Resonance Condition Research Articles

Resonance scattering generated by rotating bodies

Abstract The scattering of rotating bodies to a polarized plane wave, including the dielectric cylinder and sphere, is studied. The resonance caused by rotation is emphasized. Numerical results prove that the resonance scattering caused by rotation can be realized in the optical range. It is sensitive to the rotation dimensionless parameter γ. The internal Mie mode corresponding to the electromagnetic field intensity changes with γ, and the resonant mode appears when the particle rotates at a specific speed. Moreover, the resonant mode changes with γ. It causes resonance scattering to appear in the same particle at different speeds. Inside particles, resonant rings are composed of a series of array points and are determined by γ. Under resonance conditions, the energy near the rotating cylinder is consistent with its rotation direction. In contrast, the direction of energy flow in the rotating sphere model is opposite to the direction of particle rotation. This work provides a novel idea for the design of ultra-sensitive sensors and resonators. It has promising applications in optical communication, optical microscopy, and optical signal processing.

Study of the axial-vector and tensor resonant contributions to the D→VPℓ+νℓ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D \\rightarrow VP\\ell ^+\ u _\\ell $$\\end{document} decays based on SU(3) flavor analysis

Semileptonic three-body D→Mℓ+νℓ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D \\rightarrow M\\ell ^+\ u _\\ell $$\\end{document} decays, non-leptonic M→VP\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$M \\rightarrow VP$$\\end{document} decays, and semileptonic four-body D→M(M→VP)ℓ+νℓ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D \\rightarrow M(M \\rightarrow VP)\\ell ^+\ u _\\ell $$\\end{document} decays are analyzed using the SU(3) flavor symmetry/breaking approach, where ℓ=e/μ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\ell =e/\\mu $$\\end{document}, M=A/T\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$M=A/T$$\\end{document}, and A/T/V/P denote the axial-vector/tensor/vector/pseudoscalar mesons, respectively. In terms of SU(3) flavor symmetry/breaking, the decay amplitudes of the D→Mℓ+νℓ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D \\rightarrow M \\ell ^+ \ u _\\ell $$\\end{document} decays and the vertex coefficients of the M→VP\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$M \\rightarrow VP$$\\end{document} decays are related. The relevant non-perturbative parameters of the D→Aℓ+νℓ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D \\rightarrow A\\ell ^+\ u _\\ell $$\\end{document}, A→VP\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$A \\rightarrow VP$$\\end{document}, and T→VP\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$T \\rightarrow VP$$\\end{document} decays are constrained by the present experimental data, and the non-perturbative parameters of D→Tℓ+νℓ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D \\rightarrow T\\ell ^+\ u _\\ell $$\\end{document} decays are taken from the results in the light-front quark model since no experimental data are available at present. The branching ratios of the D→Mℓ+νℓ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D \\rightarrow M \\ell ^+ \ u _\\ell $$\\end{document}, M→VP\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$M \\rightarrow VP$$\\end{document}, and D→M(M→VP)ℓ+νℓ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D\\rightarrow M(M\\rightarrow VP)\\ell ^+\ u _\\ell $$\\end{document} decays are then predicted. We find that some processes receive both tensor and axial-vector resonant contributions, while other processes receive only axial-vector resonant contributions. In cases where both kinds of resonant contributions exist, the axial-vector contributions are dominant. Some branching ratios with axial-vector resonance states are large, and they may be measured experimentally in the near future. In addition, the sensitivities of the branching ratios of D→Aℓ+νℓ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$D \\rightarrow A \\ell ^+ \ u _\\ell $$\\end{document} and A→VP\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$A \\rightarrow VP$$\\end{document} decays to the parameters are also investigated, and some decay branching ratios are found to be sensitive to the non-perturbative parameters.

