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Irradiation of semiconductors by energetic beams generates excess electrons and holes and may cause device degradation or failure. Both gradual degradation by total ionizing radiation (TID) and sudden degradation/failure (soft/hard breakdown) by a combination of energetic heavy ions and high voltages (typically single-event effects or SEEs) are mediated by excess carriers. The role of defect dynamics in TID degradation has been adequately understood by a combination of experiments and density-functional-theory (DFT) quantum calculations, but little has been done so far to document a role for ion-induced defects in SEE. Here, we report proof-of-principle DFT calculations in a model cubic GaN system for two defect-related excess-carrier phenomena that can play a role in various forms of device degradation and failure. The first phenomenon is the existence, dynamics, and potential roles of defect-induced quasi-localized "resonant states" in the energy-band continua. These states can enhance TID-excess-carrier and hot-carrier degradation. Furthermore, they evolve and multiply during energetic-ion-induced atom recoils and defect creation (displacement damage) and can potentially serve as excess-carrier conduction paths in SEE. The second phenomenon is the conversion of isolated vacancies into nanovoids that can participate in the formation of conducting defect "nanowires" dressed by resonances or in explosive SEE hard breakdowns. [ABSTRACT FROM AUTHOR]

This paper explores the emergence of topological interface states in one-dimensional locally resonant lattices incorporating inerters in both nearest neighbor (NN) and beyond-nearest neighbor (BNN) coupling. The investigation focuses on the unique wave propagation characteristics of these lattices, particularly the presence and behavior of interface states. The non-trivial topological behavior due to broken inversion symmetry within the unit cell of the locally resonant lattice is comprehensively investigated in the presence of inerters in NN and BNN coupling. The emerging interface states in the supercell analysis exhibit specific spatial and frequency localization properties due to inerter-based BNN interactions. Additionally, the study demonstrates the ability of inerter elements with weak inertance to control the frequency of interface states while maintaining the fundamental topological properties of the lattice. The identified topological interface states in lattices with BNN coupling present an opportunity for designing diverse devices, such as waveguides, filters, sensors, and energy harvesting systems. Overall, this research enhances our comprehension of topological phenomena in inerter-based locally resonant lattices with BNN interactions and introduces possibilities for creating robust and versatile devices based on topologically protected edge/interface states. [ABSTRACT FROM AUTHOR]

Miniaturized photoionization detectors (PIDs) are used in conjunction with gas chromatography systems to detect volatile compounds in gases by collecting the current from the photoionized gas analytes. PIDs should be inexpensive and compatible with a wide range of analyte species. One such PID is based on the formation of a He plasma in a dielectric barrier discharge (DBD), which generates vacuum UV (VUV) photons from excited states of He to photoionize gas analytes. There are several design parameters that can be leveraged to increase the ionizing photon flux to gas analytes to increase the sensitivity of the PID. To that end, the methods to maximize the photon flux from a pulsed He plasma in a DBD-PID were investigated using a two-dimensional plasma hydrodynamics model. The ionizing photon flux originated from the resonance states of helium, He(3P) and He(21P), and from the dimer excimer He2*. While the photon flux from the resonant states was modulated over the voltage pulse, the photon flux from He2* persisted long after the voltage pulse passed. Several geometrical optimizations were investigated, such as using an array of pointed electrodes. However, increasing the capacitance of the dielectric enclosing the plasma chamber had the largest effect on increasing the VUV photon fluence to gas analytes. [ABSTRACT FROM AUTHOR]

The electronic structure of highly mismatched semiconductor alloys is characterized by carrier localization and strongly influenced by the local alloy microstructure. First-principles calculations can deliver valuable quantitative insight, but their associated computational expense limits alloy supercell size and imposes artificial long-range ordering, which can produce misleading results. The empirical tight-binding method (ETBM) provides a transparent approach to investigate large-scale supercells on an atomistic level, to quantitatively predict the electronic structure of semiconductor alloys. Here, we overview key aspects and considerations for establishing ETBMs. Additionally, we discuss and highlight, given that the ETBM matrix elements are described in the language of overlaps between localized atomic orbitals, that ETBMs have proven highly successful in analyzing the impact of localized and resonant impurity states, as well as disorder, on the optoelectronic properties of highly mismatched alloys. The ETBM continues to provide valuable insight for emerging material systems, including two-dimensional materials, perovskites and their heterostructures, and provides a framework to address technologically relevant questions including the importance of short-range disorder for loss mechanisms such as non-radiative Auger–Meitner recombination. Moreover, the ETBM furnishes a quantitative basis for continuum models such as k ⋅ p or localization landscape theories, allowing to explicitly incorporate disorder effects in nanostructures to underpin predictive device-level analysis. [ABSTRACT FROM AUTHOR]

Resonant intermediate states have been proposed to increase the efficiency of entangled two-photon absorption (ETPA). Although resonance-enhanced ETPA (r-ETPA) has been demonstrated in atomic systems using bright squeezed vacuum, it has not been studied in organic molecules. We investigate for the first time r-ETPA in an organic molecular dye, indocyanine green (ICG), when excited by broadband entangled photons in near-IR. Similar to many reported virtual state mediated ETPA (v-ETPA) measurements, no r-ETPA signals are measured, with an experimental upper bound for the cross section placed at 6(±2) × 10−23 cm2. In addition, the classical resonance-enhanced two-photon absorption (r-TPA) cross section of ICG at 800 nm is measured for the first time to be 20(±13) GM, where 1 GM equals 10−50 cm4 s, suggesting that having a resonant intermediate state does not significantly enhance two-photon processes in ICG. The spectrotemporally resolved emission signatures of ICG excited by entangled photons are also presented to support this conclusion. [ABSTRACT FROM AUTHOR]

We report on the high-resolution photodetachment spectroscopy of the cryogenically cooled anionic tellurium dimer (Te2−). The high-resolution resonant photoelectron spectrum yields an accurate electron affinity of 16 689.7(92) cm−1 or 2.0693(11) eV for Te2. Two resonant states of Te2− anions have been identified, positioned at 1092(17) cm−1 below and 250(11) cm−1 above the photodetachment threshold, respectively. The spectra of resonant two-photon detachment (R2PD) and autodetachment from a specific vibrational level through a Feshbach resonance exhibit notable non-Franck–Condon behaviors. Using the spectroscopic data from the current experiment, the equilibrium bond distances and spectroscopic constants of the ground state and two electronically excited states of Te2− were determined. [ABSTRACT FROM AUTHOR]

