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Main Authors: Hasan, Abir, Ekanayake, E. M. Hasantha, Lee, Kyle, Camsari, Kerem, Shukla, Nikhil
Format: Preprint
Published: 2026
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Online Access:https://arxiv.org/abs/2605.17243
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author Hasan, Abir
Ekanayake, E. M. Hasantha
Lee, Kyle
Camsari, Kerem
Shukla, Nikhil
author_facet Hasan, Abir
Ekanayake, E. M. Hasantha
Lee, Kyle
Camsari, Kerem
Shukla, Nikhil
contents Oscillator Ising machines (OIMs) are often viewed as physical systems that perform gradient descent on an energy landscape encoding Ising solutions. Here, we show that this interpretation is not generic and breaks down in a broad class of oscillator implementations. We establish that gradient-flow dynamics require a harmonic-by-harmonic quadrature relation between the oscillator waveform and its phase response. Deviations from this condition, which we term harmonic misalignment, introduce even components in the pairwise interaction function, leading to non-conservative phase dynamics and precluding a gradient-flow description. We introduce a normalized metric for this non-gradient contribution and evaluate it across representative oscillator models relevant to OIMs. This metric reveals substantial non-gradient contributions in ring oscillators and across other hardware-realistic oscillator models. These findings identify harmonic misalignment as a fundamental mechanism for the breakdown of energy-based dynamics in OIMs and motivate nonequilibrium analysis and algorithms that explicitly account for and potentially exploit non-gradient behavior.
format Preprint
id arxiv_https___arxiv_org_abs_2605_17243
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Breakdown of Gradient-Flow Dynamics in Oscillator Ising Machines from Harmonic Misalignment
Hasan, Abir
Ekanayake, E. M. Hasantha
Lee, Kyle
Camsari, Kerem
Shukla, Nikhil
Computational Physics
Oscillator Ising machines (OIMs) are often viewed as physical systems that perform gradient descent on an energy landscape encoding Ising solutions. Here, we show that this interpretation is not generic and breaks down in a broad class of oscillator implementations. We establish that gradient-flow dynamics require a harmonic-by-harmonic quadrature relation between the oscillator waveform and its phase response. Deviations from this condition, which we term harmonic misalignment, introduce even components in the pairwise interaction function, leading to non-conservative phase dynamics and precluding a gradient-flow description. We introduce a normalized metric for this non-gradient contribution and evaluate it across representative oscillator models relevant to OIMs. This metric reveals substantial non-gradient contributions in ring oscillators and across other hardware-realistic oscillator models. These findings identify harmonic misalignment as a fundamental mechanism for the breakdown of energy-based dynamics in OIMs and motivate nonequilibrium analysis and algorithms that explicitly account for and potentially exploit non-gradient behavior.
title Breakdown of Gradient-Flow Dynamics in Oscillator Ising Machines from Harmonic Misalignment
topic Computational Physics
url https://arxiv.org/abs/2605.17243