Pub Date : 2026-02-01Epub Date: 2025-12-04DOI: 10.1016/j.cjph.2025.11.030
Uzma Tabassam, Bisma Kabir
We have investigated the invariant differential yield of resonance states of + and Ξ(1530)0+ baryons in pp collisions at = 13 TeV for different multiplicity classes within the mid rapidity region of |y| < 0.5. For particle production, the PYTHIA8312 event generator is used. The model was tuned to include the flavor rope effects and string shoving mechanisms to enhance the production of hyperons and baryons. It was observed that for the higher multiplicity classes the MC predictions are close to the ALICE experimental results, whereas for the low multiplicity classes, small deviations were observed. It was observed that, in pp collisions due to absence of phase space the MC predictions do not fully agree with the ALICE experimental data. The observed deviations could be due to the limitations in the modeling and limited rope haronization and shoving effects. Strangeness enhancement was observed by analyzing the baryon to meson ratio. The ALICE and MC simulation data is fitted with the Tsallis distribution function to study the effective temperature Teff at freeze out stage of system in different multiplicity classes. The extracted Tsallis parameters do agree well with the literature values resulting in the observation that the high multiplicity events exhibit greater thermalization. Additionally, we observed the strong radial and rescattering effects in the system.
{"title":"String shoving and flavor rope effects on single and double-strange resonance productions in pp collisions at s = 13 TeV","authors":"Uzma Tabassam, Bisma Kabir","doi":"10.1016/j.cjph.2025.11.030","DOIUrl":"10.1016/j.cjph.2025.11.030","url":null,"abstract":"<div><div>We have investigated the invariant differential yield of resonance states of <span><math><mrow><mstyle><mi>Σ</mi></mstyle><msup><mrow><mo>(</mo><mn>1385</mn><mo>)</mo></mrow><mrow><mo>*</mo><mo>+</mo></mrow></msup></mrow></math></span> + <span><math><mrow><mover><mstyle><mi>Σ</mi></mstyle><mo>¯</mo></mover><msup><mrow><mo>(</mo><mn>1385</mn><mo>)</mo></mrow><mrow><mo>*</mo><mo>−</mo></mrow></msup></mrow></math></span> and Ξ(1530)<sup>0</sup>+ <span><math><mrow><mover><mstyle><mi>Ξ</mi></mstyle><mo>¯</mo></mover><msup><mrow><mo>(</mo><mn>1530</mn><mo>)</mo></mrow><mn>0</mn></msup></mrow></math></span> baryons in <em>pp</em> collisions at <span><math><msqrt><mi>s</mi></msqrt></math></span> = 13 TeV for different multiplicity classes within the mid rapidity region of |<em>y</em>| < 0.5. For particle production, the PYTHIA8312 event generator is used. The model was tuned to include the flavor rope effects and string shoving mechanisms to enhance the production of hyperons and baryons. It was observed that for the higher multiplicity classes the MC predictions are close to the ALICE experimental results, whereas for the low multiplicity classes, small deviations were observed. It was observed that, in pp collisions due to absence of phase space the MC predictions do not fully agree with the ALICE experimental data. The observed deviations could be due to the limitations in the modeling and limited rope haronization and shoving effects. Strangeness enhancement was observed by analyzing the baryon to meson ratio. The ALICE and MC simulation data is fitted with the Tsallis distribution function to study the effective temperature <em>T<sub>eff</sub></em> at freeze out stage of system in different multiplicity classes. The extracted Tsallis parameters do agree well with the literature values resulting in the observation that the high multiplicity events exhibit greater thermalization. Additionally, we observed the strong radial and rescattering effects in the system.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"99 ","pages":"Pages 283-292"},"PeriodicalIF":4.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837432","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01Epub Date: 2025-12-10DOI: 10.1016/j.cjph.2025.12.009
Anagha A , Ravi Ragoju , Vinit Kumar Tripathi
This study investigates the linear and nonlinear stability of thermal convection in a porous medium saturated by a Jeffrey fluid. The analysis incorporates the combined effects of vertical throughflow, viscous dissipation, and a variable gravity field. The linear stability theory is analyzed using the normal mode technique, while the nonlinear stability threshold is determined using the energy method. The principle of exchange of stabilities is proven, confirming that convection sets in a stationary mode. The resulting eigenvalue problem is solved numerically using the Chebyshev pseudo-spectral method. Four distinct gravity field profiles: linear, parabolic, cubic, and exponential, each decreasing with depth, are examined. A comparative analysis of the critical Rayleigh number is performed to assess the influence of the gravity variation parameter (δ), throughflow parameter (Pe), Jeffrey fluid parameter (λ), and viscous dissipation parameter (Ge). The results demonstrate that the parameters δ and Pe exert a stabilizing influence on the system, whereas Ge and λ have a destabilizing effect. Furthermore, the sensitivity of the system to these parameters is strongly dependent on the gravity profile: the cubic field shows the least sensitivity, while the exponential field exhibits the most pronounced effect. The region of subcritical instability exists only in the presence of vertical throughflow. In its absence, no subcritical instability is observed, even when varying other system parameters.
