E-Spin: A Stochastic Ising Spin Based on Electrically-Controlled MTJ for Constructing Large-Scale Ising Annealing Systems

With its unique computer paradigm, the Ising annealing machine has become an emerging research direction. The Ising annealing system is highly effective at addressing combinatorial optimization (CO) problems that are difficult for conventional computers to tackle. However, Ising spins, which compris...

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Bibliographic Details
Main Authors: Wenhan Chen, Haodi Tang, Yu Wang, Xianwu Hu, Yuming Lin, Tai Min, Yufeng Xie
Format: Article
Language:English
Published: MDPI AG 2023-01-01
Series:Micromachines
Subjects:
Online Access:https://www.mdpi.com/2072-666X/14/2/258
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Summary:With its unique computer paradigm, the Ising annealing machine has become an emerging research direction. The Ising annealing system is highly effective at addressing combinatorial optimization (CO) problems that are difficult for conventional computers to tackle. However, Ising spins, which comprise the Ising system, are difficult to implement in high-performance physical circuits. We propose a novel type of Ising spin based on an electrically-controlled magnetic tunnel junction (MTJ). Electrical operation imparts true randomness, great stability, precise control, compact size, and easy integration to the MTJ-based spin. In addition, simulations demonstrate that the frequency of electrically-controlled stochastic Ising spin (E-spin) is 50 times that of the thermal disturbance MTJ-based spin (p-bit). To develop a large-scale Ising annealing system, up to 64 E-spins are implemented. Our Ising annealing system demonstrates factorization of integers up to <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mn>2</mn><mrow><mn>64</mn></mrow></msup></mrow></semantics></math></inline-formula> with a temporal complexity of around <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>O</mi><mrow><mo>(</mo><mrow><msqrt><mi>n</mi></msqrt></mrow><mo>)</mo></mrow></mrow></semantics></math></inline-formula>. The proposed E-spin shows superiority in constructing large-scale Ising annealing systems and solving CO problems.
ISSN:2072-666X