Sur le 3-rang des corps quadratiques de discriminant premier ou presque premier, by Karim Belabas and Etienne Fouvry
The main result of this paper is the following statement: there exists a
positive density of primes p (that can be chosen to be congruent to 1 or 3
mod 4, at will), such that the ideal class group of the real quadratic field
$Q(\sqrt{p})$ has no elements of order 3.
Analogous but weaker statements hold for imaginary quadratic fields: one
obtains pseudo primes, not primes. If we insist on the 2-rank being 0, we
only get r_3(Q(\sqrt{-p}) <= 1
The result is obtained by combining sieve methods with Davenport and
Heilbronn's theory. This improves on the first author's earlier results by a
careful estimate of exponential sums, treating various error terms on
average, and considering "quasi-fundamental" discriminants instead of sieving
for squarefree numbers.
Karim Belabas and Etienne Fouvry <karim@mpim-bonn.mpg.de, fouvry@matups.matups.fr>