The characterization of few-body interactions is fundamental for understanding the properties and collisional stability of ultracold quantum gases in reduced dimensions. In this work, we theoretically investigate the atom-dimer scattering and three-body recombination processes in a two-dimensional quantum gas. By generalizing the Skorniakov–Ter-Martirosian equations to two dimensions, we obtain the exact atom-dimer scattering amplitude and systematically evaluate the validity of common theoretical approximations, revealing a distinct feature of two-dimensional (2D) collisions: while mean-field theory fails rapidly with increasing interaction strength, the single-pole approximation remains remarkably accurate across a broad interaction regime. Furthermore, we extend our exact framework to non-zero incident momenta to calculate the three-body recombination rate. Our results demonstrate that the lifetime of the 2D quantum gas exhibits a power-law dependence on the 2D gas parameter $na_\textrm{2D}^2$ with an exponent of approximately $-2.45$, showing a significant reduction in stability as interactions are enhanced. This study bridges the gap between exact few-body theory and practical many-body approximations, offering a robust benchmark for predicting the stability of cold atomic mixtures and guiding future experimental explorations of universal few-body physics in highly controllable 2D environments.

The Gaussian-state theory (GST) for bosons provides a self-consistent description for the Bose-Einstein condensates with quantum fluctuations. However, the corresponding numerical calculation of the ground-state wave function requires substantial computational resources. Noting that the Gaussian-state wave function can be factorized into a multimode coherent-squeezed state, we develop an effective theory for GST by analytically deriving the imaginary-time evolution equations for the mode functions and occupation numbers. Since, in typical situations, only a limited number of squeezed modes are occupied, the effective theory can significantly reduce the required computational resources in numerical computations. Finally, we validate the effective theory using self-bound dipolar droplets.

We investigate the effective interaction and synthetic mutual gauge field between two polar molecules subject to a combination of a static electric field (E-field) and a blue-detuned circularly polarized microwave. We consider all rotational states strongly coupled by the static E-field (up to J = 9) and demonstrate that the effective inter-molecular potential exhibits three distinct behaviors as the E-field strength increases. Specifically, two critical field strengths, denoted as ${E}_{c}^{(1)}$ and ${E}_{c}^{(2)}$ (${E}_{c}^{(1)}\lt {E}_{c}^{(2)}$), mark the transitions. When the static E-field strength E_z is below ${E}_{c}^{(1)}$, the effective interaction is characterized by an anti-dipolar potential with a short-range repulsive barrier. For ${E}_{c}^{(1)}\lt {E}_{z}\lt {E}_{c}^{(2)}$, the long-range potential becomes dipolar, but it still features a short-range repulsive barrier. However, when E_z exceeds ${E}_{c}^{(2)}$, the effective potential becomes attractive along the field axis, signaling the breakdown of three-dimensional shielding. Additionally, the synthetic magnetic flux outside the shielding core is widely tunable, ranging from nearly zero to values approaching 2$\pi$, offering a mechanism for engineering the adiabatic gauge effects arising from microwave shielding.

We consider the ground state properties of SU(3) spin-orbit-coupled (SOC) Bose-Einstein condensates (BECs) with soft-core interaction trapped in radially periodic potential. By minimizing the energy of the condensate, the effects of spin-orbit coupling and soft-core long-range interaction on the ground-state structure of such a system have been investigated for ferromagnetic and antiferromagnetic spin interaction cases. In the absence of soft-core interaction, our results show that the system has a rich variety of ground state phases, such as typical vortices, antivortices, domain wall and hexagonal vortex lattice. It is found that the spontaneous symmetry breaking and isolated density peaks appear in the system with the addition of soft-core interaction. We illustrate the physical mechanisms of different interactions in SU(3) SOC BECs.

