Higher Order Decompositions of Ordered Operator Exponentials

We present a decomposition scheme based on Lie-Trotter-Suzuki product formulae to represent an ordered operator exponential as a product of ordinary operator exponentials. We provide a rigorous proof that does not use a time-displacement superoperator, and can be applied to non-analytic functions. Our proof provides explicit bounds on the error and includes cases where the functions are not infinitely differentiable. We show that Lie-Trotter-Suzuki product formulae can still be used for functions that are not infinitely differentiable, but that arbitrary order scaling may not be achieved.Comment: 16 pages, 1 figur

On quantum mean-field models and their quantum annealing

This paper deals with fully-connected mean-field models of quantum spins with p-body ferromagnetic interactions and a transverse field. For p=2 this corresponds to the quantum Curie-Weiss model (a special case of the Lipkin-Meshkov-Glick model) which exhibits a second-order phase transition, while for p>2 the transition is first order. We provide a refined analytical description both of the static and of the dynamic properties of these models. In particular we obtain analytically the exponential rate of decay of the gap at the first-order transition. We also study the slow annealing from the pure transverse field to the pure ferromagnet (and vice versa) and discuss the effect of the first-order transition and of the spinodal limit of metastability on the residual excitation energy, both for finite and exponentially divergent annealing times. In the quantum computation perspective this quantity would assess the efficiency of the quantum adiabatic procedure as an approximation algorithm.Comment: 44 pages, 23 figure

How and when does personal life orientation predict well-being?

Abstract We examined the direct and indirect––as mediated by job satisfaction––effects of personal life orientation on life satisfaction. We also examined whether these direct and indirect associations differed between employees working onsite or remotely. Using data from 432 employees (152 working onsite and 280 working remotely), our results revealed that personal life orientation was positively related to life satisfaction and negatively related to job satisfaction. Moreover, both of these direct associations were stronger among onsite employees than among remote employees. As a result, the indirect effects of personal life orientation on life satisfaction were significantly mediated by job satisfaction among employees working onsite, but not among employees working remotely. This study thus reveals that working remotely may act as a double-edged sword by buffering the negative effects of personal life orientation on job satisfaction, but also by limiting the positive effects of personal life orientation on life satisfaction

The future of auroral E-region plasma turbulence research

The heating caused by ionospheric E-region plasma turbulence has documented global implications for the energy transfer from space into the terrestrial atmosphere. Traveling atmospheric disturbances, neutral wind motion, energy deposition rates, and ionospheric conductance have all been shown to be potentially affected by turbulent plasma heating. Therefore it is proposed to enhance and expand existing ionospheric radar capabilities and fund research into E-region plasma turbulence so that it is possible to more accurately quantify the solar-terrestrial energy budget and study phenomena related to E-region plasma turbulence. The proposed research funding includes the development of models to accurately predict and model the E-region plasma turbulence using particle-in-cell analysis, fluid-based analysis, and hybrid combinations of the two. This review provides an expanded and more detailed description of the past, present, and future of auroral E-region plasma turbulence research compared to the summary report submitted to the National Academy of Sciences Decadal Survey for Solar and Space Physics (Heliophysics) 2024–2033 (Huyghebaert et al., 2022a)

The future of auroral E-region plasma turbulence research

The heating caused by ionospheric E-region plasma turbulence has documented global implications for the energy transfer from space into the terrestrial atmosphere. Traveling atmospheric disturbances, neutral wind motion, energy deposition rates, and ionospheric conductance have all been shown to be potentially affected by turbulent plasma heating. Therefore it is proposed to enhance and expand existing ionospheric radar capabilities and fund research into E-region plasma turbulence so that it is possible to more accurately quantify the solar-terrestrial energy budget and study phenomena related to E-region plasma turbulence. The proposed research funding includes the development of models to accurately predict and model the E-region plasma turbulence using particle-in-cell analysis, fluidbased analysis, and hybrid combinations of the two. This review provides an expanded and more detailed description of the past, present, and future of auroral E-region plasma turbulence research compared to the summary report submitted to the National Academy of Sciences Decadal Survey for Solar and Space Physics (Heliophysics) 2024–2033 (Huyghebaert et al., 2022a)

