Complex discontinuities of the square root of Fredholm determinants in the Volterra Stein-Stein model

Fuente: arXiv
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Main Authors: Jaber, Eduardo Abi, Guellil, Maxime
Format: Preprint
Published: 2025
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author Jaber, Eduardo Abi
Guellil, Maxime
author_facet Jaber, Eduardo Abi
Guellil, Maxime
contents Fourier-based methods are central to option pricing and hedging when the Fourier-Laplace transform of the log-price and integrated variance is available semi-explicitly. This is the case for the Volterra Stein-Stein stochastic volatility model, where the characteristic function is known analytically. However, naive evaluation of this formula can produce discontinuities due to the complex square root of a Fredholm determinant, particularly when the determinant crosses the negative real axis, leading to severe numerical instabilities. We analyze this phenomenon by characterizing the determinant's crossing behavior for the joint Fourier-Laplace transform of integrated variance and log-price. We then derive an expression for the transform to account for such crossings and develop efficient algorithms to detect and handle them. Applied to Fourier-based pricing in the rough Stein-Stein model, our approach significantly improves accuracy while drastically reducing computational cost relative to existing methods.
format Preprint
id arxiv_https___arxiv_org_abs_2503_02965
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Complex discontinuities of the square root of Fredholm determinants in the Volterra Stein-Stein model
Jaber, Eduardo Abi
Guellil, Maxime
Mathematical Finance
Computational Finance
91G20, 45P05
Fourier-based methods are central to option pricing and hedging when the Fourier-Laplace transform of the log-price and integrated variance is available semi-explicitly. This is the case for the Volterra Stein-Stein stochastic volatility model, where the characteristic function is known analytically. However, naive evaluation of this formula can produce discontinuities due to the complex square root of a Fredholm determinant, particularly when the determinant crosses the negative real axis, leading to severe numerical instabilities. We analyze this phenomenon by characterizing the determinant's crossing behavior for the joint Fourier-Laplace transform of integrated variance and log-price. We then derive an expression for the transform to account for such crossings and develop efficient algorithms to detect and handle them. Applied to Fourier-based pricing in the rough Stein-Stein model, our approach significantly improves accuracy while drastically reducing computational cost relative to existing methods.
title Complex discontinuities of the square root of Fredholm determinants in the Volterra Stein-Stein model
topic Mathematical Finance
Computational Finance
91G20, 45P05
url https://arxiv.org/abs/2503.02965