We report on elastic and electronically inelastic integral and differential cross sections for electron collisions with the 2H-pyran and 4H-pyran molecules. The scattering calculations were performed with the Schwinger multichannel method and aimed to (i) investigate the formation of resonant states, (ii) assign and compare the resonance spectrum of these isomers, and (iii) evaluate the influence of multichannel coupling effects upon elastic and electronically inelastic scattering processes. In the elastic channel, calculations carried out at the static-exchange and static-exchange plus polarization levels of approximation revealed the presence of three shape resonances for each one of the pyran isomers. For the 2H-pyran molecule, we found two resonances related to the formation of long-lived π ∗ anion states that are centered at 1.38 or 1.32 eV (π 1 ∗) and 4.54 or 4.46 eV (π 2 ∗), depending on the polarization model used in the calculations, and a broad resonance of σ ∗ character located around 9.50–10.00 eV. The resonances observed in the case of the 4H-pyran molecule have the same character with centers located at 2.08 or 2.20 eV (π 1 ∗), 3.92 or 3.94 eV (π 2 ∗), and 9.24–10.00 or 9.50–10.00 eV (σ ∗), depending on the polarization model used in the calculations. The difference in the position of the resonances when comparing the results for the 2HPY and 4HPY molecules is explained in terms of the inductive effect. The electronically inelastic calculations employed the minimal orbital basis for single configuration interactions strategy and considered up to 129 open channels for 2H-pyran and up to 249 open channels for 4H-pyran. According to these levels of channel coupling, we computed integral and differential cross sections for the excitation from the ground state to the 1 3 A ′ , 2 3 A ′ , 1 1 A ′ ′ , and 2 1 A ′ electronic excited states of 2H-pyran and to the 1 3 B 2 , 1 3 A 1 , 1 1 B 1 , and 1 1 B 2 electronic excited states of 4H-pyran. As a general trend, for both isomers, we observed that the magnitude of the cross sections is reduced as more channels are considered open in the scattering calculations. We also obtained the total ionization cross sections for 2H- and 4H-pyran using the binary-encounter-Bethe model, which next was summed to the elastic and electronically inelastic cross sections to estimate the total cross sections. As a whole, these results correspond to the first set of cross sections for these targets published to date. Such an effort is aimed at addressing the demand of different communities regarding the expansion of the cross section data set for electron collisions with molecules of technological, environmental, and biological relevance, a need that has been raised by several reviews on the subject. [ABSTRACT FROM AUTHOR]

Bound states in the continuum (BICs) are a special kind of resonant states that remain localized even though they coexist with a continuous spectrum of radiating waves. They have already emerged as an important design principle for creating systems with high-quality (Q) factor states to enhance light–matter interaction. Many approaches have been proposed to achieve BICs, but it is still of great challenge to design multiple BICs simultaneously, and especially working at terahertz (THz) frequencies. In this paper, we propose an all-dielectric metamaterial, consisting of four hollow cylinders in each unit cell. We show dual BICs exist in such a simple structure, and as breaking the symmetry via varying the inner radius of two diagonal cylinders, they will turn to quasi-BICs with high yet finite Q-factor. These quasi-BICs are manifested themselves as two new dips in the transmission spectrum, of which the resonance shapes can be well described by the Fano formula with a few fitting parameters. We find the evolution of their Q-factors still follows the simple linear relationship with respect to the inverse square of the asymmetry parameter. Based on the multipole decomposition method, two BICs are further investigated to show different multipole components for them. Interestingly, the higher frequency BIC is closely related to the excitation of toroidal dipole (TD), which will split into two TDs as breaking the symmetry. The proposed metamaterial provides an alternative platform to merge the physics of BICs, Fano, and TD, and to pave the way for potential device applications (since the states of extremely high-Q factor). [ABSTRACT FROM AUTHOR]

Based on the ab initio scheme developed by the authors for calculating the asymptotic characteristics of decay channels of nuclear states—the method of orthogonal functions of cluster channels—an approach has been created that makes it possible to directly implement the results of ab initio calculations of -nucleon wave functions, as well as the partial decay widths of resonant states of compound nucleus obtained through their use, into calculations of cross sections for resonance nuclear reactions. Both calculated and reliably measured resonance energies can be employed in these calculations. Using the examples of such a theoretical analysis of the reaction cross sections for He and He, the efficiency of this approach and the wide prospects of its use in nuclear spectroscopy are demonstrated. [ABSTRACT FROM AUTHOR]

We report on the characterisation of the X $ ^+ $ + $ ^2\Sigma ^+ $ 2 Σ + ground electronic state of MgNe $ ^+ $ + by photoionisation, mass-analysed threshold-ionisation (MATI) and pulsed-field-ionisation zero-kinetic-energy photoelectron (PFI-ZEKE-PE) spectroscopy and the observation of the metastable a $ ^3\Pi _0 $ 3 Π 0 state of MgNe. Rotationally cold MgNe was generated in a laser-ablation supersonic-beam source in both the X $ ^1\Sigma ^+ $ 1 Σ + ( $ v''=0 $ v ″ = 0) ground state and a $ ^3\Pi _0\, (v''=0) $ 3 Π 0 (v ″ = 0) metastable electronic state. PFI-ZEKE-PE spectra with full resolution of the vibrational structure and partial resolution of the rotational structure were recorded from the X $ ^1\Sigma ^+ $ 1 Σ + ground state following resonant $ (1+1') $ (1 + 1 ′) two-photon excitation via selected rovibrational levels of the C $ ^1\Pi $ 1 Π intermediate state and from the a $ ^3\Pi _0 $ 3 Π 0 metastable state following single-photon excitation. The lowest six vibrational levels of the X $ ^+ $ + $ ^2\Sigma ^+ $ 2 Σ + state were observed, covering 80% of the X $ ^+ $ + $ ^2\Sigma ^+ $ 2 Σ + potential-well depth. The experimental data were used to determine potential-energy functions, dissociation energies, and molecular constants for the X $ ^1\Sigma ^+ $ 1 Σ + , a $ ^3\Pi _0 $ 3 Π 0 and C $ ^1\Pi $ 1 Π states of MgNe and the X $ ^+ $ + $ ^2\Sigma ^+ $ 2 Σ + state of MgNe $ ^+ $ + . With dissociation energies $ D_0 $ D 0 of 12(3) cm−1 and 10(3) cm−1, respectively, the X $ ^1\Sigma ^+ $ 1 Σ + and a $ ^3\Pi _0 $ 3 Π 0 states of $ ^{24} $ 24 Mg $ ^{20} $ 20 Ne are extremely weakly bound. In contrast, the X $ ^+ $ + $ ^2\Sigma ^+ $ 2 Σ + state of $ ^{24} $ 24 Mg $ ^{20} $ 20 Ne $ ^+ $ + has a dissociation energy $ D_0 $ D 0 of 185(3) cm $ ^{-1} $ − 1 and 12 bound vibrational levels. From the difference between the adiabatic ionisation energies of the X $ ^1\Sigma ^+ $ 1 Σ + (61 498.5(4) cm $ ^{-1} $ − 1 ) and the a $ ^3\Pi _0 $ 3 Π 0 (39 645.1(3) cm $ ^{-1} $ − 1 ) states, the term value of the a $ ^3\Pi _0 $ 3 Π 0 ground vibrational level is determined to be 21 853.4(5) cm $ ^{-1} $ − 1 . These results are compared with those of earlier experimental studies and ab initio quantum-chemical calculations. [ABSTRACT FROM AUTHOR]

