Researchers have developed a new way to model dephasing in attosecond experiments
Attosecond science is undoubtedly one of the fastest growing branches of physics today.
Its popularity was demonstrated by the award of the 2023 Nobel Prize in Physics to Anne L’Huillier, Paul Corkum and Ferenc Krausz for experimental methods that generate attosecond pulses of light for the study of electron dynamics in matter.
One of the most important processes in this field is dephasing. This happens when an electron loses its phase coherence because of interactions with its surroundings.
This loss of coherence can obscure the fine details of electron dynamics, making it harder to capture precise snapshots of these rapid processes.
The most common way to model this process in light-matter interactions is by using the relaxation time approximation. This approach greatly simplifies the picture as it avoids the need to model every single particle in the system.
Its use is fine for dilute gases, but it doesn’t work as well with intense lasers and denser materials, such as solids, because it greatly overestimates ionisation.
This is a significant problem as ionisation is the first step in many processes such as electron acceleration and high-harmonic generation.
To address this problem, a team led by researchers from the University of Ottawa have developed a new method to correct for this problem.
By introducing a heat bath into the model they were able to represent the many-body environment that interacts with electrons, without significantly increasing the complexity.
This new approach should enable the identification of new effects in attosecond science or wherever strong electromagnetic fields interact with matter.