Project Ideas
Project Ideas
Initiated by AJWT and uncurated. Contact to discuss, or do edit or add discussion and links.
October 2024 based on ISTCP 2024
P: 14/10/24 Martin Head Gordon. local orbitals for MP2 with fixed sparsity pattern. Some thresholding but generally very good and local. JCP 158 064105 '23 || Use these orbitals for CCMC
P: Check size consistency of CCMC (on Ne, Ne2 etc)
P: 14/10/24 Jeremy Richardson: "Breaking down the Barrier between Quantum and Classical." MASH (a deterministic version of surface hopping which couples a fictitious degree of freedom to decide which of two surfaces to hop on). Nat Commun. 15 4335 '24. JCP 158 104111 '23. || Use SCF diabatic-like states for this.
P 14/10/24 Troy van Voorhis "Bootstrap embedding". QuEmb software on GitHub to do this. || Use to look at He in clusters.
TODO Advertise HANDE hackathons on website
P: [post ByteDance] Understanding the Nodal surface - evaluate FermiNet's Nodal surface for quality (somehow)
P: [post ByteDance] Resolution of the Identity or density fitting to get HANDE 2e integrals.
P: [post ByteDance] Can we use the S+|Psi>=0 requirement to enforce Spin symmetry (S^2)
TODO: Read Pfau Science 2024
Q: How exactly are internally and externally contracted defined [Siegbahn 1980, 1983]
L: Quantum Course - Schmidt decomposition and properties of the Density Matrix
L: Quantum Course - Adiabatic connection used in DFT and ADC - how?
TODO: Interact more with Yi Sun on this Bootsctrap embedding
Q: Do complex nuclear coordinates lead to plane wave boundary conditions?
P: Do DMC on Fullerenes
P: 15/10/24 Janus Erikson: "Exact symmetrixation of localied MOs in MBE-FCI." || He has cc-pVTZ benzene results. || Do CCMCSDTQ5/pVDZ CCSDTQ/pVTZ on benzene at his geoms with Chebyshev.
P: biradicals JCP 147 164120 '20
Q: 15/10/24 Weitao Yang: "Delta SCF Excited state approaches: THeoretical Foudnations, Linear conditions for fractional charges and physical meaning of orbital energies". Delta SCF is justified by the correspondence between exact (n, w(r)) <-> (n_s, w_s(r)) correspondence (state number, potential). Functional is not of density but of n,w or 1PDM. 2403.04604. The numbering of states between n_s and n may differ. || What happens when two states cross (i.e. switch n_s value)?
Q: 15/10/24 Andy Teale: "Adiabatic Connection and reaction barriers". He defined a quantity \cal R_\lambda which corresponds to difference in adiabatic connection's W_\labda for a barrier. Shapes of this for forward and backward barriers of H_N2->HN2 very different. changing amount of HF exchange just shifts energies up and down (i.e. you get any result you want). ||Why do forward and backward barriers differ?
P: What barriers are bad in DFT and why?▒▒
P: Separating Static and Dynamic Correlation: MCPDFT and others (Gagliardi, Pernal)
Q: What is a restricted Boltzman Machine useful for?
P: Understanding UCC. How different are the different Anstzes and what effects do they have.
P: Simulate decoherence in quantum computing by coupling to a bath?
P: 16/10/24 Jiali Gao: "Multistate DFT and Applications". JPCL 13 7762 '22, JCTC 18 7403 '23. JCTC 20 8474 '24. JCTC 18 6407 '22|| Can apply this approach directly to the hDFT code or hNOCI code in RevQCMagic.▒
Q: Is MS-DFT for the HF functional just NOCI?
Q: 17/10/24. Wei Wu: "MRDFT with VB methods". Acc. Chem. Res. 54 3895 '21. KCP 157 084106 '22. JCTC 8 1608 '12.| Where are the F+...F- states in hHF/hDFT. How do they compare to the VB states?
TODO: Review of Multireference DFT
Q: 17/10/24 Chen Li: "Improving DFAs through exact constraints and exact WFs." cf Gori Giorgi PRA 75 042511 '07. hbar-> is like strong correlation. || Can we do complex scaling or tracking y changing hbar? Do NOCI with solutions with different hbar values
Q: Can we interact fragments' HF solutions by e-e-scaling the electrons? Is this just the same as bringing them in from infinity?
Q: How can we DAMP CCMC so it foesn't explode into the whole of CC space (so not needing an explicit truncation) Is it because we are not in spin eigenfunctions so we always spawn heavily into higher levels?
P: In the true CC solution, is there a lot of cancellation which might not be visible in a spin-symmetry broken stochastic snapshot (i.e. fluctuation induced sym breaking casuses lots of particles which do't cancel'
Q: 17/10/24 Piotr Piecuch: "Converging High-level CC energetics in Semistochastic, CIPSI-driven & adaptive CC(P;Q)". JCP 159 084108 '23. JCP 154 124103 '21. CCpy code availale on GitHub. ||How do the CC(P;Q) moment corrections actually work?
Q: For Ne@C70, what level of CC(P;Q) would be beeded to get <1cm-1 accuracy?
TODO: Buy "Interacting Electrons".
P: Calculate the diabaticity <Psi_\mu|\grad|Psi_nu> of different SCF states.
Q: Can the concept of diabaticity be applied to DFT? Can we calculate these adiabatic couplings in terms of densities?
September 2024
Finite Temperature holomorphic Hartree--Fock and DFT
This may alleviate some of the challenges of solutions coalescing
A Language for Electron Correlation
In order to use a generative AI language model to help tackle electron correlation, we need a language to do it in which is mostly transferrable between different molecules (and ceratinly within the same molecule). It should probably be based on localised orbitals in some way, but what is the best way of doing this? Can it be a simple type of decorator saying: correlate these orbitals? This might be a good fast starting guess for something at least.
Lindh Gradient Enhanced Kriging. JCPA for orbital version
Jiuli Gao: Mutistate DFT SOme H matrix of Densities Theophilou Subspace Theorem (1979) JPCL 2022, 13, 7762. JCTC 2022 18 6407. JPCL 12 7409 '21. JCTC 4c00545. JCPL 4838 8 2017.
Kasia Pernal: Ontop Pair Density Functional for WF THeories Apply to hNOCI
Automated construction of hHF states from dissociated atoms
tetracene noci calcs
NOCI in a larger context - water clusters
pysurf for dynamics - with NOCI? Shirin Faraji
NOCI + Piris Global Natural Orbital Functioonal
CCMC+f12 - generate the 3-e integrals from libint? Use FOrm like Ten-NO pTC2.
To Code: AFQMC