Coherent Coupling of Qubits in Small Quantum Dot Arrays

The coherent coupling of electron charges and spins is investigated in small quantum dot arrays.TNWApplied Science

Dynamics of spin-flip photon-assisted tunneling

We present time-resolved measurements of spin-flip photon-assisted tunneling and spin-flip relaxation in a doubly occupied double quantum dot. The photon-assisted excitation rate as a function of magnetic field indicates that spin-orbit coupling is the dominant mechanism behind the spin-flip under the present conditions. We are able to extract the resulting effective “spin-flip tunneling” energy, which is found to be three orders of magnitude smaller than the regular spin-conserving tunneling energy. We also measure the relaxation and dephasing times of a qubit formed out of two two-electron states with different spin and charge configurations.QN/Quantum NanoscienceApplied Science

Photon- and phonon-assisted tunneling in the three-dimensional charge stability diagram of a triple quantum dot array

We report both photon- and phonon-assisted tunneling transitions in a linear array of three quantum dots, which can only be understood by considering the full three-dimensionality of the charge stability diagram. Such tunneling transitions potentially contribute to leakage of qubits defined in this system. A detailed understanding of these transitions is important as they become more abundant and complex to analyze as quantum dot arrays are scaled up.QN/Quantum NanoscienceApplied Science