Compared to the traditional wet-mate underwater power supply method, Magnetic Coupling Resonant Wireless Power Transfer (MCR-WPT) technology boasts advantages such as excellent insulation, high safety, and convenient operation, showing promising application prospects in the field of power supply for underwater vehicles and other mobile underwater devices. In order to explore the transmission characteristics of this technology underwater, this article first establishes a traditional mathematical model, and then modifies the underwater model through analysis of changes in coil self-inductance and mutual inductance, as well as the impact of eddy current losses. Using the modified mathematical model of the underwater MCR-WPT system, the transmission characteristics are analyzed, and simulations and experimental validations are performed using MATLAB R2022a software. In the study of frequency characteristics, it is found that the system operates optimally when both ends of the circuit work at the resonant state; that is, when finput = fresonance = 100 kHz, the output performance is at its best, and the optimal resonant frequency significantly improves power and transmission efficiency. When the input frequency is less than 87.3 kHz or greater than 122.9 kHz, the output power decreases to less than half of the maximum power. In the investigation of load effects, the optimal load for maximizing system output power was identified, but the load that maximizes transmission efficiency is different from this optimal load. This study provides strong theoretical support and guidance for improving the performance of underwater wireless power transmission systems. [ABSTRACT FROM AUTHOR]

A systematic, population-level discrepancy exists between the densities of exoplanets whose masses have been measured with transit timing variations (TTVs) versus those measured with radial velocities (RVs). Since the TTV planets are predominantly nearly resonant, it is still unclear whether the discrepancy is attributed to detection biases or to astrophysical differences between the nearly resonant and non resonant planet populations. We defined a controlled, unbiased sample of 36 sub-Neptunes characterised by Kepler, TESS, HARPS, and ESPRESSO. We found that their density depends mostly on the resonant state of the system, with a low probability (of 0.002−0.001+0.010) that the mass of (nearly) resonant planets is drawn from the same underlying population as the bulk of sub-Neptunes. Increasing the sample to 133 sub-Neptunes reveals finer details: the densities of resonant planets are similar and lower than non-resonant planets, and both the mean and spread in density increase for planets that are away from resonance. This trend is also present in RV-characterised planets alone. In addition, TTVs and RVs have consistent density distributions for a given distance to resonance. We also show that systems closer to resonances tend to be more co-planar than their spread-out counterparts. These observational trends are also found in synthetic populations, where planets that survived in their original resonant configuration retain a lower density; whereas less compact systems have undergone post-disc giant collisions that increased the planet's density, while expanding their orbits. Our findings reinforce the claim that resonant systems are archetypes of planetary systems at their birth. [ABSTRACT FROM AUTHOR]

The diverse applications of light-matter interactions in science and technology stem from the qualitatively distinct ways these interactions manifest, prompting the development of physical platforms that can interchange between regimes on demand. Bosonic cQED employs the light field of high-Q superconducting cavities coupled to nonlinear circuit elements, harnessing the rich dynamics of their interaction for quantum information processing. However, implementing fast switching of the interaction regime without deteriorating the cavity coherence is a significant challenge. We present an experiment that achieves this feat, combining nanosecond-scale frequency tunability of a transmon coupled to a cavity with lifetime of hundreds of microseconds. Our implementation affords a range of useful capabilities for quantum information processing; from fast creation of cavity Fock states using resonant interaction and interchanging tomography techniques at qualitatively distinct interaction regimes on the fly, to the suppression of unwanted cavity-transmon dynamics during idle evolution. By bringing flux tunability into the bosonic cQED toolkit, our work opens up the possibility to probe the full range of light-matter interaction dynamics within a single platform and provides valuable pathways towards robust and versatile quantum information processing. Current bosonic circuit QED setups lack tunability across interaction regimes between a superconducting cavity and a nonlinear circuit element. Here the authors achieve such tunability in a cavity-transmon system by using a magnetic hose for fast flux control of the qubit while preserving the cavity coherence. [ABSTRACT FROM AUTHOR]

This paper focuses on the influence of the fractional-order (FO) resonant capacitor on the zero-voltage-switching quasi-resonant converter (ZVS QRC). The FO impedance model of the capacitor is introduced to the circuit model of the ZVS QRC; hence, a piecewise smooth FO model is developed for the converter. Numerical solutions of the converter are obtained by using both the fractional Adams–Bashforth–Moulton (F-ABM) method and Oustaloup's rational approximation method. In addition, the analytical solution of the converter is obtained by the Grünwald–Letnikov (GL) definition, which reveals the influence of the FO resonant capacitor on the zero-crossing point (ZCP) and resonant state of the converter. An experimental platform was built to verify the results of the theoretical analysis and numerical calculation. [ABSTRACT FROM AUTHOR]

During the last decades, 2D-ordered and disordered photonic systems have attracted intense attention as systems capable to control and modify the flow of light. These structures can also localize light into a bandgap by exciting states arising from cavities, defects, or photonic molecules. We report a controllable random disordered photonic system of silicon dielectric cylinders that presents a deep bandgap and, superimposed, two tunable resonant states generated from decagonal ring resonators embedded into it. These states show a high transmission intensity and a bandwidth that remains stable when its geometrical parameters for frequency tuning are modified. The ability to tune resonating frequencies with geometrical parameters of the system allows interesting applications such as sensing and filtering. [ABSTRACT FROM AUTHOR]

A resonant system consisting of an excess electron and a closed-shell atom or molecule, as a temporary negative ion, is usually in doublet-spin states that are analogous to bright states of photoexcitation of the neutral. However, anionic higher-spin states, noted as dark states, are scarcely accessed. Here, we report the dissociation dynamics of CO− in dark quartet resonant states that are formed by electron attachments to electronically excited CO (a3Π). Among the dissociations to O−(2P) + C(3P), O−(2P) + C(1D), and O−(2P) + C(1S), the latter two are spin-forbidden in the quartet-spin resonant states of CO−, while the first process is preferred in 4Σ− and 4Π states. The present finding sheds new light on anionic dark states. [ABSTRACT FROM AUTHOR]

