6 papers
Mobility edges in pseudo-unitary quasiperiodic quantum walks
Christopher Cedzich, Jake Fillman
We introduce a Floquet quasicrystal that simulates the motion of Bloch electrons in a homogeneous magnetic field in discrete time steps. We admit the hopping to be non-reciprocal w…
Absence of ballistic motion and presence of almost-ballistic motion for unitary operators with pure point spectrum
Christopher Cedzich, Jake Fillman, Luis Velázquez
We adapt two results of Simon and collaborators to the setting of discrete-time unitary dynamics. We show that pure point spectrum precludes ballistic motion, and exhibit a family…
Exponential Suppression of Transport in Electric Quantum Walks
Houssam Abdul-Rahman, Christopher Cedzich, Günter Stolz +1
We establish exact scalings for the maximal group velocity of translation-invariant quantum walks in periodic electric fields. Our main result shows that the maximal group velocity…
Observation of Metal-Insulator and Spectral Phase Transitions in Aubry-André-Harper Models
Quan Lin, Christopher Cedzich, Qi Zhou +1
Non-Hermitian extensions of the Aubry-André-Harper (AAH) model reveal a rich variety of phase transitions arising from the interplay of quasiperiodicity and non-Hermiticity. Despi…
Twenty dry Martinis for the Unitary Almost Mathieu Operator
Christopher Cedzich, Long Li
We solve the Dry Ten Martini Problem for the unitary almost Mathieu operator with Diophantine frequencies in the non-critical regime.
Absence of Bound States for Quantum Walks and CMV Matrices via Reflections
Christopher Cedzich, Jake Fillman
We give a criterion based on reflection symmetries in the spirit of Jitomirskaya--Simon to show absence of point spectrum for (split-step) quantum walks and Cantero--Moral--Velázq…