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Journal Article

#### Motivic classes of moduli of Higgs bundles and moduli of bundles with connections

##### Locator

http://dx.doi.org/10.4310/CNTP.2018.v12.n4.a3

(Publisher version)

##### Fulltext (public)

arXiv:1705.04890.pdf

(Preprint), 642KB

##### Supplementary Material (public)

There is no public supplementary material available

##### Citation

Fedorov, R., Soibelman, A., & Soibelman, Y. (2018). Motivic classes of moduli of
Higgs bundles and moduli of bundles with connections.* Communications in Number Theory and Physics,*
*12*(4), 687-766. doi:10.4310/CNTP.2018.v12.n4.a3.

Cite as: http://hdl.handle.net/21.11116/0000-0003-AABE-8

##### Abstract

Let X be a smooth projective curve over a field of characteristic zero. We calculate the motivic class of the moduli stack of semistable Higgs bundles on X. We also calculate the motivic class of the moduli stack of vector bundles with connections by showing that it is equal to the class of the stack of semistable Higgs bundles of the same rank and degree zero. We follow the strategy of Mozgovoy and Schiffmann for counting Higgs bundles over finite fields. The main new ingredient is a motivic version of a theorem of Harder about Eisenstein series claiming that all vector bundles have
approximately the same motivic class of Borel reductions as the degree of Borel
reduction tends to $-\infty$.