{"title":"Nonlinear stability analysis of jeffrey fluid in porous medium with vertical throughflow: Effects of variable gravity and viscous dissipation","authors":"Anagha A , Ravi Ragoju , Vinit Kumar Tripathi","doi":"10.1016/j.cjph.2025.12.009","DOIUrl":"10.1016/j.cjph.2025.12.009","url":null,"abstract":"<div><div>This study investigates the linear and nonlinear stability of thermal convection in a porous medium saturated by a Jeffrey fluid. The analysis incorporates the combined effects of vertical throughflow, viscous dissipation, and a variable gravity field. The linear stability theory is analyzed using the normal mode technique, while the nonlinear stability threshold is determined using the energy method. The principle of exchange of stabilities is proven, confirming that convection sets in a stationary mode. The resulting eigenvalue problem is solved numerically using the Chebyshev pseudo-spectral method. Four distinct gravity field profiles: linear, parabolic, cubic, and exponential, each decreasing with depth, are examined. A comparative analysis of the critical Rayleigh number is performed to assess the influence of the gravity variation parameter (<em>δ</em>), throughflow parameter (<em>Pe</em>), Jeffrey fluid parameter (<em>λ</em>), and viscous dissipation parameter (<em>Ge</em>). The results demonstrate that the parameters <em>δ</em> and Pe exert a stabilizing influence on the system, whereas <em>Ge</em> and <em>λ</em> have a destabilizing effect. Furthermore, the sensitivity of the system to these parameters is strongly dependent on the gravity profile: the cubic field shows the least sensitivity, while the exponential field exhibits the most pronounced effect. The region of subcritical instability exists only in the presence of vertical throughflow. In its absence, no subcritical instability is observed, even when varying other system parameters.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"99 ","pages":"Pages 236-253"},"PeriodicalIF":4.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01Epub Date: 2025-11-30DOI: 10.1016/j.cjph.2025.11.037
Y. Sekhmani , A. Baruah , A. Al-Badawi , S.K. Maurya , M.K. Jasim , M. Altanji , S.N. Gashti
This study explores the impact of the spin (κs), dilaton (κd), and shear (κsh) charges on the massless scalar quasinormal modes (QNMs), greybody factors, shadow behavior, and deflection angle of a four-dimensional dyonically charged black hole (BH) in metric-affine gravity (MAG) with torsion and nonmetricity (NMT). To assess the stability against perturbations, we analyze scalar QNMs of the BH in the frequency domain using the highly accurate 13th order Padé-averaged WKB method. Using appropriate parameter spaces, we study the influence of the spin, dilaton, and shear charges on the QNMs. The obtained frequency data indicate the stability of the BH against scalar perturbation. The frequencies generally decrease with increasing dilaton and shear charges; however, the damping rates exhibit nuanced behavior. The spin charge has the opposite effect on the QNMs in that the frequencies and damping rates increase with the spin charge consistently across the studied overtone range. Physically, it is interpreted that the additional charges effectively influence the stiffness of the spacetime and the propagation of gravitational waves. The QNMs estimated using the Padé-averaged WKB method exhibit good accuracy, and outliers in specific parameter ranges are highlighted. Next, we investigate the behavior of the deflection of light rays by dyonically charged BHs in MAG using the Gauss-Bonnet formalism. Using weak-field approximations and relevant constraints associated with the cosmological constant, we compute and analyze the optical quantities by altering the spin, dilaton, and shear charge parameters. Constraints on the spin (κs), dilaton (κd), and shear (κsh) charges, derived from Event Horizon Telescope observations of M87* and Sgr A*, highlight the fact that this BH model is a promising candidate for simulating astrophysical BHs.
