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We present a general procedure for constructing lattices of qubits with a Hamiltonian composed of nearest-neighbour two-body interactions such that the ground state encodes a cluster state. We give specific details for lattices in one-,…

Quantum Physics · Physics 2009-01-06 Tom Griffin , Stephen D. Bartlett

Generating large, non-trivial quantum chemistry test problems with known ground-state solutions remains a core challenge for benchmarking electronic structure methods. Inspired by planted-solution techniques from combinatorial optimization,…

Quantum Physics · Physics 2025-09-23 Linjun Wang , Joshua T. Cantin , Smik Patel , Ignacio Loaiza , Rick Huang , Artur F. Izmaylov

Based on a result by Yarotsky (J. Stat. Phys. 118, 2005), we prove that localized but otherwise arbitrary perturbations of weakly interacting quantum spin systems with uniformly gapped on-site terms change the ground state of such a system…

Mathematical Physics · Physics 2022-03-04 Joscha Henheik , Stefan Teufel , Tom Wessel

In this work we show that the simple Hamiltonians used in Quantum Graphity models are highly degenerate, having multiple ground states that are not lattices. In order to assess the distance of the resulting graphs from a lattice graph, we…

Statistical Mechanics · Physics 2018-08-20 Yoav Spector , Moshe Schwartz

Computing many-body ground state energies and resolving electronic structure calculations are fundamental problems for fields such as quantum chemistry or condensed matter. Several quantum computing algorithms that address these problems…

Quantum Physics · Physics 2023-01-12 Karen J. Morenz Korol , Kenny Choo , Antonio Mezzacapo

Quantum PCP conjecture is one of the most influential open problems in quantum complexity theory, which states that approximating the ground state energy for a sparse local Hamiltonian upto a constant is QMA-complete. However, even though…

Quantum Physics · Physics 2025-02-24 Kartik Anand

We show that in two spatial dimensions, when a quantum state has entanglement entropy obeying a strict area law, meaning $S(A)=\alpha |\partial A| - \gamma$ for constants $\alpha, \gamma$ independent of lattice region $A$, then it admits a…

Quantum Physics · Physics 2024-04-10 Isaac H. Kim , Ting-Chun Lin , Daniel Ranard , Bowen Shi

Multipartite quantum states saturating the Heisenberg limit of sensitivity typically require full-body correlators to be prepared. On the other hand, experimentally practical Hamiltonians often involve few-body correlators only. Here, we…

Quantum Physics · Physics 2025-12-03 Majid Hassani , Mengyao Hu , Guillem Müller-Rigat , Matteo Fadel , Jordi Tura

It is known that three fundamental questions regarding local Hamiltonians -- approximating the ground state energy (the Local Hamiltonian problem), simulating local measurements on the ground space (APX-SIM), and deciding if the low energy…

Quantum Physics · Physics 2024-09-02 James D. Watson , Johannes Bausch , Sevag Gharibian

Open quantum systems evolving according to discrete-time dynamics are capable, unlike continuous-time counterparts, to converge to a stable equilibrium in finite time with zero error. We consider dissipative quantum circuits consisting of…

Quantum Physics · Physics 2017-07-11 Peter D. Johnson , Francesco Ticozzi , Lorenza Viola

Entanglement is central to our understanding of many-body quantum matter. In particular, the entanglement spectrum, as eigenvalues of the reduced density matrix of a subsystem, provides a unique footprint of properties of strongly…

Strongly Correlated Electrons · Physics 2018-06-18 Marcello Dalmonte , Benoît Vermersch , Peter Zoller

We show that the subregion entanglement Hamiltonians of excited eigenstates of a quantum many-body system are approximately linear combinations of subregionally (quasi)local approximate conserved quantities, with relative commutation errors…

Statistical Mechanics · Physics 2022-01-07 Biao Lian

We present a quantum-classical hybrid random power method that approximates a ground state of a Hamiltonian. The quantum part of our method computes a fixed number of elements of a Hamiltonian-matrix polynomial via quantum polynomial…

Quantum Physics · Physics 2025-04-17 Taehee Ko , Hyowon Park , Sangkook Choi

An important problem in quantum information theory is to understand what makes entangled quantum systems non-local or hard to simulate efficiently. In this work we consider situations in which various parties have access to a restricted set…

Quantum Physics · Physics 2014-12-19 Hussain Anwar , Sania Jevtic , Oliver Rudolph , Shashank Virmani

Quantum Mechanical ground states of many-body systems can be important resources for various investigations: for quantum sensing, as the initial state for nonequilibrium quantum dynamics following quenches, and the simulation of quantum…

Quantum Physics · Physics 2025-11-18 Prashasti Tiwari , Dylan Lewis , Sougato Bose

We generalize the proof of stability of topological order, due to Bravyi, Hastings and Michalakis, to stabilizer Hamiltonians corresponding to low-density parity check (LDPC) codes without the restriction of geometric locality in Euclidean…

Quantum Physics · Physics 2026-02-05 Wojciech De Roeck , Vedika Khemani , Yaodong Li , Nicholas O'Dea , Tibor Rakovszky

We consider a quantum particle constrained to a curved layer of a constant width built over an infinite smooth surface. We suppose that the latter is a locally deformed plane and that the layer has the hard-wall boundary. Under this…

Quantum Physics · Physics 2020-01-30 P. Duclos , P. Exner , D. Krejcirik

The area law for entanglement entropy fundamentally reflects the complexity of quantum many-body systems, demonstrating ground states of local Hamiltonians to be represented with low computational complexity. While this principle is…

Quantum Physics · Physics 2025-02-21 Donghoon Kim , Tomotaka Kuwahara

Finding ground states of quantum many-body systems is known to be hard for both classical and quantum computers. As a result, when Nature cools a quantum system in a low-temperature thermal bath, the ground state cannot always be found…

Quantum Physics · Physics 2023-09-29 Chi-Fang Chen , Hsin-Yuan Huang , John Preskill , Leo Zhou

Topological phases are characterized by their entanglement properties, which is manifest in a direct relation between entanglement spectra and edge states discovered by Li and Haldane. We propose to leverage the power of synthetic quantum…

Quantum Gases · Physics 2022-05-04 Torsten V. Zache , Christian Kokail , Bhuvanesh Sundar , Peter Zoller