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Zeitschrift für Naturforschung A

A Journal of Physical Sciences

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Herausgegeben von: , , und

Sprache: Englisch

Erstveröffentlichung: 20. Februar 1946

Erscheinungsweise: 12 Hefte pro Jahr

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Über diese Zeitschrift

Objective
A Journal of Physical Sciences: Zeitschrift für Naturforschung A (ZNA) is an international scientific journal which publishes original research papers from all areas of experimental and theoretical physics. Authors are encouraged to pay particular attention to a clear exposition of their respective subject, addressing a wide readership. In accordance with the name of our journal, which means "Journal for Natural Sciences", manuscripts submitted to ZNA should have a tangible connection to actual physical phenomena. In particular, we welcome experiment-oriented contributions.

Manuscripts considered for publication in A Journal of Physical Sciences: Zeitschrift für Naturforschung A undergo high-level refereeing. Mere formal correctness of a paper is not sufficient for its acceptance. Moreover, articles reporting a merely marginal extension of already existing knowledge are considered unsatisfactory. Instead, the key quality a public ati on in A Journal of Physical Sciences: Zeitschrift für Naturforschung A should possess is that it makes a genuine contribution to the advancement of its topic.

Topics

Atomic, Molecular & Optical Physics
Chemical Physics
Dynamical Systems & Nonlinear Phenomena
Fundamental Concepts of Physical Sciences
Gravitation & Cosmology
Hydrodynamics & Plasma Physics
Nuclear Physics & Particle Physics
Quantum Field Theory
Solid State Physics & Materials Science
Thermodynamics & Statistical Physics

Article formats
Original research articles, research notes, letters and review articles from all areas of theoretical and experimental physics

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Editors’ Choice

Zeitschrift fü r Naturforschung A – A Journal of Physical Sciences is proud to announce a new feature, the Editor’s Choice free access article. To download the featured article free of charge, please click the link below.

vol. 80, Iss. 11: Hopf-induced desynchronization by Seungjae Lee, Lennart J. Kuklinski, Moritz Thümler and Marc Timme

vol. 80, Iss. 8: Acompactanalytical solution of the Dicke superradiance master equation via residue calculus by Raphael Holzinger and Claudiu Genes

vol. 80, Iss. 6: Galilean decoherence and quantum measurement by Heinz-Jürgen Schmidt

vol. 79, Iss. 12: Choi representation of completely positive maps i n brief by Gábor Homa, Adrian Ortega and Mátyás Koniorczyk

vol. 79, Iss. 11: Global stability analysis of an extended SUC epidemic mathematical model by Mengxin Chen, Soobin Kwak, Seokjun Ham, Youngjin Hwang and Junseok Kim

vol. 79, Iss. 9: Computerized simulation of 2-dimensional phase contrast images using spiral phase plates in neutron interferometry by Wolfgang Treimer, Frank Haußer and Martin Suda

vol. 79, Iss. 2: Arbitrary maximally entangled quantum prisoner’s dilemma by Abd El-Hakeem E. H. Abd El-Naby, Heba A. Elrayes, Ahmed M. K. Tarabia and Ahmed S. Elgazzar

vol. 78, Iss. 5: Shapes of the noncentrosymmetric TeO5E g roups in tellurite glasses with P2O5 additions by Uwe Hoppe

Vol. 75, Iss. 5: Special Issue: Physics of Non-Equilibrium Systems Issue Editors: Martin Holthaus and Andreas Engel

Vol. 74, Iss. 8: Special Issue: Trends an Perspectives in Engery Research Issue Editors: Martin Holthaus and Sascha Schäfer

Vol. 72, Iss. 2: Special Issue: Heat Transfer and Heat Conduction on the Nanoscale Guest Editors: Svend-Age Biehs, Philippe Ben-Abdallah, Achim Kittel

Vol. 71, Iss. 10: Focus Section: Emergence in Driven Solid-State and Cold-Atom Systems Guest Editors: Ludwig Mathey, Junichi Okamoto

Complete Archive Access

As of 2026, all De Gruyter journal subscriptions include access to every issue, from Volume 1, Issue 1 through to today, meaning subscribers can access even more research at no additional cost.

Geschichte

The "Zeitschrift für Naturforschung A - A Journal of Physical Sciences" (ZNA) is an international scientific journal that publishes original research papers from all areas of experimental and theoretical physics. The journal has had a tradition of excellence since its first issue in early 1946.

