2,522 research outputs found
Teores foliares de macronutrientes no feijoeiro variedade IPR-colibri submetido à adubação orgânica e inorgânica.
Inoculação com Rhizobium tropici e adubação nitrogenada em linhagens de feijoeiro do grupo preto.
Non-additivity of decoherence rates in superconducting qubits
We show that the relaxation and decoherence rates 1/T_1 and 1/T_2 of a qubit
coupled to several noise sources are in general not additive, i.e., that the
total rates are not the sums of the rates due to each individual noise source.
To demonstrate this, we calculate the relaxation and pure dephasing rates 1/T_1
and 1/T_\phi of a superconducting (SC) flux qubit in the Born-Markov
approximation in the presence of several circuit impedances Z_i using network
graph theory and determine their deviation from additivity (the mixing term).
We find that there is no mixing term in 1/T_\phi and that the mixing terms in
1/T_1 and 1/T_2 can be positive or negative, leading to reduced or enhanced
relaxation and decoherence times T_1 and T_2. The mixing term due to the
circuit inductance L at the qubit transition frequency \omega_{01} is generally
of second order in \omega_{01}L/Z_i, but of third order if all impedances Z_i
are pure resistances. We calculate T_{1,2} for an example of a SC flux qubit
coupled to two impedances.Comment: 5 pages, 2 figure
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