This paper examines the dynamic evolution of the compact three-planet system Kepler-51. Possible resonant states of the system are analyzed and a search for potential chains of mean motion resonances is carried out. Using the Posidonius software package the dynamic evolution of the system is studied over a time interval of 100 Myr, taking into account tidal interaction. Also, for various initial values of eccentricities, inclinations, arguments of periapsis and longitudes of the ascending nodes of orbits, modeling of the dynamic evolution of the planetary system is carried out within the framework of the semi-analytical theory of motion. It is shown that the compact planetary system Kepler-51 is not resonant. Under initial conditions corresponding to the masses and elements of the planets' orbits, determined from observations taking into account their errors, the evolution of the system is stable and regular over the studied interval of 100 Myr. [ABSTRACT FROM AUTHOR]

In this work, the doubly-charm and doubly-bottom pentaquark molecular states D (∗) Σ c (∗) and B (∗) Σ b (∗) are studied via the QCD sum rules. Sixteen color singlet-singlet type currents with the definite isospin-spin-parity I J P are constructed to interpolate the corresponding hadronic states with the same quantum numbers. The masses and pole residues of those doubly-heavy pentaquark molecular states are calculated, the results show that their masses are all below the corresponding meson-baryon thresholds, which means that they are possible bound states, not resonant states, moreover, the possible decay channels for the doubly-charm molecular states are given. [ABSTRACT FROM AUTHOR]

Localized and resonant state energies of double Coulomb acceptor in narrow-gap HgCdTe alloys are calculated. The simulation is made with scattering matrix technique within spherically symmetric three-band Kane model taking into account conduction band and two top valence bands. It is shown that appearance one-particle state is highly unlikely when the two-particle state is resonant. [ABSTRACT FROM AUTHOR]

As a continuation of our previous work on the conservation and breaking of the pseudospin symmetry (PSS) in resonant states [Phys. Lett. B 847, 138320 (2023)], in this work, the PSS in nuclear single-particle bound and resonant states are investigated uniformly within a relativistic framework by exploring the poles of the Green's function in spherical Woods-Saxon potentials. As the potential depths increase from zero to finite depths, the PS partners evolve from resonant states to bound states. In this progress, the PSS is broken gradually with energy, width, and density splittings. Specially, the energy and width splittings for the resonant and bound states are directly determined by the ratio of the pseudo spin-orbit potentials between the PS partners. Obvious threshold effect is observed for the energy splitting at a critical potential depth, with which one PS partner has become a quasi-bound state inside the centrifugal barrier while the other one is still a high-energy resonant state outside the centrifugal barrier. The differences in the density distributions of the lower component between the PS partners are manifested in the phase shift for the resonant states and amplitudes for bound states.

Weyl semimetal showing open-arc surface states is a prominent example of topological quantum matter in three dimensions. With the bulk-boundary correspondence present, nontrivial surface--bulk hybridization is inevitable but less understood. Spectroscopies have been often limited to verifying the existence of surface Fermi arcs, whereas its spectral shape related to the hybridization profile in energy--momentum space is not well studied. We present an exactly solvable formalism at the surface for a wide range of prototypical Weyl semimetals. The resonant surface state and the bulk influence coexist as a surface--bulk hybrid and are treated in a unified manner. Directly accessible to angle- resolved photoemission spectroscopy, we analytically reveal universal information about the system obtained from the spectroscopy of resonant topological states. We systematically find inhomogeneous and anisotropic singular responses around the surface--bulk merging borderline crossing Weyl points, highlighting its critical role in the Weyl topology. The response in scanning tunneling spectroscopy is also discussed. The results will provide much-needed insight into the surface--bulk-coupled physical properties and guide in-depth spectroscopic investigation of the nontrivial hybrid in many topological semimetal materials. [ABSTRACT FROM AUTHOR]

Coupling is a ubiquitous phenomenon observed in various systems, which profoundly alters the original oscillation state of resonant systems and leads to the unique optical properties of metasurfaces. In this study, we introduce a terahertz (THz) tunable coupling metasurface characterized by a four-fold rotation (C4) symmetry-breaking structural array achieved through the incorporation of vanadium dioxide (VO2). This disruption of the C4 symmetry results in dynamically controlled electromagnetic interactions and couplings between excitation modes. The coupling between new resonant modes modifies the peak of electromagnetic-induced transparency (EIT) within the C4 symmetric metasurfaces, simulating the mutual interference process between modes. Additionally, breaking the C4 symmetry enhances the mirror asymmetry, and imparts distinct chiral properties in the far-field during the experimental process. This research demonstrates promising applications in diverse fields, including biological monitoring, light modulation, sensing, and nonlinear enhancement. [ABSTRACT FROM AUTHOR]

Manipulating the π-electron magnetism of single-molecule junctions is an effective means to improve the electronic and spin-polarized thermoelectric transport properties. Here, using the density functional theory combined with the nonequilibrium Green's function method, we demonstrate that the electronic conductance (σ) of molecular junctions (MJs) can be significantly enhanced by organic radicals due to the shifting of resonant states. Moreover, we find that the spin-dependent quantum interference (SDQI) effects can be largely influenced by organic radicals. The SDQI effects result in nearly 100% spin filtering efficiency in open-shell molecules and greatly enhance the Seebeck coefficients. As a result, the thermoelectric performances of open-shell MJs at room temperature are greatly improved through the combined effects of radicals and SDQI. In particular, the maximum ZTsp in the four radical junctions reaches up to 36.5. Our results show great potential for improving thermoelectric performance through the utilization of quantum interference and organic radical. [ABSTRACT FROM AUTHOR]

Asymptotic normalization coefficients (ANCs) of the 0 1 + , 0 2 + , 1 1 - , 2 1 + , 3 1 - ( l ith π ) bound states of 16 O are deduced from the phase shift data of elastic α - 12 C scattering at low energies. S matrices of elastic α - 12 C scattering are constructed within cluster effective field theory (EFT), in which both bound and resonant states of 16 O are considered. Parameters in the S matrices are fitted to the precise phase shift data below the p- 15 N breakup energy for the partial waves of l = 0 , 1 , 2 , 3 , 4 , 5 , 6 , and the ANCs are calculated by using the wave function normalization factors of 16 O propagators for l = 0 , 1 , 2 , 3 . We review the values of ANCs, which are compared with other results in the literature, and discuss uncertainties of the ANCs obtained from the elastic α - 12 C scattering data in cluster EFT. [ABSTRACT FROM AUTHOR]