Molecular optomechanical cavities have recently emerged as a promising platform for frequency upconversion, enabling the quantum coherent conversion of infrared (IR) signal into the visible range. In a recent work (Zou et al 2024 Phys. Rev. Lett. 132 153602), we proposed an amplification mechanism that can enhance the intensity of the upconverted IR signals by a factor of 1000 or more within such a cavity under the ideal case without any noise. In this work, we employ the power spectrum method to investigate the noise added to the upconverted signal in a molecular optomechanical cavity along with the conversion efficiency from IR signal into visible range. In the red-detuned regime, the anti-Stokes sideband achieves superior conversion efficiency relative to the Stokes sideband. Conversely, the Stokes sideband dominates under the blue-detuned condition, which amplifies the IR signal. We further demonstrate the dependence of the added noise on the coupling strength and decay rates of the system. In particular, we find that when the IR signal is amplified, the added noise approaches the quantum limit of one quantum.

We investigate quantum phase transitions of anisotropic dipolar bosons with three-body interactions (TBIs) in a square lattice, focusing on the emergence and thermal stability of various supersolid phases. By using an inhomogeneous Gutzwiller mean-field approach and the Landau theory of phase transition, we obtain the zero- and finite-temperature phase diagrams, and derive the analytical phase boundary between incompressible and compressible phases. Interestingly, repulsive TBIs suppress the supersolid phases, and in contrast, weakly attractive TBIs enhance the parameter region of the supersolid phases. We further examine the finite-temperature melting of supersolid phases into normal fluid phases, revealing that supersolid states remain thermally stable at low temperatures and checkerboard supersolid phases exhibit greater thermal stability compared to stripe supersolid phases. Our results provide an alternative avenue for searching supersolid phases in ultracold atoms by manipulating dipolar interactions and TBIs.

Elliptically polarized high-order harmonics have attracted considerable attention due to their important applications in probing matter chirality and magnetic circular dichroism. Here, we propose a scheme for generating elliptically polarized high-order harmonics from CO₂ molecules driven by a two-dimensional asymmetric laser field. Owing to the intrinsic asymmetry of the driving field, the harmonics emitted at each molecular alignment angle exhibit nonzero ellipticity and share the same helicity, enabling the generation of elliptically polarized harmonics from unaligned molecules. Moreover, harmonics with relatively large ellipticity can be obtained by tuning the ellipticity of the fundamental field, while the harmonic ellipticity can be further manipulated by adjusting the relative phase of the two-color fields. This scheme provides a simple and robust approach for generating elliptically polarized high-order harmonics with tunable polarization properties.

This study examines the structural and dynamic properties of flattened tail current sheets during intervals of weak substorm activity, based on observations from the magnetospheric multiscale mission. Using the nonlinear magnetic field gradient algorithm and geometrical invariant techniques, the analysis focuses on two distinct events characterized by opposite signs of the B_y component. In both cases, a prominent B_y is observed at the neutral current sheet's center. Fast magnetic reconnection near the neutral sheet generates intense electron jets, with electron velocities significantly exceeding ion velocities, confirming electrons as the principal charge carriers. Magnetic field lines within the neutral sheet display clockwise rotation around the northward normal, forming left-handed spiral configurations. The curvature and torsion of these field lines differ notably between events: the first event (B_y > 0) shows maximum curvature and zero torsion at the sheet's center, while the second event (B_y < 0) exhibits minimal curvature and elevated torsion. The helix angle averages approximately 45° in the first event and shifts toward 90° in the second. Geometrical invariants reveal varying magnetic topologies, with flux tube-like structures dominating the first event and a combination of flux tubes and flux ropes emerging in the second. The prevalence of flux tubes in the first event suggests a weaker magnetic field transition, as flux ropes are more effective in transporting magnetic flux. These findings highlight the significance of current sheet geometry in governing reconnection dynamics.

