Taehee Kim, Takayuki Morifuji
Published 2010-06-22, updated 2010-07-29Version 2
We study the twisted Alexander polynomial from the viewpoint of the SL(2,C)-character variety of nonabelian representations of a knot group. It is known that if a knot is fibered, then the twisted Alexander polynomials associated with nonabelian SL(2,C)-representations are all monic. In this paper, we show that the converse holds for 2-bridge knots. Furthermore we show that for a 2-bridge knot there exists a curve component in the SL(2,C)-character variety such that if the knot is not fibered then there are only finitely many characters in the component for which the associated twisted Alexander polynomials are monic. We also show that for a 2-bridge knot of genus g, in the above curve component for all but finitely many characters the associated twisted Alexander polynomials have degree 4g-2.
Comments: 19 pages, 1 figure, revised version
Deformations of metabelian representations of knot groups into $SL(3,\mathbb{C})$
Finiteness of a section of the $SL(2,\mathbb{C})$-character variety of knot groups
On the geometry of the slice of trace--free SL(2,C)-characters of a knot group
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