Controlling the Growth and Collapse of Multielectron Bubbles in Liquid Helium by Engineering the Convective Flow

Vapor-filled multielectron bubbles (MEBs) in liquid helium offer an ideal system for studying two-dimensional electron systems in a curved geometry. In the normal state of the liquid, the bubbles can contain a substantial amount of helium vapor alongside electrons, which in turn affects the surface electron densities. In this work, we experimentally demonstrate control over both the growth and collapse of vapor-filled MEBs in liquid helium-4 by engineering the convective fluid flow within the experimental cell. We believe this simple technique can facilitate tuning the electron density, and thus, future studies on electron phases inside MEBs.