Annalen der Physik最新文献

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.

This study theoretically investigates the optical absorption spectrum of CdSe/CdS core–shell quantum dots (CSQDs) under the combined influence of quantum confinement, elastic strain, and an on-center donor impurity. Utilizing the effective mass approximation and continuum elasticity theory, we model the system's energy eigenvalues and absorption coefficients. For unstrained CSQDs, our findings demonstrate that quantum confinement strongly dictates the electronic energy levels and absorption peak positions, exhibiting a blueshift with decreasing core radius and a redshift with increasing shell thickness. Crucially, the presence of elastic strain, originating from the lattice mismatch between the core and shell materials, significantly modifies the confinement potential. This strain leads to a progressive delocalization of electron wavefunctions into the shell material, particularly for higher excited states, effectively attenuating the confinement potential. This wavefunction redistribution directly impacts the energy level spacing and causes concomitant redshifts in the absorption spectra with increasing core size. Our results provide fundamental insights into how strain and dimensionality can be precisely engineered to tune the optoelectronic properties of CdSe/CdS nanostructures, offering a pathway for designing advanced optoelectronic devices.

Infrared quantum electrodynamics (IR–QED) acquires a natural geometric interpretation once soft photons are described as adiabatically transported electron–photon clouds. Within this framework, the relevant infrared structure is encoded in a functional Berry phase associated with the space of gauge connections, and the corresponding Berry corrections modify the Rayleigh–Jeans spectrum. The infrared scaling symmetry of the Rayleigh–Jeans law leads to a simple renormalization–group equation whose solution determines the frequency dependence of an effective factor $��F_{\mathrm{eff}}��\left(�\omega �\right)��$ controlling the strength of the electron–photon cloud dressing. As a result, the energy density of the cosmic microwave background (CMB) receives a Berry-induced correction that scales as a power law and produces a frequency-dependent temperature excess in the radio domain. Although the exponent $�\gamma$ governing this scaling behavior is not fixed internally by the present formulation of IR–QED and must instead be determined phenomenologically, the existence and structure of the excess are genuine predictions of the theory. Remarkably, the resulting expression is extremely simple and naturally aligns with the deviations suggested by the ARCADE 2 data. Taken together, these results indicate that Berry phases in IR–QED may lead to observable consequences in the low-frequency tail of the CMB spectrum.

We study the thermodynamics of the recently proposed superconducting Josephson junction diode, in particular its specific heat capacity. Its low temperature behavior is determined by the interplay of two intrinsic energy scales of the microscopic Hamiltonian, associated with the superconducting gap and tunneling amplitude of conventional electrons through the junction. If the latter is large enough to overcome the former, the specific heat decays linearly with temperature, reflecting the presence of a current through the diode. In the opposite case, the specific heat decays exponentially and the diode becomes non-conducting. In the intermediate regime, where both scales are equally large, the specific heat exhibits a non-trivial power-law behavior in terms of the temperature. It is demonstrated, that switching on and off of the device is possible by changing the phase of the superconducting condensate only, which is accessible via an external magnetic field. Having magnetic textures hosting magnetic defects, such as skyrmions, antiskyrmions or domain walls as sources of such magnetic field leaves behind unique defect specific footprints in the specific heat.

We reconsider the quantum energetics and quantum thermodynamics of the charging process of a simple, two-component quantum battery model made up of a charger qubit and a single–cell battery qubit. We allow for the initial quantum state of the charger to lie anywhere on the surface of the Bloch sphere, and find the generalized analytical expressions describing the stored energy, ergotropy, and capacity of the battery, all of which depend upon the initial Bloch sphere polar angle in a manner evocative of the quantum area theorem. The origin of the ergotropy produced, as well as the genesis of the battery capacity, can be readily traced back to the quantum coherences and population inversions generated (and the balance between these two mechanisms is contingent upon the starting Bloch polar angle). Importantly, the ergotropic charging power and its associated optimal charging time display notable deviations from standard results, which disregard thermodynamic considerations. Our theoretical groundwork may be useful for guiding forthcoming experiments in quantum energy science based upon coupled two-level systems.

Spherical Fe/graphene composite microwave-absorbing materials are synthesized with liquid-phase atomization and redox composite ball-milling process. The effects of graphene content on the microstructure, electromagnetic parameters, and wave absorption properties are investigated. Results demonstrate that Fe particles maintain a nearly spherical morphology with an average diameter of approximately 2 µm, while graphene is uniformly dispersed in a sheet-like form. The crystallographic structures of both Fe and graphene are preserved after the composite formation. As the graphene content increases, both the real and imaginary components of the dielectric constant of the composite gradually increase. The dielectric loss mechanisms transitioned from polarization relaxation dominance at low graphene content to conductivity loss dominance at higher concentrations. In terms of magnetic losses, magnetic resonance primarily governs the low-frequency range, while eddy current losses dominate at medium to high frequencies. The sample with 25% graphene content exhibits the strongest electromagnetic wave attenuation capability, while the 10% sample demonstrates optimal impedance matching characteristics. When the graphene content is 15%, and the matching thickness is 1.7 mm, the material achieves a minimum reflection loss of −19.87 dB, with an effective absorption bandwidth of 4.4 GHz at a thickness of 1.2 mm.