@article {2671, title = {Quench Dynamics of a Fermi Gas with Strong Long-Range Interactions}, journal = {Phys. Rev. X}, volume = {11}, year = {2021}, month = {5/24/2021}, abstract = {

We induce strong non-local interactions in a 2D Fermi gas in an optical lattice using Rydberg dressing. The system is approximately described by a t\−V model on a square lattice where the fermions experience isotropic nearest-neighbor interactions and are free to hop only along one direction. We measure the interactions using many-body Ramsey interferometry and study the lifetime of the gas in the presence of tunneling, finding that tunneling does not reduce the lifetime. To probe the interplay of non-local interactions with tunneling, we investigate the short-time relaxation dynamics of charge density waves in the gas. We find that strong nearest-neighbor interactions slow down the relaxation. Our work opens the door for quantum simulations of systems with strong non-local interactions such as extended Fermi-Hubbard models.

}, doi = {https://doi.org/10.1103/PhysRevX.11.021036}, url = {https://arxiv.org/abs/2010.05871}, author = {Elmer Guardado-Sanchez and Benjamin M. Spar and Peter Schauss and Ron Belyansky and Jeremy T. Young and Przemyslaw Bienias and Alexey V. Gorshkov and Thomas Iadecola and Waseem S. Bakr} } @article {2808, title = {Rainbow Scars: From Area to Volume Law}, year = {2021}, month = {7/12/2021}, abstract = {

Quantum many-body scars (QMBS) constitute a new quantum dynamical regime in which rare \"scarred\" eigenstates mediate weak ergodicity breaking. One open question is to understand the most general setting in which these states arise. In this work, we develop a generic construction that embeds a new class of QMBS, rainbow scars, into the spectrum of an arbitrary Hamiltonian. Unlike other examples of QMBS, rainbow scars display extensive bipartite entanglement entropy while retaining a simple entanglement structure. Specifically, the entanglement scaling is volume-law for a random bipartition, while scaling for a fine-tuned bipartition is sub-extensive. When internal symmetries are present, the construction leads to multiple, and even towers of rainbow scars revealed through distinctive non-thermal dynamics. To this end, we provide an experimental road map for realizing rainbow scar states in a Rydberg-atom quantum simulator, leading to coherent oscillations distinct from the strictly sub-volume-law QMBS previously realized in the same system.\ 

}, url = {https://arxiv.org/abs/2107.03416}, author = {Christopher M. Langlett and Zhi-Cheng Yang and Julia Wildeboer and Alexey V. Gorshkov and Thomas Iadecola and Shenglong Xu} } @article {2498, title = {Hilbert-Space Fragmentation from Strict Confinement}, journal = {Phys. Rev. Lett.}, volume = {124}, year = {2020}, month = {5/22/2020}, abstract = {

We study one-dimensional spin-1/2 models in which strict confinement of Ising domain walls leads to the fragmentation of Hilbert space into exponentially many disconnected subspaces. Whereas most of the previous works emphasize dipole moment conservation as an essential ingredient for such fragmentation, we instead require two commuting U(1) conserved quantities associated with the total domain-wall number and the total magnetization. The latter arises naturally from the confinement of domain walls. Remarkably, while some connected components of the Hilbert space thermalize, others are integrable by Bethe ansatz. We further demonstrate how this Hilbert-space fragmentation pattern arises perturbatively in the confining limit of Z2 gauge theory coupled to fermionic matter, leading to a hierarchy of time scales for motion of the fermions. This model can be realized experimentally in two complementary settings.

}, doi = {https://doi.org/10.1103/PhysRevLett.124.207602}, url = {https://arxiv.org/abs/1912.04300}, author = {Zhi-Cheng Yang and Fangli Liu and Alexey V. Gorshkov and Thomas Iadecola} } @article {2720, title = {Localization and criticality in antiblockaded 2D Rydberg atom arrays}, year = {2020}, month = {12/7/2020}, abstract = {

Controllable Rydberg atom arrays have provided new insights into fundamental properties of quantum matter both in and out of equilibrium. In this work, we study the effect of experimentally relevant positional disorder on Rydberg atoms trapped in a 2D square lattice under anti-blockade (facilitation) conditions. We show that the facilitation conditions lead the connectivity graph of a particular subspace of the full Hilbert space to form a 2D Lieb lattice, which features a singular flat band. Remarkably, we find three distinct regimes as the disorder strength is varied: a critical regime, a delocalized but nonergodic regime, and a regime with a disorder-induced flat band. The critical regime\&$\#$39;s existence depends crucially upon the singular flat band in our model, and is absent in any 1D array or ladder system. We propose to use quench dynamics to probe the three different regimes experimentally.\ 

}, url = {https://arxiv.org/abs/2012.03946}, author = {Fangli Liu and Zhi-Cheng Yang and Przemyslaw Bienias and Thomas Iadecola and Alexey V. Gorshkov} }