Transmission Coefficient Matrix Modeling of Spin-Torque-Based $n$ -Qubit Architecture

Spin-torque-based quantum computing (QC) architecture is emerging as one of the novel technologies to meet scalability challenge due to its intra architecture spin qubit state manipulation. The existing model for spin-torque-based QC does not include the ratio of reflection barrier height to exchange interaction to the transmission coefficients. Therefore, in this paper, a modified matrix is proposed to analyze the effect of ratio of reflection barrier height to exchange interaction on electron-qubit interaction, deviation of axis of rotation for single-qubit rotation, and average error probability for two-qubit rotation in a spin-torque-based n-qubit reconfigurable architecture. In addition, the conventional and reduced quantum gates are compared for existing and modified matrices. The quantum gates performance is analyzed in terms of number of electrons required per gate for the electron-qubit interaction, gate fidelity, number of elementary quantum operations per gate, and gate execution time. Reconfigurability is accomplished through barrier height modulation to reduce the architecture hardware. Moreover, a novel nanomagnet-based spin reservoir is incorporated in the architecture for the nonlocal spin injection to facilitate only spin-based operations. High fidelity (~99%) of quantum gates is attained for the fault-tolerant QC.