History of ZNA: A Modern Journal with Tradition

Free access to virtual issue: seminal papers of eminent physicist published throughout the journal’s history

The "Zeitschrift für Naturforschung" – translated literally: Journal for Research in Natural Sciences – was founded by Alfred Klemm together with Hans Friedrich-Freksa in 1945, providing a badly needed functioning means of professional communication for scientists in postwar Germany.

In this tradition, ZNA is serving the international scientific community still today as an efficient, up-to-date communication platform which covers all areas of experimental and theoretical physics, combining rigorous publication standards with high visibility.

Please have a look at the comprehensive history of ZNA in the document "About this Journal".

Other publications in the field

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Pressure and temperature-tunable photonic crystal biosensor for early detection of CHIKV-infected cells

28. Mai 2026

Francis Segovia-Chaves

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In this work, using the transfer matrix method, we calculated the transmittance spectrum of an optical biosensor based on a defective one-dimensional photonic crystal for detecting cells infected with the Chikungunya virus. The heterostructure consists of alternating layers of GaAs and the high-critical-temperature superconductor Hg-1223, where the crystal’s periodicity is disrupted by the insertion of a cavity that acts as a sensing layer. Given that the cavity is infiltrated with plasma, platelets, and uric acid in both normal and infected states, we measured the transmittance spectrum under controlled variations in hydrostatic pressure and temperature. The results show the presence of a confined mode within the photonic band gap, whose position shifts with increasing applied pressure, enabling us to distinguish between healthy and infected cells. A maximum quality factor of 3.06 × 10 3 is reported for plasma at 10 GPa, and the confined energy decreases as the temperature is raised to 120 K. Additionally, we found that the biosensor is sensitive to increases in pressure or temperature across all cell types.
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Study of self-focusing and terahertz generation of Laguerre–Gaussian laser beams in a plasma channel under relativistic nonlinearity

26. Mai 2026

Aleena M. Ancy, Hansa Upreti, Arvinder Singh

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The generation of terahertz (THz) radiation from the propagation of Laguerre–Gaussian (LG) laser beams in a preformed plasma channel is investigated by considering relativistic nonlinearity. The transverse evolution of the laser beam is described using the moment theory approach, incorporating relativistic nonlinearity through the intensity-dependent electron mass variation. A self-consistent beam width equation is derived, accounting for diffraction, plasma channel guiding, and relativistic refractive index modification. The excitation of plasma waves by the non-linear current leads to efficient THz emission, whose yield is analytically evaluated for different LG modes. Higher-order modes exhibit stronger self-focusing and significantly improved THz efficiency due to stronger transverse intensity gradients. The influence of laser intensity, plasma density, and channel depth on beam dynamics and THz output is systematically examined. The obtained scaling shows qualitative agreement with experimental observations and numerical simulations of non-linear focusing behaviour.
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Steady magnetohydrodynamic MHD natural convection Couette flow in a vertical channel under the combined effects of radiation and heat generation/absorption

25. Mai 2026

Kabir M. Tafida, Ayuba M. Umar, Aisha Y. Abdullahi

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This paper is concerned with the steady MHD natural convection Couette flow of an electrically conducting, incompressible and viscous fluid within a vertical channel under the effect of thermal radiation and heat generation/absorption. The governing momentum and energy equations were solved using the Homotopy Perturbation Method (HPM). The presented parametric analysis indicates that the Grashof number increases buoyancy-driven convection, while higher permeability of the porous medium reduces the velocity field due to increased flow resistance. On the other hand, a higher magnetic field strength generates a Lorentz force that decelerates the fluid motion and enhances flow stability while reducing both heat and momentum transfer. At lower intensities, thermal radiation shows a dual effect on the temperature profile. Such MHD natural convection flows in vertical channels have practical applications in cooling technologies for nuclear reactors, electronic systems and fusion devices, where magnetic fields are used to control the heat transfer mechanism for maintaining stable flow conditions.
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The exact and numerical solutions for a dual-waveguide lattice laser radiation with linear gain and nonlinear losses

