Projects per year
Personal profile
Research Interests
Recent advances in laser technology have facilitated the experimental analysis of atomic structure and electron dynamics in undprecedented detail. The process of harmonic generation in particular has been central to these advances both as a basis for ultrashort and high-energy laser pulses and as a tool for elucidating ultrafast dynamics. Typically, now, we are interested in dynamics which occur on the attosecond scale (1 as = 10-18 s), which is the fundamental time scale of electronic motion in the atom.
Theoretical methods capable of describing attosecond scale electronic motion typically adopt a classical approach where an electron is driven by a laser field in the net potential of the residual ion. However, methods pioneered at QUB allow us to address the interaction of all the electrons in an atomic system. It is these multielectron interactions which mediate ultrafast dynamics and thus it is imperative to address them accurately.
Time-dependent R-matrix (TDRM) theory, and the associated TDRM and RMT (R-matrix incorporating time dependence) codes, are among the only methods in the world capable of describing multielectron and multichannel effects in ultrafast laser atom interactions. For my PhD thesis I used the TDRM method to address harmonic generation-- the production of high frequency laser light via stimulated subcycle electron motion-- and uncovered a series of multielectron aspects to the process. For instance, interference bewteen electrons competing in the harmonic generation process can lead to an increase in the harmonic yield at particular frequencies.
I have since extended these studies of ultrafast processes to experimentally relevant (mid-IR) wavelengths. Now my research focuses on extracting experimental observables from the detailed ab-initio calculations performed with RMT. To this end I have investigated several cutting-edge experimental schemes using the RMT approach, including attosecond transient absorption spectroscopy, strong-field rescattering and, most recently, XUV initiated high harmonic generation.
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Network
Projects
- 3 Active
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R1066TCP: UK Atomic, Molecular and Optical physics R-matrix consortium (UK AMOR)
18/06/2019 → …
Project: Research
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R1725TCP: ARMouReD: Atomic R-matrix Method for Relativistic Dynamics
Van Der Hart, H., Ballance, C. & Brown, A.
08/02/2017 → …
Project: Research
Research output
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Atomic and molecular suite of R-matrix codes for ultrafast dynamics in strong laser fields and electron/positron scattering
Wragg, J., Benda, J., Mašín, Z., Armstrong, G. S. J., Clarke, D. D. A., Brown, A. C., Ballance, C., Harvey, A. G., Houfek, K., Sunderland, A., Plummer, M., Gorfinkiel, J. D. & Van Der Hart, H., 11 Jun 2020, In: Journal of Physics: Conference Series. 1412, 7, 072017.Research output: Contribution to journal › Letter › peer-review
Open AccessFile -
Computational treatment of electron and photon collisions with atoms, ions, and molecules: the legacy of Philip G Burke: The legacy of Philip G Burke
Bartschat, K., Brown, A., Van Der Hart, H., Colgan, J., Scott, S. & Tennyson, J., 24 Aug 2020, In: Journal of Physics B: Atomic Molecular and Optical Physics. 53, 19, 21 p., 192002.Research output: Contribution to journal › Article › peer-review
Open AccessFile -
Courting Controversy Online: Fostering academic debate in an online world
Brown, A. & Figueira de Morisson Faria, C., 01 Oct 2020, PHYSICS WORLD, 33, 10, p. 19 1 p.Research output: Contribution to specialist publication › Article
Open Access -
Electron correlation and short-range dynamics in attosecond angular streaking
Armstrong, G. S. J., Clarke, D. D. A., Benda, J., Brown, A. C. & Van Der Hart, H., 17 Apr 2020, In: Physical Review A (Atomic, Molecular, and Optical Physics). 101, 4, 6 p., 041401(R).Research output: Contribution to journal › Article › peer-review
Open AccessFile3 Citations (Scopus)51 Downloads (Pure) -
Manipulating Twisted Electrons in Strong-Field Ionization
Maxwell, A. S., Armstrong, G. S. J., Ciappina, M. F., Pisanty, E., Kang, Y., Brown, A. C., Lewenstein, M. & Faria, C. F. D. M., 22 Oct 2020, In: Faraday Discussions.Research output: Contribution to journal › Article › peer-review
Open AccessFile
Datasets
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Electron correlation and short-range dynamics in attosecond angular streaking in the Fluorine anion
Armstrong, G. (Creator), Brown, A. (Creator), Wragg, J. (Creator), Clarke, D. (Creator) & Van Der Hart, H. (Creator), Queen's University Belfast, 10 Apr 2020
DOI: 10.17034/dc24280a-ac0a-4815-908b-a03a9cea1df0
Dataset
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Modeling tomographic measurements of photoelectron vortices in counter-rotating circularly polarized laser pulses
Armstrong, G. (Creator), Clarke, D. (Creator), Wragg, J. (Creator), Brown, A. (Creator) & Van Der Hart, H. (Creator), Queen's University Belfast, 05 Nov 2019
DOI: 10.17034/24d396fc-1744-4431-939d-0658252a854b
Dataset
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Rotational asymmetry in photodetachment from F- in circularly polarised laser fields
Armstrong, G. (Creator), Clarke, D. (Creator), Brown, A. (Creator) & Van Der Hart, H. (Creator), Queen's University Belfast, 06 Feb 2019
DOI: 10.17034/f087c320-7579-4942-a95f-f7cd66d6a0c2
Dataset
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Electron vortices in He and F-
Brown, A. (Creator), Clarke, D. (Creator), Van Der Hart, H. (Creator) & Armstrong, G. (Creator), Queen's University Belfast, 25 Oct 2018
DOI: 10.17034/668e9c0f-a1f1-4d48-b982-56b375c2fb93
Dataset
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Extreme-ultraviolet-initiated High-harmonic Generation in Ar+
Brown, A. (Supervisor), Clarke, D. (Creator) & Van Der Hart, H. (Supervisor), Queen's University Belfast, 09 Feb 2018
DOI: 10.17034/c9c652b0-40fa-4f60-a0c5-808647e9adf2
Dataset
File
Prizes
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Best Student Speaker
Brown, Andrew (Recipient), 28 Jun 2012
Prize: Prize (including medals and awards)
Activities
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The RMT project: Adventures in spin
Andrew Brown (Advisor)
10 Feb 2021Activity: Talk or presentation types › Invited talk
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The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics (Journal)
Andrew Brown (Peer reviewer)
21 Sep 2020 → 30 Sep 2020Activity: Publication peer-review and editorial work types › Publication peer-review
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Quantum Battles
Andrew Brown (Chair)
01 Jul 2020 → 03 Jul 2020Activity: Participating in or organising an event types › Participation in workshop, seminar, course
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European Journal of Physics (Journal)
Andrew Brown (Guest editor)
21 Jul 2020 → …Activity: Publication peer-review and editorial work types › Editorial activity
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The RMT project
Andrew Brown (Invited speaker)
10 Sep 2020Activity: Talk or presentation types › Invited or keynote talk at national or international conference
Press / Media
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Mathsweek Ireland promotion 2016
21/10/2016
1 Media contribution
Press/Media: Public Engagement Activities