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A common approach to minimizing the cost of quantum computations is by transforming a quantum system into a basis that can be optimally truncated. Here, we derive classical equations of motion subjected to similar unitary transformations,…

Quantum Physics · Physics 2024-04-25 Ken Miyazaki , Alex Krotz , Roel Tempelaar

Hamiltonian Truncation Methods are a useful numerical tool to study strongly coupled QFTs. In this work we present a new method to compute the exact corrections, at any order, in the Hamiltonian Truncation approach presented by Rychkov et…

High Energy Physics - Theory · Physics 2016-05-25 J. Elias-Miro , M. Montull , M. Riembau

This paper presents a simple and effective new numerical scheme for the computation of electrostatic fields exterior to a collection of close-to-touching discs. The method is presented in detail for the two-cylinder case. The key idea is to…

Numerical Analysis · Mathematics 2014-09-09 D. G. Crowdy , S. Tanveer , T. Delillo

We present an accurate and efficient real-space Density Functional Theory (DFT) framework for the ab-initio study of non-orthogonal crystal systems. Specifically, employing a local reformulation of the electrostatics, we develop a novel…

Computational Physics · Physics 2018-05-09 Abhiraj Sharma , Phanish Suryanarayana

The rapid development of ab initio nuclear structure methods towards doubly open-shell nuclei, heavy nuclei and greater accuracy occurs at the price of evermore increased computational costs, especially RAM and CPU time. While most of the…

Nuclear Theory · Physics 2026-01-19 Alberto Scalesi , Thomas Duguet , Mikael Frosini , Vittorio Somà

We recently showed that the Dephasing Representation (DR) provides an efficient tool for computing ultrafast electronic spectra and that further acceleration is possible with cellularization [M. \v{S}ulc and J. Van\'i\v{c}ek, Mol. Phys.…

Chemical Physics · Physics 2015-06-16 Miroslav Šulc , Henar Hernández , Todd J. Martínez , Jiří Vaníček

In this paper, we present a method for the Hamiltonian simulation in the context of eigenvalue estimation problems which improves earlier results dealing with Hamiltonian simulation through the truncated Taylor series. In particular, we…

Quantum Physics · Physics 2018-11-01 Ammar Daskin , Sabre Kais

We present a novel "linear combination of atomic orbitals"-type of approximation, enabling accurate electronic structure calculations for systems of up to 20 or more electronically coupled quantum dots. Using realistic single quantum dot…

Mesoscale and Nanoscale Physics · Physics 2021-03-10 Alexander Mittelstädt , Ludwig A. Th. Greif , Stefan T. Jagsch , Andrei Schliwa

Most modern calculations of many-electron atoms use basis sets of atomic orbitals. An accurate account for the electronic correlations in heavy atoms is very difficult computational problem and optimization of the basis sets can reduce…

Atomic Physics · Physics 2024-01-17 M. G. Kozlov , Yu. A. Demidov , M. Y. Kaygorodov , E. V. Triapitsyna

An approach to electron correlation effects in atoms that uses quantum trajectories is presented. A comparison with the exact quantum mechanical results for 1D Helium atom shows that the major features of the correlated ground state…

Atomic Physics · Physics 2025-02-07 Ivan P. Christov

Hamiltonian quantum simulation of bosons on digital quantum computers requires truncating the Hilbert space to finite dimensions. The method of truncation and the choice of basis states can significantly impact the complexity of the quantum…

Quantum Physics · Physics 2025-10-10 Masanori Hanada , Shunji Matsuura , Emanuele Mendicelli , Enrico Rinaldi

We review techniques for simulating fully quantum nonadiabatic dynamics using the frozen-width moving Gaussian basis functions to represent the nuclear wavefunction. A choice of these basis functions is primarily motivated by the idea of…

Chemical Physics · Physics 2018-09-05 Loïc Joubert-Doriol , Artur F. Izmaylov

We propose a system-oriented basis-set design based on even-tempered basis functions to variationally encode electronic ground-state information into molecular orbitals. First, we introduce a reduced formalism of concentric even-tempered…

Chemical Physics · Physics 2026-02-23 Weishi Wang , Casey Dowdle , James D. Whitfield

Localized basis sets in the projector augmented wave formalism allow for computationally efficient calculations within density functional theory (DFT). However, achieving high numerical accuracy requires an extensive basis set, which also…

Materials Science · Physics 2020-11-18 G. Gandus , A. Valli , D. Passerone , R. Stadler

We introduce a systematic expansion tailored to systems with strong local interactions and capable of computing response functions, including finite DC transport, analytically. The expansion is controlled by a small parameter $s^2$ that…

Strongly Correlated Electrons · Physics 2026-05-20 Pavel A Nosov , Eslam Khalaf , Patrick Ledwith

The effective field theory (EFT) for triaxially deformed even-even nuclei is generalized to include the vibrational degrees of freedom. The pertinent Hamiltonian is constructed up to next-to-leading order. The leading order part describes…

Nuclear Theory · Physics 2018-07-04 Q. B. Chen , N. Kaiser , Ulf-G. Meißner , J. Meng

We develop a comprehensive theory for the effective dynamics of Bloch electrons based on symmetry. We begin with a scheme to systematically derive the irreducible representations (IRs) characterizing the Bloch functions. Starting from a…

Mesoscale and Nanoscale Physics · Physics 2019-09-06 E. A. Fajardo , R. Winkler

We formulate the calculation of the ground-state wavefunction and energy of a system of strongly correlated electrons in terms of scattering matrices. A hierarchy of approximations is introduced which results in an incremental expansion of…

Condensed Matter · Physics 2009-10-31 P. Fulde , H. Stoll , K. Kladko

The quantum phase estimation algorithm stands as the primary method for determining the ground state energy of a molecular electronic Hamiltonian on a quantum computer. In this context, the ability to initialize a classically tractable…

We show here that the Hamiltonian for an electronic system may be written exactly in terms of fluctuation operators that transition constituent fragments between internally correlated states, accounting rigorously for inter-fragment…

Chemical Physics · Physics 2019-05-24 Anthony D. Dutoi , Yuhong Liu