Extreme many-body scarring in a quantum spin chain via weak dynamical constraints

Abstract

It has recently been established that quantum many-body scarring can prevent the thermalisation of some isolated quantum systems, starting from certain initial states. One of the first models to show this was the so-called PXP Hamiltonian, which was used to theoretically model an experiment on a chain of strongly interacting Rydberg atoms. A defining feature of the PXP Hamiltonian is a set of dynamical constraints that make certain states inaccessible to the dynamics. In this paper we construct a class of spin chain models that are parameterised by a discrete variable $\ell$ that controls the "strength" of a dynamical constraint. We show that by increasing $\ell$ the constraint becomes weaker, in the sense that fewer states are excluded from the dynamics. The PXP Hamiltonian is special case for $\ell =2$. By weakening the constraint to $\ell \ge 4$, however, we find a more extreme version of quantum scarring than in the PXP Hamiltonian, with the number of scar states growing exponentially in the system size.

6 + 3 pages

References in corpus (6)

• Probing many-body dynamics on a 51-atom quantum simulator
• Localization of interacting fermions at high temperature
• Many-body localization edge in the random-field Heisenberg chain
• Testing whether all eigenstates obey the Eigenstate Thermalization Hypothesis
• Emergent SU(2) dynamics and perfect quantum many-body scars
• Eigenstate thermalization hypothesis (ETH) and integrability in quantum spin chains