Change of the Chern number at band crossings
Abstract
Description
Let $H(ε, x)$ be a finite dimensional hermitian matrix depending on the variable $x$ taking its values on a 2D manifold and changing with $ε$. If at $ε=0$ two bands are touching, we give a formula for the change of Chern number of these bands as $ε$ passes through zero.
uuencoded version, 6 pages latex, 2 postscript figures included
uuencoded version, 6 pages latex, 2 postscript figures included