Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

arXiv:cond-mat/0510498 · AIP conference proceedings

From exotic phases to microscopic Hamiltonians

Roderich Moessner

Published Jan 1, 2006• 1 citation
arXivHTMLPDF

Abstract

We report recent analytical progress in the quest for spin models realising exotic phases. We focus on the question of ‘reverse‐engineering’ a local, SU(2) invariant S=1/2 Hamiltonian to exhibit phases predicted on the basis of effective models, such as large‐N or quantum dimer models. This aim is to provide a point‐of‐principle demonstration of the possibility of constructing such microscopic lattice Hamiltonians, as well as to complement and guide numerical (and experimental) approaches to the same question. In particular, we demonstrate how to utilise peturbed Klein Hamiltonians to generate effective quantum dimer models. These models use local multi‐spin interactions and, to obtain a controlled theory, a decoration procedure involving the insertion of Majumdar‐Ghosh chainlets on the bonds of the lattice. The phases we thus realise include deconfined resonating valence bond liquids, a devil’s staircase of interleaved phases which exhibits Cantor deconfinement, as well as a three‐dimensional U(1) liquid phase exhibiting photonic excitations.

DOI
10.1063/1.2178029

Related papers

SU(2)-invariant spin- 12 Hamiltonians with resonating and other valence bond phases

Kumar S. Raman, Roderich Moessner, Shivaji L. Sondhi

We construct a family of rotationally invariant, local, $S=1∕2$ Klein Hamiltonians on various lattices that exhibit ground-state manifolds spanned by nearest-neighbor valence bond states. We show that with selected perturbations such models can be driven into phases modeled by well-understood quantum dimer models on the corresponding lattices. Specifically, we show that the perturbation procedure is arbitrarily well controlled by a new parameter which is the extent of decoration of the reference lattice. This strategy leads to Hamiltonians that exhibit (i) ${Z}_{2}$ resonating valence bond (RVB) phases in two dimensions, (ii) $U(1)$ RVB phases with a gapless ``photon'' in three dimensions, and (iii) a Cantor deconfined region in two dimensions. We also construct two models on the pyrochlore lattice, one model exhibiting a ${Z}_{2}$ RVB phase and the other a $U(1)$ RVB phase.

arXiv:cond-mat/0502146•Physical Review B•Aug 5, 2005•67 citations

SU(2)-invariant spin-1/2 Hamiltonians with RVB and other valence bond phases

Raman, K. S., Roderich Moessner, Sondhi, S. L.

We construct a family of rotationally invariant, local, S=1/2 Klein Hamiltonians on various lattices that exhibit ground state manifolds spanned by nearest-neighbor valence bond states. We show that with selected perturbations such models can be driven into phases modeled by well understood quantum dimer models on the corresponding lattices. Specifically, we show that the perturbation procedure is arbitrarily well controlled by a new parameter which is the extent of decoration of the reference lattice. This strategy leads to Hamiltonians that exhibit i) $Z_2$ RVB phases in two dimensions, ii) U(1) RVB phases with a gapless ``photon'' in three dimensions, and iii) a Cantor deconfined region in two dimensions. We also construct two models on the pyrochlore lattice, one model exhibiting a $Z_2$ RVB phase and the other a U(1) RVB phase.

•Jan 1, 2005•1 citation

Quantum dimer models emerging from large-spin ultracold atoms

Bhuvanesh Sundar, Todd C. Rutkowski, Erich J. Mueller +1 more

We propose an experimental protocol for using cold atoms to create and probe quantum dimer models, thereby exploring the Pauling-Anderson vision of a macroscopic collection of resonating bonds. This process can allow the study of exotic crystalline phases, fractionalization, topological spin liquids, and the relationship between resonating dimers and superconductivity subjects which have been challenging to address in solid-state experiments. Our key technical development is considering the action of an off-resonant photoassociation laser on large spin atoms localized at the sites of a deep optical lattice. The resulting superexchange interaction favors nearest-neighbor singlets. We derive an effective Hamiltonian in terms of these dimer degrees of freedom, finding that it is similar to well-known quantum dimer models, which boast a rich variety of valence bond crystal and spin liquid phases. We numerically study the ground state, explain how to tune the parameters, and develop a protocol to directly measure the dimers and their resonating patterns.

arXiv:1702.05514•Physical Review A•Apr 23, 2019•4 citations

Engineering SU(2) invariant spin models to mimic quantum dimer physics on the square lattice

