In this work, we report, for the first time, an implementation of fermionic auxiliary-field quantum Monte Carlo (AFQMC) using matrix product state (MPS) trial wavefunctions, dubbed MPS-AFQMC. Calculating overlaps between MPS and arbitrary Slater determinants up to a multiplicative error, crucial subroutine in MPS-AFQMC, is proven be #P-hard. Nonetheless, tested several promising heuristics successfully improving phaseless AFQMC energies. We also proposed way evaluate local energy force bias...

We develop a microscopic theory for the multimode polariton dispersion in materials coupled to cavity radiation modes. Starting from light-matter Hamiltonian, we devise general strategy obtaining simple matrix models of curves based on structure and spatial location multi-layered 2D inside optical cavity. Our exposes connections between seemingly distinct that have been employed literature resolves an ambiguity has arisen concerning experimental description polaritonic band structure....

We explore different ways of incorporating accurate trial wave functions into free projection auxiliary-field quantum Monte Carlo (fp-AFQMC). States employed include coupled-cluster singles and doubles, multi-Slater, symmetry-projected mean-field functions. adapt a recently proposed fast multi-Slater local energy evaluation algorithm for fp-AFQMC, making the use long expansions from selected configuration interaction methods feasible. demonstrate how these serve to mitigate sign problem...

This study evaluates the precision of widely recognized quantum chemical methodologies, CCSD(T), DLPNO-CCSD(T), and localized ph-AFQMC, for determining thermochemistry main group elements. DLPNO-CCSD(T) which offer greater scalability compared to canonical have emerged over past decade as pivotal in producing precise benchmark data. Our investigation includes closed-shell, neutral molecules, focusing on their heat formation atomization energy sourced from four specific small molecule data...

We introduce a black-box auxiliary field quantum Monte Carlo (AFQMC) approach to perform highly accurate electronic structure calculations using configuration interaction singles and doubles (CISD) trial states. This method consistently provides more energy estimates than coupled cluster with perturbative triples (CCSD(T)), often regarded as the gold standard in chemistry. level of precision is achieved at lower asymptotic computational cost, scaling O(N6) compared O(N7) CCSD(T). provide...

A BSTRACT Background: Most frequent concerns among patients who attend orthopaedic centres is chronic low back pain. Material and Methods: Study aimed to compare effectiveness of psychological counselling in addition standard medical care for with pain by measuring their improvement the Visual Analogue Scale (VAS), 36-Item Short Form Survey (SF-36), Oswestry Disability Index (ODI) Hospital Anxiety Depression (HADS). Comparing Groups B at 6 12 weeks on VAS measure. Results: Group demonstrated...

Abstract Adiponectin is a prime determinant of the status insulin resistance. Association studies between adiponectin ( ADIPOQ ) gene single nucleotide polymorphisms (SNPs) and metabolic diseases have been reported earlier. However, results are ambiguous due to apparent contradictions. Hence, we investigated (1) association SNPs: −11377C/G, +10211T/G, +45T/G +276G/T for risk towards type 2 diabetes (T2D) and, (2) genotype-phenotype these SNPs with various biochemical parameters in two...

We present efficient algorithms for using selected configuration interaction (sCI) trial wave functions in phaseless auxiliary field quantum Monte Carlo (ph-AFQMC). These advances, geared toward optimizing computational performance longer expansions, allow us to use up a million configurations the state ph-AFQMC. In one example, we found cost of ph-AFQMC per sample increase only by factor about 3 calculation with 104 compared that single one, demonstrating tiny overhead due expansion. This...

Type 2 diabetes (T2D) is a syndrome of multiple metabolic disorders and genetically heterogeneous. India comprises one the largest global populations with highest number reported type cases. However, limited information about T2D associated loci available for Indian populations. It is, therefore, pertinent to evaluate previously candidates as well identify novel genetic variations in understand extent heterogeneity. We chose do cost effective high-throughput mass-array genotyping studied...

We report the development of a python-based auxiliary-field quantum Monte Carlo (AFQMC) program, ipie, with preliminary timing benchmarks and new AFQMC results on isomerization [Cu2O2]2+. demonstrate how implementations for both central graphical processing units (CPUs GPUs) are achieved in ipie. show an interface ipie PySCF as well straightforward template adding estimators to Our against other C++ codes, QMCPACK Dice, suggest that is faster or similarly performing all chemical systems...

