138 citations · 486 across the 23 of their papers we have counts for
24 papers
An -independent tensor decomposition for SU()
Stefan Keppeler, Malin Sjodahl, Bernanda Telalovic
To facilitate a simultaneous treatment of an arbitrary number of colors in representation theory-based descriptions of QCD color structure, we derive an -independent reduction o…
Wigner 6j symbols with gluon lines: completing the set of 6j symbols required for color decomposition
Stefan Keppeler, Simon Plätzer, Malin Sjodahl
We construct a set of Wigner 6j symbols with gluon lines (adjoint representations) in closed form, expressed in terms of similar 6j symbols with quark lines (fundamental representa…
Wigner 6j symbols for SU(N): Symbols with at least two quark-lines
Judith Alcock-Zeilinger, Stefan Keppeler, Simon Plätzer +1
We study a class of SU(N) Wigner 6j symbols involving two fundamental representations, and derive explicit formulae for all 6j symbols in this class. Our formulae express the 6j sy…
Birdtracks for SU(N)
Stefan Keppeler
I gently introduce the diagrammatic birdtrack notation, first for vector algebra and then for permutations. After moving on to general tensors I review some recent results on Hermi…
The Berry-Keating operator on a lattice
Jens Bolte, Sebastian Egger, Stefan Keppeler
We construct and study a version of the Berry-Keating operator with a built-in truncation of the phase space, which we choose to be a two-dimensional torus. The operator is a Weyl…
A Gutzwiller trace formula for large hermitian matrices
Jens Bolte, Sebastian Egger, Stefan Keppeler
We develop a semiclassical approximation for the dynamics of quantum systems in finite-dimensional Hilbert spaces whose classical counterparts are defined on a toroidal phase space…