Electrodynamic Interactions Research Articles

Transparency, nonclassicality, and nonreciprocity in chiral waveguide quantum electrodynamics

We examine quantum statistical properties of transmission and reflection from a chiral waveguide coupled to qubits for arbitrary input powers. We report on several remarkable features of output fields such as transparency, quantum nonreciprocity, and the second-order correlation function g(2)(0) values less than unity. In particular, for two qubits detuned antisymmetrically with respect to the central waveguide frequency, we find transparency in forward transmission and in photon numbers for arbitrary values of the input powers provided the phase separation between qubits is an integer multiple of π. Values of g(2)(0) less than unity can be reached even for nonzero value of the intrinsic damping by using phase separation different from integer multiple of π, marking the transition from classical to quantum light. We also uncover a different type of critical coupling regime for qubits that enables complete suppression of forward-propagating amplitude transmission at specific driving powers, giving rise to enhanced nonreciprocal effects in both transmission and quantum fluctuations in amplitudes. Forward propagation amplifies the quantum fluctuations in amplitudes, while backward propagation significantly suppresses them. These findings open pathways for controlling light-matter interactions in chiral quantum electrodynamics, with potential applications in quantum information and nonreciprocal quantum devices. Published by the American Physical Society 2025

Juno Observations Set New Constraints on the Electrodynamic Interaction Between Io and Jupiter.

Juno's highly elliptical polar orbits provide unprecedented in-situ observations of the electrodynamic interaction between Jupiter and its volcanic moon Io. These observations occur in regions never sampled before both near Io's orbit and near Jupiter's ionosphere and at distances between the two. Magnetic field data obtained during multiple traversals of magnetic field lines mapping to Io's orbit reveal remarkably rich and complex magnetic signatures near flux tubes connected to Io's orbital position. Here we present a methodology to model the distribution of currents along Io's flux tube (IFT) and Alfvén wings in such a way as to match the magnetic field signature observed during Juno's traversals of the IFT and Alfvén wings downstream of Io. We obtain the location, size and morphology of the current-carrying region as well as the distribution of currents within the IFT and Alfvén wings. The observed field-aligned currents exhibit strong filamentation, with upward and downward currents splitting into secondary cells rather than forming uniform structures. Additionally, there is a strong correlation between total field-aligned current intensity, particle energy flux, and Poynting flux, indicating efficient energy transfer and coupling in the Jupiter-Io system. Using all of Juno's traversals up to perijove (PJ) pass 42, we estimate the strength of the interaction with regards to distance along Io's extended tail, Io's position in the plasma torus and the magnetic field intensity at the footprint in Jupiter's ionosphere, illuminating the interaction of Jovian magnetospheric plasma with Io and setting important constraints in the Io-Jupiter interaction.

Electrospinning of LaB6/PEDOT:PSS/PEO Fiber Composites of Unique Morphologies.

We present a direct electrospinning fabrication technique for the manufacture of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate)/poly(ethylene oxide) (PEDOT:PSS/PEO) polymer fibers containing embedded cubic lanthanum hexaboride (LaB6) particles. We focus on the impact of relative humidity on the formation of uniform polymer fibers and show that a relative humidity of 5% is optimal, resulting in an average fiber thickness of 266 ± 88 nm. As the relative humidity is increased, the fibers contain beads as a consequence of Rayleigh instabilities. The addition of lanthanum hexaboride cubic particles to the polymer solution before electrospinning results in the encapsulation of the LaB6 particles inside the fibers. We investigate the effect of LaB6 particle size on morphology and observe that particles of ∼500 nm yield a fiber-cube-fiber morphology, while 2 μm particles result in fewer embedded cubes along the length of the polymer fibers. This phenomenon likely arises from electrodynamic interactions between the LaB6 particles in the polymer solution and the electric field lines generated during electrospinning between the spinneret and the collector. Our results display the versatility of the electrospinning technique in the fabrication of unique polymer/hexaboride composite fibers.

