@article { ISI:000565826800008,
title = {Braiding photonic topological zero modes},
journal = {Nat. Phys.},
volume = {16},
number = {9},
year = {2020},
month = {SEP},
pages = {989+},
publisher = {NATURE PUBLISHING GROUP},
type = {Article},
abstract = {A remarkable property of quantum mechanics in two-dimensional space is its ability to support {\textquoteleft}anyons{\textquoteright}, particles that are neither fermions nor bosons. Theory predicts that these exotic excitations can exist as bound states confined near topological defects, such as Majorana zero modes trapped in vortices in topological superconductors. Intriguingly, in the simplest cases the non-trivial phase that arises when such defects are {\textquoteleft}braided{\textquoteright} around one another is not intrinsically quantum mechanical; instead, it can be viewed as a manifestation of the geometric (Pancharatnam-Berry) phase in wave mechanics, which makes possible the simulation of such phenomena in classical systems. Here, we report the experimental measurement of the geometric phase owing to such a braiding process. These measurements are obtained with an interferometer constructed from highly tunable two-dimensional arrays of photonic waveguides. Our results introduce photonic lattices as a versatile platform for the experimental study of topological defects and their braiding, and complement ongoing efforts in the study of solid-state systems and cold atomic gases. The non-zero geometric phase acquired by the braiding of vortex modes in photonic waveguide lattices demonstrates their potential to serve as a platform for the study of both Abelian and non-Abelian braiding in bosonic systems.},
issn = {1745-2473},
doi = {10.1038/s41567-020-1007-5},},
author = {Noh, Jiho and Schuster, Thomas and Iadecola, Thomas and Huang, Sheng and Wang, Mohan and Chen, Kevin P. and Chamon, Claudio and Rechtsman, Mikael C.}
}
@article { ISI:000535205600016,
title = {Hilbert-Space Fragmentation from Strict Confinement},
journal = {Phys. Rev. Lett.},
volume = {124},
number = {20},
year = {2020},
month = {MAY 22},
pages = {207602},
publisher = {AMER PHYSICAL SOC},
type = {Article},
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 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 Z(2) gauge theory coupled to fermionic matter, leading to a hierarchy of timescales for motion of the fermions. This model can be realized experimentally in two complementary settings.},
issn = {0031-9007},
doi = {10.1103/PhysRevLett.124.207602},
author = {Yang, Zhi-Cheng and Liu, Fangli and Gorshkov, V, Alexey and Iadecola, Thomas}
}
@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:000461964300002,
title = {Braiding and gapped boundaries in fracton topological phases},
journal = {Phys. Rev. B},
volume = {99},
number = {12},
year = {2019},
month = {MAR 19},
pages = {125132},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {We study gapped boundaries of Abelian type-I fracton systems in three spatial dimensions. Using the X-cube model as our motivating example, we give a conjecture, with partial proof, of the conditions for a boundary to be gapped. In order to state our conjecture, we use a precise definition of fracton braiding and show that bulk braiding of fractons has several features that make it insufficient to classify gapped boundaries. Most notable among these is that bulk braiding is sensitive to geometry and is {\textquoteleft}{\textquoteleft}nonreciprocal{{\textquoteright}{\textquoteright}}; that is, braiding an excitation a around b need not yield the same phase as braiding b around a. Instead, we define fractonic {\textquoteleft}{\textquoteleft}boundary braiding,{{\textquoteright}{\textquoteright}} which resolves these difficulties in the presence of a boundary. We then conjecture that a boundary of an Abelian fracton system is gapped if and only if a {\textquoteleft}{\textquoteleft}boundary Lagrangian subgroup{{\textquoteright}{\textquoteright}} of excitations is condensed at the boundary; this is a generalization of the condition for a gapped boundary in two spatial dimensions, but it relies on boundary braiding instead of bulk braiding. We also discuss the distinctness of gapped boundaries and transitions between different topological orders on gapped boundaries.},
issn = {2469-9950},
doi = {10.1103/PhysRevB.99.125132},
author = {Bulmash, Daniel and Iadecola, Thomas}
}
@article {ISI:000476695900010,
title = {Exact Localized and Ballistic Eigenstates in Disordered Chaotic Spin Ladders and the Fermi-Hubbard Model},
journal = {Phys. Rev. Lett.},
volume = {123},
number = {3},
