Karol Życzkowski (1960–present) is a Polish physicist and mathematician. He is a professor of physics at the Atomic Physics Department, Institute of Physics, of the Jagiellonian University in Kraków, Poland, and also at the Center for Theoretical Physics of the Polish Academy of Sciences in Warsaw.He worked as a Humboldt Fellow at the University of Essen (1989-1990) and as senior Fulbright Fellow at the University of Maryland, College Park (1996/97). In 2005/06 visiting scientist at the Perimeter Institute, Waterloo (Ontario).