22. Mai 2026

Reda A. Ibrahim, Ahmet Bekir, Emad H. M. Zahran

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In this research, the Laser Radiation Propagation in a Dual-Waveguide Lattice with linear gain and nonlinear losses equation (LRPDWL) are considered. The exact solutions of the mentioned model are extracted via two techniques. The first one: is the so-called ( G ′/ G )-Expansion Technique that surrenders to the homogenous balance principle, while the second is the effective numerical and semi-analytic technique called the Differential Transform Technique (DTT). The initial conditions for the Differential Transform Technique emerged from the exact solution achieved by ( G ′/ G ) - Technique ( G ′/ G )-T). The optical properties of dissipative solitons in one-dimensional laser radiation within a dual-waveguide lattice have been investigated for the first time using the Newton iterative method for the proposed model. With an appropriate choice of parameters, a balance between nonlinear losses and linear localized gain can be achieved. Our study introduces new exact solution forms that reveal the optical characteristics of dissipative solitons in the model. Comparing the numerical solution with its corresponding ( G ′/ G ) solution via the absolute error is considered and it shows the agreement between both forms of solutions. The two-dimensional and three-dimensional behavior of all obtained solutions has been simulated and documented using the Mathematica program.
Open Access
Analysis of stochastic solitary wave solutions, bifurcation behavior, and modulation instability in the stochastic breaking soliton equation

22. Mai 2026

Saliha Manzoor, Farrah Ashraf, Mustafa Inc, Siti Sabariah Abas

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This paper investigates stochastic solitary wave solutions to the stochastic breaking soliton equation and analyze the bifurcation behavior and modulation instability of the solutions to random perturbations. Even though some research has been done on deterministic soliton models, there has not been adequate research on the stochasticity of the stochastic breaking soliton equation. Despite these studies, the dynamics and stability of its solitary wave solutions are still not fully studied, leaving an important research gap. The modified extended direct algebraic method is used to obtain the exact stochastic solitary waves solutions of the model under consideration to fill this research gap. The novelty of this paper is that it is the first one where the modified extended direct algebraic approach has been employed to the stochastic breaking soliton equation to obtain a series of new analytical stochastic solutions. Moreover, bifurcation analysis and modulation instability are investigated to understand the impact of system parameters and multiplicative noise on the qualitative behavior of the solutions. It is found that the stochastic perturbations have an important influence on the wave dynamics and can cause the changes between the stable and unstable regimes. The main contributions the work has made are the construction of new exact stochastic solutions, study of bifurcation behavior and understanding of modulation instability under noise. The results highlight the effectiveness of the proposed approach and offer deeper insight into stochastic nonlinear wave systems.
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Role of grating parameters on the excitation of plasmon–polaritons in graphene

22. Mai 2026

Naser Hatefi-Kargan, Ahmadreza Daraei

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In this paper, the effect of grating parameters on the excitation of plasmon–polaritons in a graphene layer placed on a rectangular grating is investigated. By solving the electromagnetic wave equation inside the device structure, the transmittance spectra of the device and the absorbance spectra of the graphene layer are calculated by varying the structure parameters. The results show that with the decrease of the Fermi energy level in the graphene layer, plasmon–polaritons are excited at longer wavelengths. With the increase of the grating ridge height, the absorbance at peak spectra points increases, and then saturates. The start of the saturation point depends on the grating ridge material. The results indicate that the best value for the grating ridge height is 0.7 or 0.4 times the grating period when the grating ridge material is doped silicon or gold, respectively. Duty cycle affects the efficiency of plasmon–polariton excitation, where the best values for the duty cycle are 0.75 or 0.65 when the grating ridge material is doped silicon or gold, respectively. With the choice of these best values one can excite plasmon–polaritons in the graphene layer more efficiently, which is useful for sensing and photodetection applications.
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Specific heat and susceptibility of S = 1/2 antiferromagnets on square, triangular, and kagome lattices

21. Mai 2026

Chisa Hotta

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We study the temperature dependence of the thermodynamic properties of spin-1/2 antiferromagnets on two-dimensional lattices. Our analysis employs the sine-square deformation (SSD), in which a real-space envelope function is applied to the Hamiltonian so that the local energy scale is smoothly reduced to zero at the system boundaries. The quantum eigenstates of the SSD Hamiltonian exhibit bulk-like behavior near the system center, effectively mimicking the thermodynamic limit even in small finite-size calculations. Using these fictitious bulk states, we compute the energy density, specific heat, and magnetic susceptibility as functions of temperature. We find that both the triangular- and kagome-lattice antiferromagnets show either a shoulder or a pronounced double-peak structure in the low-temperature specific heat, whereas the kagome case particularly shows a strong enhancement of magnetic susceptibility down to the lowest temperature range. These direct comparisons, together with the square-lattice and one-dimensional cases, reveal that although both frustrated systems retain a substantial amount of entropy, the low-energy excitations below ∼ 0.5 J $\sim 0.5J$ of the kagome lattice are predominantly governed by the magnetic excited states, whereas not much for the triangular lattice.
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Spin excitation of the Heisenberg antiferromagnet with frustration: from the bounce-lattice antiferromagnet through the maple-leaf-lattice antiferromagnet to the exact-dimer system