On the kinetics of internal gravity waves beyond the hydrostatic regime

We present a new derivation of the kinetic equation for weak, non-hydrostatic internal gravity wave turbulence. The equation is equivalent to the one obtained by Caillol & Zeitlin (Dyn. Atmos. Oceans, vol. 32, issue 2, 2000, pp. 81–112), but it takes a canonical form. We show that it conserves the energy without involving the resonance condition in frequency, and look for the isotropic part of the steady, scale-invariant solutions. We provide a parametrization of the resonant manifold of non-hydrostatic internal gravity wave triadic interactions. This allows us to simplify the collision integral, and to evaluate the transfer coefficients of all triadic interactions. In the hydrostatic limit, our equation is equivalent to the Hamiltonian description of Lvov & Tabak (Phys. Rev. Lett., vol. 87, issue 16, 2001, 168501).

Experimental and numerical investigation of the Doppler-shifted resonance condition for high frequency Alfvén eigenmodes on ASDEX Upgrade

Abstract The Doppler-shifted resonance condition for high frequency Alfvénic eigenmodes has been extensively studied on ASDEX Upgrade in the presence of one or a combination of two neutral beam injected (NBI) fast ion populations. In general, only centrally deposited NBI sources drive these modes, while off-axis sources globally stabilize the mode activity. For the case of a single central NBI source, the observed trend is: the highest frequency modes are driven by the lowest energy and lowest pitch angle NBI sources, in line with the expectation from the Doppler-shifted resonance condition. The expected mode frequencies are determined analytically from the two-fluid cold plasma dispersion relation and the most unstable frequency relation, while the mode growth rates are estimated using the fast ion slowing down distribution functions from the ASCOT code. The overall mode frequency trend in a source-to-source variation is tracked, although a systematic overestimate of ∼1 MHz is observed. Possible causes of this overestimate include the finite size of the resonant fast ion drift orbit and non-linear effects such as mode sideband formation. Alternatively, the expected mode frequencies are determined by tracking the growth rate maxima trajectories, this method improves the agreement with the experimentally measured values. A combination of two central mode-driving NBI sources results in the suppression of the mode driven by the lowest energy and the lowest pitch angle NBI source. Computing the analytically expected mode frequency following the method outlined above, again, generally tracks the experimentally observed trend. The mode’s Alfvénic nature allows for a practical application to track the core hydrogen fraction by following the mode frequency changes in response to a varying ion mass density. Such application is demonstrated in a discharge where the average ion mass is varied from ∼2m p to ∼1.5m p (where m p is the proton mass) via a hydrogen puff in a deuterium plasma, in the presence of a strong mode activity. The expected mode frequency changes are computed from the existence of the resonance condition, and the values track the measured results with an offset of ∼0.5 MHz. Overall, the results suggest an intriguing possibility to monitor and control the D-T ion fraction in the core of a fusion reactor in real time using a non-invasive diagnostic.

Fully strange tetraquark resonant states as the cousins of X(6900)

We conduct systematic calculations of the S-wave fully strange systems with “normal” (JPC=0++,1+−,2++) and “exotic” (JPC=0+−,1++,2+−) C-parities, which are the strange analog of the fully charmed tetraquark state X(6900). Within a constituent quark potential model, we employ the Gaussian expansion method to solve the four-body Schrödinger equation and the complex scaling method to identify resonant states. We obtain a series of resonant states and zero-width states in the mass range of 2.7 to 3.3 GeV, with their widths ranging from less than 1 to about 50 MeV. Their rms radii strongly indicate that they are compact tetraquark states. Among these states, the T4s,2++(2714) may be the most likely one to be observed experimentally. We urge the experimental exploration of the 2++ sss¯s¯ state around 2.7 GeV in the ϕϕ channel. Since the lowest S-wave sss¯s¯ state is around 2.7 GeV, the compact wave sss¯s¯ states are expected to be heavier. Hence, ϕ(2170) and X(2370) are unlikely to be compact tetraquark states. Published by the American Physical Society 2024

Analytic continuation in the coupling constant for resonances in ${}^9_{\Lambda}$Be

Abstract The application scope of the analytic continuation in the coupling constant (ACCC) can be extended to the exchange parameters of the effective nucleon-nucleon interaction in microscopic cluster model. Based on such exchange parameter dependent ACCC (abbreviated as EPD-ACCC), we study the ${}_{\Lambda}^9$Be system in the framework of $\alpha+\alpha+\Lambda$ microscopic cluster model. The resonant states of $\alpha+\alpha+\Lambda$ are obtained through EPD-ACCC. Meanwhile, the complex scaling method (CSM) is applied as a comparison. A good agreement between these two theoretical approaches is obtained. This work demonstrate a reliable method EPD-ACCC for estimating the multi-cluster resonances in light hypernuclei.