An assessment of electroneutrality implementations for accurate electrochemical ion transport models

During the diffusion and migration of ions in electrolytes, the electrodynamic ion-ion interactions prevent charge separation despite different ionic mobilities, ultimately enforcing electroneutrality in the bulk electrolyte. To model ion transport accurately, a method to enforce electroneutrality must be implemented. In this study, four strategies to implement electroneutrality are discussed and evaluated. The ion distributions that result from a transport model with the different electroneutrality implementations are calculated, considering various electrolytes and sets of electrochemical parameters. The meaningfulness and applicability of each implementation are assessed through spatial charge accumulations, transference numbers, and experimental data from the literature. Combining the electrochemical ion transport models with the electroneutrality constraint for all ions is shown to result in an overdetermined system of equations if the driving forces are calculated under neglection of diffusion potentials. The often-reported model simplification of using the electroneutrality constraint to resolve the transport of one specific species explicitly results in non-physically correct mass transport. A practical approach to precisely describe the measured physicochemical ion movements is obtained by equilibrating spatial charges with the ion conduction for every time step in the ion transport model, which is reasonably applicable to multi-ion systems in three-dimensional frameworks. This comprehensive assessment aims to guide readers in selecting an appropriate electroneutrality implementation framework for ion transport models.

Power dissipation and entropy production rate of high-dimensional optical matter systems.

Entropy production is an essential aspect of creating and maintaining nonequilibrium systems. Despite their ubiquity, calculation of entropy production rates is challenging for high-dimensional systems, so it has only been reported for simple (i.e., l-particle) systems. Moreover, there is a dearth of nontrivial experimental systems where precise measurements of entropy production rate and characterization of the nonequilibrium steady state (NESS) are simultaneously possible. We report an approach to calculate the entropy production rate of overdamped, nonconservative, N-body systems and demonstrate this on a six-particle triangle optical matter (OM) system as a nontrivial example. OM systems consist of (nano-)particles organized into ordered arrays that are bound by electrodynamic interactions associated with the scattering and interference of light, and the associated induced-polarizations in and among the particles in coherent optical beams. The flux of laser light in OM systems in a solution environment necessitates that they dissipate energy, produce entropy, and relax to a NESS. The NESS may have several ordered particle configurations (i.e., isomers) that can interchange by barrier crossing processes. Understanding the power dissipation and entropy production rate of a NESS in an OM system along different (collective) modes of motion can advance understanding of the relative stability of the NESSs as well as inform design and control of OM structures. Therefore, we compute the components of the entropy production rate and power dissipation along the collective coordinates of the 6 Ag nanoparticle triangle OM system from OM NESS trajectory data and verify the Seifert relation [U. Seifert, Rep. Prog. Phys. 75, 126001 (2012)10.1088/0034-4885/75/12/126001] for these complex systems with a nuanced interpretation.

Influence of annealing on optical, morphological and electrophysical properties of granular silver nanostructures

The optical, morphological and electrophysical properties of silver nanostructures fabricated by electron beam evaporation and annealed at temperatures of 145 and 195 °C were studied. All samples are characterized by the presence of a pronounced surface plasmon absorption resonance band in the visible range and represent close-packed monolayers of nanoparticles, the average sizes of which increase from ~10 nm in the original samples to ~35–40 nm and ~45–60 nm in the annealed ones, depending on the annealing temperature. The influence of various factors on the spectral characteristics of samples, including the size of nanoparticles and electrodynamic interactions between nanoparticles, is discussed. It has been shown that all granular nanostructures studied, both initial and annealed, are highly resistive. It has been established that for the initial and annealed at 145 °C samples, near low values of the applied voltage, a dependence of the current on the irradiation wavelength can be traced, with its value changing up to two orders of magnitude for certain wavelengths.

Construction of superconducting dome and emergence of quantum critical region in holography

In this work, we investigate an extended model of holographic superconductor by a nonlinear electrodynamic interaction coupled to a complex scalar field. This nonlinear interaction term can make a quantum phase transition at zero temperature with finite charge carrier density. By solving full equations of motion, we can construct various shapes of the superconducting phase in the phase diagram. With a specific choice of interaction coefficients, we can construct a phase diagram with a superconducting dome. Also, we find a new geometric solution inside the superconducting dome, which turns out to be a Lifshitz-type geometry. This geometry is characterized by a dynamical critical exponent, which plays a crucial role near the quantum critical point. We refer to this region of the phase diagram as a quantum critical region. Published by the American Physical Society 2024

Electrodynamic interaction between tumor treating fields and microtubule electrophysiological activities.

