Hasil untuk "cond-mat.other"

Alexander Fritzsche, Riccardo Sorbello, Ronny Thomale et al.

We explore the effect of self-orthogonality at exceptional points (EPs) in non-Hermitian Parity-Time-symmetric systems. Using a driven three-band lattice model, we show that the Rabi frequency diverges as the system approaches an EP due to the coalescence of eigenstates. We demonstrate that this divergence manifests in experimentally accessible power oscillations, establishing a direct observable for self-orthogonality. Our results provide a pathway for probing EP physics in various metamaterial platforms.

Iskander Mukatayev, Benoît Sklénard, Valerio Olevano et al.

X-ray photoelectron spectroscopy (XPS) measures electron removal energies, providing direct access to core and valence electron binding energies, hence probing the electronic structure. In this work, we benchmark for the first time the ab initio many-body GW approximation on the complete electron binding energies of noble gas atoms (He-Rn), which spans 100~keV. Our results demonstrate that GW achieves an accuracy within 1.2% in XPS binding energies, by systematically restoring the underestimation from density-functional theory (DFT, error of 14%) or the overestimation from Hartree-Fock (HF, error of 4.7%). Such results also imply the correlations of $d$ electrons are very well described by GW.

K. V. Kulikov, D. V. Anghel, A. T. Preda et al.

We investigate reorientation effects under external periodic drive in the nanomagnet dynamics coupled to a Josephson junction. The Kapitsa pendulum is introduced as a mechanical analog to this system and we demonstrate the reorientation of the easy axis of the nanomagnet. The magnetic field generated by the Josephson junction and external drive plays the role of the oscillating force of the suspension point in the Kapitsa pendulum. The high frequency oscillations change the orientation of the magnetic moment. The magnetic field of the quasiparticle current determines the frequency dependence of the magnetic moment's orientation. We obtain simple analytical formulas for the stable position of the magnetic moment, both under the external periodic drive and without it. The influence of external periodic drive on the voltage of complete reorientation have been demonstrated.

S. Dekhili, M. A. Achabou

H. Ebert, J. Braun, D. Koedderitzsch et al.

The formal basis for fully relativistic Korringa-Kohn-Rostoker (KKR) or multiple scattering calculations for the electronic Green function in case of a general potential is discussed. Simple criteria are given to identify situations that require to distinguish between right and left hand side solutions to the Dirac equation when setting up the electronic Green function. In addition various technical aspects of an implementation of the relativistic KKR for general local and non-local potentials will be discussed.

Alexey Galda, Valerii M. Vinokur

The understanding of out-of-equilibrium physics, especially dynamic instabilities and dynamic phase transitions, is one of the major challenges of contemporary science, spanning the broadest wealth of research areas that range from quantum optics to living organisms. Focusing on nonequilibrium dynamics of an open dissipative spin system, we introduce a non-Hermitian Hamiltonian approach, in which non-Hermiticity reflects dissipation and deviation from equilibrium. The imaginary part of the proposed spin Hamiltonian describes the effects of Gilbert damping and applied Slonczewski spin-transfer torque. In the classical limit, our approach reproduces Landau-Lifshitz-Gilbert-Slonczewski dynamics of a large macrospin. We reveal the spin-transfer torque-driven parity-time symmetry-breaking phase transition corresponding to a transition from precessional to exponentially damped spin dynamics. Micromagnetic simulations for nanoscale ferromagnetic disks demonstrate the predicted effect. Our findings can pave the way to a general quantitative description of out-of-equilibrium phase transitions driven by spontaneous parity-time symmetry breaking.

C. Dunn‐Lewis, H. Luk, Brett A. Comstock et al.

Recreational Golfers, B. Leary, J. Statler et al.

O. Farley, N. Harris, A. Kilding

M. Barr, Volker W. Nolte

Mao-Sung Wu, Zonghui Guo, Jiin-Jiang Jow

R. A. Medeiros, B. Lourenção, R. Rocha‐Filho et al.

J. Fernández-Fernández, Vanessa Kinner, A. Ferrauti

L. Herrington

Valerio Olevano, Andrey Titov, Massimo Ladisa et al.

We present two possible approaches to calculate the momentum distribution n(p) and the Compton profile within the framework of the ab initio GW approximation on the self-energy. The approaches are based on integration of the Green's function along either the real or the imaginary axes. Examples will be presented on the jellium model and on real bulk sodium. Advantages and drawbacks of both methods are discussed in comparison with accurate quantum Monte Carlo (QMC) calculations and x-ray Compton scattering experiments. We illustrate the effect of many-body correlations and disentangle them from band-structure and anisotropy effects by a comparison with density functional theory in the local density approximation. Our results suggest the use of G0W0 momentum distributions as reference for future experiments and theory developments.

Michael D Duehring, C. R. Feldmann, W. Ebben

J. Ghigiarelli, E. Nagle, Fredric L Gross et al.

Ghigiarelli, JJ, Nagle, EF, Gross, FL, Robertson, RJ, Irrgang, JJ, and Myslinski, T. The effects of a 7-wk heavy elastic band and weight chain program on upper body strength and upper body power in a sample of Division 1-AA football players. J Strength Cond Res 23(3): 756-764, 2009-The purpose of this study was to explore the effects of a 7-week heavy elastic band and weighted-chain program on maximum muscular strength and maximum power in the bench press exercise. Thirty-six (n = 36) healthy men aged 18-30 years old, from the Robert Morris University football team, volunteered to participate in this study. During the first week, predicted 1 repetition maximum (1RM) bench press and a 5RM speed bench press tests were conducted. Subjects were randomly divided into 3 groups (n = 12): elastic band (EB), weighted chain (WC), and traditional bench (C). During weeks 2-8 of the study, subjects were required to follow the prescribed resistance training program. Mean and SD of the predicted 1RM bench press and 5RM speed bench press were computed. A two-factor (method X time) analysis was applied to identify significant differences between the training groups. Significance was set at α = 0.05. Results indicated a significant time (p < 0.05) but no group effect for both predicted 1RM (kg) and 5RM peak power tests (watts). Although not significant, results did show greater nonsignificant improvements in the EB (848-883 W) and WC groups (856-878 W) vs. control (918-928 W) when the 2 highest and greatest values were selected regarding peak power. The use of EB and WC in conjunction with a general offseason strength and conditioning program can increase overall maximum upper-body strength in a sample of Division 1-AA football players. These types of training modalities add a unique training style and more flexibility with respect to exercise prescription for athletes and strength practitioners.

K. Beekhuizen, Maurice Davis, M. Kolber et al.

H. Bevan, N. Owen, D. Cunningham et al.

Peter A. Bellezza, E. Hall, P. Miller et al.