{"title":"Quasinormal spectra, greybody factors, optical shadows, and light deflection by dyonically charged black holes in metric-affine gravity with torsion and nonmetricity","authors":"Y. Sekhmani , A. Baruah , A. Al-Badawi , S.K. Maurya , M.K. Jasim , M. Altanji , S.N. Gashti","doi":"10.1016/j.cjph.2025.11.037","DOIUrl":"10.1016/j.cjph.2025.11.037","url":null,"abstract":"<div><div>This study explores the impact of the spin (<em>κ<sub>s</sub></em>), dilaton (<em>κ<sub>d</sub></em>), and shear (<em>κ<sub>sh</sub></em>) charges on the massless scalar quasinormal modes (QNMs), greybody factors, shadow behavior, and deflection angle of a four-dimensional dyonically charged black hole (BH) in metric-affine gravity (MAG) with torsion and nonmetricity (NMT). To assess the stability against perturbations, we analyze scalar QNMs of the BH in the frequency domain using the highly accurate 13<sup>th</sup> order Padé-averaged WKB method. Using appropriate parameter spaces, we study the influence of the spin, dilaton, and shear charges on the QNMs. The obtained frequency data indicate the stability of the BH against scalar perturbation. The frequencies generally decrease with increasing dilaton and shear charges; however, the damping rates exhibit nuanced behavior. The spin charge has the opposite effect on the QNMs in that the frequencies and damping rates increase with the spin charge consistently across the studied overtone range. Physically, it is interpreted that the additional charges effectively influence the stiffness of the spacetime and the propagation of gravitational waves. The QNMs estimated using the Padé-averaged WKB method exhibit good accuracy, and outliers in specific parameter ranges are highlighted. Next, we investigate the behavior of the deflection of light rays by dyonically charged BHs in MAG using the Gauss-Bonnet formalism. Using weak-field approximations and relevant constraints associated with the cosmological constant, we compute and analyze the optical quantities by altering the spin, dilaton, and shear charge parameters. Constraints on the spin (<em>κ<sub>s</sub></em>), dilaton (<em>κ<sub>d</sub></em>), and shear (<em>κ<sub>sh</sub></em>) charges, derived from Event Horizon Telescope observations of M87* and Sgr A*, highlight the fact that this BH model is a promising candidate for simulating astrophysical BHs.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"99 ","pages":"Pages 177-198"},"PeriodicalIF":4.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01Epub Date: 2025-12-05DOI: 10.1016/j.cjph.2025.12.006
Duy Van Pham , Yi-Xuan Lu , Yu-Hsiang Wang , Carlo C.Sta. Maria , Ming-Hsien Lee , Chien-Chih Lai , Rupesh S. Devan , Yuan-Ron Ma
Two-dimensional 4H-SnS2 single crystals of several square millimeters were grown using chemical vapor transport method. A bulk 4H-SnS2 can be easily exfoliated into few-layer 4H-SnS2 using mechanical exfoliation technique. Few-layer and multilayer 4H-SnS2 of 3, 8, 13, 27, 43, and 71 monolayers were stably obtained in ambient. The Raman spectra of few-layer and multilayer 4H-SnS2 reveal a single dominant A1g Raman mode. The A1g Raman mode of few-layer 4H-SnS2 is redshifted and broadened with reduced layer number, indicating that the phonon confinement effect is layer-dependent. The Raman tensor of the few-layer 4H-SnS2 can be fixed with the phonon confinement effect. This effect also significantly influences the thermodynamic properties of few-layer 4H-SnS2. The results provide valuable insights for the design of next-generation photonic and thermoelectric devices based on 4H-SnS2.
