INQNET Pizza Seminar

Speaker: Dr Xiang Cheng

Time: 12:30pm Pacific
Place: in the Downs-Lauritsen 257
Zoom: https://caltech.zoom.us/j/81370143470

Title: High-dimensional entanglement and chip-scale quantum information processing
Abstract: Towards building a quantum internet, quantum systems with high dimensions and multiple degrees of freedom are sought to improve the channel capacity between quantum nodes and enable fault-tolerant quantum computing. Biphoton frequency comb, with naturally multimode characteristics, enables entanglement generation in large dimensions both in frequency and time domain. Consequently, large-alphabet encoding can be explored in its spectro-temporal quantum modes. A biphoton frequency comb with high-dimensional time-frequency entanglement can be generated by passing spontaneous parametric downconversion photons through a cavity, verified with up to 648 dimensionalities in time-frequency/polarization spaces, as a fundamental resource for dense secure information processing. A singly-filtered scheme is proposed to improve the distribution rate of the high-dimensional entangled state with proof-of-principle QKD demonstration. A polarization-spatial-momentum quantum SWAP gate on silicon-on-insulator platform is demonstrated with high-fidelity and quantum coherence preservation. Such on-chip gate serves as an ideal quantum interface to bridge two degrees of freedom to construct a quantum photonic interconnect between chip-scale subsystems. Our efforts aim to construct a high-rate quantum internet exploiting the quantum nature of high dimensions and multiple degrees of freedom of the photonic systems.