This paper investigates the nonlinear modulation and stability of weakly two-dimensional wave packets in dusty plasmas, aiming to clarify the influence of multidimensional effects on wave evolution and frequency modulation. Employing the Davey–Stewartson (DS) equation for dust acoustic wave (DAW) dynamics, we analytically derived the dispersion relation and modulational instability conditions. Furthermore, the dependence of growth rate and modulation frequency on the wave number, density ratio, and temperature ratio is quantified. It is found that shorter waves boost frequency and instability (moderate k max). Higher electron-dust density raises frequency but suppresses instability; higher ion temperature weakens instability but lifts the high-k frequency. These findings enrich the theoretical framework for nonlinear wave modulation in dusty plasmas and guide plasma experimental diagnostics and stability control.

We provide a theoretical proposal to achieve nonreciprocal optical routers based on a spinning microcavity exciton polariton system coupled to a tapered fiber. The mechanism for routers is revealed by nonreciprocal optomechanically induced transparency, which is obtained by transmission spectra and nonreciprocal isolate rates. Due to Sagnac effects, the transmission of photon signals along clockwise and counterclockwise directions exhibits distinct characteristics at a special frequency, resulting in clockwise or counterclockwise unidirectional transmission. Therefore, in such nonreciprocal routers, the transmission direction, output frequency, and output intensity for photon signals can be precisely controlled by adjusting Sagnac effects, pump fields, and the coupling of photon, phonon, and exciton modes. Moreover, the vacuum and thermal noise of the system cannot deteriorate the router performance. Our results open new pathways for constructing nonreciprocal optical routers, which may be useful for developing quantum networks and integrated photonic circuits.

We consider quantum droplets in Bose–Einstein condensates with three-body recombination and external feeding in a spherically symmetric harmonic trap. A quantum droplet is a self-bound state which arises due to the delicate balance between the mean-field effect and quantum fluctuation. We find effective potentials for flat- and sharp-top droplets and show that the potentials in both cases are minimized for certain values of the width. The width of a droplet oscillates periodically with time and the oscillation amplitude depends sensitively on the initial width of a droplet around the minimum of the effective potential. The maximum width of a droplet decreases gradually with time due to the loss of atoms arising from the three-body recombination. It shows that this loss of atoms can be managed by appropriately feeding the condensate from an external source to generate stable droplets. We examine the stability of a droplet by fixed point analysis and find that the region of stability is affected with the change of external feeding and three-body loss.

We discover three novel classes of pulse-trains in an optical Kerr nonlinear medium possessing all orders of dispersion up to the fourth order. We show that both single- and double-humped pulse-trains can be formed in the nonlinear medium. A distinguishing property is that these structures have different amplitudes, widths and wave numbers but equal velocity which depends on the three dispersion parameters. More importantly, we find that the relation between the amplitude and duration of all the newly obtained pulse-trains is determined by the sign of a joint parameter solely. The results show that those optical waves are general, in the sense that no specified conditions on the material parameters are taken on. Considering the long-wave limit, the derived pulse-trains degenerate to soliton pulses of the quartic and dipole kinds. Results in this study may be useful for experimental realization of pulse-trains in highly dispersive optical fibers and further understanding of their optical transmission properties.

A theoretical investigation is presented on the generation of terahertz (THz) radiation through the nonlinear interaction of a cubic frequency chirped Hermite–Cosh–Gaussian (HChG) laser beam with an underdense plasma. The structured intensity profile of the HChG beam, characterized by its mode index, beam width parameter, decentered parameter, and Cosh envelope, enables enhanced spatial confinement and field gradients, which are very significant for efficient THz generation. The incorporation of a cubic frequency chirp modulates the temporal phase of the laser pulse, thereby increasing the interaction duration between the laser and plasma electrons. This leads to a stronger ponderomotive force, which drives a transient nonlinear current density at the beat frequency, resulting in the emission of THz radiation. Analytical expressions for the nonlinear current and THz field amplitude are derived, and parametric analysis reveals that the THz output is highly sensitive to the chirp coefficient, laser intensity, mode index, and plasma density profile. We found that higher-order spatial modes and carefully adjusted beam positioning (decentering) further enhance THz output. The best results were achieved at a lower chirp value (b = 0.00099), which outperformed traditional linear and quadratic chirping. This study demonstrates that cubic chirping significantly enhances the THz conversion efficiency compared to linear and quadratic chirps, offering a tunable and high-intensity THz source for applications in spectroscopy, imaging, wireless communication, ultrafast material characterization, and medical diagnostics.