{"title":"Phonon confinement effect on breathing vibrations of monolayer and few-layer metal dichalcogenides","authors":"Duy Van Pham , Yi-Xuan Lu , Yu-Hsiang Wang , Carlo C.Sta. Maria , Ming-Hsien Lee , Chien-Chih Lai , Rupesh S. Devan , Yuan-Ron Ma","doi":"10.1016/j.cjph.2025.12.006","DOIUrl":"10.1016/j.cjph.2025.12.006","url":null,"abstract":"<div><div>Two-dimensional 4H-SnS<sub>2</sub> single crystals of several square millimeters were grown using chemical vapor transport method. A bulk 4H-SnS<sub>2</sub> can be easily exfoliated into few-layer 4H-SnS<sub>2</sub> using mechanical exfoliation technique. Few-layer and multilayer 4H-SnS<sub>2</sub> of 3, 8, 13, 27, 43, and 71 monolayers were stably obtained in ambient. The Raman spectra of few-layer and multilayer 4H-SnS<sub>2</sub> reveal a single dominant A<sub>1g</sub> Raman mode. The A<sub>1g</sub> Raman mode of few-layer 4H-SnS<sub>2</sub> is redshifted and broadened with reduced layer number, indicating that the phonon confinement effect is layer-dependent. The Raman tensor of the few-layer 4H-SnS<sub>2</sub> can be fixed with the phonon confinement effect. This effect also significantly influences the thermodynamic properties of few-layer 4H-SnS<sub>2</sub>. The results provide valuable insights for the design of next-generation photonic and thermoelectric devices based on 4H-SnS<sub>2</sub>.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"99 ","pages":"Pages 450-460"},"PeriodicalIF":4.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145920902","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper, a biomimetic membrane-pumping system is presented that can be used to control the yield-stress fluids (Bingham viscoplastic fluid) in an inclined microchannel, with the synergy between external magnetic fields and thermal radiation. The pump works by having synchronized membrane vibrations forming rhythmic compression and expansion cycles which produce controlled flow. The governing equations are solved using a strong mathematical framework that is based on the lubrication theory and non-dimensional analysis, where solutions are validated numerically using the bvp5c high-fidelity collocation version (MATLAB bvp5c). It is found that the combination of the Bingham number (yield stress), the strength of the magnetic field (Hartmann number), and the inclination of the channels predetermines the flow profiles, thermal transport, and shear stress. A parametric analysis indicates that both the yield stress and magnetic field effects substantially inhibit flow while channel orientation can enhance membrane-actuated flow rates. The results show a 47.43 % reduction in flow through the channel with an increase in Hartmann number from 1 to 3; and when a small Bingham number (0.04) is introduced, flow through the channel is reduced by an additional 10.86 %. Conversely, flow through the channel increases by 77.24 % at an angle of π/4. These findings illustrate that the pumping efficiency will be determined by the interaction of the magnetic dampening, yield stress resistance, and gravitational assistive forces acting on the fluid. The irreversibility of thermodynamics is also measured through entropy generation and the Bejan number. Such findings reveal a trade-off between flow and entropy suppression which is operational, and can be used to design transformative paradigms of microfluidic pump optimization, especially in biomedical and thermal management processes that need to handle complex fluids under thermal and magnetic limitations.
{"title":"Entropy generation in membrane-actuated pumping of yield-stress fluids in an inclined microchannel: Influence of heat and magnetic fields","authors":"K.V. Prasad , Hanumesh Vaidya , Mahalingappa Naganur , Rajashekhar V. Choudhari","doi":"10.1016/j.cjph.2025.12.012","DOIUrl":"10.1016/j.cjph.2025.12.012","url":null,"abstract":"<div><div>In this paper, a biomimetic membrane-pumping system is presented that can be used to control the yield-stress fluids (Bingham viscoplastic fluid) in an inclined microchannel, with the synergy between external magnetic fields and thermal radiation. The pump works by having synchronized membrane vibrations forming rhythmic compression and expansion cycles which produce controlled flow. The governing equations are solved using a strong mathematical framework that is based on the lubrication theory and non-dimensional analysis, where solutions are validated numerically using the bvp5c high-fidelity collocation version (MATLAB bvp5c). It is found that the combination of the Bingham number (yield stress), the strength of the magnetic field (Hartmann number), and the inclination of the channels predetermines the flow profiles, thermal transport, and shear stress. A parametric analysis indicates that both the yield stress and magnetic field effects substantially inhibit flow while channel orientation can enhance membrane-actuated flow rates. The