Annalen der Physik最新文献

Optical excitation and detection of forward volume magnetostatic spin waves by femtosecond laser pulses are challenging as they require a special configuration of an optical scheme to perform both the launching of spin dynamics and its measurement as well. In this paper, we demonstrate excitation and detection of forward spin waves by using the oblique incidence of both pump and probe femtosecond pulses. The excited wave's propagation over 100 microns was demonstrated. Experimental analysis and theoretical calculations of the dispersion, group, and phase velocities verify the forward nature of the excited spin waves. This study opens a pathway for the utilization of forward spin wave configuration in various optomagnonics studies.

A theoretical framework is introduced for deriving expressions for electromagnetic (EM) potentials and fields of single atomic or molecular emitters modeled as oscillating dipoles, which follows a recently developed method to solve inhomogeneous wave equations for time-dependent distributions of charge. This framework is first used to evaluate the physical implications of the simplifying assumptions made in the standard approach to the quantization of EM fields and the impact of such assumptions on the predicted energy and momentum quantization. Then, the exact relationships between the potentials and the oscillating (transition) dipole properties derived under the present framework are used to quantize EM fields radiated by single emitters and to achieve agreement with the classical dipole radiation pattern, while maintaining the quantum mechanical description of electromagnetic radiation in terms of the probability distribution of quantum modes. Contributions of the present analysis to the understanding of photon emission from excited atoms or molecules stimulated by light or vacuum field fluctuations are highlighted, and possible experimental tests and practical applications are proposed.

This research explores the innovative generation of 3D arrays of optical beams and vortices using superposition of several distinct modified zone plate. Initial simulations successfully demonstrated the method's capability to create identical horizontal double spots at various separations, with transverse intensity profiles indicating uniform intensity levels. Subsequent investigations expanded the method's applications, producing diverse geometric configurations including square, diamond, hexagonal, and octagonal arrays. The study further showcased the ability to create complex 3D arrays of petal-shaped optical beams with varying numbers of petals arranged in specific patterns. Moreover, the technique was adapted to generate arrays of optical vortices with different topological charges across multiple focal planes, illustrating significant versatility. Results, highlighted through detailed simulation outcomes and experimental validations, underscore the potential of these 3D optical structures in various fields such as optics, photonics, and advanced imaging systems.

In this study, the dynamics of a quasi 1D Bose–Einstein condensate is investigated with the help of homotopy perturbation and Bernoulli sub-equation function methods, and their effectiveness is compared. The quasi-1D condensate, composed of interacting atoms at low temperatures and low densities, is modeled by the 1D Gross–Pitaevskii equation, which provides highly accurate results under the assumptions of mean-field theory. In this context, the equation is considered both in the absence of a trap potential and in the presence of the Pöschl–Teller trap potential, which holds special significance in quantum mechanics. For the first time, the analysis of the 1D Gross–Pitaevski equation with the Pöschl–Teller trap potential is carried out using the Bernoulli sub-equation function and homotopy perturbation methods.

We demonstrate the generation of high-order, 1D Hermite–Gaussian (HG) laser beams with independently tunable orthogonal directions in an off-axis pumped Nd:YVO₄ solid-state laser. These HG modes are successfully converted to Laguerre–Gaussian (LG) modes using a mode converter. We independently adjusted the pump beam displacement in the horizontal and vertical directions, achieving HG modes up to the 87th order. With an input power of 4 W, the HG₁,₀ mode exhibited an output power of 1.96 W and an optical-to-optical conversion efficiency of 49%, while the HG₈₇,₀ mode delivered an output power of 1.1 W with a corresponding efficiency of 27.6%. Continuous selection of the mode order in a specific dimension was realized by independently controlling the off-axis displacements in two orthogonal directions. Finally, using a cylindrical lens mode converter, we successfully converted the HG modes into LG modes. This laser system can serve as a versatile source for applications including long-range free-space optical communication, optical trapping and manipulation of particles, optical sensing, and laser-driven electron acceleration.

We present a fully digital approach for simulating single-mode squeezed states using an enhanced bosonic encoding strategy on a circuit model, and demonstrate it on a superconducting quantum processor through a cloud platform. By mapping up to $�2^n$ photonic Fock states onto $�n$ qubits, our framework leverages Gray-code-based encodings to reduce gate overhead compared to conventional one-hot or binary mappings. We further optimize resource usage by restricting the simulation to Fock states with even numbers of photons only, effectively doubling the range of photon numbers that can be represented for a given number of qubits. To overcome noise and finite coherence in current hardware, we employ a variational quantum simulation protocol, which adapts shallow, parameterized circuits through iterative optimization. Implemented on the Zuchongzhi-2 superconducting platform, our method demonstrates squeezed-state dynamics via a parameter sweep from vacuum state preparation ($��r�=�0�$) to squeezing levels that extend beyond the conventional truncation bound of encoded Fock space ($��r�>�1.63�$). Results of our demonstration, corroborated by quantum state tomography and Wigner-function analysis, confirm high-fidelity state preparation and demonstrate the potential of Gray-code-inspired techniques for realizing continuous-variable physics on near-term, qubit-based quantum processors.