We analyse the eigenvalues of the Schrödinger equation with the Hellmann potential obtained by means of the generalized parametric Nikiforov–Uvarov (NU) method under the Greene–Aldrich approximation. We show that the NU eigenvalues yield the correct result when the screening parameter δ vanishes but their slope at δ = 0 differs considerably from the exact one. In addition, the NU eigenvalues behave pathologically at large values of the radial quantum number n and it is necessary to restrict its values to $0\leqslant n\lt {n}_{{\rm{\max }}}$.

The classical ensemble model (CEM) was applied to study the double ionization (DI) yield and correlated dynamics of electron pairs during non-sequential double ionization (NSDI) of oxygen molecules exposed to a counter-rotating two-color elliptically polarized (TCEP) laser field. Numerical simulations revealed a gradual reduction in the DI yield with increasing angle between the major axes of the two elliptically polarized laser components. This angular dependence arises from asymmetric suppression effects that the laser field exerts on the potential barrier of the diatomic molecule, with larger angles decreasing the efficiency of the barrier suppression. Concurrently, as molecular orientation angles increase, the increased travel time of the rescattering electron enhances recollision energies, thereby shifting the joint temporal distribution of ionization and recollision events toward diagonal alignment and altering the dominant NSDI pathways in oxygen molecules.

We propose to trap circular Rydberg atoms (CRAs) via a ponderomotive potential well formed by a superimposed vortex light beam. We analytically calculate the ponderomotive potential energy for a Bessel vortex light beam. We work out a corrected version of the classical circular orbit approximation for a CRA which fits the exact result much better than the usual approximation. We reveal the three-dimensional characteristics of the potential well for some benchmark values of the CRA principal quantum number and beam parameters such as the frequency, the opening angle and topological charge of the vortex. We investigate how we can achieve similar trapping effects for different principal quantum numbers by varying beam parameters. The potential provides a lattice structure along the beam axis where one CRA could be trapped at each lattice site.

Spin-density (charge) separation, marked by distinct propagation velocities of spin and density excitations, epitomizes strong correlations, historically confined to one-dimensional (1D) systems. The recent experimental work of Dhar et al (2025 Nature 642 53), using a weakly interacting 3D Bose–Einstein condensate of ¹³³Cs atoms confined in a 2D optical lattice to realize spin-density separation and demonstrate boson anyonization, motivates a deeper exploration into how dimensionality and interactions govern quantum correlations. In this work, we investigate this in two-component bosonic mixtures with finite-range interactions, probing 1D and 3D dynamics. Using path integral effective field theory within the one-loop approximation, we derive analytical expressions for zero-temperature ground-state energy and quantum depletion, seamlessly recovering contact interaction results in the contact limit. By crafting an effective action for decoupled density and spin modes, we compute dynamic structure factors (DSFs), revealing how finite-range interactions sculpt spin-density separation. A pivotal finding is the dimensionality-driven divergence in DSF peak dynamics: in 1D, peaks ascend to higher frequencies with increasing interaction strength, yielding sharp responses; in 3D, peaks descend to lower frequencies, with broader density wave profiles. These insights highlight dimensionality’s critical role in collective excitations and provide a robust theoretical blueprint for probing interaction-driven quantum phenomena via Bragg spectroscopy, paving new pathways for the exploration of dimensionally tuned quantum correlations in ultracold quantum gases.