Tumor treating fields (TTFields) are a type of sinusoidal alternating current electric field that has proven effective in inhibiting the reproduction of dividing tumor cells. Despite their recognized impact, the precise biophysical mechanisms underlying the unique effects of TTFields remain unknown. Many of the previous studies predominantly attribute the inhibitory effects of TTFields to mitotic disruption, with intracellular microtubules identified as crucial targets. However, this conceptual framework lacks substantiation at the mesoscopic level. This study addresses the existing gap by constructing force models for tubulin and other key subcellular structures involved in microtubule electrophysiological activities under TTFields exposure. The primary objective is to explore whether the electric force or torque exerted by TTFields significantly influences the normal structure and activities of microtubules. Initially, we examine the potential effect on the dynamic stability of microtubule structures by calculating the electric field torque on the tubulin dimer orientation. Furthermore, given the importance of electrostatics in microtubule-associated activities, such as chromosome segregation and substance transport of kinesin during mitosis, we investigate the interaction between TTFields and these electrostatic processes. Our data show that the electrodynamic effects of TTFields are most likely too weak to disrupt normal microtubule electrophysiological activities significantly. Consequently, we posit that the observed cytoskeleton destruction in mitosis is more likely attributable to non-mechanical mechanisms.

A recursive cell multipole method for atomistic electrodynamics models.

For large plasmonic nanoparticles, retardation effects become important once their length becomes comparable to the wavelength of light. However, most models do not incorporate retardation effects due to the high computational cost of solving for the optical properties of large atomistic electrodynamics systems. In this work, we derive and implement a recursive fast multipole method (FMM) in Cartesian coordinates that includes retardation effects. In this method, higher-order electrodynamic interaction tensors used for the FMM are calculated recursively, thus greatly reducing the implementation complexity of the model. This method allows for solving of the optical properties of large atomistic nanoparticles with controlled accuracy; in practice, taking the expansion to the fifth order provides a good balance of accuracy and computational time. Finally, we study the effects retardation has on the near- and far-field properties of large plasmonic nanoparticles with over a million atoms using this method. We specifically focus on nanorods and their dimers, which are known to generate highly confined fields in their junctions. In the future, this method can be applied to simulations in which accurate near-field properties are required, such as surface-enhanced Raman scattering.

Dynamic Trapping and Manipulation of Self-Assembled Ag Nanoplates as Efficient Plasmonic Tweezers.

Plasmonic tweezers based on periodic nanostructures have been used to manipulate particles through multiple and uniform local surface plasmon (LSP) fields. However, the coverage area of periodic nanostructures is limited, which restricts the range of trapping and manipulation. In this paper, we present a novel approach to achieve large-scale manipulation and trapping of microspheres by uniformly coupled LSP fields on a short-range disordered self-assembled Ag nanoplates (DSNP) film. The DSNP film is prepared by simple and low-cost methods─chemical growth and self-assembly technique, which overcome the challenges of preparing periodic nanostructures with a large coverage area. The uniform and coupled plasmon fields generated by this film provide enhanced electrodynamic interactions with particles, enabling the non-invasive and repeatable trapping of particles in solution. Utilizing sensitive LSPRs, dynamic manipulating particles was achieved by controlling the laser position. This large-scale platform of stable manipulation enabled by the DSNP film opens up new possibilities for the trapping and manipulation of nanoparticles in a variety of applications.

Poynting Fluxes, Field‐Aligned Current Densities, and the Efficiency of the Io‐Jupiter Electrodynamic Interaction

AbstractJuno's highly inclined orbits provide opportunities to sample high‐latitude magnetic field lines connected to the orbit of Io, among the other Galilean satellites. Its payload offers both remote‐sensing and in‐situ measurements of the Io‐Jupiter interaction. These are at discrete points along Io's footprint tail and at least one event (12th perijove) was confirmed to be on a flux tube Alfvénically connected to Io, allowing for an investigation of how the interaction evolves down‐tail. Here we present Alfvén Poynting fluxes and field‐aligned current densities along field lines connected to Io and its orbit. We explore their dependence as a function of down‐tail distance and show the expected decay as seen in UV brightness and electron energy fluxes. We show that the Alfvén Poynting and electron energy fluxes are highly correlated and related by an efficiency that is fully consistent with acceleration from Alfvén wave filamentation via a turbulent cascade process.

