Study of Using Variational Quantum Linear Solver for Solving Poisson Equation

Quantum computing is promising in speeding up the system of linear equations (SLE) solving process. However, its performance is limited by noise. The variational quantum linear solver (VQLS) algorithm is expected to be more resilient to noise than gate-based quantum computing algorithms. This is because error correction is not available yet and VQLS is based on cost function minimization. In this paper, the gate insulator Poisson equation is solved using VQLS. The results are compared to technology computer-aided design (TCAD) results and gate-based quantum algorithm results. We show that, even without error-free qubits, the IBM-Q quantum computer hardware can solve a 2-variable SLE with high fidelity. We further demonstrate that, through VQLS simulation, an 8-variable SLE can be solved with fidelity as high as 0.96.