Unraveling fractionalized excitations with time-dependent ARPES in quantum gas microscopes

One of the most illusive features of the cuprates is the missing spectral weight of electrons measured in angle-resolved-photoemission spectroscopy (ARPES) beyond the so-called Fermi arcs. It has been proposed that a fractionalization of the electron into spinon and chargon might explain this phenomenon by a formation of a spinon Fermi sea, indicative of a quantum spin liquid. However, evidence for this conjecture remains scarce. Here, we propose to directly transfer spectral weight of spinons to states which are unoccupied in the ground state by strong magnetic field gradient pulses. We demonstrate our protocol in a one-dimensional t-J model, where we show that the whole spinon dispersion can be imaged by time-dependent ARPES after applying the gradient. Long-lived coherent oscillations are visible in the spectrum, which we explain by beyond mean-field interactions between spinons. Moving to the two-dimensional tJ model relevant for the cuprates, we recover spectral weight at low frequencies in two spatial dimensions, indicating that our protocol might lead to a more complete understanding of Fermi arcs. As our protocol is challenging to achieve in the solid state, we show how to implement time dependent ARPES in quantum gas microscopes, opening up the possibility to directly compare pump-probe experiments on cuprates and quantum simulators of the Hubbard model. Our work paves the way to studying emergent fractionalized excitations via non-equilibrium probes in quantum gas microscopes.