Pauli semigroups and unistochastic quantum channels

Autorzy Puchała Z.; Rudnicki Ł.; Życzkowski K.
Tytuł Pauli semigroups and unistochastic quantum channels
Czasopismo Physics Letters A
Rok 2019
Status Published
Tom 383
Numer 20
Strony 2376-2381
URL https://arxiv.org/abs/1903.12448
Abstrakt <p>We adopt the perspective of similarity equivalence, in gate set tomography called the gauge, to analyze various properties of quantum operations belonging to a semigroup, <span style="font-size:122%"><span style="font-family:stixgeneral">Φ</span><span style="font-family:stixgeneral">=</span><em>e</em><em>^{Lt}</em></span>,and therefore given through the Lindblad operator. We first observe that the non unital part of the channel decouples from the time evolution. Focusing on unital operations we restrict our attention to the single-qubit case, showing that the semigroup embedded inside the tetrahedron of Pauli channels is bounded by the surface composed of product probability vectors and includes the identity map together with the maximally depolarizing channel. Consequently, every member of the Pauli semigroup is unitarily equivalent to a unistochastic map, describing a coupling with one-qubit environment initially in the maximally mixed state, determined by a unitary matrix of order four.</p>