English

Determinants of Mahler measures and special values of $L$-functions

Number Theory 2025-05-27 v2 Algebraic Geometry K-Theory and Homology

Abstract

We consider Mahler measures of two well-studied families of bivariate polynomials, namely Pt=x+x1+y+y1+tP_t=x+x^{-1}+y+y^{-1}+\sqrt{t} and Qt=x3+y3+1t3xyQ_t=x^3+y^3+1-\sqrt[3]{t}xy, where tt is a complex parameter. In the cases when the zero loci of these polynomials define CM elliptic curves over number fields, we derive general formulas for their Mahler measures in terms of LL-values of cusp forms. For each family, we also classify all possible values of tt in number fields of degree not exceeding 44 for which the corresponding elliptic curves have complex multiplication. Finally, for all such values of tt in totally real number fields of degree n=2n=2 and n=4n=4, corresponding to elliptic curves Ft\mathcal{F}_t (resp. Ct\mathcal{C}_t), we prove that determinants of n×nn\times n matrices whose entries are Mahler measures corresponding to their Galois conjugates are non-zero rational multiples of L(n)(Ft,0)L^{(n)}(\mathcal{F}_t,0) (resp. L(n)(Ct,0)L^{(n)}(\mathcal{C}_t,0)).

Keywords

Cite

@article{arxiv.2409.14714,
  title  = {Determinants of Mahler measures and special values of $L$-functions},
  author = {Detchat Samart and Zhengyu Tao},
  journal= {arXiv preprint arXiv:2409.14714},
  year   = {2025}
}

Comments

38 pages, 6 tables, 2 figures: Minor errors fixed. Conjectural identities for non-CM curves have also been incorporated in Section 7 and the appendix