The cumulant expansion of the Green's function is a computationally efficient beyond-GW approach renowned for its significant enhancement of satellite features in materials. In contrast to the ubiquitous GW approximation of many-body perturbation theory, cumulant expansions performed on top of GW (GW + C) have demonstrated the capability to handle multi-particle processes by incorporating higher-order correlation effects or vertex corrections, yielding better agreements between experiment and theory for satellite structures. While widely employed in condensed matter physics, very few applications of GW + C have been published on molecular systems.
View Article and Find Full Text PDFJ Chem Theory Comput
June 2024
Upon ionization of an atom or a molecule, another electron (or more) can be simultaneously excited. These concurrently generated states are called "satellites" (or shakeup transitions) as they appear in ionization spectra as higher-energy peaks with weaker intensity and larger width than the main peaks associated with single-particle ionizations. Satellites, which correspond to electronically excited states of the cationic species, are notoriously challenging to model using conventional single-reference methods due to their high excitation degree compared to the neutral reference state.
View Article and Find Full Text PDFDue to the infinite summation of bubble diagrams, the GW approximation of Green's function perturbation theory has proven particularly effective in the weak correlation regime, where this family of Feynman diagrams is important. However, the performance of GW in multireference molecular systems, characterized by strong electron correlation, remains relatively unexplored. In the present study, we investigate the ability of GW to handle closed-shell multireference systems in their singlet ground state by examining four paradigmatic scenarios.
View Article and Find Full Text PDFCochlear implantation (CI) allows rehabilitation for patients with severe to profound hearing impairment. Although the use of a robotic assistant provides technical assistance to the surgeon, the assessment of the impact of its use on auditory outcomes remains uncertain. We aim to compare the hearing results of patients who underwent bilateral cochlear implantation; one side was performed with manual insertion and the other side with robot-assisted insertion.
View Article and Find Full Text PDFJ Chem Theory Comput
July 2023
The family of Green's function methods based on the approximation has gained popularity in the electronic structure theory thanks to its accuracy in weakly correlated systems combined with its cost-effectiveness. Despite this, self-consistent versions still pose challenges in terms of convergence. A recent study [Monino and Loos 2022, 156, 231101.
View Article and Find Full Text PDFState-specific electronic structure theory provides a route toward balanced excited-state wave functions by exploiting higher-energy stationary points of the electronic energy. Multiconfigurational wave function approximations can describe both closed- and open-shell excited states and avoid the issues associated with state-averaged approaches. We investigate the existence of higher-energy solutions in complete active space self-consistent field (CASSCF) theory and characterize their topological properties.
View Article and Find Full Text PDFWe explored whether moralization and attitude extremity may amplify a preference to share politically congruent ("myside") partisan news and what types of targeted interventions may reduce this tendency. Across 12 online experiments ( = 6,989), we examined decisions to share news touching on the divisive issues of gun control, abortion, gender and racial equality, and immigration. Myside sharing was systematically observed and was consistently amplified when participants (i) moralized and (ii) were attitudinally extreme on the issue.
View Article and Find Full Text PDFCurr Opin Psychol
December 2022
Political conspiracist communities emerge and bind around hard-to-falsify narratives about political opponents or elites convening to secretly exploit the public in contexts of perceived political conflict. While the narratives appear descriptive, we propose that their content as well as the cognitive systems regulating their endorsement and dissemination may have co-evolved, at least in part, to reach coalitional goals: To drive allies' attention to the social threat to increase their commitment and coordination for collective action, and to signal devotion to gain within-group status. Those evolutionary social functions may be best fulfilled if individuals endorse the conspiratorial narrative sincerely.
View Article and Find Full Text PDFAt the beginning of 2020, COVID-19 became a global problem. Despite all the efforts to emphasize the relevance of preventive measures, not everyone adhered to them. Thus, learning more about the characteristics determining attitudinal and behavioral responses to the pandemic is crucial to improving future interventions.
