Erratum: Phonon-mediated decay of singlet-triplet qubits in double quantum dots [Phys. Rev. B89, 085410 (2014)]

Abstract

In our original paper, we investigated the phonon-mediated decay of singlet-triplet qubits in double quantum dots (DQDs) in the biased and unbiased regime, where we inadvertently omitted relevant references regarding the dephasing mechanism which does not require hyperfine or spin-orbit interaction. Here, we wish to correct this omission and note that this mechanism corresponds to a two-phonon Raman process and has been studied before for impurity atoms [1][2][3][4], particularly in the presence of singlet states [2][3][4]. The same mechanism is used in Ref.[5] to analyze the dephasing of singlet-triplet qubits in unbiased DQDs. We note that the conclusions of our original paper and Ref.[5] substantially differ from each other. While Ref.[5] finds dominant dephasing times due to this Raman process, we find that this process for dephasing is negligible in the unbiased regime for realistic DQD parameter values (see Appendix H in our original paper).

Acoustic phonons and strain in core/shell nanowires

“…As electrons and holes interact with lattice vibrations, understanding of the quantum mechanical behavior of the system requires knowledge of the phonon bath. For instance, it is well-known that phonons can be dominant decay channels for spin qubits [33][34][35][36][37][38]. The shell of core/shell NWs not only induces static strain, it also affects the phonon modes.…”

Intrinsic Metastabilities in the Charge Configuration of a Double Quantum Dot

“…Away from these edges, the rates fall off exponentially by 3 orders of magnitude until a small background rate is reached which varies weakly with gate voltages and is well above the smallest detectable rate. Photon assisted tunneling, residual interdot tunneling or a higher order process, possibly involving phonons [18], could give rise to such a background rate. The switching frequency f ¼ ðΓ −1 L þ Γ −1 R Þ −1 of the complete process, i.e., from left to right dot and back, peaks close to the triple points, see Fig.…”

“…Spin echo and dynamical decoupling techniques were successfully employed to isolate the electronic system from the slowly fluctuating nuclear spins of the GaAs host material [3,[12][13][14][15], enhancing the coherence time T 2 from below 1 μs to much longer times exceeding 0.2 ms. A fundamental limit T 2 ≤ 2T 1 is set by the spin relaxation time T 1 . In a magnetic field, spins relax through spin-phonon coupling mediated by the spin-orbit interaction [2,[16][17][18]. Since here the spin-orbit coupling is weak, very long T 1 times result, exceeding 1 s at 1 T [19], leaving ample room for further improvements of the spin qubit coherence.…”

Decoherence-enhanced quantum measurement of a quantum-dot spin qubit

“…Specifically, the singlet steady state, found from the condition p(t) = 0, is The singlet steady state depends explicitly on the strengths of the phonon-couplings relative to the QPC coupling strengths. The Markovian approach to the system dynamics used here neglects pure dephasing effects, which become particularly important when real transitions are absent [13,[22][23][24][25][26]. How ever, the dynamics of the system studied here is dominated by environmentally induced real transitions (see discussion below) and pure dephasing effects are not expected to have a large impact on the system dynamics in the parameter regime of interest here.…”