A 
          
            
              PT
            
          
        -Symmetric Dual-Core System with the Sine-Gordon Nonlinearity and Derivative Coupling

We study solitons in a zig-zag lattice of magnetic dipoles. The lattice comprises two sublattices of parallel chains with magnetic dipoles at their vertices. Due to orthogonal easy planes of rotation for dipoles belonging to different sublattices, the total dipolar energy of this system is separable into a sum of symmetric and chiral long-ranged interactions between the magnets where the last takes the form of Dzyaloshinskii-Moriya coupling. For a specific range of values of the offset between sublattices, the dipoles realize an equilibrium magnetic state in the lattice plane, consisting of one chain settled in an antiferromagnetic parallel configuration and the other in a collinear ferromagnetic fashion. If the offset grows beyond this value, the internal Dzyaloshinskii-Moriya field stabilizes two Bloch domain walls at the edges of the antiferromagnetic chain. The dynamics of these solitons is studied by deriving the long-wavelength lagrangian density for the easy axis antiferromagnet. We find that the chiral couplings between sublattices give rise to an effective magnetic field that stabilizes the solitons in the antiferromagnet. When the chains displace respect to each other, an emergent Lorentz force accelerates the domain walls along the lattice.

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“…In the non-dissipative continuum limit, the dynamics of magnetization fields in af is determined by the lagrangian density [9,12,21,22]:…”

Section: Afm Field Theorymentioning

confidence: 99%

Magnetic solitons due to interfacial chiral interactions

Mellado

Tapia²

2023

J. Phys.: Condens. Matter

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“…In the relativistic fields and in two dimensions (1+1), two sine-Gordon and ϕ 4 systems have been studied more than the others. The sine-Gordon equation appears in numerous and unrelated areas [1]. This system with the simplified Lagrangian…”

Section: Introductionmentioning

confidence: 99%

Investigating Emergency Department Nurses’ Educational Needs and Exploring Strategies to Meet Challenges Against Management of These Needs: A Qualitative Study

et al. 2023

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Background: Nurses who are occupied in emergency departments play a critical role in health services provision and patient care. Considering the importance of providing appropriate and immediate care in emergency departments, nurses need to acquire sufficient skills and up-to-date knowledge. Objectives: This study aimed to identify the educational needs of nurses working in the emergency department and explore strategies to meet challenges against the elimination of these needs. Methods: This qualitative study was conducted using a content analysis approach. This study selected the emergency departments of two large educational hospitals affiliated with Shiraz University of Medical Sciences, Shiraz, southern Iran. This study was conducted on 15 emergency department nurses selected via purposive sampling with maximum variation within January 2020 and March 2021.The data were collected by performing 15 in-depth, semi-structured interviews (11 face-to-face and 4 telephone interviews due to the coronavirus disease 2019 pandemic) and making field notes. Then, the recorded interviews were transcribed verbatim and analyzed using the qualitative content analysis approach proposed by Graneheim and Lundman. The consolidated criteria for reporting qualitative studies (COREQ) was used to report the findings of this study. Results: Three main themes, namely the need for comprehensive and continuous education, challenges of managing educational needs, and strategies to meet educational needs, were extracted following data analysis. Conclusions: Clarifying the educational needs of nurses and exploring strategies to solve these challenges can be effective by providing continuous practical training and adopting effective teaching-learning strategies to promote nurses’ education and improve their performance in clinical skills. Accordingly, the provision of appropriate infrastructure for mobile health applications and utilization of mobile-based educational applications in emergency departments have to be taken into account by hospital managers and health policymakers.

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“…Also predicted were realizations of this symmetry in atomic Bose-Einstein condensates [42], magnetism [43], mechanical chains of coupled pendula [44], and electronic circuits [45] (in the latter case, the prediction was also demonstrated experimentally). In terms of the theoretical analysis, PT -symmetric extensions were also elaborated for Korteweg -de Vries [46,47], Burgers [48], and sine-Gordon [49] equations, as well as in a system combining the PT symmetry with the optical emulation of the spin-orbit coupling [50].…”

Section: Introductionmentioning

confidence: 99%

Making the P T $$\mathbb {PT}$$ Symmetry Unbreakable

Lutsky

Luz

Granot

et al. 2018

Springer Tracts in Modern Physics

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It is well known that typical PT -symmetric systems suffer symmetry breaking when the strength of the gain-loss terms, i.e., the coefficient in front of the non-Hermitian part of the underlying Hamiltonian, exceeds a certain critical value. In this article, we present a summary of recently published and newly produced results which demonstrate various possibilities of extending the PT symmetry to arbitrarily large values of the gain-loss coefficient. First, we recapitulate the analysis which demonstrates a possibility of the restoration of the PT symmetry and, moreover, complete avoidance of the breaking in a photonic waveguiding channel of a subwavelength width. The analysis is necessarily based on the system of Maxwell's equations, instead of the usual paraxial approximation. Full elimination of the PT -symmetry-breaking transition is found in a deeply subwavelength region. Next, we review a recently proposed possibility to construct stable one-dimensional (1D) PT -symmetric solitons in a paraxial model with arbitrarily large values of the gain-loss coefficient, provided that the self-trapping of the solitons is induced by self-defocusing cubic nonlinearity, whose local strength grows sufficiently fast from the center to periphery. The model admits a particular analytical solution for the fundamental soliton, and provides full stability for families of fundamental and dipole solitons. It is relevant to stress that this model is nonlinearizable, hence the concept of the PT symmetry in it is also an essentially nonlinear one. Finally, we report new results for unbreakable PT -symmetric solitons in 2D extensions of the 1D model: one with a quasi-1D modulation profile of the local gain-loss coefficient, and another with the fully-2D modulation. These settings admit particular analytical solutions for 2D solitons, while generic soliton families are found in a numerical form. The quasi-1D modulation profile gives rise to a stable family of single-peak 2D solitons, while their dual-peak counterparts tend to be unstable. The soliton stability in the full 2D model is possible if the local gain-loss term is subject to spatial confinement.2 exciton-polariton condensates [36]- [38], and in other physically relevant contexts. In particular, the transitions from unbroken to broken PT symmetry was observed in many experiments. One of prominent experimentally demonstrated applications of the PT symmetry in optics is unidirectional transmission of light [39].Other classical waveguiding settings also admit emulation of the PT symmetry, as demonstrated in acoustics [40] and predicted in optomechanical systems [41]. Also predicted were realizations of this symmetry in atomic Bose-Einstein condensates [42], magnetism [43], mechanical chains of coupled pendula [44], and electronic circuits [45] (in the latter case, the prediction was also demonstrated experimentally). In terms of the theoretical analysis, PT -symmetric extensions were also elaborated for 47], Burgers [48], and sine-Gordon [49] equations, as well as in a system combi...

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A PT -Symmetric Dual-Core System with the Sine-Gordon Nonlinearity and Derivative Coupling

Cited by 8 publications

References 96 publications

Magnetic solitons due to interfacial chiral interactions

Magnetic solitons due to interfacial chiral interactions

Investigating Emergency Department Nurses’ Educational Needs and Exploring Strategies to Meet Challenges Against Management of These Needs: A Qualitative Study

Making the P T $$\mathbb {PT}$$ Symmetry Unbreakable

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