Hi, I'm working on LLP exclusion plots on my current paper. I need to add a discussion regarding the most sensitive ATLAS/CMS searches why they come out on top when constraining LLPs. These "searches" are usually the ones that CheckMATE outputs in its result file e.g. "atlas_conf_2020_048" or "atlas_conf_2019_040". Do u know any relevant paper that I can consult about them? I just need to know why they are stronger in constraining LLPs than the other searches. I also wouldn't mind any paper that can be relevant in comparing the different signal regions that constrains LLPs e.g. "EM12" or "MB-SSd-2-4000-28".

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What is your go to software/website for designing publication ready figures(making schematics and combining existing plots etc), either in Linux or Mac?

Hello everybody!

I am finalising my Master's thesis on the measurability of dark photons, and working out all the feedback I got from my supervisor. I had a last meeting with my supervisor this morning, but I forgot to ask about a certain part of feedback and I was wondering if you guys could help me out, as he normally does not respond to emails. In the image I provided, I am talking about the proper decay length of a dark photon. Could anyone explain how I can improve this part? Does it say 'decay time' in the feedback?

Thank you in advance!

In the Hartree-Fock method, one computes the energy of an interacting quantum-many body system, described by 𝐻, via taking a non-interacting trial ground state, |𝜓_HF⟩, and minimizing the total Hartree-Fock energy, 𝐸_HF = ⟨𝜓_HF|𝐻|𝜓_HF⟩ with respect to the atomic orbitals (subject to orthonormality). Doing so then yields a set of self-consistent Hartree-Fock equations which allows you to determine both the Hartree-Fock energy and precise form of the atomic orbitals.

However, I am confused how one uses this technique to do anything other than compute the total Hartree-Fock energy. For example, I was reading this paper, https://arxiv.org/abs/2012.05255, and the authors used Hartree-Fock to detect the presence of different ordered phases in this material, WTe2. But how exactly does computing the Hartree-Fock energy allow one to explore this type of physics? How does one use this method to predict phase transitions and different ordering phases based off the interaction strength?

Is the idea that, once you've solved the Hartree-Fock equations and constructed the optimal atomic orbitals and Hartree-Fock potential, you've essentially reduced the interacting electron problem back to an independent electron problem, and, from there, you can apply the usual machinery of solid-state physics to compute whatever quantities you’re interested in?

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A few years ago we held a graduate student panel, where many recently accepted grad students answered questions about the application process. That thread is here, and has a lot of great information in it.

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How exactly does one apply the Hartree-Fock approximation to study real materials?

For some context: lately, I’ve been trying to study transition metal dichalcogenides (specifically WTe2), and, in several papers that I’ve come across, much of the theoretical modeling of this material is done via Hartree-Fock. See the supplementary section of https://arxiv.org/abs/2010.05390 or https://arxiv.org/abs/2012.05255, for instance.

I was under the impression that the Hartree-Fock algorithm scales with the number of atoms (N) like N^4. Bearing this in mind, how is it at all computationally feasible to use this approach to study bulk, solid state systems which are comprised of a enormous, macroscopic number of atoms?

Almost all of the resources and implementations that I’ve come across online are geared towards molecules and quantum chemistry simulations, which are comprised of only a few atoms. A couple weeks ago, I wrote my own Hartree-Fock implementation and self-consistent field algorithm based off of these programs, and I was able to simulate basic things like hydrogen or water molecules. However, I have no idea how one would extend such a program to simulate actual materials. Ideally, I would like to become proficient enough to reproduce the results from the above papers, but I’m unsure how to apply this procedure to real condensed matter systems, as my program isn’t capable of dealing with more than 10-20 atoms. Anyone have any suggestions or resources?

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