Adaptive dynamics of Ising spins in one dimension leveraging Reinforcement Learning

Fuente: arXiv
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Autori principali: Kumar, Anish, Mishra, Pawan Kumar, Singh, Riya, Mishra, Shradha, Giri, Debaprasad
Natura: Preprint
Pubblicazione: 2024
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author Kumar, Anish
Mishra, Pawan Kumar
Singh, Riya
Mishra, Shradha
Giri, Debaprasad
author_facet Kumar, Anish
Mishra, Pawan Kumar
Singh, Riya
Mishra, Shradha
Giri, Debaprasad
contents A one-dimensional flocking model using active Ising spins is studied, where the system evolves through the reinforcement learning approach \textit{via} defining state, action, and cost function for each spin. The orientation of spin with respect to its neighbouring spins defines its state. The state of spin is updated by altering its spin orientation in accordance with the $\varepsilon$-greedy algorithm (action) and selecting a finite step from a uniform distribution to update position. The $\varepsilon$ parameter is analogous to the thermal noise in the system. The cost function addresses cohesion among the spins. By exploring the system in the plane of the self-propulsion speed and $\varepsilon$ parameter, four distinct phases are found: disorder, flocking, flipping, and oscillatory. In the flipping phase, a condensed flock reverses its direction of motion stochastically. The mean reversal time $\langle T \rangle $ exponentially decays with $\varepsilon$. A new phase, an oscillatory phase, is also found, which is a chaotic phase with a positive Lyapunov exponent. The findings obtained from the reinforcement learning approach for the active Ising model system exhibit similarities with the outcomes of other conventional techniques, even without defining any explicit interaction among the spins.
format Preprint
id arxiv_https___arxiv_org_abs_2411_19602
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Adaptive dynamics of Ising spins in one dimension leveraging Reinforcement Learning
Kumar, Anish
Mishra, Pawan Kumar
Singh, Riya
Mishra, Shradha
Giri, Debaprasad
Soft Condensed Matter
Statistical Mechanics
A one-dimensional flocking model using active Ising spins is studied, where the system evolves through the reinforcement learning approach \textit{via} defining state, action, and cost function for each spin. The orientation of spin with respect to its neighbouring spins defines its state. The state of spin is updated by altering its spin orientation in accordance with the $\varepsilon$-greedy algorithm (action) and selecting a finite step from a uniform distribution to update position. The $\varepsilon$ parameter is analogous to the thermal noise in the system. The cost function addresses cohesion among the spins. By exploring the system in the plane of the self-propulsion speed and $\varepsilon$ parameter, four distinct phases are found: disorder, flocking, flipping, and oscillatory. In the flipping phase, a condensed flock reverses its direction of motion stochastically. The mean reversal time $\langle T \rangle $ exponentially decays with $\varepsilon$. A new phase, an oscillatory phase, is also found, which is a chaotic phase with a positive Lyapunov exponent. The findings obtained from the reinforcement learning approach for the active Ising model system exhibit similarities with the outcomes of other conventional techniques, even without defining any explicit interaction among the spins.
title Adaptive dynamics of Ising spins in one dimension leveraging Reinforcement Learning
topic Soft Condensed Matter
Statistical Mechanics
url https://arxiv.org/abs/2411.19602