Tachyons with any spin

W Spin for Any Spin

The collinear group SU(6)w enables us to discuss vertices, form factors and other collinear processes in an SU(6)-theory which is consistent with relativistic invariance. It leads, however, to a classification of the particles which is different from that of the “staticL SU(6)s. The general “W-spin” properties of an arbitrary spin state constructed from any number of basic spin i objects are di...

The Dirac Algebra for Any Spin∗

Tachyons today

Much of my work as a Pappalardo Fellow has involved some puzzles that arise in certain string theories because of a very peculiar type of particle, called a tachyon. Here I’ll explain what a tachyon is and why it’s important to solve these puzzles. Along the way we’ll compare and contrast string theories with conventional particle theories. I should first clarify that when I say “theory” here I...

Inflation from Geometrical Tachyons

We propose an alternative formulation of tachyon inflation using the geometrical tachyon arising from the time dependent motion of a BPS D3-brane in the background geometry due to k parallel NS5-branes arranged around a ring of radius R. Due to the fact that the mass of this geometrical tachyon field is √ 2/k times smaller than the corresponding open-string tachyon mass, we find that the slow r...

Quantum Cosmology and Tachyons

We discuss the relevance of the classical and quantum rolling tachyons inflation in the frame of the standard, p-adic and adelic minisuperspace quantum cosmology. The field theory of tachyon matter proposed by Sen in a zero-dimensional version suggested by Kar leads to a model of a particle moving in a constant external field with quadratic damping. We calculate the exact quantum propagator of ...