results show a 47.43 % reduction in flow through the channel with an increase in Hartmann number from 1 to 3; and when a small Bingham number (0.04) is introduced, flow through the channel is reduced by an additional 10.86 %. Conversely, flow through the channel increases by 77.24 % at an angle of π/4. These findings illustrate that the pumping efficiency will be determined by the interaction of the magnetic dampening, yield stress resistance, and gravitational assistive forces acting on the fluid. The irreversibility of thermodynamics is also measured through entropy generation and the Bejan number. Such findings reveal a trade-off between flow and entropy suppression which is operational, and can be used to design transformative paradigms of microfluidic pump optimization, especially in biomedical and thermal management processes that need to handle complex fluids under thermal and magnetic limitations.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"99 ","pages":"Pages 504-534"},"PeriodicalIF":4.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145920903","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01Epub Date: 2025-12-01DOI: 10.1016/j.cjph.2025.11.038
He Huang , Masayuki Aikawa , Shuichiro Ebata , Kenta Sugihara , Zolbadral Tsoodol , Naoyuki Ukon , Hiromitsu Haba , Sándor Takács , Ferenc Ditrói , Zoltán Szűcs , Tamás Tornyi
Technetium radioisotopes have garnered interest in medical applications. In this study, niobium-93 foils were irradiated with a 50-MeV alpha-particle beam to determine the production cross sections of technetium radioisotopes including 96g,95m,95g,94g,93m,93gTc, along with 93mMo, 95m,95g,92m,91m,90Nb, 89gZr and 88,87gY. The stacked-foil activation technique and gamma-ray spectrometry were adopted for this experiment. The results were compared with the theoretical values of TALYS based TENDL-2023 library, and the previously published experimental data. Physical thick target yields (TTY) were deduced based on the measured cross sections.
{"title":"Activation cross sections of alpha-particle-induced reactions on niobium-93 up to 50 MeV","authors":"He Huang , Masayuki Aikawa , Shuichiro Ebata , Kenta Sugihara , Zolbadral Tsoodol , Naoyuki Ukon , Hiromitsu Haba , Sándor Takács , Ferenc Ditrói , Zoltán Szűcs , Tamás Tornyi","doi":"10.1016/j.cjph.2025.11.038","DOIUrl":"10.1016/j.cjph.2025.11.038","url":null,"abstract":"<div><div>Technetium radioisotopes have garnered interest in medical applications. In this study, niobium-93 foils were irradiated with a 50-MeV alpha-particle beam to determine the production cross sections of technetium radioisotopes including <sup>96g,95m,95g,94g,93m,93g</sup>Tc, along with <sup>93m</sup>Mo, <sup>95m,95g,92m,91m,90</sup>Nb, <sup>89g</sup>Zr and <sup>88,87g</sup>Y. The stacked-foil activation technique and gamma-ray spectrometry were adopted for this experiment. The results were compared with the theoretical values of TALYS based TENDL-2023 library, and the previously published experimental data. Physical thick target yields (TTY) were deduced based on the measured cross sections.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"99 ","pages":"Pages 573-587"},"PeriodicalIF":4.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145920905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01Epub Date: 2025-12-18DOI: 10.1016/j.cjph.2025.12.020
Xueling Liu , Jing Huang , Yufeng Zhang , Junlin Li
As is well known, most models in scientific research and engineering feature asymmetric potentials. Gaining a deeper understanding of how the symmetry-breaking phenomenon affects the response mechanisms of systems is both meaningful and crucial. In this paper, we primarily explore the dynamic properties, including bifurcation and chaos, of a bi-frequency excited fractional Duffing oscillator with distributed time delay, whose symmetry is disrupted by a quadratic nonlinearity. First, via the method of direct partition of motions, the original system is transformed into an equivalent integer-order slow system, where the saddle-node bifurcation and vibrational resonance, induced by system parameters, are observed. It is found that the saddle-node bifurcation will transition to a pitchfork bifurcation if the quadratic nonlinearity vanishes. Then, by applying the Melnikov method to the system, we rigorously define two distinct critical conditions for chaos, each corresponding to the left and right sides of homoclinic orbits. Bifurcation diagram, largest Lyapunov exponents, and phase portrait, further confirm the accuracy of the theoretical predictions. Finally, to suppress the chaos, a parameter periodic excitation is introduced, and additionally, a criterion for chaos inhibition is established. Numerical simulations reveal that the control effect is both pronounced and noticeable. This work provides a theoretical basis for detecting the bifurcation and chaos in fractional models with asymmetric characteristics.