Matthieu Mambrini, Sylvain Capponi, Fabien Alet

We consider the spin-$1/2$ Hamiltonians proposed by Cano and Fendley [Phys. Rev. Lett. 105, 067205 (2010)], which were built to promote the well-known Rokshar-Kivelson (RK) point of quantum dimer models to spin-$1/2$ wave functions. We first show that these models, besides the exact degeneracy of RK point, support gapless spinless excitations as well as a spin gap in the thermodynamic limit, signatures of an unusual spin liquid. We then extend the original construction to create a continuous family of SU(2) invariant spin models that reproduces the phase diagram of the quantum dimer model and, in particular, show explicit evidences for existence of columnar and staggered phases. The original models thus appear as multicritical points in an extended phase diagram. Our results are based on the use of a combination of numerical exact simulations and analytical mapping to effective generalized quantum dimer models.

arXiv:1507.07703•Physical Review B•Oct 16, 2015•8 citations

Two-dimensional lattice gauge theories with superconducting quantum circuits

D. Marcos, Philippe Widmer, E. Rico +4 more

A quantum simulator of [Formula: see text] lattice gauge theories can be implemented with superconducting circuits. This allows the investigation of confined and deconfined phases in quantum link models, and of valence bond solid and spin liquid phases in quantum dimer models. Fractionalized confining strings and the real-time dynamics of quantum phase transitions are accessible as well. Here we show how state-of-the-art superconducting technology allows us to simulate these phenomena in relatively small circuit lattices. By exploiting the strong non-linear couplings between quantized excitations emerging when superconducting qubits are coupled, we show how to engineer gauge invariant Hamiltonians, including ring-exchange and four-body Ising interactions. We demonstrate that, despite decoherence and disorder effects, minimal circuit instances allow us to investigate properties such as the dynamics of electric flux strings, signaling confinement in gauge invariant field theories. The experimental realization of these models in larger superconducting circuits could address open questions beyond current computational capability.

arXiv:1407.6066•Annals of Physics•Sep 19, 2014•122 citations

Quantum simulations made easy plane

Andreas Martin Läuchli, Roderich Moessner

Ever since Heisenberg's proposal of a quantum-mechanical origin of ferromagnetism in 1928, the spin model named after him has been central to advances in magnetism, featuring in proposals of novel many-body states such as antiferromagnets, emergent gauge fields in their confined (valence bond crystal) and deconfined (resonating valence bond spin liquids) versions. Between them, these cover much of our understanding of modern magnetism specifically and topological states of matter in general. Many exciting phenomena predicted theoretically still await experimental realisation, and cold atomic systems hold the promise of acting as analogue 'quantum simulators' of the relevant theoretical models, for which ingenious and intricate set-ups have been proposed. Here, we identify a new class of particularly simple quantum simulators exhibiting many such phenomena but obviating the need for fine-tuning and for amplifying perturbatively weak superexchange or longer-range interactions. Instead they require only moderate on-site interactions on top of uncorrelated, one-body hopping--ingredients already available with present experimental technology. Between them, they realise some of the most interesting phenomena, such as emergent synthetic gauge fields, resonating valence bond phases, and even the celebrated yet enigmatic spin liquid phase of the kagome lattice.