year = {2019},
month = {JUL 16},
pages = {036403},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {We demonstrate the existence of exact atypical many-body eigenstates in a class of disordered, interacting one-dimensional quantum systems that includes the Fermi-Hubbard model as a special case. These atypical eigenstates, which generically have finite energy density and are exponentially many in number, are populated by noninteracting excitations. They can exhibit Anderson localization with area-law eigenstate entanglement or, surprisingly, ballistic transport at any disorder strength. These properties differ strikingly from those of typical eigenstates nearby in energy, which we show give rise to diffusive transport as expected in a chaotic quantum system. We discuss how to observe these atypical eigenstates in cold-atom experiments realizing the Fermi-Hubbard model, and comment on the robustness of their properties.},
issn = {0031-9007},
doi = {10.1103/PhysRevLett.123.036403},
author = {Iadecola, Thomas and Znidaric, Marko}
}
@article {ISI:000473018400004,
title = {Ground-state degeneracy of non-Abelian topological phases from coupled wires},
journal = {Phys. Rev. B},
volume = {99},
number = {24},
year = {2019},
month = {JUN 20},
pages = {245138},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {We construct a family of two-dimensional non-Abelian topological phases from coupled wires using a non-Abelian bosonization approach. We then demonstrate how to determine the nature of the non-Abelian topological order (in particular, the anyonic excitations and the topological degeneracy on the torus) realized in the resulting gapped phases of matter. This paper focuses on the detailed case study of a coupled-wire realization of the bosonic su(2)(2) Moore-Read state, but the approach we outline here can be extended to general bosonic su(2)(k) topological phases described by non-Abelian Chern-Simons theories. We also discuss possible generalizations of this approach to the construction of three-dimensional non-Abelian topological phases.},
issn = {2469-9950},
doi = {10.1103/PhysRevB.99.245138},
author = {Iadecola, Thomas and Neupert, Titus and Chamon, Claudio and Mudry, Christopher}
}
@article {ISI:000465163400005,
title = {Hierarchical Majoranas in a programmable nanowire network},
journal = {Phys. Rev. B},
volume = {99},
number = {15},
year = {2019},
month = {APR 19},
pages = {155138},
publisher = {AMER PHYSICAL SOC},
type = {Article},
abstract = {We propose a hierarchical architecture for building {\textquoteleft}{\textquoteleft}logical{{\textquoteright}{\textquoteright}} Majorana zero modes using {\textquoteleft}{\textquoteleft}physical{{\textquoteright}{\textquoteright}} Majorana zero modes at the Y-junctions of a hexagonal network of semiconductor nanowires. Each Y-junction contains three {\textquoteleft}{\textquoteleft}physical{{\textquoteright}{\textquoteright}} Majoranas, which hybridize when placed in close proximity, yielding a single effective Majorana mode near zero energy. The hybridization of effective Majorana modes on neighboring Y-junctions is controlled by applied gate voltages on the links of the honeycomb network. This gives rise to a tunable tight-binding model of effective Majorana modes. We show that selecting the gate voltages that generate a Kekule vortex pattern in the set of hybridization amplitudes yields an emergent {\textquoteleft}{\textquoteleft}logical{{\textquoteright}{\textquoteright}} Majorana zero mode bound to the vortex core. The position of a logical Majorana can be tuned adiabatically, without moving any of the {\textquoteleft}{\textquoteleft}physical{{\textquoteright}{\textquoteright}} Majoranas or closing any energy gaps, by programming the values of the gate voltages to change as functions of time. A nanowire network supporting multiple such {\textquoteleft}{\textquoteleft}logical{{\textquoteright}{\textquoteright}} Majorana zero modes provides a physical platform for performing adiabatic non-Abelian braiding operations in a fully controllable manner.},
issn = {2469-9950},
doi = {10.1103/PhysRevB.99.155138},
author = {Yang, Zhi-Cheng and Iadecola, Thomas and Chamon, Claudio and Mudry, Christopher}
}
@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:000433040400001,
title = {Floquet Supersymmetry},
journal = {PHYSICAL REVIEW LETTERS},
volume = {120},
number = {21},
year = {2018},
month = {MAY 24},
pages = {210603},
issn = {0031-9007},
doi = {10.1103/PhysRevLett.120.210603},
author = {Iadecola, Thomas and Hsieh, Timothy H.}
}
@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}
}