Zeno physics of the Ising chain with symmetry-breaking boundary dephasing

Abstract

In few-qubit systems, the quantum Zeno effect arises when measurement occurs sufficiently frequently that the spins are unable to relax between measurements. This can compete with Hamiltonian terms, resulting in interesting relaxation processes which depend non-monotonically on the ratio of measurement rate to coherent oscillations. While Zeno physics for a single qubit is well-understood, an interesting open question is how the Zeno effect is modified by coupling the measured spin to a non-trivial bulk. In this work, we study the effect of coupling a one-dimensional transverse field Ising to a Zeno spin which lives at the boundary. We find that sharp singularities occur in the boundary relaxation dynamics, which can be tied to the emergence or destruction of edge modes that can be found analytically. Finally, we provide numerical evidence that the dynamical singularities are stable in the presence of integrability-breaking interactions.