Imprinting the quantum statistics of photons on free electrons

Abstract

The fundamental interaction between free electrons and light stands at the base of both classical and quantum physics, with applications in free-electron acceleration, radiation sources, and electron microscopy. Yet, to this day, all experiments involving free-electron light interactions are fully explained by describing the light as a classical wave, disregarding its quantum nature. Here, we observe quantum statistics effects of photons on free-electron-light interactions. We demonstrate interactions passing continuously from Poissonian to super-Poissonian and up to thermal statistics, unveiling a surprising manifestation of Bohr's Correspondence Principle: the transition from quantum walk to classical random walk on the free-electron energy ladder. The electron walker serves as the probe in non-destructive quantum detection, measuring the photon-correlation $g^{(2)}(0)$ and higher-orders $g^{(n)}(0)$. Unlike conventional quantum-optical detectors, the electron can perform both quantum weak measurements and projective measurements by evolving into an entangled joint-state with the photons. Our findings suggest free-electron-based non-destructive quantum tomography of light, and constitute an important step towards combined attosecond-temporal and sub-A-spatial resolution microscopy.

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• Advances in ultrafast plasmonics
• Quantum-coherent light-electron interaction in an SEM
• Observation of 2D Cherenkov radiation
• Creation of Optical Cat and GKP States Using Shaped Free Electrons
• Free Electrons Can Induce Entanglement Between Photons
• Phase-locked photon-electron interaction without a laser
• Creating large Fock states and massively squeezed states in optics using systems with nonlinear bound states in the continuum
• Compton Scattering Driven by Quantum Light
• Boosting the efficiency of Smith-Purcell radiators using nanophotonic inverse design
• Inelastic Electron Scattering at a Single-Beam Structured Light Wave
• Imaging the field inside nanophotonic devices
• Self-trapping of slow electrons in the energy domain
• Single-electron Nano-chip Free-electron Laser
• Superradiant Electron Energy Loss Spectroscopy
• Double-superradiant cathodoluminescence
• Wave manipulation via delay-engineered periodic potentials
• Quantum state features of the FEL radiation from the occupation number statistics