scholarly journals Chaos-Preserving Reduction of the Spin-Flip Model for VCSELs: Failure of the Adiabatic Elimination of the Spin-Population Difference

2019 ◽  
Vol 25 (6) ◽  
pp. 1-8
Author(s):  
Martin Virte ◽  
Francesco Ferranti
2000 ◽  
Vol 65 (5-6) ◽  
pp. 285-301 ◽  
Author(s):  
Nenad Juranic ◽  
Zsolt Zolnai ◽  
Slobodan Macura

The magnetization exchange between two groups of equivalent spins each having different populations and overall relaxation rates has been analyzed. The results suggest that either the spin population difference or the overall relaxation rate difference in an exchange spectrum can produce cross-peaks with volumes larger than that of the corresponding diagonal line. This is important for interpretation of the magnetization exchange between water and macromolecular protons where both the population differences and auto-relaxation rate differences can be very large. Theoretical predictions of peak volume evolution were experimentally verified in the intermolecular magnetization exchange between the water and labile amide proton in a model system N-acetylglycine/water.


2018 ◽  
Author(s):  
Shannon Houck ◽  
Nicholas Mayhall

<div>Many multiconfigurational systems, such as single-molecule magnets, are difficult to study using traditional computational methods due to the simultaneous existence of both spin and spatial degeneracies. In this work, a new approach termed n-spin-flip Ionization Potential/Electron Affinity (<i>n</i>SF-IP or <i>n</i>SF-EA) is introduced which combines the spin-flip method of Anna Krylov with particle-number changing IP/EA methods. We demonstrate the efficacy of the approach by applying it to the strongly-correlated N<sub>2</sub><sup>+</sup> as well as several double exchange systems. We also demonstrate that when these systems are well-described by a double exchange model Hamiltonian, only 1SF-IP/EA is required to extract the double exchange parameters and accurately predict energies for the low-spin states. This significantly reduces the computational effort for studying such systems. The effects of including additional excitations (using a RAS-<i>n</i>SF-IP/EA scheme) are also examined, with particular emphasis on hole and particle excitations.</div>


2018 ◽  
Author(s):  
Shannon Houck ◽  
Nicholas Mayhall

<div>Many multiconfigurational systems, such as single-molecule magnets, are difficult to study using traditional computational methods due to the simultaneous existence of both spin and spatial degeneracies. In this work, a new approach termed n-spin-flip Ionization Potential/Electron Affinity (<i>n</i>SF-IP or <i>n</i>SF-EA) is introduced which combines the spin-flip method of Anna Krylov with particle-number changing IP/EA methods. We demonstrate the efficacy of the approach by applying it to the strongly-correlated N<sub>2</sub><sup>+</sup> as well as several double exchange systems. We also demonstrate that when these systems are well-described by a double exchange model Hamiltonian, only 1SF-IP/EA is required to extract the double exchange parameters and accurately predict energies for the low-spin states. This significantly reduces the computational effort for studying such systems. The effects of including additional excitations (using a RAS-<i>n</i>SF-IP/EA scheme) are also examined, with particular emphasis on hole and particle excitations.</div>


2020 ◽  
Vol 102 (6) ◽  
Author(s):  
Brian Kaufman ◽  
Tamás Rozgonyi ◽  
Philipp Marquetand ◽  
Thomas Weinacht

2020 ◽  
Vol 2 (3) ◽  
Author(s):  
Sadashige Matsuo ◽  
Kazuyuki Kuroyama ◽  
Shunsuke Yabunaka ◽  
Sascha R. Valentin ◽  
Arne Ludwig ◽  
...  

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 728
Author(s):  
Jessica McDonnell ◽  
Nicholas P Murray ◽  
Sungwoo Ahn ◽  
Stefan Clemens ◽  
Erik Everhart ◽  
...  

The majority of the population identifies as right-hand dominant, with a minority 10.6% identifying as left-hand dominant. Social factors may partially skew the distribution, but it remains that left-hand dominant individuals make up approximately 40 million people in the United States alone and yet, remain underrepresented in the motor control literature. Recent research has revealed behavioral and neurological differences between populations, therein overturning assumptions of a simple hemispheric flip in motor-related activations. The present work showed differentially adaptable motor programs between populations and found fundamental differences in methods of skill acquisition highlighting underlying neural strategies unique to each population. Difference maps and descriptive metrics of coherent activation patterns showed differences in how theta oscillations were utilized. The right-hand group relied on occipital parietal lobe connectivity for visual information integration necessary to inform the motor task, while the left-hand group relied on a more frontal lobe localized cognitive based approach. The findings provide insight into potential alternative methods of information integration and emphasize the importance for inclusion of the left-hand dominant population in the growing conceptualization of the brain promoting the generation of a more complete, stable, and accurate understanding of our complex biology.


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