Coulomb-correlated electron number states in a transmission electron microscope beam

We demonstrate the generation of Coulomb-correlated pair, triple and quadruple states free electrons by femtosecond photoemission from a nanoscale field emitter inside transmission electron microscope. Event-based spectroscopy allows spatial spectral characterization ensemble emitted each laser pulse. identify distinctive energy momentum correlations arising acceleration-enhanced interparticle exchange, revealing strong few-body Coulomb interactions at an scale about two electronvolts. State-sorted beam caustics show discrete increase in virtual source size longitudinal shift for few-electron states, associated with transverse correlations. observe field-controllable antibunching, attributed primarily to deflection. The pronounced characteristics these number allow filtering schemes that control statistical distribution pulse charge. In this way, fraction specific can be actively suppressed or enhanced, facilitating preparation highly non-Poissonian beams microscopy lithography, including future heralding correlated multi-electron probing.