2020/09/30 by Shiyu Zhou, Dmitry Green, Edward D. Dahl +1 · 22 citations
Mathematics · Physics and Astronomy · #Advanced Condensed Matter Physics #Algorithm #Combinatorics #Computer science #Hamiltonian (control theory) #Mathematical physics #Mathematics #Path integral formulation #Physics #Quantum #Quantum annealing #Quantum computer #Quantum many-body systems #Quantum mechanics #Quantum simulator #Theoretical and Computational Physics #Theoretical computer science #Topology (electrical circuits) #Vertex (graph theory) #Wave function #cond-mat.str-el
paper · pdf · doi:10.1103/physrevb.104.l081107
published in Physical review. B./Physical review. B 104(8) (American Physical Society) · 6 pages, 5 figures
openalex publication_date 2021/08/13 · arxiv created 2021/08/18 · arxiv updated 2021/08/25 · openalex created_date 2021/08/30 · openalex updated_date 2026/08/05
We build and probe a ℤ2 spin liquid in a programmable quantum device, the D-Wave DW-2000Q. Specifically, we observe the classical eight-vertex and six-vertex (spin ice) states and transitions between them. To realize this state of matter, we design a Hamiltonian with combinatorial gauge symmetry using only pairwise-qubit interactions and a transverse field, i.e., interactions which are accessible in this quantum device. The combinatorial gauge symmetry remains exact along the full quantum annealing path, landing the system onto the classical eight-vertex model at the endpoint of the path. The output configurations from the device allow us to directly observe the loop structure of the classical model. Moreover, we deform the Hamiltonian so as to vary the weights of the eight vertices and show that we can selectively attain the classical six-vertex (ice) model, or drive the system into a ferromagnetic state. We present studies of the classical phase diagram of the system as a function of the eight-vertex deformations and effective temperature, which we control by varying the relative strengths of the programmable couplings, and we show that the experimental results are consistent with theoretical analysis. Finally, we identify additional capabilities that, if added to these devices, would allow us to realize ℤ2 quantum spin liquids on which to build topological qubits.