Paul A Johnson retweetledi
I refuse to let AI take away the hard earned joy of failing to write for 4 hours, going for a little walk, then failing to write for another 4 hours.
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Paul A Johnson
184 posts
Paul A Johnson
@johnsontheochem
Strong electron correlation with Bethe Ansatz wavefunctions
Katılım Ocak 2021
128 Takip Edilen154 Takipçiler
Paul A Johnson retweetledi
[2510.06144] Connections between Richardson-Gaudin States, Perfect-Pairing, and Pair Coupled-Cluster Theory #compchem arxiv.org/abs/2510.06144
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My final stop in Europe, before returning to my @MSUChem office, will be Paris, where I will speak at QSCP-XXVII (qscpxxvii.sciencesconf.org). Here are a few pictures from Menton, where I attended the annual meeting of IAQMS, and, in part 2 of 2, from the neighboring Monaco. 1/2
Piotr Piecuch@PiecuchPiotr
After WATOC 2025, I relocated to Menton, 🇫🇷, to attend the annual meeting of IAQMS (iaqms.org/index.php). After electing new members & selecting the 2025 medalist, we had a nice dinner. Here I am with 2 legends of electronic structure theory: Profs. Hardy Gross & Rod Bartlett
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got some matrix elements to compute, needed some background music.
youtu.be/VM-2OVNt-eQ?si…
YouTube
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New preprint:
arxiv.org/abs/2506.09379
(is any still here btw?)
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coded a Hessian correctly the first time.
That can't be right.
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Meant to be a short project at the start of sabbatical, but here we are almost two years later...
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Next paper will clean up with Slater-Condon rules, removing deadweight states.
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Seniority-based CI works well for strongly correlated systems at an exponential cost. The goal here is to replace it with a short excitation-based CI of correlated states.
arxiv.org/abs/2501.07803
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didn't quite make the arXiv deadline. big one coming soon.
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Paul A Johnson retweetledi
Prof. Jiří Čížek, a true legend in the history of quantum chemistry who introduced coupled-cluster approach to electronic structure theory, has passed away. I was fortunate to work with him during my @UWaterloo years, when I was a member of Prof. Joe Paldus' group. R.I.P., Jiří
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Paul A Johnson retweetledi
Need a better basis for the Hilbert space: Richardson-Gaudin states
Condensed Matter Theory Center@condensed_the
Can AI solve strong correlation problems?The short answer is 'no' as training becomes exponentially difficult because of the exponential growth of Hilbert space. It seems quantum computers would not solve such problems either in the near future as logical qubits do not exist yet
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