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Related papers: Variation After Response in Quantum Monte Carlo

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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

An equation of motion formalism for excited states in variational Monte Carlo is derived and a pilot implementation for the Jastrow-modified antisymmetric geminal power is tested. In single excitations across a range of small molecules,…

Strongly Correlated Electrons · Physics 2016-05-12 Luning Zhao , Eric Neuscamman

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 systematically-improvable approach to core excitations in variational Monte Carlo. Building on recent work in excited-state-specific Monte Carlo, we show how a straightforward protocol, starting from a quantum chemistry guess,…

Chemical Physics · Physics 2020-10-28 Scott M. Garner , Eric Neuscamman

We present a variational Monte Carlo algorithm for estimating the lowest excited states of a quantum system which is a natural generalization of the estimation of ground states. The method has no free parameters and requires no explicit…

Computational Physics · Physics 2024-09-04 David Pfau , Simon Axelrod , Halvard Sutterud , Ingrid von Glehn , James S. Spencer

The authors present a technique using variational Monte Carlo to solve for excited states of electronic systems. The technique is based on enforcing orthogonality to lower energy states, which results in a simple variational principle for…

Chemical Physics · Physics 2021-10-15 Shivesh Pathak , Brian Busemeyer , João N. B. Rodrigues , Lucas K. Wagner

We employ quantum Monte Carlo to obtain chemically accurate vertical and adiabatic excitation energies, and equilibrium excited-state structures for the small, yet challenging, formaldehyde and thioformaldehyde molecules. A key ingredient…

Computational Physics · Physics 2019-08-02 Monika Dash , Jonas Feldt , Saverio Moroni , Anthony Scemama , Claudia Filippi

We perform excited-state variational Monte Carlo and diffusion Monte Carlo calculations using a simple and efficient wave function ansatz. This ansatz follows the recent variation-after-response formalism, accurately approximating a…

Strongly Correlated Electrons · Physics 2018-12-24 Nick S. Blunt , Eric Neuscamman

We present a variational Monte Carlo (VMC) method that works equally well for the ground and the excited states of a quantum system. The method is based on the minimization of the variance of energy, as opposed to the energy itself in…

Computational Physics · Physics 2007-05-23 Imran Khan , Bo Gao

We present the extension of variational Monte Carlo (VMC) to the calculation of electronic excitation energies and oscillator strengths using time-dependent linear-response theory. By exploiting the analogy existing between the linear…

Chemical Physics · Physics 2018-11-08 Bastien Mussard , Emanuele Coccia , Roland Assaraf , Matt Otten , C. J. Umrigar , Julien Toulouse

We present a discussion of recent progress in excited-state-specific quantum chemistry and quantum Monte Carlo alongside a demonstration of how a combination of methods from these two fields can offer reliably accurate excited state…

Chemical Physics · Physics 2023-02-07 Leon Otis , Eric Neuscamman

We introduce several improvements to the penalty-based variational quantum Monte Carlo (VMC) algorithm for computing electronic excited states of Entwistle $\textit{et al.}$ [M. T. Entwistle $\textit{et al.}$, Nat. Commun. $\textbf{14}$,…

Chemical Physics · Physics 2024-09-23 P. Bernát Szabó , Zeno Schätzle , Mike T. Entwistle , Frank Noé

Quantum Monte Carlo (QMC) is a stochastic method which has been particularly successful for ground-state electronic structure calculations but mostly unexplored for the computation of excited-state energies. Here, we show that, within a…

Chemical Physics · Physics 2018-08-09 Anthony Scemama , Anouar Benali , Denis Jacquemin , Michel Caffarel , Pierre-François Loos

We investigate the use of different variational principles in quantum Monte Carlo, namely energy and variance minimization, prompted by the interest in the robust and accurate estimate of electronic excited states. For two prototypical,…

Chemical Physics · Physics 2021-11-19 Alice Cuzzocrea , Anthony Scemama , Wim J. Briels , Saverio Moroni , Claudia Filippi

We review the use of continuum quantum Monte Carlo (QMC) methods for the calculation of energy gaps from first principles, and present a broad set of excited-state calculations carried out with the variational and fixed-node diffusion QMC…

Materials Science · Physics 2018-08-22 Ryan J. Hunt , Marcin Szyniszewski , Genki I. Prayogo , Ryo Maezono , Neil D. Drummond

Obtaining accurate ground and low-lying excited states of electronic systems is crucial in a multitude of important applications. One ab initio method for solving the Schr\"odinger equation that scales favorably for large systems is…

Chemical Physics · Physics 2023-01-19 Mike Entwistle , Zeno Schätzle , Paolo A. Erdman , Jan Hermann , Frank Noé

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

Quantum Monte Carlo methods are first-principle approaches that approximately solve the Schr\"odinger equation stochastically. As compared to traditional quantum chemistry methods, they offer important advantages such as the ability to…

Chemical Physics · Physics 2020-02-11 Jonas Feldt , Claudia Filippi

We extend our hybrid linear-method/accelerated-descent variational Monte Carlo optimization approach to excited states and investigate its efficacy in double excitations. In addition to showing a superior statistical efficiency when…

Chemical Physics · Physics 2022-02-24 Leon Otis , Isaac M. Craig , Eric Neuscamman

We examine applicability of the valence bond basis correlator product state ansatz, equivalent to the restricted Boltzmann machine quantum artificial neural network ansatz, and variational Monte Carlo method for direct optimization of…

Strongly Correlated Electrons · Physics 2020-08-12 Tanja Duric , Tomislav Seva
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