Optical nonreciprocal transmission with unidirectional amplification in a gain-assisted cavity-QED system is investigated. The results demonstrate that unidirectional amplification of this system is induced by the phase difference between the atom–cavity coupling strengths associated with the optical gain and a phase-controlled unidirectional amplifier can be achieved. The optimal parameter conditions for the observation of ideal unidirectional amplification are obtained analytically, and are shown to be dependent on phase, atom–cavity and cavity–cavity coupling strength, and atomic dissipation. In particular, it is found that atomic dissipation is another essential condition for the realization of nonreciprocal amplification other than breaking of the time-reversal symmetry, and our unidirectional amplifier is robust against atom–cavity coupling mismatch. Such unidirectional amplifiers are crucial nonreciprocal devices for controlling photon transmission and may have potential applications in quantum information processing.

We investigate the dynamic behavior of vector soliton train propagating in optical media, modeled by the coherently coupled nonlinear Schrodinger (NLS) equation. It is shown that an increase in phase parameters, induces an increase in intensity of the periodic soliton train, as well as the number of pulses for each transverse electric (TE) and transverse magnetic (TM) mode. From the perturbation approach, when examining the propagation states for the transverse electric and magnetic (TEM) mode, we found a family of three bound-vector soliton states with a different propagation parameter at the first order, representing the three possible distinct vector optical fields reconfiguration of the initial profiles one of which is the ‘replication'. At the second order, we obtain an eigenvalue problem with an optical external field, giving rise to five high intensity periodic vector soliton structures described by elliptic functions. Such vector soliton trains are intended to complement single-pulse solitons for multi-channel communication applications.​​​​

The existence of absolute parametric instability in an inhomogeneous plasma is revisited in a one-dimensional three-wave model. Non-resonant daughter waves are considered to match the conditions of radio-frequency (RF)-plasma interactions in magnetically confined plasma. Our model shows that such absolute instability has an extremely high threshold and cannot be induced for typical RF-plasma interactions, even if the linear growth rate of the instability achieves the level of ion-cyclotron frequency. As a result, we suggest that it is appropriate to neglect absolute instability when non-resonant daughter waves are involved.

The effects of the Rashba spin-orbit interaction and external electric and magnetic fields on the thermodynamic properties of parabolic quantum dots are investigated. An explicit partition function is derived, and thermodynamic quantities, including specific heat, entropy, and magnetic susceptibility, are analyzed. The behavior of Shannon entropy-related thermodynamic quantities is examined under varying magnetic fields and Hamiltonian parameters through numerical analysis. The results reveal a pronounced Schottky anomaly in the heat capacity at lower temperatures. The susceptibility exhibits a progressive enhancement and transitions to higher values with changes in the quantum dot parameters. In the presence of the Rashba spin-orbit interaction, the specific heat increases with temperature, reaches a peak, and then decreases to zero. Additionally, the susceptibility increases with the β parameter for varying Rashba spin-orbit interaction coefficients, and at a fixed temperature, it further increases with the Rashba coefficient.

In this study, we proposed a bifunctional sensor of high sensitivity and slow light based on monolayer ${{\rm{MoS}}}_{2}/{\rm{TOPAS}}$ structure in the terahertz range. The proposed metamaterial is formed by a structured unit matrix that combines square and cross shapes made of ${{\rm{MoS}}}_{2}$ and ${\rm{TOPAS}}$. The plasmon-induced transparency (PIT) spectra appeared under the excitation of a transverse magnetic (TM)-polarization wave, the proposed PIT effect is originated from the near-field coupling of two bright modes. The Lorentzian mode theory spectrum describes the destructive interference between the two bright modes, and the fitted results are consistent with the Finite-Difference Time-Domain (FDTD) simulation results. Furthermore, the effect of geometrical sizes, like coupling distance, structure size, and intersection angle between square and cross shape on the PIT window is analyzed, along with the effects of carrier concentration in ${{\rm{MoS}}}_{2}$. A figure of merit of $1.10\,{{\rm{RIU}}}^{-1}$ is obtained. The slow light performance of the proposed ${{\rm{MoS}}}_{2}$-based metamaterial is investigated, a maximum time delay of $0.52\,{\rm{ps}}$ is obtained and the delay band width product (DBP) is 0.76. It is more efficient to store and transmit the information over signal channels. Therefore, the proposed ${{\rm{MoS}}}_{2}$-based metamaterial can be used in electromagnetically induced transparency applications, such as sensors, optical memory devices, and flexible terahertz functional devices.

