US Patent 11308415 Quantum analog-digital interconversion for encoding and decoding quantum signals

Methods, systems, and apparatus for quantum analog-digital conversion. In one aspect, a method includes obtaining a quantum analog signal; applying a hybrid analog-digital encoding operation to the quantum analog signal and a qudit in an initial state to obtain an evolved state of the qudit, wherein the hybrid analog-digital encoding operation is based on a swap operation comprising multiple adder operations; and providing the qudit in the evolved state as a quantum digital encoding of the quantum analog signal.