PEE threads and bit-threads in BTZ black brane and finite-cutoff AdS$_3$

Abstract: We develop PEE thread flows for the planar BTZ black brane and finite-cutoff holography. Exact geodesic-distance kernels define source-resolved PEE thread currents whose superposition gives divergenceless bit-thread fields. In BTZ, boundary-boundary and boundary-horizon sectors reproduce the entanglement contour and thermal horizon flux. At finite cutoff, the two-point PEE kernels are smooth and select macroscopic flows that are generically non-geodesic despite being built from geodesic elementary threads. We compare these PEE-selected flows with independent normal-geodesic bit-thread flows and show that they saturate the same RT bottleneck while differing in boundary calibration, endpoint pairing and off-bottleneck structure. The resulting constructions make explicit both the endpoint organization of finite-cutoff entanglement and the nonuniqueness of holographic max flows.