Study on nonlinear coupled dynamic response of the integrated polar ocean nuclear energy platform

An integrated polar ocean nuclear energy platform is capable of providing adequate electrical and thermal energy essential for polar oceanic development activities. Precisely forecasting the platform's motion response within the marine environment is pivotal for the assurance of its safety. A scenario where the natural frequencies of heave, roll, and pitch of such an integrated polar ocean nuclear energy platform align closely to a 2:1:1 ratio, and when the wave frequency nearly matches the aggregate of the platform's natural heave and pitch frequencies, could induce a phenomenon known as sum-type nonlinear internal resonance. This phenomenon can significantly amplify the swing (roll or pitch) motion of the platform, posing a grave risk to both personnel and equipment onboard. Investigating these nonlinear internal resonance phenomena within the nuclear energy platform is critical for informing both the design and practical deployment of these platforms. Following the validation of the numerical simulation against experimental results, a detailed analysis of sum-type nonlinear internal resonance phenomena in the integrated polar ocean nuclear energy platform under regular wave conditions was performed using a combination of numerical simulations and nonlinear dynamics theory. It was observed that upon exceeding a certain wave height threshold, the platform enters a state of sum-type nonlinear internal resonance, engendering highly complex motion patterns. Notably, irrespective of initial conditions, this resonance triggers the roll motion of the platform, facilitating the external dissipation of energy in a half-sub-harmonic vibration manner. Increasing damping can effectively suppress the occurrence of nonlinear internal resonance phenomena in the platform. In designing the integrated polar ocean nuclear energy platform, it's crucial to avoid having the natural frequency ratios of heave, pitch, and roll align as 2:1:1. If unavoidable, adding side plates to increase damping can mitigate the effects of sum-type nonlinear internal resonance.

The influence of the quasi-electrostatic support on the amplification of space charge waves in the amplification section of a superheterodyne free electron laser

Abstract In this work, a theoretical study of the influence of a quasi-electrostatic support on the amplification level of the slow space charge wave (SCW) in the amplification section of a superheterodyne free electron laser (FEL) was carried out. One of the ways to significantly increase the saturation level of the slow SCW is maintaining the conditions of a three-wave parametric resonance between the slow, fast SCWs and the resulting pump electric field. This can be done by introducing the quasi-electrostatic support in the superheterodyne FEL amplification section. Also, it was found that the generated pump electric field significantly influences the maintenance of parametric resonance conditions. As a result, this increases the saturation level of the slow SCW by 70%. Finally, the quasi-electrostatic support significantly reduces the maximum value of the electrostatic undulator pump field strength, which is necessary to achieve the maximum saturation level of the slow SCW.

An Energy Approach to the Modal Identification of a Variable Thickness Quartz Crystal Plate

The primary objective of modal identification for variable thickness quartz plates is to ascertain their dominant operating mode, which is essential for examining the vibration of beveled quartz resonators. These beveled resonators are plate structures with varying thicknesses. While the beveling process mitigates some spurious modes, it still presents challenges for modal identification. In this work, we introduce a modal identification technique based on the energy method. When a plate with variable thickness is in a resonant state of thickness–shear vibration, the proportions of strain energy and kinetic energy associated with the thickness–shear mode in the total energy reach their peak values. Near this frequency, their proportions are the highest, aiding in identifying the dominant mode. Our research was based on the Mindlin plate theory, and appropriate modal truncation were conducted by retaining three modes for the coupled vibration analysis. The governing equation of the coupled vibration was solved for eigenvalue problem, and the modal energy proportions were calculated based on the determined modal displacement and frequency. Finally, we computed the eigenvalue problems at different beveling time, as well as the modal energies associated with each mode. By calculating the energy proportions, we could clearly identify the dominant mode at each frequency. Our proposed method can effectively assist engineers in identifying vibration modes, facilitating the design and optimization of variable thickness quartz resonators for sensing applications.

