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We investigate to what extent a suitably chosen system Hamiltonian can counteract local dissipative processes and preserve entanglement in the stationary state. The results determine prospects and limitations of dissipative state…

Quantum Physics · Physics 2014-03-27 Simeon Sauer , Clemens Gneiting , Andreas Buchleitner

We prove the existence of gapped quantum Hamiltonians whose ground states exhibit an infinite entanglement length, as opposed to their finite correlation length. Using the concept of entanglement swapping, the localizable entanglement is…

Quantum Physics · Physics 2007-05-23 F. Verstraete , M. A. Martin-Delgado , J. I. Cirac

We revisit the question of the relation between entanglement, entropy, and area for harmonic lattice Hamiltonians corresponding to discrete versions of real free Klein-Gordon fields. For the ground state of the d-dimensional cubic harmonic…

Quantum Physics · Physics 2011-01-18 M. B. Plenio , J. Eisert , J. Dreissig , M. Cramer

Motivated by the mathematical definition of entanglement we undertake a rigorous analysis of the separability and non-distillability properties in the neighborhood of those three-qubit mixed states which are entangled and completely…

Quantum Physics · Physics 2009-11-10 Roman Orus , Rolf Tarrach

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 which have entangled excited…

Quantum Physics · Physics 2015-05-20 Niel de Beaudrap , Tobias J. Osborne , Jens Eisert

To gain an advantage, quantum technologies utilize phenomena particular to quantum mechanics. Two such phenomena are squeezing and entanglement. Having generated states that exhibit these features, verification of their generation with…

Quantum Physics · Physics 2021-06-02 Russell P Rundle

Ground state preparation is classically intractable for general Hamiltonians. On quantum devices, shallow parameterized circuits can be effectively trained to obtain short-range entangled states under the paradigm of variational quantum…

Quantum Physics · Physics 2024-04-11 Hao-Kai Zhang , Shuo Liu , Shi-Xin Zhang

Entanglement between the constituents of a quantum system is an essential resource in the implementation of many quantum processes and algorithms. Indeed, universal quantum computation is possible by measuring individual qubits comprising…

Quantum Physics · Physics 2012-02-10 David L. Feder

An important task in quantum physics is the estimation of local quantities for ground states of local Hamiltonians. Recently, [Ambainis, CCC 2014] defined the complexity class P^QMA[log], and motivated its study by showing that the physical…

Quantum Physics · Physics 2020-04-09 Sevag Gharibian , Justin Yirka

In recent years, the entanglement spectra of quantum states have been identified to be highly valuable for improving our understanding on many problems in quantum physics, such as classification of topological phases, symmetry-breaking…

Quantum Physics · Physics 2019-06-04 Bin Cheng , Man-Hong Yung

A fundamental problem in quantum many-body physics is that of finding ground states of local Hamiltonians. A number of recent works gave provably efficient machine learning (ML) algorithms for learning ground states. Specifically, [Huang et…

In this thesis we present new results relevant to two important problems in quantum information science: the development of a theory of entanglement and the exploration of the use of controlled quantum systems to the simulation of quantum…

Quantum Physics · Physics 2008-10-21 Fernando G. S. L. Brandao

We investigate whether pure entangled states can be associated to a measurement basis in which all vectors are local unitary transformations of the original state. We prove that for bipartite states with a local dimension that is either $2,…

Quantum Physics · Physics 2023-08-28 Florian Pimpel , Martin J. Renner , Armin Tavakoli

Recently it was shown that the so-called guided local Hamiltonian problem -- estimating the smallest eigenvalue of a $k$-local Hamiltonian when provided with a description of a quantum state ('guiding state') that is guaranteed to have…

Quantum Physics · Physics 2024-02-08 Chris Cade , Marten Folkertsma , Jordi Weggemans

We establish a connection between ground states of local quantum Hamiltonians and thermal states of classical spin systems. For any discrete classical statistical mechanical model in any spatial dimension, we find an associated quantum…

Quantum Physics · Physics 2012-03-05 W. Dür , M. Van den Nest

We consider the problem whether graph states can be ground states of local interaction Hamiltonians. For Hamiltonians acting on n qubits that involve at most two-body interactions, we show that no n-qubit graph state can be the exact,…

Quantum Physics · Physics 2008-03-18 M. Van den Nest , K. Luttmer , W. Dür , H. J. Briegel

We consider whether or not Hamiltonians which are sums of commuting projectors have "trivial" ground states which can be constructed by a local quantum circuit of bounded depth and range acting on a product state. While the toric code only…

Quantum Physics · Physics 2013-04-16 M. B. Hastings

Projected entangled pair states (PEPS) constitute a variational family of quantum states with area-law entanglement. PEPS are particularly relevant and successful for studying ground states of spatially local Hamiltonians. However,…

Quantum Physics · Physics 2025-11-13 Dylan Harley , Freek Witteveen , Daniel Malz

Entanglement is one of the key feature of quantum world that has no classical counterpart. This arises due to the linear superposition principle and the tensor product structure of the Hilbert space when we deal with multiparticle systems.…

Quantum Physics · Physics 2011-09-14 Arun Kumar Pati

We consider the computational complexity of Hamiltonians which are sums of commuting terms acting on plaquettes in a square lattice of qubits, and we show that deciding whether the ground state minimizes the energy of each local term…

Quantum Physics · Physics 2011-09-29 Norbert Schuch