@article { ISI:000510146100001,
title = {Quantum many-body scar states with emergent kinetic constraints and finite-entanglement revivals},
journal = {Phys. Rev. B},
volume = {101},
number = {2},
year = {2020},
month = {JAN 29},
pages = {024306},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {We construct a set of exact, highly excited eigenstates for a nonintegrable spin-1/2 model in one dimension that is relevant to experiments on Rydberg atoms in the antiblockade regime. These states provide a new solvable example of quantum many-body scars: their sub-volume-law entanglement and equal energy spacing allow for infinitely long-lived coherent oscillations of local observables following a suitable quantum quench. While previous works on scars have interpreted such oscillations in terms of the precession of an emergent macroscopic SU(2) spin, the present model evades this description due to a set of emergent kinetic constraints in the scarred eigenstates that are absent in the underlying Hamiltonian. We also analyze the set of initial states that give rise to periodic revivals, which persist as approximate revivals on a finite timescale when the underlying model is perturbed. Remarkably, a subset of these initial states coincides with the family of area-law entangled Rokhsar-Kivelson states shown by Lesanovsky to be exact ground states for a class of models relevant to experiments on Rydberg-blockaded atomic lattices.},
issn = {2469-9950},
doi = {10.1103/PhysRevB.101.024306},
author = {Iadecola, Thomas and Schecter, Michael}
}
@article {ISI:000467378000002,
title = {Interplay between magnetic and vestigial nematic orders in the layered J(1)-J(2) classical Heisenberg model},
journal = {Phys. Rev. B},
volume = {99},
number = {17},
year = {2019},
month = {MAY 6},
pages = {174404},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {We study the layered J(1)-J(2) classical Heisenberg model on the square lattice using a self-consistent bond theory. We derive the phase diagram for fixed J(1) as a function of temperature T, J(2), and interplane coupling J(z). Broad regions of (anti)ferromagnetic and stripe order are found, and are separated by a first-order transition near J(2) approximate to 0.5 (in units of vertical bar J(1)vertical bar). Within the stripe phase the magnetic and vestigial nematic transitions occur simultaneously in first-order fashion for strong J(z). For weaker J(z), there is in addition, for J(2){*} < J(2) < J(2){*}{*}, an intermediate regime of split transitions implying a finite temperature region with nematic order but no long-range stripe magnetic order. In this split regime, the order of the transitions depends sensitively on the deviation from J(2){*} and J(2){*}{*}, with split second-order transitions predominating for J(2){*} << J(2) << J(2){*}{*}. We find that the value of J(2){*} depends weakly on the interplane coupling and is just slightly larger than 0.5 for vertical bar J(z)vertical bar less than or similar to 0.01. In contrast, the value of J(2){*}{*} increases quickly from J(2){*} at vertical bar J(z)vertical bar less than or similar to 0.01 as the interplane coupling is further reduced. In addition, the magnetic correlation length is shown to directly depend on the nematic order parameter and thus exhibits a sharp increase (or jump) upon entering the nematic phase. Our results are broadly consistent with the predictions based on itinerant electron models of the iron-based superconductors in the normal state and, thus, help substantiate a classical spin framework for providing a phenomenological description of their magnetic properties.},
issn = {2469-9950},
doi = {10.1103/PhysRevB.99.174404},
author = {Syljuasen, Olav F. and Paaske, Jens and Schecter, Michael}
}
@article { ISI:000498849400002,
title = {Quantum many-body scars from magnon condensation},
journal = {Phys. Rev. B},
volume = {100},
number = {18},
year = {2019},
month = {NOV 27},
pages = {184312},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {We study the eigenstate properties of a nonintegrable spin chain that was recently realized experimentally in a Rydberg-atom quantum simulator. In the experiment, long-lived coherent many-body oscillations were observed only when the system was initialized in a particular product state. This pronounced coherence has been attributed to the presence of special {\textquoteleft}{\textquoteleft}scarred{{\textquoteright}{\textquoteright}} eigenstates with nearly equally spaced energies and putative nonergodic properties despite their finite energy density. In this paper we uncover a surprising connection between these scarred eigenstates and low-lying quasiparticle excitations of the spin chain. In particular, we show that these eigenstates can be accurately captured by a set of variational states containing a macroscopic number of magnons with momentum pi. This leads to an interpretation of the scarred eigenstates as finite-energy-density condensates of weakly interacting pi magnons. One natural consequence of this interpretation is that the scarred eigenstates possess long-range connected correlations in both space and time. We verify numerically the presence of this spatiotemporal long-range order and explain how it is consistent with established no-go theorems precluding its existence in ground states and at thermal equilibrium.},
issn = {2469-9950},
doi = {10.1103/PhysRevB.100.184312},
author = {Iadecola, Thomas and Schecter, Michael and Xu, Shenglong}
}
@article { ISI:000488514800006,
title = {Weak Ergodicity Breaking and Quantum Many-Body Scars in Spin-1 XY Magnets},
journal = {Phys. Rev. Lett.},
volume = {123},
number = {14},
year = {2019},
month = {OCT 1},
pages = {147201},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {We study the spin-1 XY model on a hypercubic lattice in d dimensions and show that this well-known nonintegrable model hosts an extensive set of anomalous finite-energy-density eigenstates with remarkable properties. Namely, they exhibit subextensive entanglement entropy and spatiotemporal long-range order, both believed to be impossible in typical highly excited eigenstates of nonintegrable quantum many-body systems. While generic initial states are expected to thermalize, we show analytically that the eigenstates we construct lead to weak crgodicity breaking in the form of persistent oscillations of local observablcs following certain quantum quenches-in other words, these eigenstates provide an archetypal example of so-called quantum many-body scars. This Letter opens the door to the analytical study of the microscopic origin, dynamical signatures, and stability of such phenomena.},
issn = {0031-9007},
doi = {10.1103/PhysRevLett.123.147201},
author = {Schecter, Michael and Iadecola, Thomas}
}
@article { ISI:000449292600001,
title = {Configuration-controlled many-body localization and the mobility emulsion},
journal = {PHYSICAL REVIEW B},
volume = {98},
number = {17},
year = {2018},
month = {NOV 2},
pages = {174201},
issn = {2469-9950},
doi = {10.1103/PhysRevB.98.174201},
author = {Schecter, Michael and Iadecola, Thomas and S. Das Sarma}
}
@article { ISI:000432031700004,
title = {Cooper pair induced frustration and nematicity of two-dimensional magnetic adatom lattices},
journal = {PHYSICAL REVIEW B},
volume = {97},
number = {17},
year = {2018},
month = {MAY 10},
pages = {174412},
issn = {2469-9950},
doi = {10.1103/PhysRevB.97.174412},
author = {Schecter, Michael and Syljuasen, Olav F. and Paaske, Jens}
}
@article { ISI:000439729800001,
title = {Many-body spectral reflection symmetry and protected infinite-temperature degeneracy},
journal = {PHYSICAL REVIEW B},
volume = {98},
number = {3},
year = {2018},
month = {JUL 25},
pages = {035139},
issn = {2469-9950},
doi = {10.1103/PhysRevB.98.035139},
author = {Schecter, Michael and Iadecola, Thomas}
}
@article { ISI:000447918000003,
title = {Quantum inverse freezing and mirror-glass order},
journal = {PHYSICAL REVIEW B},
volume = {98},
number = {14},
year = {2018},
month = {OCT 22},
pages = {144204},
issn = {2469-9950},
doi = {10.1103/PhysRevB.98.144204},
author = {Iadecola, Thomas and Schecter, Michael}
}