Fig. 1
The nonclassicality of the qubit pure dephasing. We consider the qubit pure dephasing reduced from the extended spin-boson model, wherein φ (in unit of π) is the relative phase between the coupling constants of the qubit-pair to the common boson environment. The nonclassicality \({\cal{N}}\) is quantified according to Eq. (4). In this example, the Ohmic spectral density \({\cal{J}}(\omega ) = \omega exp( - \omega /\omega _{\mathrm{c}})\) with cut-off ωc = 1 and the zero-temperature limit are considered
