arXiv:2606.18515quant-phcs.LG2026-06被引 2

提出可避免梯度消失的指数级初始化方法,突破传统调参思维。

Exponentially many initializations to avoid barren plateaus

论文配图:Exponentially many initializations to avoid barren plateaus
图 1 · 摘自论文原文
  • 构建一阶矩分析框架,诊断初始化能否避开梯度集中
  • 发现存在指数级不等价的初始化方案可避免冗余梯度
  • 不同初始化导致不同最优解,需在众多可行方案中精挑细选

梯度消失(巴伦峡谷)通常被视为平均情况现象:给定一个量子线路结构,若参数随机初始化,则梯度会迅速集中。这促使人们认为只需更谨慎地初始化即可缓解问题。本文提出一种一阶矩框架,可在算子层面判断初始化是否能避开完全集中的巴伦峡谷固定点,并比较不同初始化策略的偏差。该框架不仅复现了如恒等和高斯初始化等已有方法,更揭示避免梯度集中的方式具有高度非唯一性——多种偏移、非对称、非均衡的参数分布均可有效避免集中。进一步数值实验表明,不同一阶矩特性的初始化可能收敛至不同的最小值,说明通过智能初始化规避梯度消失,实则将指数级的梯度集中问题转化为从海量可行路径中选择最佳训练起点的挑战。

原文摘要 · Abstract (English)

Barren plateaus are stated as an average-case phenomenon: pick an ansatz, initialize it naively, and concentration follows. This has led to the common view that a potential cure for barren plateaus is simply to initialize the parameters more carefully. Here we show that the situation is subtler. We introduce a first-moment framework that gives a simple operator-level diagnostic for when an initialization may escape the fully concentrated barren-plateau fixed point, and for comparing the biases induced by different initialization strategies. Our framework recovers several known initialization schemes such as identity and Gaussian initialization, but also shows that barren-plateau avoidance is highly non-unique. Indeed, many shifted, biased, and non-symmetric parameter distributions can avoid concentration, and these choices need not be equivalent. In fact, our results show that one can generate exponentially many families of inequivalent initialization strategies. Then, our numerics indicate that different first-moment-distinct initializations can lead to different attained minima, suggesting that avoiding barren plateaus via smart initializations can trade the exponential concentration problem for the challenge of selecting the right trainable pocket amongst many options.

量子机器学习梯度消失初始化策略变分量子算法

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