Excited states of the Hoyle state in 12 C are discussed by taking into account the correct boundary condition for three- α resonant states with the complex scaling method. The Coulomb interaction is considered to play an important role for stability of a breathing 3 α motion. It is expected that such a breathing mode exists in other n α systems as well. The development of a new method for solving n α systems in the complex scaling method is reported. [ABSTRACT FROM AUTHOR]

The compound Cu12Sb4S13, known as tetrahedrite, is an eco-friendly p-type thermoelectric material with earth-abundant, low-cost, and less toxic constituents. This contemporary work studied the thermoelectric properties of Gd and Se double-substituted tetrahedrites. The samples with nominal composition Cu11.95Gd0.05Sb4S13−xSex (where x = 0, 0.2, 0.4, 0.6, and 0.8) were prepared using the solid-state synthesis and sintered using high vacuum hot pressing. The structural analysis using X-ray diffraction revealed a successful tetrahedrite phase formation, and the systematic increase of lattice parameters with the selenium content (x) indicated successful Se substitution. The electron probe microanalysis revealed the presence of secondary phases Cu3SbS4, CuSbS2, and CuGdS2. The Raman spectroscopy showed a weakening Sb–S/Se bond with increased Se content in the samples. The +3 and −2 oxidation states of Gd and Se, respectively, were confirmed from the XPS study. Gd3+, a higher valence substituent at the Cu+/Cu2+ tetrahedral site, helped reduce the carrier concentration. On the other hand, the isoelectronic substitution of Se2− for S2− enhanced the thermopower and power factor by introducing resonant energy states near the Fermi level. Consequently, a maximum power factor of ∼1.35 (±0.08) mW m−1 K−2 at ∼729 K was obtained for the sample x = 0.4. The sample x = 0.4 also exhibited the lowest thermal conductivity ∼ 1.18 (±0.04) W m−1 K−1 at 729 K. The Callaway model indicates that the lowering in the lattice thermal part of conductivity of this sample is due to the combined effect of point defect and Umklapp scattering. The simultaneous improvement of carrier concentration and thermal conductivity resulted in a relatively high zT of ∼0.83 (±0.09) in the x = 0.4 sample. [ABSTRACT FROM AUTHOR]

We investigate the transmittance spectrum of a multichannel filter composed of dielectric (A) and plasma (P) materials in the microwave region within the transfer matrix formalism. Two configurations of the proposed filter are studied under the influence of an applied magnetic field: (1) a periodic structure containing (A / P) N unit cells surrounded by air and (2) the introduction of a second dielectric material (D) acting as a defect layer to produce an (A P) N / 2 / D / (A P) N / 2 structure. Our findings reveal that in the periodic case, the number of resonant states of the transmittance increases with number N ; however, the observed blue and red shifts depend on the intensity and orientation of the applied magnetic field. We present contour plots of the transmission coefficients that show the effect of the incident angle on the shifts of the photonic band gaps. Furthermore, we find that the introduction of a defect layer generates additional resonant states and merges the central resonant peak into a miniband of resonances. Moreover, we show that the number of resonant peaks and their locations can be modulated by increasing the unit cell number, N , as well as increasing the width of the inserted defect layer. Our proposed structures enable the design of novel photonic filters using magnetized plasma materials operating in the microwave region. [ABSTRACT FROM AUTHOR]

The discovery of halos, one of the most interesting phenomena in exotic nuclei, has opened up a new field in nuclear physics. To understand this unique property, the level structures of 14 B, 15 C, 22 N, 23 O, 24 F, and 25 Ne are studied with the complex momentum representation (CMR) method. We calculate the single-particle energies of bound and resonant states, and examine the occupation probabilities, density distribution, wavefunctions of the valence neutron occupied levels, and the root mean square (RMS) radii of the single-particle orbits. These results show that 14 B, 15 C, and 22 N are neutron halo nuclei dominated by s-wave configurations in - 0.08 ≤ β 2 ≤ 0 , 0.1 ≤ β 2 ≤ 0.3 , and - 0.1 ≤ β 2 ≤ 0.08 , respectively. Although the last valence neutron of 23 O, 24 F, and 25 Ne all occupy the 2 s 1 / 2 orbit (the orbit with a dominant s-wave configuration), the single-particle levels occupied by the valence neutrons are rather bound. It implies a neutron skin structure in 23 O, 24 F, and 25 Ne with spherical shape or prolate deformation. The halo phenomena are not only related to the orbital occupied by the last valence neutron but also to its separation energy. This prediction has reference value for further exploration of neutron halo in experiments. [ABSTRACT FROM AUTHOR]

We theoretically study the state‐selected photo‐recombination process of highly charged ions using the close‐coupling approximation and the full relativistic Dirac R‐matrix method combined with the Dirac Atomic R‐matrix Codes (DARC). Focusing on the interference between the direct and indirect processes and the relativistic effects on the spin‐orbit splitting, we calculate the total and partial photo‐recombination cross sections of the H‐like Ne9+, Cl16+, Fe25+, and Kr35+ ions. The energies of the incident electrons are considered as in the KLL resonant regions, in which the initial state is the 1s ground state of the H‐like ions and the recombined states includes the ground state (1s2)1S0 and six lower excited states (1s2s)1S0,3S1, and (1s2p)3P0,1,2,1P1 of the He‐like ions. We utilize the multi‐configuration Dirac‐Fock method to calculate the target state wavefunctions, transition energies, and transition probabilities of both the one‐electron one‐photon (OEOP) and two‐electron one‐photon (TEOP) transitions from the resonant captured states to the recombined states. By analyzing the calculated atomic data, we identify all resonant peaks in each partial photo‐recombination process, and our results agree well with the available results in literature. Our study reveals a significant interference effect in the photo‐recombination cross sections, especially in the partial cross sections. Moreover, we present the eigenphase as a function of the electron energy for each partial photo‐recombination channel. [ABSTRACT FROM AUTHOR]

It is known that pseudospin symmetry plays a crucial role in formation of many physical phenomena. By combining the relativistic mean field theory with the complex momentum representation method, the pseudospin symmetry in the single particle resonant states in the deformed nucleus 1 5 4 Dy is investigated through the energy and width splittings, the quadrupole deformation parameter, the radial density distributions and occupation probabilities of the pseudospin doublets. Near the continuum threshold, the pseudospin symmetry is well reserved in both bound and resonant states. The energy and width splittings of pseudospin doublets in resonant states exhibit correlations with the deformation and quantum numbers. The good pseudospin symmetry is expected with lower pseudo-orbital angular momentum projection Λ ̃ and the main quantum number N. In general, an increase in deformation tends to weaken the quality of the pseudospin symmetry. The understanding of the evolution of the pseudospin doublets in the resonant states has been deepened by studying the pseudospin symmetry in the deformed nuclei. [ABSTRACT FROM AUTHOR]

