Abstract: A method includes generating a photon and establishing a time-bin frame having a period T and multiple non-overlapping time bins of duration ?t. The method includes preparing a quantum state of the photon in a time-bin basis and in at least one additional quantum degree of freedom selected from polarization, OAM, and phase, thereby forming a composite quantum state. The method includes routing the photon to a selected emission point of a three-dimensional (3D) photonic structure having multiple emission points with respective spatial coordinates. The method includes synchronizing a sender and a receiver with a shared timing reference and time-gated detection windows aligned to the time bins, and emitting the photon from the selected emission point into a quantum channel. A combination of the time-bin state encoding quantum information and an emission-point coordinate associated with a spatial symbol and/or non-secret control metadata for protocol processing forms a composite codeword.

Abstract: A method for secure quantum communication includes generating a photon. The method includes modulating at least two quantum state dimensions selected from the group consisting of orbital angular momentum (OAM), polarization, and phase of the photon to form a composite quantum state. The method includes directing the photon to an emission point on a structure having a defined spatial coordinate corresponding to classical data. The method includes emitting the photon from the emission point into a quantum channel. The composite quantum state and emission-point spatial coordinate jointly encode secure quantum information for transmission.

Abstract: A quantum computing system may include a dual-helix quantum encoding structure a multidimensional modulation controller. The dual-helix quantum encoding structure may include a first helix chain and a second helix chain. The multidimensional modulation controller may be configured to modulate quantum information in the first and second helix chains using two or more of frequency modulation, phase modulation, and amplitude modulation. The frequency, phase, and amplitude modulation may enhance information processing, storage, parallel computation, and error correction in quantum computing systems. Alternatively or additionally, embodiments herein may provide a new direction for scaling quantum computers for large-scale, complex tasks, and may offer improvements in speed, accuracy, and efficiency.

Abstract: A method for secure quantum communication includes generating a photon. The method includes modulating at least two quantum state dimensions selected from the group consisting of orbital angular momentum (OAM), polarization, and phase of the photon to form a composite quantum state. The method includes directing the photon to an emission point on a structure having a defined spatial coordinate corresponding to classical data. The method includes emitting the photon from the emission point into a quantum channel. The composite quantum state and emission-point spatial coordinate jointly encode secure quantum information for transmission.

Abstract: A method for secure quantum communication includes generating a photon. The method includes modulating at least two quantum state dimensions selected from the group consisting of orbital angular momentum (OAM), polarization, and phase of the photon to form a composite quantum state. The method includes directing the photon to an emission point on a helical structure having a defined spatial coordinate corresponding to classical data. The method includes emitting the photon from the emission point into a quantum channel. The composite quantum state and spatial coordinate together encode secure information.