Moment-Selective Quantum Designs in Aperiodic Temporal Ensembles

Abstract

We introduce a general mechanism for engineering moment-selective temporal designs with hierarchically structured aperiodic drives. At special control settings where the driven dynamics is constrained by a finite symmetry group, lower-order moments can already reproduce Haar statistics while a selected higher-order deviation remains nonzero. A small static detuning from such a setting generically produces an exponentially long lifetime whose exponent scales inversely with the square of the detuning. We illustrate this mechanism in qubit systems through exact Fibonacci and silver-mean constructions with tetrahedral and icosahedral resonances, for which the first retained non-Haar moments occur at orders $3$ and $6$, respectively. We further show that stochastic control fluctuations produce a qualitatively different cutoff from coherent detuning. Finally, we propose a finite-time signature of the long-lived moment that can be measured without requiring observations over exponentially long times.