English
Related papers

Related papers: A new and efficient implementation of CC3

200 papers

The quantum computing scheme described in Phys. Rev. Lett. 98, 190504 (2007), when viewed as a cluster state computation, features a 3-D cluster state, novel adjustable strength error correction capable of correcting general errors through…

Quantum Physics · Physics 2009-07-16 Austin G. Fowler , Kovid Goyal

The variational cluster approximation is applied to the calculation of thermodynamical quantities and single-particle spectra of LaCoO3. Trial self-energies and the numerical value of the Luttinger-Ward functional are obtained by exact…

Strongly Correlated Electrons · Physics 2015-05-14 R. Eder

We present a new method for computing the Near-To-Far-Field (NTFF) transformation in FDTD simulations which has an overall scaling of $O(N^3)$ instead of the standard $O(N^4)$. By mapping the far field with a cartesian coordinate system the…

Computational Physics · Physics 2013-11-05 Travis Garrett

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

A practical high-accuracy relativistic method of atomic structure calculations for univalent atoms is presented. The method is rooted in the coupled-cluster formalism and includes non-perturbative treatment of single and double excitations…

Atomic Physics · Physics 2009-11-11 Sergey G. Porsev , Andrei Derevianko

Photon-induced electronic excitations are ubiquitously observed in organic chromophore. In this context, we present a simple, alternative time-independent DFT procedure, for computation of single-particle excitation energies, in particular,…

Chemical Physics · Physics 2021-03-01 Abhisek Ghosal , Tarun Gupta , Kishalay Mahato , Amlan K. Roy

In this work, we derive working equations for the Linear Response pair Coupled Cluster Doubles (LR-pCCD) ansatz and its extension to singles (S), LR-pCCD+S. These methods allow us to compute electronic excitation energies and transition…

Chemical Physics · Physics 2025-03-18 Somayeh Ahmadkhani , Katharina Boguslawsk , Paweł Tecmer

We present a computationally efficient relativistic formulation of the equation-of-motion coupled-cluster method for the double electron attachment problem. In this work, the exact two-component Hamiltonian within the atomic mean-field…

Chemical Physics · Physics 2026-03-31 Sujan Mandal , Tamoghna Mukhopadhyay , Achintya Kumar Dutta

Quantum computers have proven to be effective in simulating many quantum systems. Simulating nuclear processes and state preparation poses significant challenges, even for traditional supercomputers. This study demonstrates the feasibility…

Quantum Physics · Physics 2024-12-05 Luca Nigro , Carlo Barbieri , Enrico Prati

In Paper I, the effective one-electron potentials (OEP) method was introduced and demonstrated as an efficient approach to reduce the computational cost of evaluation of the charge-transfer interaction energy within the effective fragment…

Chemical Physics · Physics 2020-02-04 Bartosz Błasiak , Robert W. Góra , Wojciech Bartkowiak

The excited electronic states involved in the optical cycle preparation of a pure spin state of the negatively charged NV-defect in diamond are calculated using the HSE06 hybrid density functional and variational optimization of the…

Materials Science · Physics 2025-10-29 Lei Sun , Elvar Örn Jónsson , Aleksei Ivanov , Ji Chen , Hannes Jónsson

Variational Quantum Eigensolver (VQE) is a promising algorithm for near-term quantum machines. It can be used to estimate the ground state energy of a molecule by performing separate measurements of $O(N^4)$ terms. Several recent papers…

Quantum Physics · Physics 2019-09-02 Pranav Gokhale , Frederic T. Chong

We present a new method for state preparation using the Unitary Vibrational Coupled-Cluster (UVCC) technique. Our approach utilizes redundancies in the Hilbert space in the direct mapping of vibrational modes into qubits. By eliminating…

Quantum Physics · Physics 2024-12-06 Michal Szczepanik , Emil Zak

In the framework of the computational determination of highly-accurate vertical excitation energies in small organic compounds, we explore the possibilities offered by the equation-of-motion formalism relying on the approximate fourth-order…

Open-shell systems such as magnetic molecules or defects with a triplet ground state are challenging to describe in electronic structure methods, but are of great interest for quantum information applications. We demonstrate a spin-flip…

Materials Science · Physics 2022-07-12 Bradford A. Barker , David A. Strubbe

We present a study of the two dimensional circular quantum dot model Hamiltonian using a range of quantum chemical ab initio methods. Ground and excited state energies are computed on different levels of perturbation theories including the…

Chemical Physics · Physics 2022-03-23 Faruk Salihbegović , Alejandro Gallo , Andreas Grüneis

Implementing quantum algorithms is essential for quantum computation. We study the implementation of three quantum algorithms by performing homodyne measurements on a two-dimensional temporal continuous-variable cluster state. We first…

Time-dependent equation-of-motion coupled cluster (TD-EOM-CC) is used to simulate impulsive stimulated x-ray Raman scattering (ISXRS) of ultrashort laser pulses by neon, carbon monoxide, pyrrole, and p-aminophenol. The TD-EOM-CC equations…

Chemical Physics · Physics 2023-10-10 Alice Balbi , Andreas S. Skeidsvoll , Henrik Koch

The term GreenAI refers to a novel approach to Deep Learning, that is more aware of the ecological impact and the computational efficiency of its methods. The promoters of GreenAI suggested the use of Floating Point Operations (FLOPs) as a…

Machine Learning · Computer Science 2025-11-06 Andrea Asperti , Davide Evangelista , Moreno Marzolla

State-specific orbital optimized approaches are more accurate at predicting core-level spectra than traditional linear-response protocols, but their utility had been restricted on account of the risk of `variational collapse' down to the…