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arxiv: 2406.17364 · v5 · submitted 2024-06-25 · 🧮 math.NA · cond-mat.dis-nn· cond-mat.stat-mech· cs.NA· quant-ph

Annealing-based approach to solving partial differential equations

Pith reviewed 2026-05-24 00:25 UTC · model grok-4.3

classification 🧮 math.NA cond-mat.dis-nncond-mat.stat-mechcs.NAquant-ph
keywords annealingpartial differential equationseigenvalue problemsRayleigh quotientsimulated annealingnumerical methodsdiscretization
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The pith

An iterative annealing algorithm solves discretized PDEs by computing eigenvectors to arbitrary precision without adding variables.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper reformulates discretized partial differential equations as generalized eigenvalue problems that are then turned into optimization tasks using a generalized Rayleigh quotient. An algorithm is proposed that applies annealing iteratively to refine the eigenvector solutions. This iteration enables the target precision to be reached without enlarging the variable count. Simulated annealing experiments track how the required iteration count grows with system size and annealing duration. Overall performance is shown to depend on system size, annealing time, and the specific PDE characteristics.

Core claim

The central claim is that the proposed iterative algorithm enables efficient annealing-based computation of eigenvectors to arbitrary precision without increasing the number of variables, by repeatedly optimizing the generalized Rayleigh quotient for the eigenvalue problem that arises from PDE discretization.

What carries the argument

Iterative annealing optimization of the generalized Rayleigh quotient to refine eigenvector solutions for the discretized generalized eigenvalue problem.

If this is right

  • Eigenvectors for PDE-derived eigenvalue problems can be obtained to any desired accuracy by repeated annealing steps rather than by enlarging the formulation.
  • The number of iterations needed grows with system size and annealing time in a manner that can be measured directly via simulated annealing.
  • Computational cost is governed by the interplay of system size, annealing schedule, and the concrete PDE being solved.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • The same iterative refinement might apply to other linear-algebra problems that can be cast as Rayleigh-quotient optimization.
  • If the observed scaling holds for quantum annealing devices, the method could become viable for very large sparse systems where classical eigensolvers become expensive.
  • Direct comparison against standard iterative solvers such as Lanczos on the same discretized operators would quantify any practical advantage.

Load-bearing premise

The iterative computations converge reliably to the target precision for the discretized systems arising from PDEs, with scaling that remains practical as system size grows.

What would settle it

A test on the discretized Poisson equation in which the eigenvector error fails to fall below a fixed threshold no matter how many iterations or how long the annealing time is increased.

Figures

Figures reproduced from arXiv: 2406.17364 by Kazue Kudo.

Figure 1
Figure 1. Figure 1: The number of iterations required for solving the one-dimensional symmetric Poisson equation [PITH_FULL_IMAGE:figures/full_fig_p007_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: The number of precision updates required for solving the one-dimensional symmetric Poisson [PITH_FULL_IMAGE:figures/full_fig_p008_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: The number of iterations at the iterative descent stage required for solving (a) the one-dimensional [PITH_FULL_IMAGE:figures/full_fig_p009_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: The average number of iterations at the iterative descent stage for solving the one-dimensional [PITH_FULL_IMAGE:figures/full_fig_p010_4.png] view at source ↗
Figure 4
Figure 4. Figure 4: However, the coefficient α in the exponential function e αn is relatively small, even for the asymmetric Poisson equation. This suggests the proposed method, together with using an Ising machine, can outperform conventional methods for certain classes of simple prob￾lems. It is important to note that this analysis focuses on the number of iterations rather than the actual annealing time. In the simulated a… view at source ↗
read the original abstract

Solving partial differential equations (PDEs) using an annealing-based approach involves solving generalized eigenvalue problems. Discretizing a PDE yields a system of linear equations (SLE). Solving an SLE can be formulated as a general eigenvalue problem, which can be transformed into an optimization problem with an objective function given by a generalized Rayleigh quotient. The proposed algorithm requires iterative computations. However, it enables efficient annealing-based computation of eigenvectors to arbitrary precision without increasing the number of variables. Investigations using simulated annealing demonstrate how the number of iterations scales with system size and annealing time. Computational performance depends on system size, annealing time, and problem characteristics.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 0 minor

Summary. The paper proposes an annealing-based method for solving PDEs: discretize the PDE to obtain a system of linear equations, recast this as a generalized eigenvalue problem, and convert the latter into an optimization problem whose objective is the generalized Rayleigh quotient. This optimization is solved by simulated annealing; the algorithm performs iterative computations to reach arbitrary precision while keeping the number of variables fixed. Scaling behavior of iteration count with system size and annealing time is investigated via simulated annealing.

