Preprint: Realization of a Fractional Topological Phase in a Fully Unitary, Noninteracting Discrete-Time Quantum Walk

A new preprint reports the first realization of a fractional topological phase in a fully unitary, noninteracting discrete-time quantum walk implemented on finite cyclic graphs. This protocol, utilizing a single-coin split-step cyclic quantum walk, reveals topological phenomena previously inaccessible in conventional cyclic quantum-walk dynamics and enables controlled engineering of quasienergy spectra, flat bands, and topological phase transitions. (Note: This is a preliminary finding and has not yet been peer-reviewed.)