Pseudo-BCS wave function from density matrix decomposition: Application in auxiliary-field quantum Monte Carlo
نویسندگان
چکیده
We present a method to construct pseudo-BCS wave functions from the one-body density matrix. The resulting many-body function, which can be produced for any fermion systems, including those with purely repulsive interactions, has form of number-projected BCS form, or antisymmetrized geminal power (AGP). Such provide better ansatz correlated systems than single Slater determinant, and often linear combination determinants (for example truncated active space calculation). describe procedure build such function conveniently given reduced matrix system, rather mean-field solution (which gives determinant interactions). thus obtained reproduces minimizes difference between input matrices. One application is in auxiliary-field quantum Monte Carlo (AFQMC) calculations as trial control sign/phase problem. AFQMC among most accurate general methods systems. show that further reduces constraint bias leads improved accuracy compared usual functions, using two-dimensional Hubbard model an example. Furthermore, allows new systematically improvable self-consistent approach, iteratively generated by via matrix.Received 19 October 2020Revised 4 January 2021Accepted 6 2021DOI:https://doi.org/10.1103/PhysRevResearch.3.013065Published American Physical Society under terms Creative Commons Attribution 4.0 International license. Further distribution this work must maintain attribution author(s) published article's title, journal citation, DOI.Published SocietyPhysics Subject Headings (PhySH)TechniquesApproximation systemsBCS theoryHubbard modelQuantum CarloCondensed Matter, Materials & Applied Physics
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ژورنال
عنوان ژورنال: Physical review research
سال: 2021
ISSN: ['2643-1564']
DOI: https://doi.org/10.1103/physrevresearch.3.013065