PT-symmetric systems can be used as ultrasensitive sensors by exploiting the non-Hermitian degeneracy at the exceptional point. However, operating and controlling these systems at the exceptional point are usually difficult. Here, we study the effect of rotation on threshold gain of circular Bragg lasers with radial PT symmetry. We have found that, even deviating away from the exceptional point, these

In this work, we theoretically propose and experimentally demonstrate a kind of non-reflecting acoustic metamaterial fence that is perfectly impedance matched to air in a wide range of incident angles and a broad frequency band. The metamaterial fence is composed of an array of rigid cylinders with alternating layers of different cylinder diameters. It is designed by a spatially dispersive effective

Ultraviolet luminescence holds potential for diverse applications. Further development of the ultraviolet luminescence technology, however, is hindered by the common but very inconvenient photoluminescence form. Here we create a new form of ultraviolet emission persistent luminescence in the narrowband ultraviolet-B (NB-UVB, 309$-$313~nm) upon illumination by a blue light-emitting diode. On this basis

Magnetic tunnel junctions are nanoscale spintronic devices with microwave generation and detection capabilities. Here we use the rectification effect called “spin-diode” in a magnetic tunnel junction to wirelessly detect the microwave emission of another junction in the auto-oscillatory regime. We show that the rectified spin-diode voltage measured at the receiving junction end can be reconstructed

We study the consequences of drying on the internal structure of compressible materials containing pores of different sizes, which may be seen as model systems of sponges or wood. With the help of original techniques, we devised bi-porous media with different relative amounts of small and large pores, and follow the evolution of the liquid fraction simultaneously in each pore type. We show that in

The nitrogen-vacancy center in diamond has been explored extensively as a light-matter interface for quantum information applications, however it is limited by low coherent photon emission and spectral instability. Here, we present a promising interface based on an alternate defect with superior optical properties (the germanium-vacancy) coupled to a finesse 11,000 fiber cavity, resulting in a 31−15+12

We experimentally, numerically, and analytically investigate transition waves in a mechanical metamaterial comprising a chain of tristable elements. Transition waves can be initiated from different stable phases within the highly-tunable tristable energy landscape. These waves propagate via coupled translational and rotational motion that leads to formation of stationary domain walls if transition

We demonstrate that magnetic skyrmions with a mean diameter around 60~nm can be stabilized at room temperature and zero external magnetic field in an exchange-biased Pt/Co/NiFe/IrMn multilayer stack. This is achieved through an advanced optimization of the multilayer stack composition in order to balance the different magnetic energies controlling the skyrmion size and stability. Magnetic imaging is

Teleportation is a fundamental concept of quantum mechanics with an important application in extending the range of quantum communication channels via quantum relay nodes. To be compatible with real-world technology such as secure quantum key distribution over fibre networks, such a relay node should ideally operate at GHz clock rates and accept time-bin encoded qubits in the low-loss telecom band

Slow extraction of beam from synchrotrons or storage rings as required by many fixed target experiments is performed by controlled excitation and feeding of a structural lattice resonance. Due to the sensitive nature of this resonant extraction process, temporal structure of the extracted beam is modulated by the minuscule current fluctuations present on the quadrupole magnet power supplies. Such a

It is shown theoretically that in a layered heterostructure comprising piezoelectric, dielectric antiferromagnetic crystal and heavy metal (PZ/AFM/HM) it is possible to control the anisotropy of the AFM layer by applying a DC voltage across the PZ layer. In particular, we show, that by varying the DC voltage across the heterostructure and/or the DC current in the HM it is possible to vary the frequency

We propose a new filter method to generate electron beams of high polarization from bubble and blow-out wakefield accelerators. The mechanism is based on the idea to identify all electron-beam subsets with low-polarization and to filter them out by an X-shaped slit placed right behind the plasma accelerator. To find these subsets we investigate the dependence between the initial azimuthal angle and

In this manuscript, we develop a generalized theory for the scattering process produced by interface roughness on charge carriers and which is suitable for any semiconductor heterostructure. By exploiting our experimental insights into the three-dimensional atomic landscape of Ge/GeSi heterointerfaces obtained by atom probe tomography, we have been able to define the full set of interface parameters

By identifying the similarities between the coupled-wave equations and the parametrically driven nonlinear Schrdinger equation, we for the first time unveil the existence condition of quadratic solitons in continuous-wave pumped singly resonant degenerate optical parametric oscillators (SR-DOPOs). Compared to the previously explored doubly resonant DOPOs, quadratic solitons in SR-DOPOs are advantageous

We show that N-polar GaN/AlGaN/GaN heterostructures exhibit significant N deficiency at the bottom AlGaN/GaN interface, and that these N vacancies are responsible for the trapping of holes observed in unoptimized N-polar GaN/AlGaN/GaN high electron mobility transistors. We arrive at this conclusion by performing positron annihilation experiments on GaN/AlGaN/GaN heterostructures of both N and Ga polarity

Optical resonant cavities play an important role in electromagnetic wave control; they can confine electromagnetic waves and improve the interaction between light and matter. However, because of the limitations of the standing wave formation conditions for Fabry-Perot-type resonance, the miniaturization of optical resonant cavities formed using traditional materials is difficult. Recently, the miniaturization

As the semiconductor industry turns to alternate conductors to replace Cu for future interconnect nodes, much attention has been focused on evaluating the electrical performance of Ru. The typical hexagonal close-packed (hcp) phase has been extensively studied, but relatively little attention has been paid to the face-centered cubic (fcc) phase, which has been shown to nucleate in confined structures