Significance. If the iterative annealing procedure can be shown to converge reliably with practical scaling, the approach would supply a new route to PDE solution that maps directly onto annealing hardware without enlarging the variable count at each iteration. The reported scaling investigations are a positive step, but the absence of quantitative error metrics, convergence rates, or baseline comparisons leaves the practical significance difficult to evaluate.

major comments (2)
  1. [Abstract] Abstract: the central claim that eigenvectors are obtained 'to arbitrary precision' via iterative annealing is unsupported by any reported error norms, residual values, or convergence data; only the scaling of iteration count is mentioned.
  2. [Abstract] Abstract: the statement that the method 'enables efficient annealing-based computation ... without increasing the number of variables' is load-bearing for the contribution, yet no explicit comparison of problem size before and after iteration, nor any demonstration that iteration count remains sub-linear in system size, is supplied.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for the constructive feedback on the abstract claims. We address each major comment below and will revise the manuscript to provide the requested supporting evidence.

read point-by-point responses
  1. Referee: [Abstract] Abstract: the central claim that eigenvectors are obtained 'to arbitrary precision' via iterative annealing is unsupported by any reported error norms, residual values, or convergence data; only the scaling of iteration count is mentioned.

    Authors: We agree that explicit quantitative support for the 'arbitrary precision' claim is needed. The iterative procedure refines the solution by repeated annealing runs on the fixed-size generalized Rayleigh quotient, but the current version reports only iteration scaling. In the revised manuscript we will add residual norm values, error metrics, and convergence plots versus iteration count to substantiate the claim. revision: yes

  2. Referee: [Abstract] Abstract: the statement that the method 'enables efficient annealing-based computation ... without increasing the number of variables' is load-bearing for the contribution, yet no explicit comparison of problem size before and after iteration, nor any demonstration that iteration count remains sub-linear in system size, is supplied.

    Authors: The discretization determines a fixed number of variables that is unchanged by the iterative annealing steps; each iteration optimizes the same Rayleigh quotient without expanding the variable count. The manuscript already examines how iteration count scales with system size, but we acknowledge that an explicit before/after comparison and discussion of the scaling regime (including whether it remains sub-linear) would strengthen the claim. We will add this clarification and supporting analysis in the revision. revision: yes

Circularity Check

0 steps flagged

No significant circularity; derivation relies on standard equivalences

full rationale

The paper's chain proceeds from PDE discretization to a system of linear equations, reformulated as a generalized eigenvalue problem, then cast as minimization of the generalized Rayleigh quotient—an optimization problem solved iteratively by annealing. These steps invoke standard mathematical identities (Rayleigh quotient properties for eigenvectors) without redefining any quantity in terms of the target output or fitting parameters to the same data that is later 'predicted.' No self-citations appear as load-bearing premises, no uniqueness theorems are imported from prior author work, and no ansatz is smuggled via citation. Scaling investigations are performed empirically with simulated annealing on the resulting optimization problem, leaving the central claim independent of its own fitted values.

Axiom & Free-Parameter Ledger

2 free parameters · 2 axioms · 0 invented entities

The approach rests on standard numerical discretization of PDEs and the equivalence between linear systems and generalized eigenvalue problems; annealing time and iteration count function as tunable parameters whose scaling is investigated but not derived from first principles.

free parameters (2)
  • annealing time
    Abstract states that computational performance depends on annealing time and reports scaling investigations with it.
  • number of iterations
    Abstract notes that the algorithm requires iterative computations whose number scales with system size and annealing time.
axioms (2)
  • domain assumption Discretizing a PDE yields a system of linear equations that can be cast as a generalized eigenvalue problem.
    Explicitly stated as the starting point in the abstract.
  • standard math The generalized Rayleigh quotient serves as a valid objective function whose optimization yields the desired eigenvectors.
    Invoked without further justification in the abstract's description of the optimization formulation.

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Reference graph

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