@article{BurrellEisertOsborne2009,
  author    = {Burrell, Christian K. and Eisert, Jens and Osborne, Tobias J.},
  title     = {Information propagation through quantum chains with fluctuating disorder},
  issn      = {1050-2947},
  doi       = {10.1103/Physreva.80.052319},
  year      = {2009},
  abstract  = {We investigate the propagation of information through one-dimensional nearest-neighbor interacting quantum spin chains in the presence of external fields which fluctuate independently on each site. We study two fundamentally different models: (i) a model with general nearest-neighbor interactions in a field which fluctuates in both strength and direction and (ii) the XX chain placed in a fluctuating field aligned in the z direction. In both cases we find that information propagation is suppressed in a way which is quite different from the suppression observed when the XX model is placed in a statically disordered field.},
  language  = {en}
}
@article{deBeaudrapOhligerOsborneetal.2010,
  author    = {de Beaudrap, Niel and Ohliger, Matthias and Osborne, Tobias J. and Eisert, Jens},
  title     = {Solving frustration-free spin systems},
  issn      = {0031-9007},
  doi       = {10.1103/Physrevlett.105.060504},
  year      = {2010},
  abstract  = {We identify a large class of quantum many-body systems that can be solved exactly: natural frustration-free spin-1/2 nearest-neighbor Hamiltonians on arbitrary lattices. We show that the entire ground-state manifold of such models can be found exactly by a tensor network of isometries acting on a space locally isomorphic to the symmetric subspace. Thus, for this wide class of models, real-space renormalization can be made exact. Our findings also imply that every such frustration-free spin model satisfies an area law for the entanglement entropy of the ground state, establishing a novel large class of models for which an area law is known. Finally, we show that our approach gives rise to an ansatz class useful for the simulation of almost frustration-free models in a simple fashion, outperforming mean- field theory.},
  language  = {en}
}
@article{deBeaudrapOsborneEisert2010,
  author    = {de Beaudrap, Niel and Osborne, Tobias J. and Eisert, Jens},
  title     = {Ground states of unfrustrated spin Hamiltonians satisfy an area law},
  issn      = {1367-2630},
  doi       = {10.1088/1367-2630/12/9/095007},
  year      = {2010},
  abstract  = {We show that ground states of unfrustrated quantum spin-1/2 systems on general lattices satisfy an entanglement area law, provided that the Hamiltonian can be decomposed into nearest-neighbor interaction terms that have entangled excited states. The ground state manifold can be efficiently described as the image of a low-dimensional subspace of low Schmidt measure, under an efficiently contractible tree-tensor network. This structure gives rise to the possibility of efficiently simulating the complete ground space (which is in general degenerate). We briefly discuss 'non- generic' cases, including highly degenerate interactions with product eigenbases, using a relationship to percolation theory. We finally assess the possibility of using such tree tensor networks to simulate almost frustration- free spin models.},
  language  = {en}
}
@article{SchuchHarrisonOsborneetal.2011,
  author    = {Schuch, Norbert and Harrison, Sarah K. and Osborne, Tobias J. and Eisert, Jens},
  title     = {Information propagation for interacting-particle systems},
  series = {Physical review : A, Atomic, molecular, and optical physics},
  volume    = {84},
  journal   = {Physical review : A, Atomic, molecular, and optical physics},
  number    = {3},
  publisher = {American Physical Society},
  address   = {College Park},
  issn      = {1050-2947},
  doi       = {10.1103/PhysRevA.84.032309},
  pages     = {5},
  year      = {2011},
  abstract  = {We study the speed at which information propagates through systems of interacting quantum particles moving on a regular lattice and show that for a certain class of initial conditions there exists a maximum speed of sound at which information can propagate. Our argument applies equally to quantum spins, bosons such as in the Bose-Hubbard model, fermions, anyons, and general mixtures thereof, on arbitrary lattices of any dimension. It also pertains to dissipative dynamics on the lattice, and generalizes to the continuum for quantum fields. Our result can be seen as an analog of the Lieb-Robinson bound for strongly correlated models.},
  language  = {en}
}