We consider interacting electrons in a one-dimensional lattice with an incommensurate Aubry-André potential in the regime when the single-particle eigenstates are localized. We rigorously establish the persistence of ground state localization in the presence of weak many-body interaction, for almost all the chemical potentials. The proof uses a quantum many-body extension of methods adopted for...

Thought (pp. 79–111). Cambridge, MA: MIT Press. Udell, J. (2004, November 17). Name that genre: Screencast. Retrieved June 3, 2011, fromhttp://jonudell.net/udell/2004-11-17-name-that-genre-screencast.html Udell, J. (2005, November 16) What is screencasting? Retrieved November 18, 2008, from http://digitalmedia.oreilly.com/2005/11/16/what-is-screencasting.html Umulis, D. M, Gürmen, N. M., Si...

This is a late answer to question #79 by R.I. Khrapko, “Does plane wave not carry a spin?,” Am. J. Phys. 69, 405 (2001), and a complement (on gauge invariance, massive spin 1 and 1 2 , and massless spin 2 fields) to the paper by H.C. Ohanian, What is spin?, Am. J. Phys. 54, 500–505 (1985). In particular, it is confirmed that “spin” is a classical quantity which can be calculated for any field u...