Poster (After Call)

FZJ-2023-00834

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png A Circular Harmonic Oscillator Basis

Baumeister, P. F. (Corresponding author)FZJ* ; Bangun, A.FZJ* ; Weber, D.FZJ*

2022

Please use a persistent id in citations: http://hdl.handle.net/2128/33899

Abstract: Polar coordinates are frequently used to transform 2D images appearing in 4D scanning transmission electron microscopy (4D-STEM) as the dominant feature of the ronchigram is a central spot where the undeflected electron beam hits the detector. The information of interest resides in the deviations from a circular shape of the spot. The function basis of the quantum mechanical harmonic osciallator consists of Hermite polynomials and a Gaussian envelope function for the one-dimensional problem. For the two-dimensional isotropic problem, the basis can be represented either as a Cartesian product of two 1D basis functions or in polar coordinates.A unitary transformation connects both representations. To allow fast and affordable compression of STEM images, we incorporate the Cartesian product representation as it leads to two successive matrix-matrix multiplications. This compression method is particularly suitable for single-side-band (SSB) ptychography. We present the explicit shape of the associated radial functions of a circular harmonic oscillator and compression factors in relation to computational costs for a typical SSB ptychography application.

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Contributing Institute(s):

1. Jülich Supercomputing Center (JSC)
2. Physik Nanoskaliger Systeme (ER-C-1)
3. ER-C 2.0 (ER-C)

Research Program(s):

1. 5111 - Domain-Specific Simulation & Data Life Cycle Labs (SDLs) and Research Groups (POF4-511) (POF4-511)

Appears in the scientific report 2022

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Database coverage:

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