Twisted Boundary Conditions in Lattice Simulations

• Main Authors: Sachrajda, C. T, Villadoro, G
• Format: Journal Article
• Language: English
• Published: 23-11-2004
• Subjects: Physics - High Energy Physics - Lattice
• DOI: 10.48550/arxiv.hep-lat/0411033

Phys.Lett.B609:73-85,2005 By imposing twisted boundary conditions on quark fields it is possible to
access components of momenta other than integer multiples of 2pi/L on a lattice
with spatial volume L^3. We use Chiral Perturbation Theory to study
finite-volume effects with twisted boundary conditions for quantities without
final-state interactions, such as meson masses, decay constants and
semileptonic form factors, and confirm that they remain exponentially small
with the volume. We show that this is also the case for "partially twisted"
boundary conditions, in which (some of) the valence quarks satisfy twisted
boundary conditions but the sea quarks satisfy periodic boundary conditions.
This observation implies that it is not necessary to generate new gluon
configurations for every choice of the twist angle, making the method much more
practicable. For K->pipi decays we show that the breaking of isospin symmetry
by the twisted boundary conditions implies that the amplitudes cannot be
determined in general (on this point we disagree with a recent claim).