A Path Integral Approach to Option Pricing with Stochastic Volatility: Some Exact Results

TL;DR

This paper applies path integral methods from physics to derive exact solutions for option pricing models with stochastic volatility, extending classical results and providing a novel analytical framework.

Contribution

It introduces a path integral approach to derive exact option pricing formulas with stochastic volatility, generalizing previous models by Hull and White.

Findings

Derived the Hamiltonian and Lagrangian for stochastic volatility models.

Established the analogy between option pricing and quantum mechanics wavefunctions.

Generalized existing models to the correlated case with exact results.

Abstract

The Black-Scholes formula for pricing options on stocks and other securities has been generalized by Merton and Garman to the case when stock volatility is stochastic. The derivation of the price of a security derivative with stochastic volatility is reviewed starting from the first principles of finance. The equation of Merton and Garman is then recast using the path integration technique of theoretical physics. The price of the stock option is shown to be the analogue of the Schrodinger wavefuction of quantum mechacnics and the exact Hamiltonian and Lagrangian of the system is obtained. The results of Hull and White are generalized results for pricing stock options for the general correlated case are derived.