On the nature, predictors, and outcomes of longitudinal work passion profiles

Abstract Based on the dualistic model of passion, this study relies on person-centered analyses to assess how harmonious passion and obsessive passion for work combine within specific profiles of employees. We also documented the stability of these profiles over time and their associations with theoretically relevant predictors and outcomes, among a sample of 442 employees who completed a questionnaire twice over a period of 3 months. Finally, we examined whether these associations differed as a function of working remotely or onsite. Four profiles were identified and found to be highly stable over time: harmonious passion dominant, obsessive passion dominant, mixed passion-average, and low passion. Work centrality, family orientation, and supervisor expectations regarding work-related messages were all found to be related to employees’ likelihood of membership into the profiles in a way that generally supported our hypotheses. Moreover, and as expected, the harmonious passion dominant profile was associated with the highest levels of work–family enrichment, family–work enrichment, and job and life satisfaction. Lastly, none of these associations differed among employees working onsite or remotely

The ALS/FTD-related C9orf72 hexanucleotide repeat expansion forms RNA condensates through multimolecular G-quadruplexes

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are neurodegenerative diseases that exist on a clinico-pathogenetic spectrum, designated ALS/FTD. The most common genetic cause of ALS/FTD is expansion of the intronic hexanucleotide repeat (GGGGCC)n in C9orf72. Here, we investigate the formation of nucleic acid secondary structures in these expansion repeats, and their role in generating condensates characteristic of ALS/FTD. We observe significant aggregation of the hexanucleotide sequence (GGGGCC)n, which we associate to the formation of multimolecular G-quadruplexes (mG4s) by using a range of biophysical techniques. Exposing the condensates to G4-unfolding conditions leads to prompt disassembly, highlighting the key role of mG4-formation in the condensation process. We further validate the biological relevance of our findings by detecting an increased prevalence of G4-structures in C9orf72 mutant human motor neurons when compared to healthy motor neurons by staining with a G4-selective fluorescent probe, revealing signal in putative condensates. Our findings strongly suggest that RNA G-rich repetitive sequences can form protein-free condensates sustained by multimolecular G-quadruplexes, highlighting their potential relevance as therapeutic targets for C9orf72 mutation-related ALS/FTD

The ALS/FTD-related C9orf72 hexanucleotide repeat expansion forms RNA condensates through multimolecular G-quadruplexes

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are neurodegenerative diseases that exist on a clinico-pathogenetic spectrum, designated ALS/FTD. The most common genetic cause of ALS/FTD is expansion of the intronic hexanucleotide repeat (GGGGCC)n in C9orf72. Here, we investigate the formation of nucleic acid secondary structures in these expansion repeats, and their role in generating condensates characteristic of ALS/FTD. We observe significant aggregation of the hexanucleotide sequence (GGGGCC)n, which we associate to the formation of multimolecular G-quadruplexes (mG4s) by using a range of biophysical techniques. Exposing the condensates to G4-unfolding conditions leads to prompt disassembly, highlighting the key role of mG4-formation in the condensation process. We further validate the biological relevance of our findings by detecting an increased prevalence of G4-structures in C9orf72 mutant human motor neurons when compared to healthy motor neurons by staining with a G4-selective fluorescent probe, revealing signal in putative condensates. Our findings strongly suggest that RNA G-rich repetitive sequences can form protein-free condensates sustained by multimolecular G-quadruplexes, highlighting their potential relevance as therapeutic targets for C9orf72 mutation-related ALS/FTD

Capital structure revisited. Do crisis and competition matter in a Keiretsu corporate structure?

The file attached to this record is the author's final peer reviewed version.open accessWe investigate firm-level determinants of capital structure using a large sample of 4,284 Japanese firms over a nineteen-year period (i.e., over 61,000 firm-year observations), a hitherto less examined sample for this purpose. We conduct our analysis and interpret our findings predominantly within the pecking order, the trade-off and the agency theoretical frameworks. We uncover three new findings. First, our evidence indicates that insights derived from the extant literature on capital structure are cross-national and are applicable in the context of Japan, despite the unique characteristics of Japanese firms. Second, financial crisis significantly impacts the relationship between leverage and firm-level determinants, particularly accentuating the effect of asset tangibility and growth. Third, product market competition significantly impacts the observed relationship between firm-level determinants and leverage. Our results are robust, controlling for the joint effects of competition and crisis