turkmath.org

By the celebrated work of G. Shimura, our knowledge on modular forms of half-integral weight has started to grow. Like in the case of integral weight, they also have arithmetic significance, so both have attracted attention for many years. Recently, one of the breakthrough and very significant results in pure mathematics is the proof of the Sato-Tate conjecture for non-CM modular eigenforms of integral weight (even for Hilbert eigenforms) by Taylor, Barnet-Lamb, Geraghty and Harris. A special case of the Sato-Tate theorem states that signs of coefficients of integral weight Hecke eigenforms are equidistributed. That such should also be the case for half-integral weight forms was conjectured by Kohnen and Bruinier. In this talk, we will discuss the motivation behind this question and explain how the Shimura lift and the Sato-Tate theorem can be exploited to obtain sign equidistribution for certain subsets of the coefficients of half-integral weight eigenforms. Finally, we are interested in the following question: Is it possible state a conjecture like Sato-Tate in the case of half-integral weight modular forms where the question is much more complicated. We will conclude with reporting recent developments on this problem. This is a joint work with S. Purkait (Kyushu), G. Wiese (Luxembourg), S. Arias-de-Reyna (Luxembourg).