  The LUX-ZEPLIN (LZ) experiment is a dark matter detector centered on a
dual-phase xenon time projection chamber. We report searches for new physics
appearing through few-keV-scale electron recoils, using the experiment's first
exposure of 60 live days and a fiducial mass of 5.5t. The data are found to be
consistent with a background-only hypothesis, and limits are set on models for
new physics including solar axion electron coupling, solar neutrino magnetic
moment and millicharge, and electron couplings to galactic axion-like particles
and hidden photons. Similar limits are set on weakly interacting massive
particle (WIMP) dark matter producing signals through ionized atomic states
from the Migdal effect.