21. Mai 2026

Hiroki Nakano, Tôru Sakai

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The spin- S Heisenberg antiferromagnet on the two-dimensional lattice is investigated for S = 1/2 and S = 1. We consider interaction at isolated dimers ( J d ) and interaction bonds that form the bounce lattice ( J b ). For J d = J b , the system is reduced to the maple-leaf-lattice antiferromagnet. We primarily conduct highly parallelized numerical diagonalization to examine the spin excitation gap above the ground state for various J b / J d cases. For S = 1/2, we report calculations for a 42-site cluster that has not been previously treated. The S = 1 case is examined for the first time for clusters up to 24 sites. Regardless of whether S = 1/2 or 1, we find that the system has a gapped nature for small J d / J b and becomes gapless at J d / J b ∼ 1.4. For S = 1, we also find that another gapped region appears between the gapless case at J d / J b ∼ 1.4 and the boundary of the exact-dimer phase.
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Manipulation of electromagnetic wave propagation in quantum-spin-chain medium

19. Mai 2026

Taras Krokhmalskii, Taras Verkholyak, Ostap Baran, Dmytro Yaremchuk, Taras Hutak, Oleg Derzhko

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We consider a simple model of one-dimensional magnetic crystal and examine the propagation of an electromagnetic wave through such a medium. Calculating the dispersion relation k ( ω ) allows us to illustrate how the spread of the electromagnetic wave can be controlled by an external magnetic field. Our rigorous calculations should be useful for more realistic (and less tractable mathematically) models of magnetic media.
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Editorial: Special issues on “Frustrated spin systems and numerical methods” in commemoration of Johannes Richter, issue III

19. Mai 2026

Andreas Honecker, Jürgen Schnack

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Factorization, inflexibility of initial data for exact solutions and hyper-chaos landscape of waves for a kind of concatenation models in optical fibers

14. Mai 2026

Cheng-shi Liu

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This paper focuses on the exact solutions and dynamical properties of a concatenation model encompassing several high-order nonlinear Schrodinger equations arising from optical fiber communication. To the best of our knowledge, existing literature has only considered subsystems of this model under highly restrictive parameter conditions, with external drives being indispensable to induce chaotic behavior. The present work addresses all parameter regimes of the amplitude equation without introducing any external forces. Firstly, the amplitude equation is factorized for a family of parameters via the trial equation method, and a series of exact solutions are derived. Furthermore, a novel phenomenon-namely, the insensitivity of initial values for exact solutions-is identified and discussed. Secondly, for other parameter cases, the amplitude equation is analyzed from both qualitative and numerical simulation perspectives, leading to the discovery of a variety of novel internal chaotic structures with distinct topological characteristics. In addition, the sensitivity of initial values, parameter stability, bifurcations, Lyapunov exponents, and linearization at equilibrium points are investigated in detail. Two degenerate cases, which exhibit abundant dynamical behaviors, are also presented separately. These results provide a more comprehensive understanding of the dynamical behaviors of the model.
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Classical Kitaev model in a magnetic field

12. Mai 2026

Paul A. McClarty, Roderich Moessner, Karlo Penc, Jeffrey G. Rau

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Motivated by experiments on spin–orbit coupled magnets with Kitaev exchange in magnetic fields, we present an analysis of the classical Kitaev honeycomb model in the presence of a magnetic field. We show that there is a spin liquid regime that exists within a finite window of fields from zero up to a finite threshold before transitioning into the polarized paramagnet. We uncover constraints that spins need to satisfy in the ground state and show that they determine the exact limiting zero temperature behavior of the heat capacity and magnetic susceptibility within the spin liquid as a function of field. When the field is finite, both the two-point spin and the quadrupolar correlations are short-ranged, in contrast to the zero-field case. We rationalize an effective mass for the quadrupolar correlations in terms of a coarse-grained theory with fluctuating effective charge degrees of freedom. Finally, we show that weak site-dilution does not change the magnetization within the spin liquid – a kind of “perfect” compensation of the site dilution.
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Qualitative interaction dynamics of lump-type and breather structures in coupled Boussinesq system

