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The recent quantum information boom has effected a resurgence of interest in unitary coupled cluster (UCC) theory. Our group's interest in local energy landscapes of unitary ans\"atze prompted us to investigate the classical approach of…

Chemical Physics · Physics 2022-11-01 Harper R. Grimsley , Nicholas J. Mayhall

We present a procedure to solve the inverse Ising problem, that is to find the interactions between a set of binary variables from the measure of their equilibrium correlations. The method consists in constructing and selecting specific…

Disordered Systems and Neural Networks · Physics 2015-05-30 Simona Cocco , Rémi Monasson

Excited states in molecules can be difficult to investigate and generally require methods that are either computationally expensive or are not universally accurate. Recent research has focused on using higher-energy Slater determinants as…

Chemical Physics · Physics 2023-01-26 Diana-Gabriela Oprea , Hugh G. A. Burton

In single-reference coupled-cluster (CC) methods, one has to solve a set of non-linear polynomial equations in order to determine the so-called amplitudes which are then used to compute the energy and other properties. Although it is of…

Chemical Physics · Physics 2021-09-10 Antoine Marie , Fábris Kossoski , Pierre-François Loos

In electronic structure theory, restricted single-reference coupled cluster (CC) captures weak correlation but fails catastrophically under strong correlation. Spin-projected unrestricted Hartree-Fock (SUHF), on the other hand, misses weak…

Chemical Physics · Physics 2017-11-22 John A. Gomez , Thomas M. Henderson , Gustavo E. Scuseria

This paper presents an analytical and experimental design and deployment control analysis of a hyperbolic paraboloid cable net based on clustering actuation strategies. First, the dynamics and statics for clustered tensegrity structures…

Systems and Control · Electrical Eng. & Systems 2022-06-29 Shuo Ma , Kai Lu , Muhao Chen , Robert E. Skelton

In the last decade, the quantum chemical version of the density matrix renormalization group (DMRG) method has established itself as the method of choice for calculations of strongly correlated molecular systems. Despite its favourable…

Chemical Physics · Physics 2016-11-15 Libor Veis , Andrej Antalík , Jiří Brabec , Frank Neese , Örs Legeza , Jiří Pittner

A unitary coupled-cluster (UCC)-based self-consistent electron propagator theory (EPT) is proposed for the description of electron-detached and electron-attached states. Two practical schemes, termed IP/EA-UCC3 and IP/EA-qUCCSD, are…

Chemical Physics · Physics 2026-03-03 Yu Zhang , Junzi Liu

We explore the possibility of calculating electronic excited states by using perturbation theory along a range-separated adiabatic connection. Starting from the energies of a partially interacting Hamiltonian, a first-order correction is…

Chemical Physics · Physics 2014-12-15 Elisa Rebolini , Julien Toulouse , Andrew M. Teale , Trygve Helgaker , Andreas Savin

Recently, the following novel method for proving the existence of solutions for certain linear time-invariant PDEs was introduced: The operator associated to a given PDE is represented by a (larger) operator with an internal loop. If the…

Optimization and Control · Mathematics 2015-11-09 Mikael Kurula , Hans Zwart

Composite pulses are an efficient tool for robust quantum control. In this work, we derive the form of the composite pulse sequence to implement robust single-qubit gates in a three-level system, where two low-energy levels act as a qubit.…

Quantum Physics · Physics 2021-05-27 Zhi-Cheng Shi , Hai-Ning Wu , Li-Tuo Shen , Yan Xia , X. X. Yi , Shi-Biao Zheng

Topological order offers possibilities for processing quantum information which can be immune to imperfections. However, the question of its stability out of equilibrium is relevant for experiments, where coupling to an environment is…

Quantum Physics · Physics 2025-05-16 Dawid Paszko , Dominic C. Rose , Marzena H. Szymańska , Arijeet Pal

Although many convex relaxations of clustering have been proposed in the past decade, current formulations remain restricted to spherical Gaussian or discriminative models and are susceptible to imbalanced clusters. To address these…

Machine Learning · Computer Science 2013-09-27 Hao Cheng , Xinhua Zhang , Dale Schuurmans

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

We present a similarity transformation theory based on a polynomial form of a particle-hole pair excitation operator. In the weakly correlated limit, this polynomial becomes an exponential, leading to coupled cluster doubles. In the…

Strongly Correlated Electrons · Physics 2016-11-23 Matthias Degroote , Thomas M. Henderson , Jinmo Zhao , Jorge Dukelsky , Gustavo E. Scuseria

We analyze experimentally and theoretically the response of a network of spiking nodes to external perturbations. The experimental system consists of an array of semiconductor lasers that are adaptively coupled through an optoelectronic…

Adaptation and Self-Organizing Systems · Physics 2024-12-16 S. Barland , O. D'Huys , R. Veltz

We investigate the three-dimensional compressible Euler-Maxwell system, a model for simulating the transport of electrons interacting with propagating electromagnetic waves in semiconductor devices. First, we show the global well-posedness…

Analysis of PDEs · Mathematics 2024-07-02 Timothée Crin-Barat , Yue-Jun Peng , Ling-Yun Shou , Jiang Xu

A theoretical analysis is presented to show the general occurrence of phase clusters in weakly, globally coupled oscillators close to a Hopf bifurcation. Through a reductive perturbation method, we derive the amplitude equation with a…

Adaptation and Self-Organizing Systems · Physics 2014-09-17 Hiroshi Kori , Yoshiki Kuramoto , Swati Jain , István Z. Kiss , John Hudson

Many natural and man-made systems require suitable feedback to function properly. In this study, we aim to investigate the impact of additional complex conjugate feedback on globally coupled Stuart-Landau oscillators. We find that this…

Adaptation and Self-Organizing Systems · Physics 2022-09-14 K. Sathiyadevi , D. Premraj , Tanmoy Banerjee , M. Lakshmanan

The dual exponential coupled cluster (CC) theory proposed by Tribedi et al.[J. Chem. Theory Comput. 2020, 16, 10, 6317-6328] performs significantly better than the coupled cluster theory with singles and doubles excitations (CCSD) due to…

Computational Physics · Physics 2023-07-26 Anish Chakraborty , Rahul Maitra