We investigate a solid-state, reversible, alkali-ion battery (AIB) capable of regulating the density of alkali atoms in a vacuum system used for the production of laser-cooled atoms. The cold-atom sample can be used with in-vacuum chronoamperometry as a diagnostic for the voltage-controlled electrochemical reaction that sources or sinks alkali atoms into the vapor. In a combined reaction-diffusion-limited

Electronic cooling in hybrid normal metal-insulator-superconductor junctions is a promising technology for the manipulation of thermal loads in solid state nanosystems. One of the main bottlenecks for efficient electronic cooling is the electron-phonon coupling, as it represents a thermal leakage channel to the phonon bath. Graphene is a two-dimensional material that exhibits a weaker electron-phonon

In the Post-Moore era, improving energy efficiency is an urgent requirement for micro-electronics towards the Internet of Things, Artificial Intelligence, 5th-Generation. Especially, 2D materials with natural passivation, gate electrostatics, and high mobility have attracted significant attention in integrated circuits in the race towards next-generation field-effect transistors (FETs). Here, coupling

Rare-earth doped crystals have numerous applications ranging from frequency metrology to quantum information processing. To fully benefit from their exceptional coherence properties, the effect of mechanical strain on the energy levels of the dopants - whether it is a resource or perturbation - needs to be considered. We demonstrate that by applying uniaxial stress to a rare-earth doped crystal containing

We present a compact, two-stage atomic beam source that produces a continuous, narrow, collimated and high-flux beam of rubidium atoms with sub-Doppler temperatures in three dimensions, which features very low emission of near-resonance fluorescence along the atomic trajectory. The atom beam source originates in a pushed two-dimensional magneto-optical trap (2D+ MOT) feeding a slightly off-axis three-dimensional

The construction of photon-photon quantum phase gate based on photonic nonlinearity has long been a fundamental issue, which is vital for deterministic and scalable photonic quantum information processing. It requires not only strong nonlinear interaction at the single-photon level, but also suppressed phase noise and spectral entanglement for high gate fidelity. In this paper, we propose that high-quality

Integrating multiple functionalities into a single metasurface is becoming of great interest for future intelligent communication systems. While such devices have been extensively explored for reciprocal functionalities, in this work, we integrate a wide variety of nonreciprocal applications into a single platform. The proposed structure is based on spatiotemporally modulated impedance sheets supported

Conventional sound barriers impede airflow at the same time. Recent advances in acoustic metasurfaces provide a solution for air-permeable barriers utilizing the Fano-like interference. While the mechanism of Fano-like interference implies that such a realized device serves a narrow working frequency range around every destructive-interference frequency. Considering the fact that noise usually covers

We advance a protocol to measure the complex spatial degree of coherence of a partially coherent light field obeying Gaussian statistics through a generalized Hanbury Brown and Twiss (HBT) experiment. The proposed generalized HBT experiment amounts to combining a partially coherent field with a pair of coherent reference fields and measuring the intensity-intensity cross-correlation of the cumulative

We used scanning tunneling microscopy and spectroscopy (STM/STS) and X-ray photoelectron spectroscopy (XPS) to investigate the effect of nitrogen doping on the surface electronic and chemical structures of cutouts from superconducting Nb radio frequency (SRF) cavities. The goal of this work is to get insights into the fundamental physics and materials mechanisms behind the striking decrease of the

This work tackles the long-standing issue on a quantitative disentanglement of spin orbit torques (SOTs) in platinum/cobalt (Pt/Co) bilayers where both spin Hall effect (SHE) and Rashba-Edelstein effect (REE) are present. The SOTs originated from the SHE in bulk Pt and from the REE at substrate (sub.)/Pt and Pt/Co interfaces are successfully disentangled and quantified utilizing the harmonic Hall measurements

Counterdiabatic driving (CD) offers a fast and robust strategy to manipulate and prepare quantum state in multi-body systems. However, the exact CD term involving the spectral properties of the system becomes difficult to calculate and generally takes a complicated form for higher-dimensional complex systems. Recently, D. Sels { {[Proc. Natl. Acad. Sci. U.S.A. 114, E3909 (2017)]}} proposed a variational

Unidirectional wave propagation can introduce strong direction-dependent energy responses, thus greatly benefiting the construction of switching and logic devices. Such effect has drawn considerable attentions in acoustics,$^{\thinspace }$which however have not been able to practically address the essential issue of insufficient transmission efficiency in forward direction. Here we present a one-way

It has been shown that the spin Hall effect from heavy transition metals can generate sufficient spin-orbit torque and further produce current-induced magnetization switching in the adjacent ferromagnetic layer. However, if the ferromagnetic layer has in-plane magnetic anisotropy, probing such switching phenomenon typically relies on tunneling magnetoresistance measurement of nano-sized magnetic tunnel

So far physics of quantum electronic transport has not tackled the problems raised by quantum dot intermediate-band solar cells. Our study shows that this physics imposes design rules for the inter-subband transition. We developed an analytical model that correctly treats, from a quantum point-of-view, the trade-off between the absorption, the recombination and the electronic transport occurring in

With a microwave-regime cyclic three-state configuration, an enantiomer-selective state transfer~(ESST) is carried out through the two-path interference between a direct one-photon coupling and an effective two-photon coupling. The π-phase difference in the one-photon process between two enantiomers makes the interference constructive for one enantiomer but destructive for the other. Therefore only