Inductance and Electrodynamic Forces in Circular Turns with Parallel Axes

With a wireless method of transmitting electrical energy to autonomous objects, a need may arise to use connecting devices with inductively coupled structural elements. When choosing such devices, their effectiveness should be evaluated taking into account the technological and design features of the embodiment. Expressions for mutual inductance and electrodynamic forces with parallel displacement of mating turns and disk coils are considered. Simplified expressions for the derivative of the inductance coefficients in the coordinate characterizing the parallel displacement of the loops are obtained. By using the obtained expressions, the effect of parallel displacement of the loops on the electrodynamic interaction forces can be evaluated. The obtained expressions are verified by numerically comparing them with the exact solution. On this basis, the maximum level of convergence of the results has been determined.

Impedance modeling of accelerator beams with discontinuous charge density using scattered-field physics-informed neural networks

A physics-informed neural network method for solving electrodynamic interaction problems including a relativistic beam of charged particles in particle accelerators has been recently proposed. However, the method still has a limitation on modeling accelerator beams with discontinuous charge density. To remove this limitation, the scattered field formulation is introduced into this method. This approach allows us to model the field of discontinuous beam charge density such as point and ring charges. Its numerical error is shown to be smaller than that of the boundary element method. The presented approach is applied to three different vacuum chambers.

Corrections to Hawking radiation from asteroid mass primordial black holes: Formalism of dissipative interactions in quantum electrodynamics

Primordial black holes (PBHs) within the mass range $10^{17} - 10^{22}$ g are a favorable candidate for describing the all of the dark matter content. Towards the lower end of this mass range, the Hawking temperature, $T_{\rm H}$, of these PBHs is $T_{\rm H} \gtrsim 100$ keV, allowing for the creation of electron -- positron pairs; thus making their Hawking radiation a useful constraint for most current and future MeV surveys. This motivates the need for realistic and rigorous accounts of the distribution and dynamics of emitted particles from Hawking radiation in order to properly model detected signals from high energy observations. This is the first in a series of papers to account for the $\mathcal{O}(\alpha)$ correction to the Hawking radiation spectrum. We begin by the usual canonical quantization of the photon and spinor (electron/positron) fields on the Schwarzschild geometry. Then we compute the correction to the rate of emission by standard time dependent perturbation theory from the interaction Hamiltonian. We conclude with the analytic expression for the dissipative correction, i.e. corrections due to the creation and annihilation of electron/positrons in the plasma.

Tunable optical multistability and absorption in a hybrid optomechanical system assisted by an auxiliary cavity and quantum dot molecules

Coherent and tunable light-matter interaction in cavity quantum electrodynamics (C-QED) has attracted much attention for its fundamental importance and applications in emerging areas of quantum technologies. In this work, we propose a hybrid C-QED system comprising embedded quantum dot molecules (QDMs) in a primary photonic crystal (PhC) optomechanical cavity, which is further coupled to an auxiliary PhC cavity via a single-mode waveguide. We investigate the effect of the QDMs, mechanical oscillator, and the feedback from the auxiliary cavity on the multistability response shown by the mean intracavity photons in the primary optomechanical cavity. Tuning the various system parameters can control optical multistability. We further study the absorption spectra showing distinct characteristics of negative absorption (transparency dip), which strongly depend on mechanical resonator frequency. Thus, the proposed model is valuable for practically realizing efficient all-optical switching devices at low power and in various other quantum sensing devices.

Determination of Electrodynamic Forces between Coaxial Coil Turns with Current of Various Configuration

Determination of electrodynamic forces, as may be required for various practical purposes, is based on known calculation recommendations for mutual inductance coefficients, including the calculation methods with special functions, like complete elliptic integrals of the 1st and the 2nd kind, as well as spherical Legendre functions of the 2nd kind with half-integer index [1–5]. Some examples of practical tasks requiring these calculations are the assessments of mutual inductances in non-contact chargers, as well as the assessments of electrodynamic interactions in the windings of transformers, inductors, various solenoid-based loading devices, electric drives, etc. These applications are discussed in numerous publications and guides, e.g. [6–9].

An introduction to the electrodynamic interaction between Jupiter and the Galilean satellites

Dentre os planetas do Sistema Solar, Júpiter se destaca por seu tamanho, quantidade de satélites naturais, intenso campo magnético e colossal magnetosfera, atraindo por isso a atenção da humanidade desde a Antiguidade. Com a descoberta de emissões de rádio oriundas de Júpiter e do controle parcial dessas emissões por parte de satélites Jovianos, um novo cenário atraiu atenção ao planeta: a interação eletrodinâmica entre o campo magnético de Júpiter e os satélites Io, Europa, Ganimedes e Calisto, que propicia esse controle. Aqui, apresentamos brevemente o planeta Júpiter e sua magnetosfera, o que se sabe sobre a interação Júpiter-satélites, e algumas características dos satélites Galileanos.