{"title":"Bifurcation and chaos control of a fractional Duffing oscillator with asymmetric potential and distributed time delay","authors":"Xueling Liu , Jing Huang , Yufeng Zhang , Junlin Li","doi":"10.1016/j.cjph.2025.12.020","DOIUrl":"10.1016/j.cjph.2025.12.020","url":null,"abstract":"<div><div>As is well known, most models in scientific research and engineering feature asymmetric potentials. Gaining a deeper understanding of how the symmetry-breaking phenomenon affects the response mechanisms of systems is both meaningful and crucial. In this paper, we primarily explore the dynamic properties, including bifurcation and chaos, of a bi-frequency excited fractional Duffing oscillator with distributed time delay, whose symmetry is disrupted by a quadratic nonlinearity. First, via the method of direct partition of motions, the original system is transformed into an equivalent integer-order slow system, where the saddle-node bifurcation and vibrational resonance, induced by system parameters, are observed. It is found that the saddle-node bifurcation will transition to a pitchfork bifurcation if the quadratic nonlinearity vanishes. Then, by applying the Melnikov method to the system, we rigorously define two distinct critical conditions for chaos, each corresponding to the left and right sides of homoclinic orbits. Bifurcation diagram, largest Lyapunov exponents, and phase portrait, further confirm the accuracy of the theoretical predictions. Finally, to suppress the chaos, a parameter periodic excitation is introduced, and additionally, a criterion for chaos inhibition is established. Numerical simulations reveal that the control effect is both pronounced and noticeable. This work provides a theoretical basis for detecting the bifurcation and chaos in fractional models with asymmetric characteristics.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"99 ","pages":"Pages 341-355"},"PeriodicalIF":4.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01Epub Date: 2025-11-25DOI: 10.1016/j.cjph.2025.11.026
Muhammad Idrees , Junwei Hu , Yuee Xie , Fazal Badshah , Amir Khesro , Zhen-Xia Niu , Hui-Jun Li , Fuad A. Awwad , Emad A A Ismail
This study presents a theoretical investigation of the gain-assisted rotary and lateral photon drag effects induced by bidirectional rotation in chiral nanostructures composed of laterally coupled CdSe/ZnS semiconductor double quantum dot molecules. The system is driven by a combination of probe and control electromagnetic fields, where electron tunneling strength plays a pivotal role in shaping the optical, chiral, and gain-assisted responses. The chiral medium exhibits strong magnetoelectric coupling and structural asymmetry, enabling dynamic control over the rotary and lateral photon drag effects for both left- and right-circularly polarized (LCP and RCP) beams. Notably, the bidirectional rotation of the chiral nanostructure significantly enhances the drag response, with the degree of enhancement being strongly dependent on the tunneling strength. A large negative group index is observed, particularly for the RCP beam, indicating the presence of anomalous dispersion, medium gain, and high sensitivity to rotational dynamics. Additionally, the lateral photon drag demonstrates tunable beam displacement under varying tunneling strengths, offering an additional degree of control in light manipulation. Furthermore, the divergence angle between LCP and RCP beams, as well as the group indices, are shown to vary with the phase of the control field and magnetic field detuning. The electric and magnetic susceptibilities, along with the chiral coefficients, reveal enhanced dispersion and reduced absorption (even showing gain) at higher tunneling strengths. These results highlight the critical role of chirality, tunneling, gain, and rotational control in modulating light-matter interactions and pave the way for practical applications in lateral beam steering, optical communication, polarization encoding, optical tweezers, and chiral sensing technologies.
