We have studied the critical properties of the three-dimensional random anisotropy Heisenberg model by means of numerical simulations using the Parallel Tempering method. We have simulated the model with two different disorder distributions, cubic and isotropic ones, with two different anisotropy strengths for each disorder class. For the case of the anisotropic disorder, we have found evidence of universality by finding critical exponents and universal dimensionless ratios independent of the strength of the disorder. In the case of isotropic disorder distribution the situation is very involved: we have found two phase transitions in the magnetization channel which are merging for larger lattices remaining a zero magnetization low-temperature phase. Studying this region using a spin-glass order parameter we have found evidence for a spin-glass phase transition. We have estimated effective critical exponents for the spin-glass phase transition for the different values of the strength of the isotropic disorder, discussing the crossover regime.
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http://dx.doi.org/10.1103/PhysRevE.106.034123 | DOI Listing |
J Am Chem Soc
January 2025
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China.
CuO octahedra usually show elongated distortion, leading to active orbitals and planar exchange interactions, while compressed CuO octahedra with active orbitals and unidirectional exchange interactions are exceptionally rare. Here, we design and synthesize a new frustrated antiferromagnet CaCuFeO through a high-pressure and high-temperature approach, in which robust compressed CuO octahedra are realized, separating the FeO sheets that comprise zigzag spin ladders. Magnetic susceptibility and specific heat measurements exhibit a long-range antiferromagnetic order below the Néel temperature of 165 K, which is further confirmed by neutron diffraction.
View Article and Find Full Text PDFSchizophr Bull
January 2025
Psychology, Michigan State University, East Lansing, MI, 48824, United States.
Background And Hypothesis: Sequential saccade planning requires corollary discharge (CD) signals that provide information about the planned landing location of an eye movement. These CD signals may be altered among individuals with schizophrenia (SZ), providing a potential mechanism to explain passivity and anomalous self-experiences broadly. In healthy controls (HC), a key oculomotor CD network transmits CD signals from the thalamus to the frontal eye fields (FEF) and the intraparietal sulcus (IPS) and also remaps signals from FEF to IPS.
View Article and Find Full Text PDFNeuroinformatics
January 2025
Institute of Mathematics, University of Kassel, Heinrich-Plett-Str. 40, Kassel, 34132, Germany.
Accurately identifying the timing and frequency characteristics of impulse components in EEG signals is essential but limited by the Heisenberg uncertainty principle. Inspired by the visual system's ability to identify objects and their locations, we propose a new method that integrates a visual system model with wavelet analysis to calculate both time and frequency features of local impulses in EEG signals. We develop a mathematical model based on invariant pattern recognition by the visual system, combined with wavelet analysis using Krawtchouk functions as the mother wavelet.
View Article and Find Full Text PDFSci Rep
January 2025
Physics Department, University of Benin City, Edo State, Benin, Nigeria.
Yukawa potential and Hulthẻn potential are very useful potential models with applications in different areas of physics. The present study examined theoretic measure and thermodynamic properties of energy levels and wave functions for a combination of these two potentials. The effect of screening parameter on Fisher information and Shannon entropy as well as the effect of temperature on the various thermodynamic properties of the combined potentials and its subsets potentials are well studied.
View Article and Find Full Text PDFCommun Math Phys
January 2025
Centro de Modelamiento Matemático (AFB170001), UMI-CNRS 2807, Universidad de Chile, Beauchef 851, Santiago, Chile.
Our motivation in this paper is twofold. First, we study the geometry of a class of exploration sets, called , which are naturally associated with a 2D vector-valued Gaussian Free Field : . We prove that, somewhat surprisingly, these sets are a.
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