We present a method for calculating first-order response properties in phaseless auxiliary field quantum Monte Carlo by applying automatic differentiation (AD). Biases and statistical efficiency of the resulting estimators are discussed. Our approach demonstrates that AD enables calculation reduced density matrices with same computational cost scaling per sample as energy calculations, accompanied prefactor less than four our numerical calculations. investigate role self-consistency trial...

The computationally expensive evaluation and storage of high-rank reduced density matrices (RDMs) has been the bottleneck in calculation dynamic correlation for multireference wave functions large active spaces. We present a stochastic formulation configuration interaction perturbation theory that avoids need these RDMs. algorithm presented here is flexible enough to incorporate wide variety space reference functions, including selected interaction, matrix product states, symmetry-projected...

ipie is a Python-based auxiliary-field quantum Monte Carlo (AFQMC) package that has undergone substantial improvements since its initial release [Malone et al., J. Chem. Theory Comput. 19(1), 109–121 (2023)]. This paper outlines the improved modularity and new capabilities implemented in ipie. We highlight ease of incorporating different trial walker types seamless integration with external libraries. enable distributed Hamiltonian simulations large systems otherwise would not fit on single...

We extend our low-scaling variational Monte Carlo (VMC) algorithm to optimize the symmetry projected Jastrow mean field (SJMF) wavefunctions. These wavefunctions consist of a symmetry-projected product and general broken-symmetry reference. Examples include antisymmetrized geminal power (JAGP), Jastrow-Pfaffians, resonating valence bond (RVB) states among others, all which can be treated with algorithm. will demonstrate using benchmark systems including nitrogen molecule, chain hydrogen...

We present an algorithm for calculating the local energy of a multi-Slater wave function in orbital space quantum Monte Carlo (QMC). Recent developments selected configuration interaction methods have led to increased interest using trial functions various QMC methods. For ab initio Hamiltonian, our has cost scaling O(n5 + nc), as opposed O(n4nc) existing algorithms, where n is system size and nc number configurations function. method variational calculations with Jastrow function, although...

Evaluation of visual pedagogy teaching method for improving oral hygiene practice in children with Autism: An interventional study: Visual is a relatively newer approach to improve dental care autistic children. The present study aimed evaluate the children.This and prospective was conducted Department Paediatric Preventive Dentistry. Required approval obtained from Institutional Ethical Board. Written informed consent parents/caregivers. age range 5-12 years which included 100 participants...

We report identification and genetic characterization of a rare skeletal disorder that remained unidentified for decades in village Jammu Kashmir, India. The population residing this region is highly consanguineous lack understanding the has hindered clinical management counseling many affected individuals region. collected familial information identified two large extended multiplex pedigrees displaying apparent autosomal recessive inheritance an uncharacterized dysplasia. Whole exome...

We develop a local correlation variant of auxiliary-field quantum Monte Carlo (AFQMC) based on natural orbitals (LNO-AFQMC). In LNO-AFQMC, independent AFQMC calculations are performed for each localized occupied orbital using truncated set tailored orbitals. Because the size this space does not grow with system target accuracy, method has linear scaling. Applying LNO-AFQMC to molecular problems containing few hundred thousand orbitals, we demonstrate convergence total energies significantly...

We present a stochastic approach to perform strongly contracted n-electron valence state perturbation theory (SC-NEVPT), which only requires one- and two-body reduced density matrices, without introducing approximations. use this method SC-NEVPT2 for complete active space self-consistent field wave functions obtained from selected configuration interaction, although the is applicable larger class of functions, including those orbital-space variational Monte Carlo. The accuracy demonstrated...

We introduce a black-box auxiliary field quantum Monte Carlo (AFQMC) approach to perform highly accurate electronic structure calculations using configuration interaction singles and doubles (CISD) trial states. This method consistently provides more energy estimates than coupled cluster with perturbative triples (CCSD(T)), often regarded as the gold standard in chemistry. level of precision is achieved at lower asymptotic computational cost, scaling $O(N^6)$ compared $O(N^7)$ CCSD(T)....