Many-body synchronization and non-equilibrium phase transition in frustrated coupled-oscillators

2023 Fiscal Year Final Research Report

• Project/Area Number: 21K03396
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 13010:Mathematical physics and fundamental theory of condensed matter physics-related
• Research Institution: Tohoku University
• Principal Investigator: Uchida Nariya 東北大学, 理学研究科, 准教授 (10344649)
• Project Period (FY): 2021-04-01 – 2024-03-31
• Keywords: 同期現象

Outline of Final Research Achievements

In this research project, we investigated novel synchronization phenomena induced by frustration in a one-dimensional many-body system of nonlocally coupled oscillators. Firstly, by continuously varying the phase delay of the interactions, we discovered critical phenomena and novel spatiotemporal patterns analogous to directed percolation with two absorbing states, particularly in the vicinity of an anti-phase region. Secondly, we showed that when oscillators perform random walks on a lattice and both the phase delay and movement frequency are varied, collective synchronization is enhanced by movement when the phase delay is close to in-phase, while synchronization is inhibited when the phase delay is near anti-phase. Thirdly, in a system with a large number of coupled oscillator groups, we identified a new metastable state characterized by transitions between synchronized and desynchronized states.

Free Research Field

非線形物理学

Academic Significance and Societal Importance of the Research Achievements

多数の振動子が同期する現象において、振動子が同期した領域と非同期領域が共存するキメラ状態は、脳活動を司るニューロンの集団発火との関連で注目されている。キメラ状態は振動子間の結合の位相遅れが同位相と逆位相の中間にある場合に生じるが、本研究では位相遅れに加え、振動子のランダムな運動（つなぎ替え）や固有振動数の不均一性を導入することにより、複数の新たな同期パターンを見出した。脳の階層構造を模した振動子集団で見出された同期と非同期が時間的に共存する現象は、脳活動の特徴と類似する。また、ランダムな運動によって集団同期が促進されるメカニズムを解明したが、これはロボットなど移動デバイスの同期現象と関連する。