A regional classification of time spectral amplitudes in total electron content: Southeastern United States during solar cycle 24

To investigate the meso-scale structure (100 s of km) of the ionosphere at mid-latitudes, the spectral properties in calculated total electron content (TEC) at a cluster of GPS receivers in and around Florida are analyzed. The ionosphere does not respond exactly the same to periodic solar driving at different locations around the planet, due to the complex electrodynamic interactions of the coupled magnetosphere-ionosphere system. Therefore, at each GPS receiver in the cluster we compare spatio-temporal variations of the spectral amplitudes for diurnal, solar rotation, and seasonal oscillations. The amplitudes for these dominant oscillations are organized with respect to magnetic latitude of the receiver. A low-latitude and high-latitude station are also included to put the mid-latitude ionospheric response into a global context. The amplitudes of diurnal, seasonal, and solar rotation signals are well ordered by magnetic latitude, superposed with meso-scale deviations between stations separated by ∼100s of km. The results suggest that spatio-temporal variations of spectral amplitudes in the mid-latitude ionosphere are not dominated by a single process. This conclusion is based on our finding that at high latitude, the shape of the diurnal signal varies significantly less with solar activity compared to low- and mid-latitudes, and additionally, that the ratio of annual to semi-annual amplitudes fluctuates around 1 with time and from station-to-station only at mid-latitudes.

Search for Jovian decametric emission induced by Europa on the extensive Nançay Decameter Array catalog

Context. The electrodynamic interaction between the Galilean satellites and the Jovian magnetosphere generates Alfvén wings that connect the satellites to the polar atmosphere of Jupiter and induce auroral radiation through the cyclotron-maser instability. The satellite control of the Jovian decametric emission is widely known and has been studied since the 1960s, being first discovered with regard to Io and, more recently, Ganymede. The partial control of these emission by Europa and Callisto, however, has not yet been confirmed, however, hints of this control have already been found. Aims. The goal of this work is to search for evidence of control of the Jovian decametric emission by the satellite Europa. Methods. For this purpose, we analyzed the extensive digital catalog of Jovian decametric emission detected by the Nançay Decameter Array from 1990 to 2020. We analyzed distributions of the occurrence probability of the emission not induced by Io nor by Ganymede as a function of Europa phase and of the Array’s longitude with regard to the Jovian central meridian of longitude. Results. As a result, we selected 267 possible Europa-induced emission, from which 186 are from source A (Eu-A), 56 are from source C (Eu-C), and 25 are from source D (Eu-D). The general maximum frequency and duration of these emission are presented and compared to those of the other emission in the catalog and their average power is estimated as a function of the average power of the Io-induced emission. Conclusions. We conclude that Europa, just as in the case of Io and Ganymede, induces a portion of the Jovian decametric emission.

COVID-19's impacts on the scope, effectiveness, and interaction characteristics of online learning: A social network analysis.

The COVID-19 outbreak brought online learning to the forefront of education. Scholars have conducted many studies on online learning during the pandemic, but only a few have performed quantitative comparative analyses of students’ online learning behavior before and after the outbreak. We collected review data from China’s massive open online course platform called icourse.163 and performed social network analysis on 15 courses to explore courses’ interaction characteristics before, during, and after the COVID-19 pan-demic. Specifically, we focused on the following aspects: (1) variations in the scale of online learning amid COVID-19; (2a) the characteristics of online learning interaction during the pandemic; (2b) the characteristics of online learning interaction after the pandemic; and (3) differences in the interaction characteristics of social science courses and natural science courses. Results revealed that only a small number of courses witnessed an uptick in online interaction, suggesting that the pandemic’s role in promoting the scale of courses was not significant. During the pandemic, online learning interaction became more frequent among course network members whose interaction scale increased. After the pandemic, although the scale of interaction declined, online learning interaction became more effective. The scale and level of interaction in Electrodynamics (a natural science course) and Economics (a social science course) both rose during the pan-demic. However, long after the pandemic, the Economics course sustained online interaction whereas interaction in the Electrodynamics course steadily declined. This discrepancy could be due to the unique characteristics of natural science courses and social science courses.