12. Mai 2026

Snehalata Nasipuri, Prasanta Chatterjee

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We investigate the qualitative interaction dynamics of localized nonlinear wave structures in the coupled Boussinesq (CB) system using the Hirota bilinear method (HBM). Lump-type analytical wave profiles are constructed using a positive quadratic polynomial within Hirota’s perturbative framework, and their localized behavior is primarily examined through graphical analysis. The interactions between lump-type structures and one or two-kink waves are explored, revealing the formation of double lump-type structures near the central space–time region. In addition, breather structures are analyzed, exhibiting diffusion-like and interaction behaviors under suitable parameter regimes. The interaction of breather structures with periodic waves, kink waves, and bright soliton profiles is demonstrated, along with interaction scenarios involving two chains of double breathers. All results are illustrated through detailed two-dimensional, three-dimensional, and contour plots, highlighting the dominant localized dynamics near the center of the ( x , t )-plane. This study provides a qualitative understanding of lump-type and breather interaction phenomena in the CB system, highlighting its rich nonlinear wave dynamics.
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Quantum phase transition in transverse-field Ising model on Sierpiński gasket lattice

7. Mai 2026

Tymoteusz Braciszewski, Oliwier Urbański, Piotr Tomczak

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We investigate the quantum phase transition in the transverse-field Ising model on the Sierpiński gasket using finite-size scaling (FSS) and numerical renormalization group (NRG). Since next generations of the fractal lattice contain exponentially more spins, which in turn increase exponentially the Hilbert space dimension, we challenge and prove usefulness of small systems in FSS. We identified a quantum critical point at λ c ≈ 2.63 − 2.93, with critical exponents ν ≈ 0.64 − 0.71, β ≈ 0.30, γ ≈ 1.67 and z ≈ 1.33. The numerical renormalization group method produced results consistent with finite-size scaling approach ( λ c = 2.766, β = 0.316), supporting our findings. Compared to the values reported so far in the literature, critical field is in a strong disagreement, while exponents are generally similar excluding β and γ . However, it should be noted, that the lattice investigated in previous works is different from ours, while the latter is in our opinion the standard Sierpiński gasket.
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Thermo-bioconvective instability of thermotactic microorganism with nanofluid layer: Darcy–Brinkman model

28. April 2026

Yashika, Yogeshver Dutt Sharma

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Investigating bioconvection in nanofluids with thermotactic microorganisms is key to advancing technologies in fields such as biomedical engineering and thermal management, where understanding these interactions can lead to more efficient systems and innovative solutions. This study examines the initiation of bioconvection in a porous medium containing a nanofluid with thermotactic microorganisms in a dilute suspension. This system is confined between two horizontal parallel walls, heated from above. Buongiorno’s model outlines the flow governing equations, Pedley’s model is used for microorganism concentration and the porous medium is stimulated with Darcy–Brinkman model. To incorporate density effects, the Oberbeck–Boussinesq approximation is implemented. A linear stability analysis is conducted, resulting in the ordinary differential equations problem derived from normal mode analysis and using the bvp4c method. The presence of nanoparticle and modified Darcy number stabilizes the system while porosity shows the dual nature. The Péclet number pre-pone the onset of bioconvection. The system stabilizes as cell diffusivity decreases or as thermal diffusivity increases.
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Vortex formation in Kelvin–Helmholtz driven instability in dense quantum magnetoplasma

27. April 2026

Arshad M. Mirza, Bilal Ramzan, Zahid Mir, Uzma Yousaf

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In this work, we investigate nonlinear vortex formation in dense magnetized quantum plasma using a quantum hydrodynamic framework inspired by linear models in Ref. [A. Rasheed, M. Jamil, and G. Murtaza, “Kelvin–Helmholtz instability in a dense quantum magnetoplasma with exchange correlations,” Z. Naturforsch. A , vol. 78, pp. 1123–1130, 2023]. While the linear dispersion relation remains unchanged from previous studies [A. Rasheed, M. Jamil, and G. Murtaza, “Kelvin–Helmholtz instability in a dense quantum magnetoplasma with exchange correlations,” Z. Naturforsch. A , vol. 78, pp. 1123–1130, 2023], the present work extends the analysis to the nonlinear regime by incorporating convective and mode-coupling effects. We derive and solve fluid equations incorporating Fermi pressure, Bohm potential, and exchange-correlation effects, focusing on the nonlinear development of Kelvin–Helmholtz (KH) instability. Our analytical solutions reveal the presence of stationary dipolar vortex structures. Conditions for their formation, as well as the influence of quantum parameters, are discussed. The results have relevance for both astrophysical and laboratory plasma environments.
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A generalization of the Choi isomorphism with application to open quantum systems

