Attosecond chronoscopy - what happens during attosecod-scale delays?

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Discussion Overview

The discussion centers on the phenomenon of attosecond chronoscopy and the implications of attosecond-scale delays observed in atomic processes, particularly in relation to photoionization and electron dynamics. Participants explore the nature of these delays and their significance in understanding the timing of the photoelectric effect and related phenomena.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants note that while atomic processes are often idealized as instantaneous, attosecond-scale delays in photoionization have been observed, suggesting a more complex underlying dynamics.
  • There is a question about the nature of these delays, specifically whether they are simply due to the propagation of photons or involve more intricate electron dynamics leading to the emission of electromagnetic waves.
  • One participant references the historical context of attosecond measurements, mentioning a 2010 report of the shortest time measured at 20 attoseconds and inquires about any recent developments in this field.
  • Another participant points out that a photon propagates as an electromagnetic wave at approximately 0.3 nm per attosecond, raising questions about the implications of this propagation speed in relation to the observed delays.
  • Evidence is provided regarding a measurement of 247 zeptoseconds for a photon to pass through a hydrogen molecule, suggesting that such measurements are becoming increasingly precise.

Areas of Agreement / Disagreement

Participants express curiosity and raise questions about the implications of attosecond delays, but there is no consensus on the specific mechanisms or interpretations of these delays. Multiple competing views and uncertainties remain regarding the nature of the observed phenomena.

Contextual Notes

Participants acknowledge the limitations of existing knowledge and the need for further exploration into the dynamics of electron behavior and photon propagation at attosecond scales. There are references to various studies and measurements, but no definitive conclusions are drawn.

Jarek 31
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TL;DR
Getting beyond idealization of atomic processes as being instant
While naive description of atomic processes idealizes that they are instant, a decade ago they have started observing attosecond-scale delays.
~1000 articles citing 2010 Science "Delay in photoemission" https://scholar.google.pl/scholar?cites=15193546925951882986&as_sdt=2005&sciodt=0,5&hl=en

E.g. 2020 "Probing molecular environment through photoemission delays" https://www.nature.com/articles/s41567-020-0887-8
Attosecond chronoscopy has revealed small but measurable delays in photoionization, characterized by the ejection of an electron on absorption of a single photon. Ionization-delay measurements in atomic targets provide a wealth of information about the timing of the photoelectric effect, resonances, electron correlations and transport.
So what happens during such tiny delays - what can we tell about such e.g. electron dynamics leading to creation of EM wave of single optical photon?
 
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Jarek 31 said:
Summary:: Getting beyond idealization of atomic processes as being instant

So what happens during such tiny delays - what can we tell about such e.g. electron dynamics leading to creation of EM wave of single optical photon?
How far does a photon travel in an attosecond? Is the delay simply due to propagation to and from?

Since this is new to me, I was looking for information on "attosecond chronography" and could only find 'old' material. For example, in 2010, there was an announcement of the shortest time measured - 20 attoseconds. Has there been further developments?

https://phys.org/news/2010-06-photoemission-accuracy.html
https://cordis.europa.eu/article/id/32261-20-attoseconds-the-shortest-time-ever-recorded

And here I was concerned about femtoseconds.
 

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