Quantum Annealing Machines Based on Semiconductor Nanostructures

The development of quantum annealing machines (QAMs) based on superconducting qubits has progressed considerably in recent years and these machines are now widely used in both academia and commerce. On the other hand, QAMs based on semiconductor nanostructures such as quantum dots (QDs) appear to be still at the initial elementary research stage because of the difficulty in controlling the interaction between qubits. In this paper, we review a QAM based on semiconductor nanostructures such as floating gates (FGs) or QDs from the viewpoint of qubit integration. We theoretically propose the use of conventional high-density memories such as NAND flash memories for the QAM rather than the construction of a semiconductor qubit system from scratch. A large qubit system will be obtainable as a natural extension of the miniaturization of commercial-grade electronics, although further effort will likely be required to achieve high-quality qubits.