Motivated by the intriguing discovery of X (6900) by the LHCb collaboration, we undertake a comprehensive study of the s s ¯ s s ¯ tetraquark system with positive parity, employing the Gaussian expansion within the chiral quark model method. We consider two structures, the diquark–antidiquark ( s s - s ¯ s ¯ ) structure and meson–meson ( s s ¯ - s s ¯ ) structure, covering all conceivable color and spin configurations. Despite the absence of bound states in our calculations, we have identified potential resonant states with J P = 0 + , namely, R (0 , 2150) and R (0 , 2915) , as well as a resonant state with J P = 1 + , denoted as R (1 , 2950) , and a resonant state with J P = 2 + , denoted as R (2 , 2850) , utilizing the real-scaling method. By comparing their energies and widths, we suggest that R (0 , 2915) and R (1 , 2950) may share characteristics with X (6900) , while R (0 , 2150) could be a promising candidate for the experimental state f 0 (2100) . We strongly advocate for experimental investigations to shed light on the existence and properties of these resonant states. [ABSTRACT FROM AUTHOR]

The paper addresses the issue of harmonics resonance amplifications in electric power networks, for being particularly relevant due to the increasing integration of distributed energy sources and new load types, such as heat pumps and electric vehicles. To ensure appropriate parameters for the electric power quality, two methods of harmonic resonance analysis are compared: the conventional method of analyzing the nodal frequency impedance characteristics and a modern approach of using the modal analysis. Based on the frequency characteristics calculation for individual nodes, the conventional method faces limitations in terms of the accuracy and scope of information it provides. As an alternative, the paper presents a modal analysis, enabling a more precise and reliable analysis of the network resonant states. By transforming the system model into the modal domain, the modal analysis separately identifies individual resonant states and provides an insight into the impact of the network element parameters on the resonance states. The paper compares the practical applicability of the two methods on a model of a real industrial network to analyze the critical resonant states, identify the most impacting nodes, and solve the issue of the resonance phenomena by adjusting the parameters of the network elements. [ABSTRACT FROM AUTHOR]

In the electric vehicle wireless power transmission system, the high-frequency alternating magnetic field between the transmitter and receiver can have a certain impact on the health of living organisms and may even lead to lesions. In addition, metal foreign objects in an alternating magnetic field can cause their own heating or even cause fires due to the eddy current effect, so foreign object detection is an essential function in the wireless power transmission system of electric vehicles. In order to prevent metals and living organisms from entering the charging area and causing harm to the charging system and living organisms, this paper proposes a method for detecting living organisms and metal foreign objects. Firstly, the equivalent circuits for the detection systems of the living organism foreign objects and metal foreign objects are established, respectively, and the working theory of the detection system is analyzed by deriving equations. Secondly, the comb capacitor simulation model was constructed, and the comb capacitor electrode spacing, wire thickness, and capacitor spacing were designed based on the scale factor γ to explore the effects of the height and bottom area of the living organism's foreign object on the comb capacitor. We constructed a simulation model of the detection coil and designed the inner diameter D, the number of turns N, and the wire spacing S of the detection coil according to the scale factor β. An arrayed detection coil and comb capacitor combination mode is proposed to realize the function of the simultaneous detection of metal and living organism foreign objects, and a compensation capacitor is introduced to keep the detection system in a resonant state. Lastly, a platform for foreign object detection experiments was set up to detect metal screws and beef chunks compared to the detection area without foreign objects. Metal screws entering the detection area cause a 20% voltage drop in the detection circuit resistor, and beef chunks entering the detection area cause a 30% voltage drop in the detection circuit resistor, so the detection method is effective in detecting both metals and living organisms. The feasibility of the combined mode of arrayed detection coils and comb capacitors was verified. [ABSTRACT FROM AUTHOR]

We report here an R-matrix study of electron collision with the BeO + molecular ion in its X 2 Π ground state and at a single bond length, namely its equilibrium R e = 2.7023   a 0 . Firstly, a good quality configuration interaction calculation is performed for the BeO + ground and excited states. We then perform scattering calculations using the R-matrix method to yield the cross-section for electronic excitation to several of its excited states. The electron impact dissociation of BeO + through the two lowest dissociation channels, namely the Be + (2 S g) + O (3 P g) and Be + (2 S g) + O (1 D g) dissociation channels, is estimated using the electronic excitation cross-sections. Rotational excitation cross-sections are provided for the j (= 0) → j ′ (= 1 , 2 , 3) rotational transitions. Our calculations also yield e + BeO + neutral Feshbach resonances and their widths which we present systematically categorized by their symmetry and quantum defects, and BeO-bound Rydberg states at the BeO + equilibrium. The full potential energy curves for the resonant states, their widths and the bound Rydberg states, whose details we propose to give in a subsequent work, can be the starting point of other collision calculations. [ABSTRACT FROM AUTHOR]

In this paper, resonances are introduced to a class of quantum walks on Z. Resonances are defined as poles of the meromorphically extended resolvent of the unitary time evolution operator. In particular, they appear inside the unit circle. Some analogous properties to those of quantum resonances for Schrödinger operators are shown. Especially, the resonance expansion, an analogue of the eigenfunction expansion, indicates the long-time behavior of quantum walks. The decaying rate, the asymptotic probability distribution, and the weak limit of the probability density are described by resonances and associated (generalized) resonant states. The generic simplicity of resonances is also investigated. [ABSTRACT FROM AUTHOR]

The photodissociation dynamics of alkyl iodides along the C–I bond are captured by attosecond extreme-ultraviolet (XUV) transient absorption spectroscopy employing resonant ∼20 fs UV pump pulses. The methodology of previous experiments on CH3I [Chang et al., J. Chem. Phys. 154, 234301 (2021)] is extended to the investigation of a C–I bond-breaking reaction in the dissociative A-band of C2H5I, i-C3H7I, and t-C4H9I. Probing iodine 4d core-to-valence transitions in the XUV enables one to map wave packet bifurcation at a conical intersection in the A-band as well as coherent vibrations in the ground state of the parent molecules. Analysis of spectroscopic bifurcation signatures yields conical intersection crossing times of 15 ± 4 fs for CH3I, 14 ± 5 fs for C2H5I, and 24 ± 4 fs for i-C3H7I and t-C4H9I, respectively. Observations of coherent vibrations, resulting from a projection of A-band structural dynamics onto the ground state by resonant impulsive stimulated Raman scattering, indirectly reveal multimode C–I stretch and CCI bend vibrations in the A-bands of C2H5I, i-C3H7I, and t-C4H9I. [ABSTRACT FROM AUTHOR]

