Constructing quantum many-body scar Hamiltonians from Floquet automata

Understand

We provide a systematic approach for constructing approximate quantum many-body scars (QMBS) starting from two-layer Floquet automaton circuits that exhibit trivial many-body revivals.

• We do so by applying successively more restrictions that force local gates of the automaton circuit to commute concomitantly more accurately when acting on select scar states.
• With these rules in place, an effective local, Floquet Hamiltonian is seen to capture dynamics of the automaton over a long prethermal window.
• We provide numerical evidence for such a picture and use our construction to derive several QMBS models, including the celebrated PXP model.