Planckian signatures in optical harmonic generation and supercontinuum

TL;DR

This paper suggests that quantum gravity theories predicting a minimal length scale could manifest as specific spectral signatures in optical harmonic generation and supercontinuum processes, offering a potential experimental test for quantum gravity effects.

Contribution

It demonstrates that minimal length scenarios can produce observable optical signatures in nonlinear processes, linking quantum gravity predictions with experimental optics.

Findings

Amplification of photon excess energy during nonlinear optics

Specific optical frequencies predicted by minimal length theories

Potential for optical experiments to test quantum gravity models

Abstract

Many theories of quantum gravity, as string theory, loop quantum gravity, and doubly special relativity, predict the existence of a minimal length scale and outline the need to generalize the uncertainty principle. This generalized uncertainty principle relies on modified commutation relations that - if applied to the second quantization - imply an excess energy of the electromagnetic quanta with respect to $\hbar \omega$. Here we show that this "dark energy of the photon" is amplified during nonlinear optical process. Therefore, if one accepts the minimal length scenario, one must expect to observe specific optical frequencies in optical harmonic generation by intense laser fields. Other processes as four-wave mixing and supercontinuum generation may also contain similar spectral features of quantum-gravity. Nonlinear optics may hence be helpful to falsify some of the most investigated approaches to the unification of quantum mechanics and general relativity.