Initialization-controlled fault sensitivity and force-balance plateaus in noisy variational quantum optimization

arXiv:2611.04198v1 Announce Type: new Abstract: We study deep variational circuits for a periodic Heisenberg chain under local gate depolarization, at depths where noiseless training is coherently exact. Full-width initializations reach low coherent error faster than circuits with confined transverse generators, but incur a larger noise shift and need an order of magnitude more updates for noisy convergence. In many-body-localization-inspired initialization, bounding the initial transverse generator amplitudes keeps the operator support localized and suffices for low-fragility optimization, so longitudinal disorder and Floquet layer repetition are unnecessary.