Geometric Dirac operator on noncommutative torus and $M_2(\Bbb C)$
Abstract
We solve for quantum-geometrically realised spectral triples or `Dirac operators' on the noncommutative torus and on the algebra of matrices with their standard quantum metrics and associated quantum Levi-Civita connections. For , we obtain an even standard spectral triple but now uniquely determined by full geometric realisability. For , we are forced to the flat quantum Levi-Civita connection and again obtain a natural fully geometrically realised even spectral triple. In both case there is also an odd spectral triple for a different choice of a sign parameter. We also consider an alternate quantum metric on with curved quantum Levi-Civita connection and find a natural 2-parameter of almost spectral triple in that fails to be antihermitian. In all cases, we split the construction into a local tensorial level related to the quantum geometry, where we classify the results more broadly, and the further requirements relating to the Hilbert space structure. We also illustrate the Lichnerowicz formula for which applies in the case of a full geometric realisation.
Keywords
Cite
@article{arxiv.2208.07821,
title = {Geometric Dirac operator on noncommutative torus and $M_2(\Bbb C)$},
author = {E. Lira-Torres and S. Majid},
journal= {arXiv preprint arXiv:2208.07821},
year = {2023}
}
Comments
33 pages latex no figures. Moved the less interesting second quantum metric on M_2(C) into an appendix, corrected typos and added details of Lichnerowicz theorem related D^2 and Laplacian. This is a sequel to 2104.13212 (math.QA)