The dynamics of vibrational relaxation of carbon dioxide in water has been studied using femtosecond mid-infrared pump–probe spectroscopy with excitation of the anti-symmetric stretching (ν3) fundamental state of the solute. The relaxation dynamics were recorded at a constant pressure of 500 bars and in the temperature range between 300 and 600 K, thereby covering the liquid-to-near-critical region of the solvent. The excited state of the ν3-mode is deactivated in two competing pathways: (i) direct relaxation to the ground state with resonant transfer of the excess vibrational energy into the bending–librational continuum of the water solvent and (ii) relaxation to the bending fundamental state with transfer into the intramolecular bending mode of H2O. The rate of pathway (i) decreases with increasing temperature, from ∼1/(9 ps) at 300 K to ∼(1/16 ps) at 600 K and obeys Fermi's golden rule strictly, provided that the spectral density of energy-accepting solvent states is derived from the stationary infrared absorption profile of H2O. The rate of pathway (ii) is 1/(23 ps) and assumed to be temperature-independent within our data analysis. Finally, the bending fundamental of CO2 can also relax to the ground state by resonantly transferring the remaining excess energy to the librational fundamentals of the solvent. [ABSTRACT FROM AUTHOR]

We theoretically investigate the two-photon absorption signals of a three-band (g, e, f) system diagonally coupled to an over-damped Brownian oscillator bath, which induces random Gaussian modulations of energy levels with an arbitrary degree of correlation. For fast modulation, extra 2ωeg and 2ωfe peaks may obscure the g–f transitions in the classical two-photon absorption (CTPA) spectra for nearly resonant e states. These peaks arise from one-photon resonant g–e or e–f transitions. In the slow modulation limit, these peaks vanish because of the short tails of the Gaussian line shape. CTPA strongly depends on the correlations between energy fluctuations. In entangled two-photon absorption, the extra peaks are eliminated because of the broad one-photon but narrow two-photon spectrum of the twin photons. The variation of the coherences between f states with the correlation between energy fluctuations is explored. [ABSTRACT FROM AUTHOR]

Dark resonating states render an important role in curtailing the dominant radiative losses in various photonic structures like metamaterials (MMs), photonic crystals, waveguides, etc. Currently, radiative losses are the major degrading factors toward the strong confinement of electromagnetic radiation for MMs' applications in sensing, imaging, filters, modulators, nonlinear studies, etc. Generally, the dark states cannot be excited through the direct interaction of electromagnetic radiations with the metastructures. However, indirect excitation at suitable structural asymmetries can trigger the evolution of dark resonating states or trapped modes. In this work, we have experimentally demonstrated mode hybridization of such dark (sub-radiant) resonating states without the direct involvement of interacting bright (super-radiant) states in a metasurface consisting of asymmetric split-ring resonators. Our study further reveals that the lattice mode plays a crucial role in determining the line shapes of the split (hybridized) modes. Such tuning of dark resonance modes can find potential applications in metasurfaces-based sensing, non-linear devices besides other potential applications desiring multi-channel strong field confinement. [ABSTRACT FROM AUTHOR]

The exceptional performance of the wireless power transfer (WPT) system hinges on its resonant state. However, the capacitance drift caused by manufacturing tolerance and temperature will result in a state of detuning. In this manuscript, a PWM-controlled switched impedance (PCSI) topology that can express inductive and capacitive is proposed to eliminate line mismatches resulting from the above factors. Firstly, the PCSI topology is introduced, and its placement is determined based on the characteristics of the inductor–capacitor–capacitor series (LCC-S) network. Secondly, the working principle of the proposed topology is introduced. Finally, the simulation and experimental results show that the system could be restored to its resonant state by adjusting the PCSI topology. Under different values of resonant capacitors, the PCSI topology enhances the output power of the system by 40 W~150 W compared to the previous state, and the efficiency is increased by 9~13%. [ABSTRACT FROM AUTHOR]

We propose a new strategy to achieve a high average zT in electron-doped SnTe by applying the two-band (TB) and single parabolic band (SPB) models to the electronic transport properties of Sn0.97M0.03Te (M = Ga , In, Bi, and Sb) reported in the literature. To achieve a high average zT at temperatures from 300 to 823 K, both zT at 300 and 823 K should be high with a steadily increasing zT over the temperatures. The p-type SnTe is known to have a light valence band and a heavy valence band that are approximately 0.40 eV apart. The Bi-doped SnTe exhibits one of the highest zT among all the other doped samples at 300 K (0.09) and the highest zT at 823 K (0.9), with a steadily increasing zT in between. The TB model confirms the presence of the resonant state at 300 K which is responsible for the high zT at 300 K. The B-factor, which is related to the theoretical maximum zT, calculated by the SPB model indicates a steady increase in zT with increasing temperature. The temperature-dependent B-factor of the Bi-doped SnTe suggests that the initial position of its Fermi level at 300 K calculated by the TB model may be responsible for the temperature coefficient of the B-factor, which determines the zT at 823 K. According to the SPB model, experimental zT of 0.9 of the Bi-doped SnTe can be further improved to 1.03 (14% improvement) at 823 K upon carrier concentration optimization. To achieve a high average zT in SnTe, electron doping with a dopant that forms a resonant state and placing the Fermi level at the light valence band in the vicinity of the heavy valence band maximum are both essential. [ABSTRACT FROM AUTHOR]

A computational method is proposed to calculate bound and resonant states by solving the Klein–Gordon and Dirac equations for real and complex energies, respectively. The method is an extension of a non-relativistic one, where the potential is represented in a Coulomb–Sturmian basis. This basis facilitates the exact analytic evaluation of the Coulomb Green's operator in terms of a continued fraction. In the extension to relativistic problems, we cast the Klein–Gordon and Dirac equations into an effective Schrödinger form. Then the solution method is basically an analytic continuation of non-relativistic quantities like the angular momentum, charge, energy and potential into the effective relativistic counterparts. [ABSTRACT FROM AUTHOR]

