What makes a nanoscale device vibrate without any external push?

Apply a static voltage to a nanoscale mechanical device and, under the right conditions, it spontaneously starts vibrating on its own — no periodic drive needed. Pinning down exactly when and why this happens has been computationally brutal because the physics involves large quantum state spaces, strong interactions, and complicated electrodes all at once. This work builds a tensor-network method that sidesteps the usual bottlenecks, mapping out the full landscape of these self-oscillations and revealing a tell-tale spike in vibration fluctuations that reliably precedes the quiet, stable oscillation regime.