Ryszard Horodecki (born 30 September 1943) is a Polish physicist and a professor of University of Gdańsk. He contributed largely to the field of quantum informatics. In his most widely cited paper, 'Separability of Mixed States: Necessary and Sufficient Conditions' written together with his sons, Michał and Paweł, he proposed the idea currently known as the Peres-Horodecki criterion. With over 12,000 citations, he is considered to be one of the leading Polish physicists.