Fault-Tolerant Photonic Quantum Computing via Time-Reflection Dynamics

Abstract I introduce time-reflection photonic quantum computing, an architecture in which qubits are encoded in pairs of counterpropagating photonic modes that evolve along dual temporal channels. By engineering gates that implement time reflections between these channels, the dynamics become intrinsically reversible, causing dominant error processes—dephasing, photon loss, and phase noise—to be continuously unwound and rephased without external feedback or active errorcorrection cycles. This builtin selfcorrection enables ultralowenergy quantum information processing at room temperature and substantially reduces hardware complexity compared with superconducting or trappedion platforms. My analytical modeling and numerical simulations show that timereflection circuits preserve coherence over large depths, maintain high fidelities in the presence of realistic noise, and support the implementation of a universal gate set using photonic resources. These results establish timereflection photonic architectures as a promising, energyefficient route toward scalable quantum information processing.