We investigate the properties of the excited state of 4 He , 4 He ∗ , within the framework of Efimov physics and its connection to the unitary point of the nuclear interaction. We explore two different approaches to track the trajectory of 4 He ∗ as it crosses the 3 H +p threshold and potentially becomes a resonant state. The first approach involves an analytical continuation of the energy with respect to the Coulomb coupling, while the second approach introduces an artificial four-body force that it is gradually released. By utilizing Padé approximants and extrapolation techniques, we estimate the energy and width of the resonance. Our results suggest a central energy value of E R = 0.060 (3) MeV and a width of Γ / 2 = 0.036 (6) MeV using the Coulomb analysis, and E R = 0.068 (1) MeV and Γ / 2 = 0.007 (5) MeV with the four-body force analysis. Interestingly, these results are consistent with calculations based on ab-initio nuclear interactions but differ from the accepted values of the 0 + resonance energy and width. This highlights the challenges in accurately determining the properties of resonant states in light nuclei and calls for further investigations and refinements in theoretical approaches. [ABSTRACT FROM AUTHOR]

The conductance and electronic transmission of Dirac electrons and holes across multibarrier Cantor-like graphene are investigated using on the transfer matrix method and Landauer–Buttiker formalism. Electric and magnetic fields are applied to the top of a monolayer graphene to generate multiple electromagnetic barriers separated by quantum wells. The impact of the magnetic and electric fields as well as the quantum size on the behavior of the transmission coefficient and conductance is discussed. The results indicate that the transmission coefficients exhibit oscillations indicating the existence of resonant states in miniband energies separated by minigap energies. This phenomenon known as the bifurcation process is more pronounced for a higher number of barriers. The behavior observed in the conductance variation reflects of the transmission coefficient especially for lower energies. Furthermore, the contour plot of the transmission coefficient shows the predominant impact of the incidence angle on the symmetry of the minigaps and minibands. These results are expected to be beneficial for experiments that improve the performance of new generations of devices based on multibarrier Cantor-like graphene systems. [ABSTRACT FROM AUTHOR]

Single molecules trapped in the solid state at liquid helium temperatures are promising quantum emitters for the development of quantum technologies owing to their remarkable photostability and their lifetime-limited optical coherence time of the order of 10 ns. The coherent preparation of their electronic state requires resonant excitation with a Rabi period much shorter than their optical coherence time. Sculpting the optical excitation with sharp edges and a high on–off intensity ratio (∼3 × 105) from a single-frequency laser beam, we demonstrate sub-nanosecond drive of a single dibenzanthanthrene molecule embedded in a naphthalene matrix at 3.2 K, over more than 17 Rabi periods. With pulses tailored for a half-Rabi period, the electronic excited state is prepared with fidelity as high as 0.97. Using single-molecule Ramsey spectroscopy, we prove up to 5 K that the optical coherence lifetime remains at its fundamental upper limit set by twice the excited-state lifetime, making single molecules suitable for quantum bit manipulations under standard cryogen-free cooling technologies. [ABSTRACT FROM AUTHOR]

Based on the recently demonstrated resonant wave–wave process, it is shown that electrons can be accelerated to ultra-relativistic energies in the magnetospheres of radio pulsars. The energization occurs via the resonant interaction of the electron wave (described by the Klein–Gordon (KG) equation) moving in unison with an intense electromagnetic (EM) wave; the KG wave/particle continuously draws energy from EM. In a brief recapitulation of the general theory, the high-energy (resonantly enhanced) electron states are investigated by solving the KG equation, minimally coupled to the EM field. The restricted class of solutions that propagate in phase with EM radiation (functions only of ζ = ω t − k z ) are explored to serve as a possible basis for the proposed electron energization in the radio pulsars. We show that the wave–wave resonant energization mechanism could be operative in a broad class of radio pulsars with periods ranging from milliseconds to normal values (∼1 s); this could drive the magnetospheric electrons to acquire energies from 100 s of TeVs (millisecond pulsars) to 10 ZeVs (normal pulsars). [ABSTRACT FROM AUTHOR]

The present paper finds that the coexistence of multiple primary instability waves may cause a non-trivial nonlinear interaction and breakdown process, which has not been reported before. In the considered Mach 6 flat-plate boundary layer, a global resolvent analysis reports three optimal disturbances (local maxima): a high-frequency planar wave, a low-frequency oblique wave and a stationary streak. For the dominant planar and oblique waves, a parabolised stability equation analysis identifies the initial non-modal transient growth and downstream modal growth. Initiated by these two optimal disturbances jointly, the complete linear and nonlinear instability processes until breakdown to turbulence are shown with direct numerical simulation. Owing to the transient growth, the oblique wave may be more significant than the planar wave in the breakdown. The oblique wave and scales of nonlinear interactions are pronounced in the outer layer, whose significance may not be comprehensively characterised by the wall pressure measurement. Fourier modes characterising the oblique-wave oblique breakdown, the planar-wave fundamental resonance, the planar-wave subharmonic resonance and the combination resonance related to a detuned mode are observed successively. The detuned mode seems to dominate the near-wall dynamics in the late nonlinear stage, characterised by $\varLambda$ -like structures. Meanwhile, the existence of this detuned mode is independent of the initial amplitude ratio and the absolute amplitude of the oblique and planar waves. Weakly nonlinear stability analyses demonstrate that the detuned mode is mainly a consequence of the secondary instability under the combination of planar and oblique primary waves. Wave vector plots reveal the resonant state of multiple triads. Energy budget and amplitude-correction analyses provide a clear physical image of energy transfer. [ABSTRACT FROM AUTHOR]

Emerging artificial acoustically soft boundaries (ASBs) have shown great potential for developing compact sound absorptive devices with excellent ventilation performance. However, current realizations of ASBs suffer from narrow-band limitations, which necessitate a stringent matching of resonant characteristics between dissipated meta-atoms and ASBs to achieve perfect absorption. In this study, we propose a paradigm to construct a broadband ASB (BASB) by coupling two multi-band ASBs with the help of coiled space resonators (CSRs) that possess multiple harmonically resonant states. We explore the modulation mechanism of CSRs using coupled mode theory. By elaborately hybridizing dissipated meta-atoms and the proposed BASB, we numerically and experimentally realize a sound metaliner that exhibits ultra-broadband absorption (267–1430 Hz) with high efficiency (A > 90 %). Our design strategy overcomes the narrow-band limitation of conventional ASBs and enables more flexible and robust ventilated sound absorbing devices. [ABSTRACT FROM AUTHOR]

In this paper, a nice theoretical scheme is presented to investigate resonant and bound states in weakly bound nuclear systems by the use of isospectral potentials together with hyperspherical harmonics expansion. In this scheme, a new potential is constructed which is strictly isospectral with the original shallow potential and has properties that are desirable to calculate resonances more accurately and elegantly. The effectiveness of the method has been checked in terms of its application to the 0+ resonances in the neutron-rich isotopes 18,20C in the two-neutron plus core three-body cluster model. The results are in excellent agreement with the available data. [ABSTRACT FROM AUTHOR]