English
Related papers

Related papers: Improved Stochastic Multireference Perturbation Th…

200 papers

Simulating many-body quantum systems is a promising task for quantum computers. However, the depth of most algorithms, such as product formulas, scales with the number of terms in the Hamiltonian, and can therefore be challenging to…

Quantum Physics · Physics 2023-04-19 Oriel Kiss , Michele Grossi , Alessandro Roggero

Multi-scale, multi-fidelity numerical simulations form the pillar of scientific applications related to numerically modeling fluids. However, simulating the fluid behavior characterized by the non-linear Navier Stokes equations are often…

The determination of quartic force fields for use in vibrational second-order perturbation (VPT2) calculations, currently available in numerous electronic structure packages, becomes very expensive as the size of the molecule increases,…

Chemical Physics · Physics 2026-04-23 Saikiran Kotaru , Chen Qu , Apurba Nandi , Paul L. Houston , Joel M. Bowman

The continuous time stochastic process is a mainstream mathematical instrument modeling the random world with a wide range of applications involving finance, statistics, physics, and time series analysis, while the simulation and analysis…

Quantum Physics · Physics 2023-10-04 Xi-Ning Zhuang , Zhao-Yun Chen , Cheng Xue , Yu-Chun Wu , Guo-Ping Guo

In this work, we introduce three algorithmic improvements to reduce the cost and improve the scaling of orbital space variational Monte Carlo (VMC). First, we show that by appropriately screening the one- and two-electron integrals of the…

Chemical Physics · Physics 2018-07-30 Iliya Sabzevari , Sandeep Sharma

Automated active space selection is arguably one of the most challenging and essential aspects of multiconfigurational methods. In this work we propose an effective quantum information-assisted complete active space optimization (QICAS)…

Quantum Physics · Physics 2024-09-19 Lexin Ding , Stefan Knecht , Christian Schilling

The original formulation (Phys. Rev. Lett. 119, 063002, 2017) of the natural orbital functional - second-order M{\o}ller-Plesset (NOF-MP2) method is based on the MP2 that uses the canonical Hartree-Fock molecular orbitals. The current work…

Chemical Physics · Physics 2018-08-22 Mario Piris

We present an efficient implementation of a one-step relativistic second-order multireference perturbation theory based on the multireference driven similarity renormalization group (MR-DSRG) using the exact two-component (X2C) Hamiltonian,…

Chemical Physics · Physics 2026-05-13 Zijun Zhao , Francesco A. Evangelista

This paper is concerned with risk-sensitive performance analysis for linear quantum stochastic systems interacting with external bosonic fields. We consider a cost functional in the form of the exponential moment of the integral of a…

Optimization and Control · Mathematics 2017-07-31 Igor G. Vladimirov , Ian R. Petersen , Matthew R. James

The efficient scheduling of multi-task jobs across multiprocessor systems has become increasingly critical with the rapid expansion of computational systems. This challenge, known as Multiprocessor Multitask Scheduling (MPMS), is essential…

Networking and Internet Architecture · Computer Science 2026-02-10 Wenxin Li

Calculations of excited states in Green's function formalism often invoke the diagonal approximation, in which the quasiparticle states are taken from a mean-field calculation. Here, we extend the stochastic approaches applied in the…

Computational Physics · Physics 2023-09-28 Annabelle Canestraight , Xiaohe Lei , Khaled Ibrahim , Vojtech Vlcek

Symplectic N-body integrators are widely used to study problems in celestial mechanics. The most popular algorithms are of 2nd and 4th order, requiring 2 and 6 substeps per timestep, respectively. The number of substeps increases rapidly…

Astrophysics · Physics 2009-10-31 J. E. Chambers , M. A. Murison

In this work, we develop a new orbital optimization approach, perturbative Super-CI (Super-CIPT), for the two-component complete active space self-consistent field (2C-CASSCF) method. By variationally optimizing spinor orbitals and…

Chemical Physics · Physics 2026-03-04 Yang Guo , Achintya Kumar Dutta

Applications of quantum simulation algorithms to obtain electronic energies of molecules on noisy intermediate-scale quantum (NISQ) devices require careful consideration of resources describing the complex electron correlation effects. In…

Quantum Physics · Physics 2020-04-17 Mekena Metcalf , Nicholas P. Bauman , Karol Kowalski , Wibe A. de Jong

A recently proposed method for computer simulations in the isothermal-isobaric (NPT) ensemble, based on Langevin-type equations of motion for the particle coordinates and the ``piston'' degree of freedom, is re-derived by straightforward…

Soft Condensed Matter · Physics 2016-08-31 A. Kolb , B. Duenweg

We extend the Mixed Quantum-Classical Initial Value Representation (MQC-IVR), a semiclassical method for computing real-time correlation functions, to electronically nonadiabatic systems using the Meyer-Miller-Stock-Thoss (MMST) Hamiltonian…

Chemical Physics · Physics 2018-01-17 Matthew S. Church , Timothy J. H. Hele , Gregory S. Ezra , Nandini Ananth

We present a family of modified Hermite integrators of arbitrary order possessing superior behaviour for the integration of Keplerian and near-Keplerian orbits. After recounting the derivation of Hermite N-body integrators of arbitrary…

Earth and Planetary Astrophysics · Physics 2020-06-23 Alexander J. Dittmann

Recent quantum algorithms pertaining to electronic structure theory primarily focus on threshold-based dynamic construction of ansatz by selectively including important many-body operators. These methods can be made systematically more…

Quantum Physics · Physics 2024-08-26 Chayan Patra , Debaarjun Mukherjee , Sonaldeep Halder , Dibyendu Mondal , Rahul Maitra

Noncollinear (NC) magnetism and spin-orbit coupling (SOC) are indispensable for predictive ab initio materials simulations with pronounced relativistic effects and magnetic frustration, yet they significantly increase the cost of…

This study examines several techniques to improve the efficiency of the linearized multireference driven similarity renormalization group truncated to one- and two-body operators [MR-LDSRG(2)]. We propose a sequential MR-LDSRG(2)…

Chemical Physics · Physics 2019-03-29 Tianyuan Zhang , Chenyang Li , Francesco A. Evangelista