22. April 2026

Heinz-Jürgen Schmidt

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Completely positive transformations play an important role in the description of state changes in quantum mechanics, including the time evolution of open quantum systems. One useful tool to describe them is the so-called Choi isomorphism, which maps completely positive transformations to positive semi-definite matrices. Accordingly, there are numerous proposals to generalize the Choi isomorphism. In the present paper, we show that the 1976 paper of Gorini, Kossakowski, and Sudarshan (GKS) already holds the key for a further generalization and study the resulting GKS isomorphism. As an application, we compute the GKS matrix of the time evolution of a general open quantum system up to second order in time.
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Finite observability, conservation laws, and state-dependent effective laws: a Ludwig-style perspective on climate physics

20. April 2026

Gerrit Lohmann

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Many physical theories are formulated in terms of continuous fields, infinite resolution and exact trajectories, while empirical access to complex systems is inherently finite. This tension is particularly acute in climate physics, where multiscale dynamics, effective closures and historically evolving observations constrain what can be operationally defined. Building on Günther Ludwig’s axiomatic programme, we develop a framework in which physical meaning is grounded in finite observation and statistically stable regularities. Climate states are represented as probability distributions over observables constrained by conservation laws, rather than as points in phase space. Within this setting, we argue that the governing laws of climate physics are necessarily state-dependent effective laws. This necessity is understood in an operational sense: under finite resolution and regime-limited empirical access, no state-independent effective closure can be validated across distinct climate regimes, even if the underlying dynamical equations remain universal. Abrupt transitions, long intrinsic timescales and regime dependence are therefore properties of transition statistics rather than deterministic trajectories. By placing climate physics in direct analogy with statistical mechanics, we identify it as part of a broader class of physical theories in which probability, conservation and effective description are foundational.
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Mathematical Kelvin formulation of the second law of thermodynamics

20. April 2026

Matthias Heidrich

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A mathematical Kelvin formulation of the second law of thermodynamics in the form of a limit is proposed: If the efficiency of a heat engine approaches unity, then the rejected work vanishes. This limit allows deriving the behavior of a Carnot cycle near absolute zero of temperature. Also, the unattainability of absolute zero can be shown. In turn, these results allow deriving the behavior of the entropy near absolute zero, as has already been shown previously. The point of view is the phenomenological, macroscopic, and nonstatistical one of classical thermodynamics.
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Magnetic intensity-driven frequency change of smart microcore-based hydrogen-phononic adsorber system for nanomass sensing

13. April 2026

Lamine Elaihar, Hicham Bourouina, Soumia Khouni, Abir Lamari

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This study investigates the nonlocal frequency shift in an adatom-microstructure system by incorporating the effects of nonlocal elasticity, adatom distribution, and magnetic fields. The model features a sandwich microbeam composed of functionally graded porous (FGP) face sheets and a core embedded with a uniformly distributed periodic square hole (PSH) network. The material properties of all three layers vary through the thickness following a power-law distribution. The influence of the external magnetic field is modeled using Maxwell’s equations, while the small-scale effects are captured via Eringen’s nonlocal strain gradient theory. Interactions between adatoms and the substrate surface are described using Lennard–Jones (6, 12) and Morse potentials, which account for the energy changes due to adsorption. To compute the resonance frequency shift, the governing mechanical equations are formulated based on both the Euler–Bernoulli and Levinson beam models and solving the problem requires the use of the differential quadrature method (DQM) as well as Navier solution method (NSM). The results clearly demonstrate that the perforated core configuration significantly affects the frequency shift, adatom adsorption level, magnetic field intensity, and nonlocal mechanical response. These outcomes are essential for optimizing the design of mass-sensitive MEMS/NEMS resonators, including hydrogen, biomolecule, and magnetic-field sensors.
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Lie symmetries, bifurcation analysis and soliton solutions of the viscous-capillarity compressible fluid model

