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Related papers: Computing excited states of molecules using normal…

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A numerical simulation of vibrational excitation of molecules was devised, and used to excite computational models of common molecules into a prescribed, pure, normal vibration mode in the ground electronic state, with varying, controlable…

Astrophysics · Physics 2009-11-11 Renaud Papoular

In this work we set up a model Hamiltonian to study the excited state quantum dynamics of 1,1-difluoroethylene, a molecule that has equivalent atoms exchanged by a torsional symmetry operation leading to equivalent minima on the potential…

Chemical Physics · Physics 2023-06-07 Sandra Gómez , Nadja Singer , Leticia González , Graham Worth

We present a generalization of the variational principle that is compatible with any Hamiltonian eigenstate that can be specified uniquely by a list of properties. This variational principle appears to be compatible with a wide range of…

Chemical Physics · Physics 2020-02-07 Jacqueline A. R. Shea , Elise Gwin , Eric Neuscamman

Understanding the properties of excited states of complex molecules is crucial for many chemical and physical processes. Calculating these properties is often significantly more resource-intensive than calculating their ground state…

Quantum Physics · Physics 2025-05-08 Manuel Hagelüken , Marco F. Huber , Marco Roth

We present a method for finding individual excited states' energy stationary points in complete active space self-consistent field theory that is compatible with standard optimization methods and highly effective at overcoming difficulties…

Strongly Correlated Electrons · Physics 2019-04-12 Lan Nguyen Tran , Jacqueline A. R. Shea , Eric Neuscamman

Utilizing quantum computer to investigate quantum chemistry is an important research field nowadays. In addition to the ground-state problems that have been widely studied, the determination of excited-states plays a crucial role in the…

The possibility of performing quantum chemical calculations using quantum computers has attracted much interest. In this regard, variational quantum deflation (VQD) is a quantum-classical hybrid algorithm for the calculation of excited…

Chemical Physics · Physics 2022-06-06 Soichi Shirai , Takahiro Horiba , Hirotoshi Hirai

During the noisy intermediate-scale quantum (NISQ) era, quantum computational approaches refined to overcome the challenge of limited quantum resources are highly valuable. However, the accuracy of the molecular properties predicted by most…

Quantum Physics · Physics 2023-12-20 Shih-Kai Chou , Jyh-Pin Chou , Alice Hu , Yuan-Chung Cheng , Hsi-Sheng Goan

The process of dynamic state estimation (filtering) based on point process observations is in general intractable. Numerical sampling techniques are often practically useful, but lead to limited conceptual insight about optimal…

Machine Learning · Statistics 2016-09-13 Yuval Harel , Ron Meir , Manfred Opper

We propose a new method to characterize the spatial distribution of particles' vibrations in solids with much lower computational costs compared to the usual normal mode analysis. We excite the specific vibrational mode in a two dimensional…

Soft Condensed Matter · Physics 2016-05-24 Elsen Tjhung , Takeshi Kawasaki

A method is presented in which the ground-state subspace is projected out of a Hamiltonian representation. As a result of this projection, an effective Hamiltonian is constructed where its ground-state coincides with an excited-state of the…

Quantum Physics · Physics 2023-08-14 P. Jouzdani , S. Bringuier , M. Kostuk

One of the primary challenges prohibiting demonstrations of practical quantum advantages for near-term devices amounts to excessive measurement overheads for estimating relevant physical quantities such as ground state energies. However,…

We propose a state-specific orbital optimization scheme for improving the accuracy of excited states of the electronic structure Hamiltonian for the use on near-term quantum computers, which can be combined with any overlap-based…

Quantum Physics · Physics 2025-10-16 Guorui Zhu , Joel Bierman , Jianfeng Lu , Yingzhou Li

Variational optimization of orbitals in time-independent density functional calculations of excited electronic states presents a significant challenge, as excited states typically correspond to saddle points on the electronic energy…

Chemical Physics · Physics 2026-04-02 Yorick L. A. Schmerwitz , Elli Selenius , Gianluca Levi

Using the effective rotational Hamiltonian method, we have conducted an analysis of the D218O ground and the first excited vibration state rotational energy levels. The analysis was based on the effective Hamiltonians represented in several…

Chemical Physics · Physics 2021-01-18 I. A. Vasilenko , O. V. Naumenko , E. R. Polovtseva , A. D. Bykov

The excitation of vibrational modes in molecules affects the outcome of chemical reactions, for example by providing molecules with sufficient energy to overcome activation barriers. In this work, we introduce a quantum algorithm for…

Quantum Physics · Physics 2021-12-01 Soran Jahangiri , Juan Miguel Arrazola , Nicolás Quesada , Alain Delgado

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

Variational quantum algorithms on bosonic quantum processors are an emerging paradigm for quantum chemistry calculations, exploiting the natural alignment between molecular structure and harmonic oscillator-based hardware. We introduce the…

Quantum Physics · Physics 2026-04-21 Marlon F. Jost , Sijia S. Dong

Some of us have recently reported in Science 321 232 (2008) vibrational cooling of translationally cold Cs_2 molecules into the lowest vibrational level v=0 of the singlet X 1Sigma_g ground electronic state. Starting from a sample of cold…

Quantum computing methods for excited-state calculations remain underexplored in Noisy Intermediate-Scale Quantum (NISQ) hardware, despite their critical role in photochemistry and material science. Herein, we propose a resource-efficient…

Quantum Physics · Physics 2025-06-16 Qianjun Yao , He Li