{"title":"Gain-assisted enhanced rotary and lateral photon drags in bidirectionally rotating chiral nanostructures","authors":"Muhammad Idrees , Junwei Hu , Yuee Xie , Fazal Badshah , Amir Khesro , Zhen-Xia Niu , Hui-Jun Li , Fuad A. Awwad , Emad A A Ismail","doi":"10.1016/j.cjph.2025.11.026","DOIUrl":"10.1016/j.cjph.2025.11.026","url":null,"abstract":"<div><div>This study presents a theoretical investigation of the gain-assisted rotary and lateral photon drag effects induced by bidirectional rotation in chiral nanostructures composed of laterally coupled CdSe/ZnS semiconductor double quantum dot molecules. The system is driven by a combination of probe and control electromagnetic fields, where electron tunneling strength plays a pivotal role in shaping the optical, chiral, and gain-assisted responses. The chiral medium exhibits strong magnetoelectric coupling and structural asymmetry, enabling dynamic control over the rotary and lateral photon drag effects for both left- and right-circularly polarized (LCP and RCP) beams. Notably, the bidirectional rotation of the chiral nanostructure significantly enhances the drag response, with the degree of enhancement being strongly dependent on the tunneling strength. A large negative group index is observed, particularly for the RCP beam, indicating the presence of anomalous dispersion, medium gain, and high sensitivity to rotational dynamics. Additionally, the lateral photon drag demonstrates tunable beam displacement under varying tunneling strengths, offering an additional degree of control in light manipulation. Furthermore, the divergence angle between LCP and RCP beams, as well as the group indices, are shown to vary with the phase of the control field and magnetic field detuning. The electric and magnetic susceptibilities, along with the chiral coefficients, reveal enhanced dispersion and reduced absorption (even showing gain) at higher tunneling strengths. These results highlight the critical role of chirality, tunneling, gain, and rotational control in modulating light-matter interactions and pave the way for practical applications in lateral beam steering, optical communication, polarization encoding, optical tweezers, and chiral sensing technologies.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"99 ","pages":"Pages 25-36"},"PeriodicalIF":4.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145693083","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01Epub Date: 2025-12-06DOI: 10.1016/j.cjph.2025.11.034
Gemechu Muleta Kumssa
This paper aims to investigate the star formation efficiency of molecular cloud cores that are affected by gravitational forces, turbulence, magnetization, and rotation. It intends to include the impacts of magnetic tension and assess the restoring force it provides. By applying the standard equations that dictate magnetohydrodynamic collapse within a rotating context, the study will ascertain the time necessary for the cloud to collapse. Following this, a mathematical model for star formation efficiency is formulated, incorporating the collapse time while also taking into account the effects of magnetic tension. The function of the magnetic field is particularly complex, operating in two distinct roles. On one side, the tension within the magnetic field lines aids the inward movement of matter towards the central core, thus facilitating mass accumulation. On the other hand, the magnetic pressure opposes gravity, reducing mass in fall rate. This complex interaction ultimately leads to a decrease in star formation efficiency, as indicated by the findings of this study.
{"title":"Star formation efficiency of molecular clouds: In terms of the cloud collapsing time and magnetic braking time","authors":"Gemechu Muleta Kumssa","doi":"10.1016/j.cjph.2025.11.034","DOIUrl":"10.1016/j.cjph.2025.11.034","url":null,"abstract":"<div><div>This paper aims to investigate the star formation efficiency of molecular cloud cores that are affected by gravitational forces, turbulence, magnetization, and rotation. It intends to include the impacts of magnetic tension and assess the restoring force it provides. By applying the standard equations that dictate magnetohydrodynamic collapse within a rotating context, the study will ascertain the time necessary for the cloud to collapse. Following this, a mathematical model for star formation efficiency is formulated, incorporating the collapse time while also taking into account the effects of magnetic tension. The function of the magnetic field is particularly complex, operating in two distinct roles. On one side, the tension within the magnetic field lines aids the inward movement of matter towards the central core, thus facilitating mass accumulation. On the other hand, the magnetic pressure opposes gravity, reducing mass in fall rate. This complex interaction ultimately leads to a decrease in star formation efficiency, as indicated by the findings of this study.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"99 ","pages":"Pages 322-330"},"PeriodicalIF":4.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145837354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-02-01Epub Date: 2025-12-09DOI: 10.1016/j.cjph.2025.12.004
N. Priyobarta , Ksh. Newton Singh , S.K. Maurya , B. Mishra
We are presenting realistic models of neutron star supported by the SLy4, Togashi, and Walecka equation of states (EoS) in gravity. Considering both linear (i.e., ) and non-linear matter-curvature models (i.e., ), we derived modified TOV equations for each model and solved them numerically. The strength of the matter-curvature coupling is scaled by the coupling constant α in non-linear and (β, γ) in linear interactions. In the non-linear and linear couplings, only with the Walecka EoS can generate maximum masses above 2.5M⊙ which can accommodate the higher mass neutron stars in the mass-gap. All the EoS became more stiff for (α, β, γ) < 0 that produce more maximum masses. The causality is checked by the density range which is about 2 × 1015g/cm3 for Togashi, 3.06 × 1015g/cm3 for SLy4 and 5.08 × 1015g/cm3 for Walecka EoS. The larger causality density range in Walecka EoS makes it more stable while neutron stars are subjected to radial perturbation. Under small radial oscillation, all the EoS can hold more Mmax by increasing the coupling strength (α, β, γ) < 0. The gravitational redshift in all the models is below 0.4, which is far below the Buchdahl redshift limit, i.e., ≤ 2. At the end, we used the GW170817 constraints to validate the results with observational values to constraint the predicted radii of the known GWs and pulsars.
