Fig. 2: Decoherence and coherence generation in DQD charge qubit due to the presence of a phononic environment.
From: Tunable phonon-induced steady-state coherence in a double-quantum-dot charge qubit
a Decoherence: dynamics of \(\langle {\hat{\sigma }}_{x}(t)\rangle\) and \(\langle {\hat{\sigma }}_{y}(t)\rangle\) for ε = 0, starting from an initial state with coherence \(\langle {\hat{\sigma }}_{x}(0)\rangle =0.2\), \(\langle {\hat{\sigma }}_{y}(0)\rangle =-0.2\), \(\langle {\hat{\sigma }}_{z}(0)\rangle =0\). Here the final steady state has no coherence. b Coherence generation: dynamics of \(\langle {\hat{\sigma }}_{x}(t)\rangle\) and \(\langle {\hat{\sigma }}_{y}(t)\rangle\) for ε = 1, starting from a completely mixed initial state: \(\langle {\hat{\sigma }}_{x}(0)\rangle =0\), \(\langle {\hat{\sigma }}_{y}(0)\rangle =0\), \(\langle {\hat{\sigma }}_{z}(0)\rangle =0\). Here the final steady state has coherence. Other parameters: tc = 0.5, γb = 0.03, ωmax = 10, β = 10. All energies are measured in units of ωc, which is set to 1.
