3 research outputs found
Hierarchies of Susy Splittings and Invisible Photinos as Dark Matter
We explore how to generate hierarchies in the splittings between
superpartners. Some of the consequences are the existence of invisible
components of dark matter, new inflaton candidates, invisible monopoles and a
number of invisible particles that might dominate during various eras, in
particular between BBN and recombination and decay subsequently.Comment: 16 pages. v3: Ref. 27 has been modified. v4: Published versio
Holographic Brownian Motion in Magnetic Environments
Using the gauge/gravity correspondence, we study the dynamics of a heavy
quark in two strongly-coupled systems at finite temperature: Super-Yang-Mills
in the presence of a magnetic field and non-commutative Super-Yang-Mills. In
the former, our results agree qualitatively with the expected behavior from
weakly-coupled theories. In the latter, we propose a Langevin equation that
accounts for the effects of non-commutativity and we find new interesting
features. The equation resembles the structure of Brownian motion in the
presence of a magnetic field and implies that the fluctuations along
non-commutative directions are correlated. Moreover, our results show that the
viscosity is smaller than the commutative case and that the diffusion
properties of the quark are unaffected by non-commutativity. Finally, we
compute the random force autocorrelator and verify that the
fluctuation-dissipation theorem holds in the presence of non-commutativity.Comment: 34 pages. v2: typos corrected. v3: title and abstract slightly
modified in order to better reflect the contents of the paper; footnote 3 and
one reference were also added; version accepted for publication in JHE