7. April 2026

Naseem Abbas, Bruno Antonio Pansera, Muhammad Idrees, Shah Muhammad

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The dynamics of compressible fluids with viscosity and capillarity remain only partially understood, particularly in relation to phase transitions and nonlinear wave propagation. Due to the difficulties posed by its mixed-type nature, where eigenvalue variations result in hyperbolic–elliptic transitions and shock formation, thorough symmetry-based and bifurcation analyses of the one-dimensional viscous–capillarity compressible van der Waals system (the p -system) remain limited despite prior research. This paper examines the model using soliton solutions, bifurcation theory, and Lie symmetry techniques. Symmetry analysis identifies invariant structures, making analytical and numerical treatment easier. Soliton solutions reveal robust nonlinear waveforms that accurately model shock structures and capillary-driven interfacial phenomena, while bifurcation analysis reveals critical stability thresholds controlled by viscosity and surface tension. In the natural sciences and engineering, where phase transitions and interfacial effects are crucial, the results offer practical significance and a deeper theoretical understanding of nonlinear compressible flows.
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Field-induced states and thermodynamics of the frustrated Heisenberg antiferromagnet on a square lattice

12. März 2026

Andreas Honecker, M. E. Zhitomirsky, Alexander Wietek, Johannes Richter

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We investigate the ground-state and finite-temperature properties of the J 1 – J 2 Heisenberg antiferromagnet on the square lattice in the presence of an external magnetic field. We focus on the highly frustrated regime around J 2 ≈ J 1 /2. The h – T phase diagram is investigated with particular emphasis on the finite-temperature transition into the “up-up-up-down” state that is stabilized by thermal and quantum fluctuations and manifests itself as a plateau at one half of the saturation magnetization in the quantum case. We also discuss the enhanced magnetocaloric effect associated to the ground-state degeneracy that arises at the saturation field for J 2 = J 1 /2. For reference, we first study the classical case by classical Monte Carlo simulations. Then, we turn to the extreme quantum limit of spin-1/2 where we perform zero- and finite-temperature Lanczos calculations.
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Tensor-network study of the ground state of the maple-leaf Heisenberg antiferromagnet

12. März 2026

Samuel Nyckees, Pratyay Ghosh, Frédéric Mila

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We study the quantum phase diagram of the spin-1/2 nearest-neighbor Heisenberg model on the maple-leaf lattice using infinite projected entangled pair states (iPEPS) combined with a corner transfer matrix renormalization group scheme adapted to C 3 -symmetric lattices. Focusing on the fully antiferromagnetic J – J d model with J h = J t ≔ J , we map out the ground-state phase diagram as a function of the dimer coupling J d . Our results show that the system hosts only two phases: a magnetically ordered canted-120° phase and an exact dimer singlet product phase. We identify a first-order transition between these two phases at J d / J ≈ 1.45. Within the magnetically ordered phase, we observe small but finite magnetic moments. We also resolve the quantum renormalization of the canting angle, which deviates from the classical prediction over almost the entire magnetically ordered phase.
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Analysis of nonlinear dynamics, bifurcation, and chaos in a low-pass electrical transmission line system

3. März 2026

Mati ur Rahman, Sonia Akram

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This study presents a comprehensive analytical and dynamical investigation of a nonlinear low-pass electrical transmission line model derived from Kirchhoff’s circuit laws by incorporating nonlinear inductive capacitive effects. The governed model accounts for both quadratic and cubic nonlinearities as well as higher-order spatial dispersion, providing a generalized framework to explore rich nonlinear phenomena including bistability, modulational instability, and solitary wave propagation. To extract exact traveling-wave solutions, the Riccati–Bernoulli sub-ODE method is used, which efficiently reduces the governing nonlinear partial differential equation to an integrable form. Various families of localized structures are obtained, such as dark, bright, hyperbolic, trigonometric, mixed, and hybrid soliton profiles under distinct parametric regimes. The corresponding three-dimensional, contour, and two-dimensional graphical representations signify how nonlinear, dispersive, and higher-order terms modulate the amplitude, polarity, and symmetry of the evolving waveforms. Furthermore, a detailed chaotic assessment of the reduced dynamical system is carried out through phase portraits, power spectra, bifurcation diagrams, return maps, and Lyapunov exponent analysis. The coexistence of positive and negative Lyapunov exponents confirms the system’s chaotic nature and sensitive dependence on initial conditions, while bifurcation transitions highlight parameter-dependent shifts between periodic, quasi-periodic, and chaotic regimes. The interplay between analytical soliton structures and numerical chaos analysis provides a comprehensive physical picture of the nonlinear energy transport in the nonlinear low-pass electrical transmission line framework. The findings demonstrate the versatility of the Riccati–Bernoulli approach in capturing multi-type nonlinear excitations and chaotic transitions, establishing its potential for modeling real-world phenomena such as nonlinear signal propagation in electrical transmission networks, ultrafast pulse modulation in optical fibers, and controlled wave localization in metamaterial systems.
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Unconventional orders in the maple-leaf ferro-antiferromagnetic Heisenberg model