arXiv:1504.04380•Apr 16, 2015•8 citations
We report recent analytical progress in the quest for spin models realising exotic phases. We focus on the question of ‘reverse‐engineering’ a local, SU(2) invariant S=1/2 Hamiltonian to exhibit phases predicted on the basis of effective models, such as large‐N or quantum dimer models. This aim is to provide a point‐of‐principle demonstration of the possibility of constructing such microscopic lattice Hamiltonians, as well as to complement and guide numerical (and experimental) approaches to the same question. In particular, we demonstrate how to utilise peturbed Klein Hamiltonians to generate effective quantum dimer models. These models use local multi‐spin interactions and, to obtain a controlled theory, a decoration procedure involving the insertion of Majumdar‐Ghosh chainlets on the bonds of the lattice. The phases we thus realise include deconfined resonating valence bond liquids, a devil’s staircase of interleaved phases which exhibits Cantor deconfinement, as well as a three‐dimensional U(1) liquid phase exhibiting photonic excitations.
We construct a family of rotationally invariant, local, S=1∕2S=1∕2S=1∕2 Klein Hamiltonians on various lattices that exhibit ground-state manifolds spanned by nearest-neighbor valence bond states. We show that with selected perturbations such models can be driven into phases modeled by well-understood quantum dimer models on the corresponding lattices. Specifically, we show that the perturbation procedure is arbitrarily well controlled by a new parameter which is the extent of decoration of the reference lattice. This strategy leads to Hamiltonians that exhibit (i) Z2{Z}_{2}Z2​ resonating valence bond (RVB) phases in two dimensions, (ii) U(1)U(1)U(1) RVB phases with a gapless ``photon'' in three dimensions, and (iii) a Cantor deconfined region in two dimensions. We also construct two models on the pyrochlore lattice, one model exhibiting a Z2{Z}_{2}Z2​ RVB phase and the other a U(1)U(1)U(1) RVB phase.
We construct a family of rotationally invariant, local, S=1/2 Klein Hamiltonians on various lattices that exhibit ground state manifolds spanned by nearest-neighbor valence bond states. We show that with selected perturbations such models can be driven into phases modeled by well understood quantum dimer models on the corresponding lattices. Specifically, we show that the perturbation procedure is arbitrarily well controlled by a new parameter which is the extent of decoration of the reference lattice. This strategy leads to Hamiltonians that exhibit i) Z2Z_2Z2​ RVB phases in two dimensions, ii) U(1) RVB phases with a gapless ``photon'' in three dimensions, and iii) a Cantor deconfined region in two dimensions. We also construct two models on the pyrochlore lattice, one model exhibiting a Z2Z_2Z2​ RVB phase and the other a U(1) RVB phase.
We propose an experimental protocol for using cold atoms to create and probe quantum dimer models, thereby exploring the Pauling-Anderson vision of a macroscopic collection of resonating bonds. This process can allow the study of exotic crystalline phases, fractionalization, topological spin liquids, and the relationship between resonating dimers and superconductivity subjects which have been challenging to address in solid-state experiments. Our key technical development is considering the action of an off-resonant photoassociation laser on large spin atoms localized at the sites of a deep optical lattice. The resulting superexchange interaction favors nearest-neighbor singlets. We derive an effective Hamiltonian in terms of these dimer degrees of freedom, finding that it is similar to well-known quantum dimer models, which boast a rich variety of valence bond crystal and spin liquid phases. We numerically study the ground state, explain how to tune the parameters, and develop a protocol to directly measure the dimers and their resonating patterns.
We consider the spin-1/21/21/2 Hamiltonians proposed by Cano and Fendley [Phys. Rev. Lett. 105, 067205 (2010)], which were built to promote the well-known Rokshar-Kivelson (RK) point of quantum dimer models to spin-1/21/21/2 wave functions. We first show that these models, besides the exact degeneracy of RK point, support gapless spinless excitations as well as a spin gap in the thermodynamic limit, signatures of an unusual spin liquid. We then extend the original construction to create a continuous family of SU(2) invariant spin models that reproduces the phase diagram of the quantum dimer model and, in particular, show explicit evidences for existence of columnar and staggered phases. The original models thus appear as multicritical points in an extended phase diagram. Our results are based on the use of a combination of numerical exact simulations and analytical mapping to effective generalized quantum dimer models.
A quantum simulator of [Formula: see text] lattice gauge theories can be implemented with superconducting circuits. This allows the investigation of confined and deconfined phases in quantum link models, and of valence bond solid and spin liquid phases in quantum dimer models. Fractionalized confining strings and the real-time dynamics of quantum phase transitions are accessible as well. Here we show how state-of-the-art superconducting technology allows us to simulate these phenomena in relatively small circuit lattices. By exploiting the strong non-linear couplings between quantized excitations emerging when superconducting qubits are coupled, we show how to engineer gauge invariant Hamiltonians, including ring-exchange and four-body Ising interactions. We demonstrate that, despite decoherence and disorder effects, minimal circuit instances allow us to investigate properties such as the dynamics of electric flux strings, signaling confinement in gauge invariant field theories. The experimental realization of these models in larger superconducting circuits could address open questions beyond current computational capability.
Ever since Heisenberg's proposal of a quantum-mechanical origin of ferromagnetism in 1928, the spin model named after him has been central to advances in magnetism, featuring in proposals of novel many-body states such as antiferromagnets, emergent gauge fields in their confined (valence bond crystal) and deconfined (resonating valence bond spin liquids) versions. Between them, these cover much of our understanding of modern magnetism specifically and topological states of matter in general. Many exciting phenomena predicted theoretically still await experimental realisation, and cold atomic systems hold the promise of acting as analogue 'quantum simulators' of the relevant theoretical models, for which ingenious and intricate set-ups have been proposed. Here, we identify a new class of particularly simple quantum simulators exhibiting many such phenomena but obviating the need for fine-tuning and for amplifying perturbatively weak superexchange or longer-range interactions. Instead they require only moderate on-site interactions on top of uncorrelated, one-body hopping--ingredients already available with present experimental technology. Between them, they realise some of the most interesting phenomena, such as emergent synthetic gauge fields, resonating valence bond phases, and even the celebrated yet enigmatic spin liquid phase of the kagome lattice.