The factorized form of unitary coupled cluster theory (UCC) is a promising wave-function ansatz for the variational quantum eigensolver algorithm. Here, we present a quantum-inspired classical algorithm for UCC based on an exact operator identity for the individual UCC factors. We implement this algorithm for calculations of the H linear chain and the HO molecule with single and double ζ basis sets to provide insights into UCC as a wave-function ansatz. We find that for weakly correlated molecules, the factorized form of the UCC provides similar accuracy to conventional coupled cluster theory (CC); for strongly correlated molecules, where CC often breaks down, UCC significantly outperforms the configuration interaction (CI) ansatz. As a result, the factorized form of the UCC is an accurate, efficient, and reliable electronic structure method in both the weakly and strongly correlated regions. This classical algorithm now allows robust benchmarking of anticipated results from quantum computers and application of coupled-cluster techniques to more strongly correlated molecules.
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http://dx.doi.org/10.1021/acs.jctc.0c01052 | DOI Listing |
Tob Control
January 2025
La Trobe University Australian Research Centre in Sex Health and Society, Melbourne, Victoria, Australia.
Background: Smoking rates have declined markedly in Australia over time; however, lesbian, bisexual and queer (LBQ) women continue to smoke at higher rates than heterosexual women. Understanding the factors influencing smoking in this population is crucial for developing targeted cessation interventions and other supports.
Methods: Experiences of and motivations for smoking among 42 LBQ cisgender and transgender women and non-binary people in Australia who currently or previously smoked were explored through semi-structured interviews.
Sci Rep
January 2025
Department of the Environment, College of Basic Sciences, Hamedan Branch, Islamic Azad University, Hamedan, Iran.
In this study, the contamination, ecological and human health risks as well as source apportionment of As, Cd, Co, Cr, Cu, Mn, Ni, Pb, Zn, and V in street dusts of different land-uses in Kermanshah, Iran were investigated. A total of 192 dust samples were taken from 16 sites and were analyzed for their elemental contents using ICP-OES. The computed mean values for the geo-accumulation index (I-geo) and the pollution index (PI) ranged from - 6.
View Article and Find Full Text PDFNeurol Clin Pract
April 2025
Department of Neurology (AS), Massachusetts General Hospital, Harvard Medical School, Boston; Department of Public Health Sciences (RBAB), University of North Carolina at Charlotte; Disparities Research Unit, Department of Medicine, Massachusetts General Hospital; Department of Psychiatry, Harvard Medical School; Harvard Medical School (DH, SW), Boston; and City University of New York at Hunter College (DH, SW).
Background And Objectives: Limited English proficiency (LEP) impairs health access-including outpatient specialty care-and quality care, i.e., inappropriate use of diagnostic tests.
View Article and Find Full Text PDFUnlabelled: Members of the gut microbiome encounter a barrage of host- and microbe-derived microbiocidal factors that must be overcome to maintain fitness in the intestine. The long-term stability of many gut microbiome strains within the microbiome suggests the existence of strain-specific strategies that have evolved to foster resilience to such insults. Despite this, little is known about the mechanisms that mediate this resistance.
View Article and Find Full Text PDFPhys Rev Lett
December 2024
Physics Division, Argonne National Laboratory, Lemont, Illinois 60439, USA.
The transverse-momentum-dependent distributions (TMDs), which are defined by gauge-invariant 3D parton correlators with staple-shaped lightlike Wilson lines, can be calculated from quark and gluon correlators fixed in the Coulomb gauge on a Euclidean lattice. These quantities can be expressed gauge invariantly as the correlators of Coulomb-gauge-dressed fields, which reduce to the standard TMD correlators under principal-value prescription in the infinite boost limit. In the framework of large-momentum effective theory, a quasi-TMD defined from such correlators in a large-momentum hadron state can be matched to the TMD via a factorization formula, whose exact form is derived using soft collinear effective theory and verified at one-loop order.
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