Chern-Simons Invariants

Associated to a hyperbolic knot there is a Chern-Simons Invariant. The value is an element of the additive real numbers modulo the subgroup generated by 1/2. Thus all Chern-Simons invariants are given as reals between 0 and 1/2.

There is a naturally defined complex volume for hyperbolic manifolds, with the imaginary part given by 2π2 times the Chern-Simons invariant. The values of the complex volumes are also available from KnotInfo.

The initial data is for knots with 7 or fewer tetrahedra in their decompositions (see tetrahedral enumeration). Initial data for knots with 6 or fewer tetrahedra was taken from [1]. Initial data for knots with 7 tetrahedra was taken from [2].

Walter Neumann provided us with a complete set of data for knots of 12 or fewer crossings, using the program Snap.


[1] Callahan, Dean, and Weeks, "The simplest hyperbolic knots".

[2] Champanerkar, Kofman, and Patterson, "The next simplest hyperbolic knots".

[3] P. Kirk and E. Klassen, Chern-Simons invariants of 3-manifolds decomposed along tori and the circle bundle over the representation space of T2, Comm. Math. Phys. 153 (1993), no. 3, 521-557.

[4] R. Meyerhoff, Geometric invariants of 3-manifolds, Math. Intelligencer 14 (1992), 37-153.

[5] W.D. Neumann, Extended Bloch group and the Cheeger-Chern-Simons class, Geom. Topol. 8 (2004), 413--474.

[6] W.D. Neumann, D. Zagier, Volumes of hyperbolic 3-manifolds, Topology 24 (1985) 307-332.