Phonon-induced decoherence of a pair of singlet-triplet spin qubits

Abstract

The investigation begins with studying the eigenvalue spectrum of the two-ST0 qubits hosted by a pair of double quantum dots. The simulation assumed that the tunneling energy in the quantum-dot system is adjustable so that analysis of the effect of tunneling energy on the energy spectrum and phonon-induced decoherence can be carried out conveniently. In order to plot the relaxation rate and dephasing rate as a function of tunneling energy, a different combination of tunneling energy and value of detuning is chosen in the large detuning region for further numerical analysis.

The simulation result shows the energy spectrum based on the Hamiltonian of the system and investigation of the phonon-induced decoherence due to the electron-phonon interaction. This study finds that the electron phonon interaction within each double quantum dots dominate in the first order contribution. It should be taken under consideration in the calculation of the phonon-induced relaxation and dephasing rate in the two-ST0 qubits system.