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Related papers: A variational Monte Carlo approach for core excita…

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We present a variational function that targets excited states directly based on their position in the energy spectrum, along with a Monte Carlo method for its evaluation and minimization whose cost scales polynomially for a wide class of…

Strongly Correlated Electrons · Physics 2016-01-22 Luning Zhao , Eric Neuscamman

We present a simple and efficient wave function ansatz for the treatment of excited charge-transfer states in real-space quantum Monte Carlo methods. Using the recently-introduced variation-after-response method [J. Chem. Phys. 145, 081103…

Chemical Physics · Physics 2017-11-20 N. S. Blunt , Eric Neuscamman

Variational Monte Carlo methods have recently been applied to the calculation of excited states; however, it is still an open question what objective function is most effective. A promising approach is to optimize excited states using a…

Computational Physics · Physics 2023-12-04 William A. Wheeler , Kevin G. Kleiner , Lucas K. Wagner

Variational algorithms for strongly correlated chemical and materials systems are one of the most promising applications of near-term quantum computers. We present an extension to the variational quantum eigensolver that approximates the…

Quantum Physics · Physics 2020-08-26 William J. Huggins , Joonho Lee , Unpil Baek , Bryan O'Gorman , K. Birgitta Whaley

A Monte Carlo method is presented to evaluate quantum states with many particles moving in the continuum. The scattering state is generated at each time by a Monte Carlo random sampling algorithm. The same calculation are repeated until the…

Nuclear Theory · Physics 2013-06-06 Zhen-Xiang Xu , Chong Qi

We propose a method to calculate the charge dynamical structure factors for the ground states of correlated electron systems based on the variational Monte Carlo method. Our benchmarks for the one- and two-dimensional Hubbard models show…

Strongly Correlated Electrons · Physics 2020-02-25 Kota Ido , Masatoshi Imada , Takahiro Misawa

We review a recent approach for the simulation of many-body interacting systems based on an efficient generalization of the Lanczos method for Quantum Monte Carlo simulations. This technique allows to perform systematic corrections to a…

Strongly Correlated Electrons · Physics 2007-05-23 Sandro Sorella

We develop a formalism to directly evaluate the matrix of force constants within a Quantum Monte Carlo calculation. We utilize the matrix of force constants to accurately relax the positions of atoms in molecules and determine their…

Computational Physics · Physics 2020-04-06 Yu Yang Fredrik Liu , Bartholomew Andrews , Gareth J. Conduit

The possibility to simulate the properties of many-body open quantum systems with a large number of degrees of freedom is the premise to the solution of several outstanding problems in quantum science and quantum information. The challenge…

Quantum Physics · Physics 2019-07-03 Alexandra Nagy , Vincenzo Savona

We introduce a novel method of efficiently simulating the non-equilibrium steady state of large many-body open quantum systems with highly non-local interactions, based on a variational Monte Carlo optimization of a matrix product operator…

Quantum Physics · Physics 2024-09-18 Dawid A. Hryniuk , Marzena H. Szymańska

Neutral molecules with sufficiently large dipole moments can bind electrons in diffuse nonvalence orbitals with most of their charge density far from the nuclei, forming so-called dipole-bound anions. Because long-range correlation effects…

Chemical Physics · Physics 2018-10-30 Hongxia Hao , James Shee , Shiv Upadhyay , Can Ataca , Kenneth D. Jordan , Brenda M. Rubenstein

Monte Carlo methods are used to study the phase transition in ammonium chloride from the orientationally ordered $\delta$ phase to the orientationally disordered $\gamma$ phase. An effective pair potential is used to model the interaction…

chem-ph · Physics 2008-02-03 Robert Q. Topper , David L. Freeman

We revisit here the lowest vertical excitations of cyanine dyes using quantum Monte Carlo and leverage on recent developments to systematically improve on previous results. In particular, we employ a protocol for the construction of compact…

Chemical Physics · Physics 2021-11-22 Alice Cuzzocrea , Saverio Moroni , Anthony Scemama , Claudia Filippi

A quantum Monte Carlo method is introduced to optimize excited state trial wavefunctions. The method is applied in a correlation function Monte Carlo calculation to compute ground and excited state energies of bosonic van der Waals clusters…

Computational Physics · Physics 2009-11-06 M. P. Nightingale , Vilen Melik-Alaverdian

We propose a new variational Monte Carlo (VMC) method with an energy variance extrapolation for large-scale shell-model calculations. This variational Monte Carlo is a stochastic optimization method with a projected correlated condensed…

Nuclear Theory · Physics 2012-02-14 Takahiro Mizusaki , Noritaka Shimizu

We study lithium systems over a range of number of atoms, e.g., atomic anion, dimer, metallic cluster, and body-centered cubic crystal by the diffusion Monte Carlo method. The calculations include both core and valence electrons in order to…

Computational Physics · Physics 2015-07-29 Kevin Rasch , Lubos Mitas

We demonstrate that a broad class of excited state variational principles is not size consistent. In light of this difficulty, we develop and test an approach to excited state optimization that transforms between variational principles in…

Chemical Physics · Physics 2017-09-01 Jacqueline A. R. Shea , Eric Neuscamman

We develop a variational Monte Carlo (VMC) method for electron-phonon coupled systems. The VMC method has been extensively used for investigating strongly correlated electrons over the last decades. However, its applications to…

Strongly Correlated Electrons · Physics 2014-06-02 Takahiro Ohgoe , Masatoshi Imada

In this work we develop tools that enable the study of non-adiabatic effects with variational and diffusion Monte Carlo methods. We introduce a highly accurate wave function ansatz for electron-ion systems that can involve a combination of…

Chemical Physics · Physics 2014-10-29 Norm M. Tubman , Ilkka Kylänpää , Sharon Hammes-Schiffer , David M. Ceperley

We report quantum Monte Carlo calculations of ground and low-lying excited states for nuclei with A \leq 7 using a realistic Hamiltonian containing the Argonne v18 two-nucleon and Urbana IX three-nucleon potentials. A detailed description…

Nuclear Theory · Physics 2008-11-26 B. S. Pudliner , V. R. Pandharipande , J. Carlson , Steven C. Pieper , R. B. Wiringa