to
those of exactly chiral lattice fermions.Comment: 7 pages, 3 figures, presented at the 31st International Symposium on
Lattice Field Theory (Lattice 2013), 29 July-3 August 2013, Mainz, German
Development of Spherical Ultrasonic Motor for Critical Environment
In recent years, due to advances in science technology, space satellites have made progress. So, the presence of space debris has become problem in the world because they may collide each other. In our study, we have developed Spherical Ultrasonic Motor (SUSM) for space use with 3 DOF to drive the satellite thruster and resolve it. We aim that the satellites enter the atmosphere when the satellites reached the end of life, and SUSM controls thrusters when they inject for the directional control. We have made experiments of measuring torque, durability and lifetime. It shows that the torque and lifetime meets target value. But durability does not meet target value. To resolve it, we have applied stator lining materials and shifted frequency with 0.4kHz from resonant frequency and we have shown that it meets durability required specifications
Lattice study of meson correlators in the epsilon-regime of two-flavor QCD
We calculate mesonic two-point functions in the epsilon-regime of two-flavor
QCD on the lattice with exact chiral symmetry. We use gauge configurations of
size 16^3 32 at the lattice spacing a \sim 0.11 fm generated with dynamical
overlap fermions. The sea quark mass is fixed at \sim 3 MeV and the valence
quark mass is varied in the range 1-4 MeV, both of which are in the
epsilon-regime. We find a good consistency with the expectations from the
next-to-leading order calculation in the epsilon-expansion of (partially
quenched) chiral perturbation theory. From a fit we obtain the pion decay
constant F=87.3(5.6) MeV and the chiral condensate Sigma^{MS}=[239.8(4.0) MeV
]^3 up to next-to-next-to-leading order contributions.Comment: 20 pages, 12 figures, final version to appear in PR
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