{"title":"Realistic modeling of neutron star structures with linear and non-linear matter-curvature coupling in f(R,Lm,T)− gravity using SLy4, Togashi, and Walecka equation of state","authors":"N. Priyobarta , Ksh. Newton Singh , S.K. Maurya , B. Mishra","doi":"10.1016/j.cjph.2025.12.004","DOIUrl":"10.1016/j.cjph.2025.12.004","url":null,"abstract":"<div><div>We are presenting realistic models of neutron star supported by the SLy4, Togashi, and Walecka equation of states (EoS) in <span><math><mrow><mi>f</mi><mo>(</mo><mi>R</mi><mo>,</mo><msub><mi>L</mi><mi>m</mi></msub><mo>,</mo><mi>T</mi><mo>)</mo><mo>−</mo></mrow></math></span>gravity. Considering both linear (i.e., <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>,</mo><msub><mi>L</mi><mi>m</mi></msub><mo>,</mo><mi>T</mi><mo>)</mo></mrow><mo>=</mo><mi>R</mi><mo>+</mo><mi>β</mi><mi>T</mi><mo>+</mo><mn>2</mn><mi>γ</mi><msub><mi>L</mi><mi>m</mi></msub></mrow></math></span>) and non-linear matter-curvature models (i.e., <span><math><mrow><mi>f</mi><mrow><mo>(</mo><mi>R</mi><mo>,</mo><msub><mi>L</mi><mi>m</mi></msub><mo>,</mo><mi>T</mi><mo>)</mo></mrow><mo>=</mo><mi>R</mi><mo>+</mo><mi>α</mi><mi>T</mi><mspace></mspace><msub><mi>L</mi><mi>m</mi></msub></mrow></math></span>), we derived modified TOV equations for each model and solved them numerically. The strength of the matter-curvature coupling is scaled by the coupling constant <em>α</em> in non-linear and (<em>β, γ</em>) in linear interactions. In the non-linear and linear couplings, only with the Walecka EoS can generate maximum masses above 2.5<em>M</em><sub>⊙</sub> which can accommodate the higher mass neutron stars in the mass-gap. All the EoS became more stiff for (<em>α</em>, <em>β, γ</em>) < 0 that produce more maximum masses. The causality is checked by the density range which is about 2 × 10<sup>15</sup><em>g</em>/<em>cm</em><sup>3</sup> for Togashi, 3.06 × 10<sup>15</sup><em>g</em>/<em>cm</em><sup>3</sup> for SLy4 and 5.08 × 10<sup>15</sup><em>g</em>/<em>cm</em><sup>3</sup> for Walecka EoS. The larger causality density range in Walecka EoS makes it more stable while neutron stars are subjected to radial perturbation. Under small radial oscillation, all the EoS can hold more <em>M</em><sub>max</sub> by increasing the coupling strength (<em>α, β, γ</em>) < 0. The gravitational redshift in all the models is below 0.4, which is far below the Buchdahl redshift limit, i.e., ≤ 2. At the end, we used the GW170817 constraints to validate the results with observational values to constraint the predicted radii of the known GWs and pulsars.</div></div>","PeriodicalId":10340,"journal":{"name":"Chinese Journal of Physics","volume":"99 ","pages":"Pages 162-176"},"PeriodicalIF":4.6,"publicationDate":"2026-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145797745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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