A Power Boosting Method for Wireless Power Transfer Systems Based on a Multilevel Inverter and Dual-Resonant Network

With the deepening of research on wireless power transfer (WPT) technology, there is an urgent need to improve the output power of WPT systems. Therefore, this paper proposes a power boosting method based on a multilevel inverter and dual-resonant network. The system adopts a five-level inverter whose output voltage contains rich fundamental and harmonic components. The transmitting side adopts a dual-resonant compensation network, and, through its parameter configuration, the system can be in a resonant state at both the fundamental and third harmonic frequencies. The receiving side adopts two receiving channels which can simultaneously receive power at both frequencies, thus boosting the output power. Firstly, the overall structure and operating principle of the system are introduced. Then, the relationship between the system output power and efficiency with the inverter modulation parameters is obtained and the strategy for selecting the optimal operating points of the inverter is designed by comprehensively considering the THD of the inverter output voltage and the efficiency of the system. Furthermore, the proposed system is simulated in a Matlab/Simulink platform. Finally, an experimental setup is created to verify the proposed method. The results show that, compared with the single-channel WPT system, the proposed method can enhance the output power from 160 W to 310 W with a boosting coefficient of nearly double and with the highest efficiency exceeding 92%.

Terahertz Sensing with Extraordinary Optical Transmission Hole Arrays

Purpose: The purpose of this paper is to substantiate the enhanced performance of hyperbolic anisotropic (HA) meta-surfaces at anomalous extraordinary optical transmission (EOT) resonances. These resonances exhibit distinct transmission peaks highly sensitive to environmental changes, making them particularly valuable for sensing applications. By demonstrating improved transmission efficiency and sensitivity, this study aims to contribute to developing advanced sensing technologies that leverage the unique properties of HA meta-surfaces in detecting minute variations in their surroundings. Methodology: To verify the enhanced sensing performance of anomalous EOT resonances, this study employs a well-established experimental method involving depositing a thin analyte layer of varying thicknesses onto the meta-surface. The study aims to determine which resonance condition provides optimal sensitivity by comparing the performance between regular and anomalous EOT resonances. It explores the improved performance of HA meta-surfaces at anomalous EOT resonances, which occur under certain non-standard conditions, offering potentially superior sensing capabilities compared to regular EOT. Findings: The results indicate that when the analyte is applied to the non-patterned side of the metasurface, the anomalous EOT resonance achieves superior sensing performance. This enhanced sensitivity can be attributed to the unique interaction dynamics between the incident THz waves and the meta-surface structure under abnormal conditions. Unique Contribution to Theory, Policy and Practice: This phenomenon is beneficial in the terahertz (THz) range, making HA meta-surfaces ideal for thin-film label-free sensing applications. The EOT resonance occurs due to the interaction between incident light and the periodic structure of the holes, leading to enhanced light transmission at specific wavelengths. The findings highlight the potential of using anomalous EOT resonances in HA meta-surfaces to develop highly sensitive and efficient sensors for detecting changes in thin films, paving the way for advanced sensing technologies in various scientific and industrial applications.

Bragg resonances in the yttrium iron garnet – platinum – yttrium iron garnet layered structure

We studied theoretically the interaction between the spin current in a conductor with a strong spin-orbit coupling (platinum, Pt) and the spin wave in yttrium iron garnet ferromagnetic layers (YIG) with periodic thickness modulation under conditions of Bragg resonances and interlayer coupling. It is shown that in the YIG/Pt/YIG sandwich structure the conditions for two Bragg resonances in the first Brillouin area in the spin wave spectrum are fulfilled. The spin current in Pt allows frequency tuning of the resonances and control the depth of the spin wave band gap corresponding to the resonance conditions.

