GPU-Accelerated Simulations of Single and Two Electron-Spin Qubit Operations in Semiconductor Devices.*

Although experimental physicists can control the output of electron-spin setups in the lab, it is hard to know exactly what happened to the particles during the manipulation. We present GPU-accelerated simulations that provide valuable insights into how a particle behaves while in the metaphorical “black box” that is the experimental device. In particular, we show how the most general measurements can be implemented for dynamic qubits via a POVM protocol. We provide high fidelity simulations of entanglement distillation for electrons carried by surface acoustic waves. Furthermore, we compare two methods for generating entanglement between electron-spin qubits using the power-of-SWAP operation. By using realistic experimental parameters, we show that entanglement generation via electron-electron collisions in a harmonic channel cannot be implemented for multidimensional systems. We provide an alternative by demonstrating that a method based on the exchange energy across a tunnel barrier is more viable than previously thought. These findings pave the way to designing efficient entangling quantum logic gates.