899 research outputs found
Comments on Observables for Identity-Based Marginal Solutions in Berkovits' Superstring Field Theory
We construct an analytic solution for tachyon condensation around
identity-based marginal solutions in Berkovits' WZW-like open superstring field
theory. Using this, which is a kind of wedge-based solution, the gauge
invariant overlaps for the identity-based marginal solutions can be calculated
analytically. This is a straightforward extension of a method in bosonic string
field theory, which has been elaborated by the authors, to superstring. We also
comment on a gauge equivalence relation between the tachyon vacuum solution and
its marginally deformed one. From this viewpoint, we can find the vacuum energy
of the identity-based marginal solutions to be zero, which agrees with the
previous result as a consequence of zero mode counting.Comment: 16 page
First-principles interatomic potentials for ten elemental metals via compressed sensing
Interatomic potentials have been widely used in atomistic simulations such as
molecular dynamics. Recently, frameworks to construct accurate interatomic
potentials that combine a systematic set of density functional theory (DFT)
calculations with machine learning techniques have been proposed. One of these
methods is to use compressed sensing to derive a sparse representation for the
interatomic potential. This facilitates the control of the accuracy of
interatomic potentials. In this study, we demonstrate the applicability of
compressed sensing to deriving the interatomic potential of ten elemental
metals, namely, Ag, Al, Au, Ca, Cu, Ga, In, K, Li and Zn. For each elemental
metal, the interatomic potential is obtained from DFT calculations using
elastic net regression. The interatomic potentials are found to have prediction
errors of less than 3.5 meV/atom, 0.03 eV/\AA\ and 0.15 GPa for the energy,
force and the stress tensor, respectively, which enable the accurate prediction
of physical properties such as lattice constants and the phonon dispersion
relationship.Comment: 11 pages, 5 figure
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