Dynamical Casimir effect with screened scalar fields

Understanding the nature of dark energy and dark matter is one of modern physics' greatest open problems. Scalar-tensor theories with screened scalar fields like the chameleon model are among the most popular proposed solutions. In this article, we present the first analysis of the impact of a chameleon field on the dynamical Casimir effect, whose main feature is the particle production associated with a resonant condition of boundary periodic motion in cavities. For this, we employ a recently developed method to compute the evolution of confined quantum scalar fields in a globally hyperbolic spacetime by means of time-dependent Bogoliubov transformations. As a result, we show that particle production is reduced due to the presence of the chameleon field. In addition, our results for the Bogoliubov coefficients and the mean number of created particles agree with known results in the absence of a chameleon field. Our results initiate the discussion of the evolution of quantum fields on screened scalar field backgrounds.

Resonant Raman Auger spectroscopy on transient core-excited Ne ions

Abstract Short-lived core-ionized neon atoms were investigated by measuring under resonant Raman conditions the Auger decay following the excitation of a second core electron into a Rydberg state. Making use of intense and narrow bandwidth x-ray free-electron laser pulses, the photoexcitation spectrum of the femtosecond-lived Ne+1s02s22p6np series was characterized. Energy position and lifetimes of the lower-lying Rydberg states were determined and the final state configurations following the decay of the Ne+1s02s22p63p double-core hole resonance were partially resolved.

Non-thermal fusion burning processes, relevant collective modes and gained perspectives

Abstract New tridimensional plasma structures, that are oscillatory and classified as non-separable ballooning modes, can emerge in inhomogeneous plasmas and undergo resonant mode-particle interactions, e.g. with a minority population, that can lead them to modify their spatial profiles. Thus, unlike the case of previously known ballooning modes their amplitudes are not separable functions of time and space. The relevant resonance conditions are intrinsically different from those of the well-known Landau conditions for (ordinary) plasma waves: they involve the mode geometry and affect different regions of the distribution in momentum space at different positions in configuration space. A process for a transfer of energy among different particle populations is envisioned.

Effects of extreme temperature environments on nonlinear vibrations of the cable-stayed functionally graded beam

A cable-stayed functionally graded beam (CSFGB) model is proposed for the first time to study nonlinear behaviors of the system exposed to extreme temperatures. To this end, the in-plane one-to-one internal resonance between the global mode (FGB's mode) and the local mode (cable's mode) is explored under the condition of external primary resonance. First, governing differential equations of the system considering temperature effects are derived by using Hamilton's principle. To obtain the modal function of the FGB, the in-plane eigenvalue problem is solved through the separation-of-variables method. Subsequently, ordinary differential equations (ODEs) are yielded according to Galerkin discretization. The method of multiple time scales is then applied to deal with the ODEs and derive the modulation equations. Based on the above theoretical solutions, the frequency-/force-response curves at three different temperatures are delineated via Newton-Raphson method and the continuation of fixed points. Meanwhile, the time histories and phase portraits are also provided by directly integrating the ODEs. The results show that temperature changes have a significant influence on nonlinear characteristics of the system.

Artificial Intelligence‐Enhanced Metamaterial Bragg Multilayers for Radiative Cooling

A full numerical study combining artificial intelligence (AI) methods and electromagnetic simulation software on a multilayered structure for radiative cooling (RC) is investigated. The original structure is made of SiO2/Si nanometer‐thick layers that make a Bragg mirror for wavelengths in the solar irradiance window (0.3–4 μm). The structures are then optimized in terms of the calculated net cooling power and characterized via the reflected and absorbed incident light as a function of their structural parameters. This investigation provides with optimal designs of beyond‐Bragg, all‐dielectric, ultra‐broadband mirrors that provide net cooling powers in the order of ≈100 W m−2, similar to the best‐performing structures in literature. Furthermore, it explains AI's success in producing these structures and enables the analysis of resonant conditions in metal‐free multilayers with unconventional layer thickness distributions, offering innovative tools for designing highly efficient structures in RC.

