Direct observation of the transverse near field of an edge excitation and associated slow secondary dynamics in a fractional quantum Hall state

Abstract

We report stroboscopic time-resolved photoluminescence (PL) microscopy and spectroscopy revealing the transverse near field of an edge excitation in a $ν=1/3$ fractional quantum Hall (FQH) state. Time-resolved $y$-$t$ maps reveal an immediate PL response extending more than $30~μ\mathrm{m}$ into the bulk transverse to the edge when the edge magnetoplasmon (EMP) passes the mesa boundary. The nearly instantaneous nature of this long-range response identifies it as the non-radiative, quasi-electrostatic near field, revealing the EMP as a spatially extended collective excitation rather than a strictly one-dimensional charge-density oscillation. We also observe secondary bulk-side responses distinct from the immediate transverse near-field response. The coexistence of these immediate and secondary responses shows that electrically launched edge excitations produce bulk-side dynamics on widely separated time scales.