A mid-infrared femtosecond pulse laser with a single cycle and high intensity is an ideal driving light source for generating isolated attosecond pulses. Due to current experimental limitations, it is difficult to directly achieve this type of laser light source in the laboratory. In this paper, we obtain such an ideal light source by adding a Ti sapphire pulse to the combined pulse laser consisting of two mid-infrared pulses. Specifically, by combining the synthesized pulse consisting of 8 fs/1200 nm/1.62 × 10¹⁴ W cm⁻² and 12 fs/1800 nm/2.71 × 10¹⁴ W cm⁻² with an additional 8 fs/800 nm/1.26 × 10¹⁴ W cm⁻² Ti sapphire pulse, the resulting electric field waveform is very close to that of a 1170 nm femtosecond pulse with an intensity of 1.4 × 10¹⁵ W cm⁻², a single-cycle pulse width, and a carrier-envelope phase of 0.25π. Numerical simulations show that both cases produce high-order harmonic emission spectra with broadband supercontinuum spectra, however, the bandwidth of the supercontinuum spectra and the harmonic intensities in the synthesized pulses are significantly better than those in the single 1170 nm pulse. After inverse Fourier transform, we obtain 66 as a high-intensity isolated attosecond pulse, whose intensity is five orders of magnitude higher than that of a monochromatic field. Here, the phase differences between three combined pulse lasers have little effect on the numerical simulation results when they vary in the range of 0.3π.

The noise feature of a single-mode class-A laser amplifier is investigated by solving the Maxwell–Bloch equations of motion in the presence of the fluctuation force of cavity Langevin. The aim is to calculate the simultaneous fluctuations that are superimposed on the amplitude and phase of the cavity electric field, as well as the atomic population inversion. The correlation function of these fluctuations yields the amplitude, phase, and spontaneous emission noise fluxes, respectively. The amplitude and spontaneous emission noise fluxes exhibit the Lorentzian profiles in both the below-threshold state and the injection-locking region of the above-threshold state. While noise is typically viewed negatively in science and engineering, this research highlights its positive role as a valuable tool for measuring the optical properties of a laser amplifier. For instance, the degree of first-order temporal coherence (DFOTC) is derived by taking the Fourier transform of the amplitude noise flux. The damping rate of DFOTC is associated with the coherence time of the light emitted by the laser amplifier. Furthermore, the uncertainty relation between noise bandwidth and coherence time is confirmed. Finally, it is demonstrated that the input pumping noise flux, together with the output amplitude and spontaneous emission noise fluxes, satisfy the principle of flux conservation.

The properties of the non-trivial quantum state in an all-optical environment come mainly from the higher-order quantum electrodynamics effect, which remains one of the few unverified predictions of this theory due to its weak signal. Here, we propose a scheme specifically designed to detect this quantum vacuum, where a tightly focused pump laser interacts with an optical frequency comb (OFC) in its resonant cavity. When the OFC pulse passes through the vacuum polarized by the high-intensity pump laser, its carrier frequency and envelope change. This can be intuitively understood as the asymmetric photon acceleration induced by the ponderomotive force of the pump laser. By leveraging the exceptional ultrahigh frequency and temporal resolution of the OFC, this scheme holds the potential to improve the accuracy of quantum vacuum signal. Combining theoretical and simulation results, we discuss possible experimental conditions, and the detectable OFC signal is shown to be orders of magnitude better than the instrumental detection threshold. This shows our scheme can be verified on the forthcoming laser systems.

