qu an tph ] 1 4 Ju l 2 02 1 Dephasing superchannels

Zbigniew Pucha la, 2 Kamil Korzekwa, Roberto Salazar, Pawe l Horodecki, and Karol Życzkowski 4 Institute of Theoretical and Applied Informatics, Polish Academy of Sciences, 44-100 Gliwice, Poland Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, 30-348 Kraków, Poland International Centre for Theory of Quantum Technologies, University of Gdańsk, Wita Stwosza 63, 80-308 Gdańsk, Poland Center for Theoretical Physics, Polish Academy of Sciences, 02-668 Warszawa, Poland (Dated: July 15, 2021)