Quantum spin liquids of Rydberg excitations in a honeycomb lattice induced by density-dependent Peierls phases
We show that the nonlinear transport of bosonic excitations in a two-dimensional honeycomb lattice of spin-orbit-coupled Rydberg atoms gives rise to disordered quantum phases which are topological and may be candidates for quantum spin liquids. As recently demonstrated by Lienhard et al. [Phys. Rev....
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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American Physical Society
2023-02-01
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| Series: | Physical Review Research |
| Online Access: | http://doi.org/10.1103/PhysRevResearch.5.013157 |
| _version_ | 1827285362915934208 |
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| author | Simon Ohler Maximilian Kiefer-Emmanouilidis Michael Fleischhauer |
| author_facet | Simon Ohler Maximilian Kiefer-Emmanouilidis Michael Fleischhauer |
| author_sort | Simon Ohler |
| collection | DOAJ |
| description | We show that the nonlinear transport of bosonic excitations in a two-dimensional honeycomb lattice of spin-orbit-coupled Rydberg atoms gives rise to disordered quantum phases which are topological and may be candidates for quantum spin liquids. As recently demonstrated by Lienhard et al. [Phys. Rev. X 10, 021031 (2020)2160-330810.1103/PhysRevX.10.021031] the spin-orbit coupling breaks time-reversal and chiral symmetries and leads to a tunable density-dependent complex hopping of spin excitations which behave as hard-core bosons. Using exact diagonalization (ED), we numerically investigate the phase diagram resulting from the competition between density-dependent and direct transport terms as well as density-density interactions. In mean-field approximation there is a phase transition from a condensate to a 120^{∘} phase when the amplitude of the complex hopping exceeds that of the direct one. In the full model a new phase emerges close to the mean-field critical point as a result of quantum correlations induced by the density dependence of the complex hopping. We show that without density-density interactions this phase is a genuine disordered one, has large spin chirality, and is characterized by a nontrivial many-body Chern number. The Chern number is found to be robust to disorder. ED simulations of small lattices with up to 30 lattice sites give indications for a nondegenerate ground state with finite spin and collective gaps and thus for a bosonic integer quantum Hall phase, protected by U(1) symmetry. On the other hand, while staying finite, the many-body gap varies substantially when different twisted boundary conditions are applied, which points to a gapless phase. For very strong negative nonlinear hopping amplitudes we find another disordered regime with vanishing spin gap. This phase also has a large spin chirality and could be a gapless spin liquid but lies outside the parameter regime experimentally accessible in the Rydberg system. |
| first_indexed | 2024-04-24T10:12:19Z |
| format | Article |
| id | doaj.art-eaee1920626d4d2ab45befc5f324c2fe |
| institution | Directory Open Access Journal |
| issn | 2643-1564 |
| language | English |
| last_indexed | 2024-04-24T10:12:19Z |
| publishDate | 2023-02-01 |
| publisher | American Physical Society |
| record_format | Article |
| series | Physical Review Research |
| spelling | doaj.art-eaee1920626d4d2ab45befc5f324c2fe2024-04-12T17:29:00ZengAmerican Physical SocietyPhysical Review Research2643-15642023-02-015101315710.1103/PhysRevResearch.5.013157Quantum spin liquids of Rydberg excitations in a honeycomb lattice induced by density-dependent Peierls phasesSimon OhlerMaximilian Kiefer-EmmanouilidisMichael FleischhauerWe show that the nonlinear transport of bosonic excitations in a two-dimensional honeycomb lattice of spin-orbit-coupled Rydberg atoms gives rise to disordered quantum phases which are topological and may be candidates for quantum spin liquids. As recently demonstrated by Lienhard et al. [Phys. Rev. X 10, 021031 (2020)2160-330810.1103/PhysRevX.10.021031] the spin-orbit coupling breaks time-reversal and chiral symmetries and leads to a tunable density-dependent complex hopping of spin excitations which behave as hard-core bosons. Using exact diagonalization (ED), we numerically investigate the phase diagram resulting from the competition between density-dependent and direct transport terms as well as density-density interactions. In mean-field approximation there is a phase transition from a condensate to a 120^{∘} phase when the amplitude of the complex hopping exceeds that of the direct one. In the full model a new phase emerges close to the mean-field critical point as a result of quantum correlations induced by the density dependence of the complex hopping. We show that without density-density interactions this phase is a genuine disordered one, has large spin chirality, and is characterized by a nontrivial many-body Chern number. The Chern number is found to be robust to disorder. ED simulations of small lattices with up to 30 lattice sites give indications for a nondegenerate ground state with finite spin and collective gaps and thus for a bosonic integer quantum Hall phase, protected by U(1) symmetry. On the other hand, while staying finite, the many-body gap varies substantially when different twisted boundary conditions are applied, which points to a gapless phase. For very strong negative nonlinear hopping amplitudes we find another disordered regime with vanishing spin gap. This phase also has a large spin chirality and could be a gapless spin liquid but lies outside the parameter regime experimentally accessible in the Rydberg system.http://doi.org/10.1103/PhysRevResearch.5.013157 |
| spellingShingle | Simon Ohler Maximilian Kiefer-Emmanouilidis Michael Fleischhauer Quantum spin liquids of Rydberg excitations in a honeycomb lattice induced by density-dependent Peierls phases Physical Review Research |
| title | Quantum spin liquids of Rydberg excitations in a honeycomb lattice induced by density-dependent Peierls phases |
| title_full | Quantum spin liquids of Rydberg excitations in a honeycomb lattice induced by density-dependent Peierls phases |
| title_fullStr | Quantum spin liquids of Rydberg excitations in a honeycomb lattice induced by density-dependent Peierls phases |
| title_full_unstemmed | Quantum spin liquids of Rydberg excitations in a honeycomb lattice induced by density-dependent Peierls phases |
| title_short | Quantum spin liquids of Rydberg excitations in a honeycomb lattice induced by density-dependent Peierls phases |
| title_sort | quantum spin liquids of rydberg excitations in a honeycomb lattice induced by density dependent peierls phases |
| url | http://doi.org/10.1103/PhysRevResearch.5.013157 |
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