Tutorial on Scale and Conformal Symmetries in Diverse Dimensions

We review the relation between scale and conformal symmetries in various models and dimensions. We present a dimensional reduction from relativistic to non-relativistic conformal dynamics.Comment: Addendum added that includes author S.-H. Ho; Sodano Fest, Perugia, Italy, January 201

Lorentz Violation in a Diffeomorphism-Invariant Theory

In a diffeomorphism invariant theory, symmetry breaking may be a mask for coordinate choice.Comment: 8 pages, no figures. Submitted to the CPT'07 Proceeding

Fractional and Majorana Fermions: The Physics of Zero Energy Modes

We describe the occurrence and physical role of zero-energy modes in the Dirac equation with a topologically non-trivial background.Comment: 11 pages, 12 figures, talks given at the Nobel Symposium, Stockholm, Sweden, May 2010 and Semat Lecture, CCNY, New York, NY, April 2011; uses float.st