This research examines the dynamics of a cosh-Gaussian laser pulse travelling through a vacuum and its impact on electron acceleration. We examine the impact of several critical factors, such as laser electric field amplitude, decentered parameter, beam waist, and laser chirp parameter, on the energy gain of electrons using coupled momentum equations. Our results indicate that the energy acquisition of electrons escalates with the amplitude of the laser electric field, decentered parameter, and chirp parameter. An appropriate beam waist is essential for attaining energy-efficient electron acceleration in a vacuum. Through the optimization of these parameters, we get a maximum electron energy gain of 2.80 GeV. This study highlights the significance of customized laser pulse attributes in improving electron acceleration and aids in the progression of high-energy particle physics.

This article primarily establishes a two-soliton system and employs the Lewis–Riesenfeld invariant inverse control method to achieve shortcuts to adiabaticity (STA) technology. We study an atomic soliton Josephson junctions (SJJs) device and subsequently compare and analyze it with atomic bosonic Josephson junctions. Moreover, we use higher-order expressions of the auxiliary equations to optimize the results and weaken the detrimental effect of the sloshing amplitude. We find that in the adiabatic shortcut evolution of two systems with time-containing tunnelling rates, the SJJs system is more robust over a rather short time evolution. In comparison with linear ramping, the STA technique is easier to achieve with the precise modulation of the quantum state in the SJJs system.

A way to enhance the growth of stimulated Raman instability in laser-plasma interactions was investigated. This relies on the application of density modulation of a co-propagating electron beam in plasmas. In the stimulated Raman scattering process, an electromagnetic pump wave decays into a low-frequency wave and a scattered electromagnetic sideband wave. In this process, the pump wave produces an oscillatory velocity associated with the plasma electrons and the beam electrons. These oscillatory velocities combine with the existing low-frequency mode, producing ponderomotive force that drives high-frequency sideband waves. The sidebands couple to the pump wave, driving the beam-mode. A modulation of the electron beam density enhances the growth rate of the instability. The theoretical calculations show about 40% enhancements in growth of Raman instability at resonance (where the electron beam density modulation parameter approaches to unity) for the plasma density of the order of 10¹⁸ cm⁻³.

Gas targets have been used to measure the scattering length in neutron–proton (n–p) scattering experiments. Changes in electron dynamics within the gas target have a negligible effect on the dynamics of nucleons. However, electron dynamics are sensitively related to the specific form of the n–p interaction during the scattering process. We propose a theoretical approach to explore electron dynamics and determine the parameters of the n–p interaction. This approach is based on a three-body scattering process involving a neutron, a proton and an electron. Numerical results indicate significant differences in electron dynamics with varying values of n–p interaction parameters, providing additional information beyond scattering cross-sections to accurately determine these parameters.

We investigate spatiotemporal periodic patterns in harmonically trapped Bose–Einstein condensates (BECs) driven by a periodic modulation of the interaction. Resonant with the breathing mode, we show the emergence of a square lattice pattern containing two orthonormal stripes. We study the time evolutions of the lattice patterns for different driving strengths and dissipations. We find that its spatial periodicity and temporal oscillating frequency match the Bogoliubov dispersion, which is the intrinsic property of the system and relevant to the parametric amplification of elementary excitations. In the circumstances of strong driving strength and low dissipation, we further observe the triad interaction and the resulting superlattice state, which are well explained by the nonlinear amplitude equation for superimposed stripes. These results shed light on unexplored nonlinear spatiotemporal dynamics of two-dimensional patterns in harmonically trapped BECs that can pave the way for engineering exotic patterns by state-of-the-art experiments.

The characteristics of nonlinear and supernonlinear Alfvén waves propagating in a multicomponent plasma composed of a double spectral electron distribution and positive and negative ions were investigated. The Sagdeev technique was employed, and an energy equation was derived. Our findings show that the proposed system reveals the existence of a double-layer solution, periodic, supersoliton, and superperiodic waves. The phase portrait and potential analysis related to these waves were investigated to study the main features of existing waves. It was also found that decreasing the electron temperature helps the superperiodic structure to be excited in our plasma model. Our results help interpret the nonlinear and supernonlinear features of the recorded Alfvén waves propagating in the ionosphere D-region.