Helium Overview

Revision note (September 5, 2026): A simulator energy-accounting error was found and corrected and the He-4 configuration was rerun with explicit metrics (see Nuclear Structure Validation, Section 0). The configuration at 5.27 fm is stable and bound with true energy conserved to numerical precision, but its dynamical state is a 1:1 tidal lock with \(\pm 35^\circ\) libration, not a 1:2 resonance: the 18.6 THz inner rotation set by the initial conditions converts to libration within 0.1 ps. Measured frequencies: orbit 9.27 THz, libration 11.8 THz, inner-separation breathing 145.8 THz. On this page, read "18.6 THz inner rotation" as the second harmonic of the 9.27 THz orbital frequency (all harmonic arithmetic is unchanged: \(320 \times 18.6 = 640 \times 9.3\) THz) and "1:2 resonance" as the initial configuration whose dynamical state is the tidal lock. Claims that 5.27 fm is "optimal" or that 2:1 has the "best energy conservation" are withdrawn (the ranking metric was the accounting artifact); 5.27 fm is the widest locked configuration and the one whose orbital frequency matches the ionization harmonic. Arguments that use 18.6 THz as a physical rotation rate (gyroscopic resistance, rotation energy \(h \times 18.6\) THz) should be re-read with the measured frequencies; energy-scale conclusions (\(hf \gg k_B T\)) are unchanged or strengthened, since the breathing mode is far higher.