Annalen der Physik最新文献

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.

In 1873, German mathematician and theoretical physicist Wilhelm Veltmann (1832–1902), who taught in secondary schools for most of his career, published in Annalen der Physik an article that caught the attention of influential scientists such as Hendrik Antoon Lorentz or Alfred Potier at the École Polytechnique in France. Veltmann was the first to find a theoretical explanation for the impossibility of detecting the Earth's motion in the ether using optical devices involving reflection, refraction, interference, diffraction, etc. We briefly review his contribution, which was instrumental in the birth of “optical relativity” in the 19th century.

We report an experimental study on the high-pressure syntheses and characterizations of the samarium (Sm) hydrides system, for which the theoretical predictions have long struggled to accurately describe the crystal structures and superconducting properties. By laser heating Sm and ammonia borane (BH₃NH₃) compressed in diamond anvil cells (DACs), we successfully synthesized a series of Sm hydrides, including P6₃/mmc SmH₉, Im-3m SmH₆, I4/mmm SmH₄, Pm-3n SmH₃, P6/mmm SmH₂, and Fm-3m SmH_2-x. Electrical transport measurements performed in four independent experimental runs revealed metallic behavior without any signature of superconductivity, while some samples exhibited anomalies suggestive of magnetic or electronic transitions. These findings establish Sm hydrides as a model platform for probing the interplay between strong electronic correlations, magnetism, and superconductivity in high-pressure hydrides, highlighting the complex role of 4f electrons in governing their physical properties.

One of the grand challenges in physics is the exploration of room-temperature superconductivity and the promising candidate is hydrides under high-pressure. In this review, we introduce a custom-designed diamond anvil cell equipped with boron-doped diamond electrodes that enables both the synthesis and in situ evaluation of superconductivity under extreme conditions without complex experimental configurations. The metallic boron-doped diamond epitaxial film is selectively grown on the diamond anvil surface by microwave-assisted plasma chemical vapor deposition, combined with lithographic patterning techniques. We describe the fabrication process of the boron-doped diamond electrodes and demonstrate their application to the synthesis and transport measurements of superconducting hydrides. This approach provides a powerful and reusable platform for exploring new superconductors at ultrahigh pressures.