3 research outputs found
The light bound states of supersymmetric SU(2) Yang-Mills theory
Supersymmetry provides a well-established theoretical framework for
extensions of the standard model of particle physics and the general
understanding of quantum field theories. We summarise here our investigations
of N=1 supersymmetric Yang-Mills theory with SU(2) gauge symmetry using the
non-perturbative first-principles method of numerical lattice simulations. The
strong interactions of gluons and their superpartners, the gluinos, lead to
confinement, and a spectrum of bound states including glueballs, mesons, and
gluino-glueballs emerges at low energies. For unbroken supersymmetry these
particles have to be arranged in supermultiplets of equal masses. In lattice
simulations supersymmetry can only be recovered in the continuum limit since it
is explicitly broken by the discretisation. We present the first continuum
extrapolation of the mass spectrum of supersymmetric Yang-Mills theory. The
results are consistent with the formation of supermultiplets and the absence of
non-perturbative sources of supersymmetry breaking. Our investigations also
indicate that numerical lattice simulations can be applied to non-trivial
supersymmetric theories.Comment: 19 pages, 6 figure
Acceleration of the Arnoldi method and real eigenvalues of the non-Hermitian Wilson-Dirac operator
In this paper, we present a method for the computation of the low-lying real
eigenvalues of the Wilson-Dirac operator based on the Arnoldi algorithm. These
eigenvalues contain information about several observables. We used them to
calculate the sign of the fermion determinant in one-flavor QCD and the sign of
the Pfaffian in N=1 super Yang-Mills theory. The method is based on polynomial
transformations of the Wilson-Dirac operator, leading to considerable
improvements of the computation of eigenvalues. We introduce an iterative
procedure for the construction of the polynomials and demonstrate the
improvement in the efficiency of the computation. In general, the method can be
applied to operators with a symmetric and bounded eigenspectrum.Comment: 11 pages, 6 figure