24. Februar 2026

Lasse Gresista, Dominik Kiese, Simon Trebst, Yasir Iqbal

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Motivated by the search for unconventional orders in frustrated quantum magnets, we present a multi-method investigation into the nature of the quantum phase diagram of the spin-1/2 Heisenberg model on the maple-leaf lattice with three symmetry-inequivalent nearest-neighbor interactions. It has been argued that the parameter regime with antiferromagnetic couplings on hexagons J h and ferromagnetic couplings on triangles J t and dimer J d bonds is potentially host to a cornucopia of emergent phases with unconventional orders. Our analysis indeed identifies an extended region where any conventional dipolar magnetic order is absent. A hexagonal singlet state is found in the region around J d = J t = 0, while a dimerized hexagonal singlet order of a lattice nematic character appears proximate to the phase boundary with the c120° antiferromagnetic order. Interestingly, upon traversing the bulk of the paramagnetic (PM) region, we find a variety of distinct correlation profiles, which are qualitatively different from those of the hexagonal singlet and dimerized hexagonal singlet orders but feature no appreciable spin-nematic response, while the boundary with the ferromagnetic phase shows evidence of spin-nematic order. This PM region is thus likely host to an ensemble of nonmagnetic phases, which could putatively include quantum spin liquids. Our phase diagram is built from a complementary application of state-of-the-art implementations of the cluster mean-field and pseudo-fermion functional renormalization group approaches, together with an unconstrained Luttinger–Tisza treatment of the model providing insights from the semi-classical limit.
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Thermodynamics of the Heisenberg antiferromagnet on the maple-leaf lattice

4. Februar 2026

Robin Schäfer, Paul L. Ebert, Noah Hassan, Johannes Reuther, David J. Luitz, Alexander Wietek

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We study the Heisenberg antiferromagnet on the maple-leaf lattice using several numerical approaches, focusing on the numerical linked-cluster expansion (NLCE), which exhibits an unconventional convergence extending to low and even zero temperatures. We evaluate thermodynamic properties as well as spin–spin correlations through the equal-time structure factor. Within NLCE, the specific heat capacity reveals a two-peak structure at T 1 ≈ 0.479 J and T 2 ≈ 0.131 J, reminiscent of the corresponding result for the triangular lattice. At intermediate temperatures, the spin–spin structure factor develops features that reflect the absence of reflection symmetry in the lattice. The zero-temperature convergence of NLCE enables reliable estimates of the ground-state energy and points to a short-range correlated paramagnetic ground state composed of resonating hexagonal motifs. The NLCE results are benchmarked against pseudo-Majorana functional renormalization group, finite-temperature Lanczos, and classical Monte Carlo simulations.

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Special Issue: Frustrated spin systems and numerical methods; Guest Editors: Andreas Honecker and Jürgen Schnack

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Special Issue: Frustrated spin systems and numerical methods; Guest Editors: Andreas Honecker and Jürgen Schnack

Journal Impact Factor	1.3	2024, Journal Citation Reports (Clarivate, 2025)
5-year Journal Impact Factor	1.2	2024, Journal Citation Reports (Clarivate, 2025)
Journal Citation Indicator	0.33	2024, Journal Citation Reports (Clarivate, 2025)
CiteScore	3	2024, Scopus (Elsevier B.V., 2025)
SCImago Journal Rank	0.253	2024, SJR (Scimago Lab, 2025; Data Source: Scopus)
Source Normalized Impact per Paper	0.511	2024, CWTS Journal Indicators (CWTS B.V., 2025; Data Source: Scopus)

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