Strong-Coupling Modification of Singlet-Fission Dynamical Pathways.

We investigate theoretically the influence of strong light-matter coupling on the initial steps of the phototriggered singlet-fission process. In particular we focus on intramolecular singlet fission in a TIPS-pentacene dimer derivative described by a vibronic Hamiltonian including the optically active singlet excited states, doubly excited and charge transfer states, as well as the final triplet-triplet pair state. Quantum dynamics simulations of up to four dimers in the cavity indicate that the modified resonance condition imposed by the cavity strongly quenches the passage through the intermediate charge transfer and double-excitation states, thus largely reducing the triplet-triplet yield in the bare system. Subsequently, we modify the system parameters and construct a model Hamiltonian where the optically active singlet excitation lies below the final triplet-triplet state such that the yield of the bare system becomes insignificant. In this case we find that using the upper polariton as the doorway state for photoexcitation can lead to a much enhanced yield. This pathway is operative provided that the system is sufficiently rigid to prevent vibronic losses from the upper polariton to the dark-states manifold.

Surface plasmon resonance enhanced terahertz spin current emission in Au nanoparticles/ferromagnet thin film heterostructure

We present a design of an ultrafast spin current emitter utilizing the Au nanoparticles/Co/Pt heterostructures, which facilitate significant enhancement in terahertz radiation. Using Au nanoparticles synthesized by thermal annealing and embedded in Co/Pt bilayers, we show that the Au nanoparticles fulfill surface plasmon resonance conditions under the illumination of femtosecond laser pulses, and enhanced terahertz spin currents are generated in the Co thin film. The terahertz signal amplitude of Au nanoparticles/Co/Pt sample exhibits an enhancement of 70% and 45% compared to that observed in Au thin film/Co/Pt and Co/Pt samples, respectively. By integrating experimental analysis and numerical calculations, we ascribe the enhancement of terahertz emission amplitude to the contribution of spin current generated by surface plasmon resonance in the Co thin film, which may result from the magnetization enhancement induced by surface plasmon-excited electromagnetic fields at the Au nanoparticles/Co interface, and the plasmon-induced spin current density is approximately 1 × 1029 electrons s−1 m−2. This plasmon-induced spin current establishes a connection between the fields of plasmonic and spintronic physics, thereby promoting the development of spintronic terahertz emitters.

The Subject as Vibrant Matter

In the article Hartmut Rosa’s concept ‘resonance’ and Jacques Rancière’s concept ‘le partage du sensible’ are explored through an aesthetic and musical interpretation of teaching. The main aim is to bring understanding into how educational practices, in particular teaching practice, can bring life into subject matter, and construe it as meaningful, significant, and important in times of social acceleration and alienation (Rosa, 2015; Stiegler, 2010). Besides texts from Rosa and Rancière, the article draws on discussions from music philosophy (Bucht, 2009; Lingis, 2004), and educational philosophy (Benner, 2015; Mollenhauer, 2014; Uljens, 1998). The article suggests that Rosa’s concept of ‘resonance’ and Rancière’s concept of ‘le partage du sensible’, read together and against each other, bring insights into discussions about the phenomenological nature of teaching, described as a sort of experiential frequency-modulation that aims for resonant relationships between students and the world. While Rancière’s aesthetics can be used to highlight the abstract logics and politics of educational relations, Rosa’s sociology of resonance provides a valuable complement that grounds teaching practice in lived experience. Resonance implies, according to Rosa, an aspect of constitutive inaccessibility, which requires that both subject and world are sufficiently “closed” or self-consistent so that both sides can speak “in their own voice”, while also remaining open to be affected or reached by each other. Interpreting this resonant state educationally, and from the perspective of Rancière’s aesthetics, turns teaching into a resonance-enabling practice where students, as unique subjects, are allowed to confront the teaching content in its pure materiality; to hear it sing with its own voice, key, and rhythm.