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A spin Hall Ising machine.

ORAL · Invited

Abstract

Ising Machines (IMs) are physical systems designed to find solutions to combinatorial optimization (CO) problems mapped onto the IM via the coupling strengths of its binary spins. Using the intrinsic dynamics and different annealing schemes, the IM relaxes over time to its lowest energy state, which is the solution to the CO problem. Here we present the world's most miniaturized, and the first spin Hall nano-oscillator (SHNO) based Ising machine. One of the most intriguing properties of SHNOs is their ability to synchronize to each other and to an external source. We demonstrate robust phase binarization due to injection locking at twice the natural frequency of SHNOs and analyze the binarization behavior as a function of injection locking power and frequency.  We then show binarization in 1x2 and 2x2 SHNO interconnected arrays. The phase binarization manifests itself as distinct microwave output power levels, which are readily distinguished using electrical means. In addition, we use phase-resolved Brillouin Light Scattering (phase-BLS) microscopy to directly observe the individual phases of the precessing magnetization in each nano-constriction. The different states can be accessed using either different injected power levels or a detuned frequency of the injected signal. We then propose pathways to control the coupling between SHNOs in order to gain flexibility in terms of mapped problems, and realize truly miniaturized, ultra-fast, and large-scale oscillator-based Ising Machines.

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Publication: "Phase-binarized spin Hall nano-oscillator arrays: Towards spin Hall Ising machines"; Under consideration at PRA.

Presenters

  • Afshin Houshang

    University of Gothenburg, 1Physics Department, University of Gothenburg, 41296 Gothenburg, Sweden., Physics Department, University of Gothenburg

Authors

  • Afshin Houshang

    University of Gothenburg, 1Physics Department, University of Gothenburg, 41296 Gothenburg, Sweden., Physics Department, University of Gothenburg

  • Mohammad Zahedinejad

    Physics Department, University of Gothenburg, 412 96 Gothenburg, Sweden

  • Shreyas Muralidhar

    Physics Department, University of Gothenburg, 412 96 Gothenburg, Sweden

  • Roman Khymyn

    University of Gothenburg, Sweden, University of Gothenburg, Physics Department, University of Gothenburg, Physics Department, University of Gothenburg, 412 96 Gothenburg, Sweden

  • Mona Rajabali

    University of Gothenburg

  • Himanshu Fulara

    Indian Institute of Technology Roorkee, 1Physics Department, University of Gothenburg, 41296 Gothenburg, Sweden. 2Department of Physics, Indian Institute of Technology Roorkee, Roorkee 247667, India, Indian Institute of Technology Roorkee, India, Physics Department, University of Gothenburg

  • Ahmad Awad

    Gothenburg University, Physics Department, University of Gothenburg

  • Johan Åkerman

    Goteborg Univ, University of Gothenburg, 1Physics Department, University of Gothenburg, 41296 Gothenburg, Sweden., University of Gothenburg, Sweden, Physics Department, University of Gothenburg, Physics Department, University of Gothenburg, 412 96 Gothenburg, Sweden

  • Jakub Checinski

    AGH University of Science and Technology, Institute of Electronics, Al. Mickiewicza 30, 30-059 Krakow, Poland

  • Mykola Dvornik

    NanOsc AB, NanOsc AB, Gothenburg, Sweden., University of Gothenburg, Sweden, Physics Department, University of Gothenburg, 412 96 Gothenburg, Sweden.