Work

Quantum computing and quantum optics with recoiled free electrons

Year: 2026

Type: article

Abstract: Coherent interactions between free electrons and optical fields offer a promising route to quantum control, nonclassical state generation, and programmable quantum dynamics. At kiloelectron-volt electron energies, the emission or absorption of optical photons produces appreciable quantum recoil, resolving the electron into a discrete and controllable energy ladder. Starting from relativistic quantum electrodynamics, we derive an exact recoil-resolved interaction Hamiltonian in a traveling-wave picture. The resulting recoil ladder forms a high-dimensional qudit with programmable couplings and sufficient controllability for universal quantum computation. We demonstrate its use for analog quantum simulation, including one-dimensional curved-spacetime models and synthetic black-hole horizons, as well as for quantum information processing, where multiple logical qubits and high-fidelity gates can be realized within a single electron. In parallel, the same recoil-enabled dynamics allow the controlled creation of complex hybrid electron-photon states, in which engineered ladder transitions imprint nonclassical correlations and structure onto the emitted light. Together, these results establish recoiled free electrons as a versatile platform bridging quantum optics, quantum control, Hamiltonian engineering, quantum simulation, and quantum information processing.

Source: Physical Review Research

DOI: 10.1103/4rv2-8jxw

Authors: Maxim Sirotin, Andrei Rasputnyi, Tomáš Chlouba, Roy Shiloh, Peter Hommelhoff