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Bibliographic Details
Main Author: Stammer, Philipp
Format: Preprint
Published: 2023
Subjects:
Online Access:https://arxiv.org/abs/2309.05010
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author Stammer, Philipp
author_facet Stammer, Philipp
contents The optical phase of the driving field in the process of high harmonic generation and the coherence properties of the harmonics are fundamental concepts in attosecond physics. Here, we consider to drive the process by incoherent classical and non-classical light fields exhibiting an undetermined optical phase. With this we introduce the notion of quantum optical coherence into high harmonic generation, and show that high harmonics can be generated from incoherent radiation despite having a vanishing electric field. We explicitly derive the quantum state of the harmonics when driven by carrier-envelope phase unstable fields and show that the generated harmonics are incoherent and exhibiting zero electric field amplitudes. We find that the quantum state of each harmonic is diagonal in its photon number basis, but nevertheless has the exact same photon statistics as the widely considered coherent harmonics. From this we conclude that assuming coherent harmonic radiation can originate from a preferred ensemble fallacy. These findings have profound implications for attosecond experiments and how to infer about the harmonic radiation properties.
format Preprint
id arxiv_https___arxiv_org_abs_2309_05010
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Absence of quantum optical coherence in high harmonic generation
Stammer, Philipp
Quantum Physics
The optical phase of the driving field in the process of high harmonic generation and the coherence properties of the harmonics are fundamental concepts in attosecond physics. Here, we consider to drive the process by incoherent classical and non-classical light fields exhibiting an undetermined optical phase. With this we introduce the notion of quantum optical coherence into high harmonic generation, and show that high harmonics can be generated from incoherent radiation despite having a vanishing electric field. We explicitly derive the quantum state of the harmonics when driven by carrier-envelope phase unstable fields and show that the generated harmonics are incoherent and exhibiting zero electric field amplitudes. We find that the quantum state of each harmonic is diagonal in its photon number basis, but nevertheless has the exact same photon statistics as the widely considered coherent harmonics. From this we conclude that assuming coherent harmonic radiation can originate from a preferred ensemble fallacy. These findings have profound implications for attosecond experiments and how to infer about the harmonic radiation properties.
title Absence of quantum optical coherence in high harmonic generation
topic Quantum Physics
url https://arxiv.org/abs/2309.05010