View Article and Find Full Text PDFChanging collective behaviour and supporting non-pharmaceutical interventions is an important component in mitigating virus transmission during a pandemic. In a large international collaboration (Study 1, N = 49,968 across 67 countries), we investigated self-reported factors associated with public health behaviours (e.g.
View Article and Find Full Text PDFIn 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 that are then used to compute the energy and other properties. Although it is of common practice to converge to the (lowest-energy) ground-state solution, it is also possible, thanks to tailored algorithms, to access higher-energy roots of these equations that may or may not correspond to genuine excited states. Here, we explore the structure of the energy landscape of variational CC and we compare it with its (projected) traditional version in the case where the excitation operator is restricted to paired double excitations (pCCD).
View Article and Find Full Text PDFThe pair coupled cluster doubles (pCCD) method (where the excitation manifold is restricted to electron pairs) has a series of interesting features. Among others, it provides ground-state energies very close to what is obtained with doubly occupied configuration interaction (DOCI), but with a polynomial cost (compared with the exponential cost of the latter). Here, we address whether this similarity holds for excited states by exploring the symmetric dissociation of the linear H molecule.
View Article and Find Full Text PDFJ Phys Condens Matter
June 2021
We explore the non-Hermitian extension of quantum chemistry in the complex plane and its link with perturbation theory. We observe that the physics of a quantum system is intimately connected to the position of complex-valued energy singularities, known as exceptional points. After presenting the fundamental concepts of non-Hermitian quantum chemistry in the complex plane, including the mean-field Hartree-Fock approximation and Rayleigh-Schrödinger perturbation theory, we provide a historical overview of the various research activities that have been performed on the physics of singularities.
View Article and Find Full Text PDFMis information and misunderstanding of science can partially explained by cognitive processes rooted in our evolutionary past. Science communication can use this knowledge to overcome these cognitive limits.
View Article and Find Full Text PDFSpinal muscular atrophy (SMA) is a devastating motor neuron disorder caused by mutations in the survival motor neuron (SMN) gene. It remains unclear how SMN deficiency leads to the loss of motor neurons. By screening Schizosaccharomyces pombe, we found that the growth defect of an SMN mutant can be alleviated by deletion of the actin-capping protein subunit gene acp1.
View Article and Find Full Text PDFBehav Brain Sci
November 2019
Baumard suggests that the advent, through phenotypic plasticity mechanisms, of future-oriented preferences and creative mindsets in eighteenth-century Great Britain explains the wave of innovations that drove the British Industrial Revolution. We argue that, although this approach is promising, Baumard's model would benefit from being supplemented by demographic, economic, and sociological explanations independent of Life History Theory (LHT).
View Article and Find Full Text PDFBehav Brain Sci
August 2019
De Dreu and Gross’s description of the proximate mechanisms conditioning success in intergroup conflict omits humans’ deontological morality. Drawing on research on sacralization and moral objectivism, I show how “moral rigidity” may have evolved through partner selection mechanisms to foster coalitions’ cohesion and combativeness in intergroup conflict [corrected]. De Dreu and Gross's argument that attack and defense are distinct strategies underpinned by different neuropsychological circuitries is an original refinement of the theory of conflict.
View Article and Find Full Text PDFBehav Brain Sci
January 2018
Whitehouse makes no room for evolutionary approaches to extreme behaviors based on partner choice and mutualism, which have been convincingly invoked to make sense of ordinary morality. Extended to intergroup warfare, these evolutionary mechanisms may play a pivotal role in explaining the existence of extreme - though not functionally sacrificial - behaviors, benefiting non-kin fellow fighters, together with the distinctive phenomenology those behaviors display.
View Article and Find Full Text PDFTreatment of chronic hepatitis C virus (HCV) infection remains a priority in the veterans affairs (VA) health care system nationwide, as there is a high burden of liver disease due to HCV infection among US veterans. The combination of sofosbuvir and simeprevir was the first all-oral antiviral regimen used in clinical practice to treat veterans with HCV infection. In this study, we report a single-center experience showing both the feasibility and effectiveness of this all-oral combination to treat HCV genotype 1 infection.
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