Physical Review Letters

We study the influence of electron puddles created by doping of a 2D topological insulator on its helical edge conductance. A single puddle is modeled by a quantum dot tunnel coupled to the helical edge. It may lead to significant inelastic backscattering within the edge because of the long electron...

To describe the microscopic properties of matter, quantum mechanics uses wave functions, whose structure and time dependence is governed by the Schrödinger equation. In atoms the charge distributions described by the wave function are rarely observed. The hydrogen atom is unique, since it only has o...

We obtain an analytical bound on the efficiency of wireless power transfer to a weakly coupled device. The optimal source is solved for a multilayer geometry in terms of a representation based on the field equivalence principle. The theory reveals that optimal power transfer exploits the properties ...

We have observed the Bose-Einstein condensation of an atomic gas in the (quasi)uniform three-dimensional potential of an optical box trap. Condensation is seen in the bimodal momentum distribution and the anisotropic time-of-flight expansion of the condensate. The critical temperature agrees with th...

We demonstrate orbital angular momentum (OAM) transfer by chiral plasmonic nanostructures designed on both sides of a thin suspended metallic membrane. We show how far-field vortex beams with tunable OAM indices can be tailored through nanostructure designs. We reveal the crucial role played by the ...

By applying the optical nanocircuit concepts to metasurfaces, we propose an effective route to locally control light transmission over a deeply subwavelength scale. This concept realizes the optical equivalent of a transmit-array, whose use is demonstrated for light bending and focusing with unprece...

A virial expansion of fluid pressure in powers of the density can be used to calculate a wealth of thermodynamic information, but the Nth virial coefficient, which multiplies the Nth power of the density in the expansion, becomes rapidly more complicated with increasing N. This Letter shows that the...

The energy released in a magnetic material by reversing spins as they relax toward equilibrium can lead to a dynamical instability that ignites self-sustained rapid relaxation along a deflagration front that propagates at a constant subsonic speed. Using a trigger heat pulse and transverse and longi...

Surface plasmons in metal hole arrays have been studied extensively in the context of extraordinary optical transmission, but so far these arrays have not been studied as resonators for surface plasmon lasing at optical frequencies. We experimentally study a metal hole array with a semiconductor (In...

The composite fermion formalism elegantly describes some of the most fascinating behaviors of interacting two-dimensional carriers at low temperatures and in strong perpendicular magnetic fields. In this framework, carriers minimize their energy by attaching two flux quanta and forming new quasipart...

We report anisotropic magnetoresistance in Pt|Y₃Fe₅O₁₂ bilayers. In spite of Y₃Fe₅O₁₂ being a very good electrical insulator, the resistance of the Pt layer reflects its magnetization direction. The effect persists even when a Cu layer is inserted between Pt and Y₃Fe₅O₁₂, excluding the contribution ...

We experimentally and numerically investigate the expansion of initially localized ultracold bosons in homogeneous one- and two-dimensional optical lattices. We find that both dimensionality and interaction strength crucially influence these nonequilibrium dynamics. While the atoms expand ballistica...

The idea of atoms defying ionization in ultrastrong laser fields has fascinated physicists for the last three decades. In contrast to extensive theoretical work on atoms stabilized in strong fields only few experiments limited to intermediate intensities have been performed. In this work we show exc...

We present a one-to-one comparison of polymer segmental fluctuations as measured by small angle neutron scattering in a network under deformation with those obtained by neutron spin echo spectroscopy. This allows an independent proof of the strain dependence of the chain entanglement length. The exp...

It was recently shown theoretically that the time-dependent heat conduction equation is form invariant under curvilinear coordinate transformations. Thus, in analogy to transformation optics, fictitious transformed space can be mapped onto (meta)materials with spatially inhomogeneous and anisotropic...

We introduce a generalization of the conventional renormalization schemes used in dimensional regularization, which illuminates the renormalization scheme and scale ambiguities of perturbative QCD predictions, exposes the general pattern of nonconformal {β_i} terms, and reveals a special degeneracy o...

Micron-sized self-propelled (active) particles can be considered as model systems for characterizing more complex biological organisms like swimming bacteria or motile cells. We produce asymmetric microswimmers by soft lithography and study their circular motion on a substrate and near channel bound...

We demonstrate a link between the growth process, the stoichiometry of LaAlO₃, and the interfacial electrical properties of LaAlO₃/SrTiO₃ heterointerfaces. Varying the relative La:Al cation stoichiometry by a few atomic percent in films grown at 1×10^-3  Torr results in a 2 and 7 order-of-magnitude c...

We propose to use the intrinsic two-level system (TLS) defect states found naturally in integrated optomechanical devices for exploring cavity QED-like phenomena with localized phonons. The Jaynes-Cummings-type interaction between TLS and mechanics can reach the strong coupling regime for existing n...

The fundamental ground tone vibration of H₂, HD, and D₂ is determined to an accuracy of 2×10^-4  cm^-1 from Doppler-free laser spectroscopy in the collisionless environment of a molecular beam. This rotationless vibrational splitting is derived from the combination difference between electronic excita...

Oxygen vacancies created in anatase TiO₂ by UV photons (80–130 eV) provide an effective electron-doping mechanism and induce a hitherto unobserved dispersive metallic state. Angle resolved photoemission reveals that the quasiparticles are large polarons. These results indicate that anatase can be tu...

Huygens’ principle is a well-known concept in electromagnetics that dates back to 1690. Here, it is applied to develop designer surfaces that provide extreme control of electromagnetic wave fronts across electrically thin layers. These reflectionless surfaces, referred to as metamaterial Huygens’ su...

The neutron-rich isotopes of cadmium up to the N=82 shell closure have been investigated by high-resolution laser spectroscopy. Deep-uv excitation at 214.5 nm and radioactive-beam bunching provided the required experimental sensitivity. Long-lived isomers are observed in ¹²⁷Cd and ¹²⁹Cd for the firs...

We use direct numerical simulation of the Navier-Stokes equations for a two-phase flow (water and air) to study the dynamics of the modulational instability of free surface waves and its contribution to the interaction between the ocean and atmosphere. If the steepness of the initial wave exceeds a ...

Geometric frustration, the inability of an ordered system to find a unique ground state plays a key role in a wide range of systems. We present a new experimental approach to observe large-scale geometric frustration with 1500 negatively coupled lasers arranged in a kagome lattice. We show how dissi...

The conservative cascade of kinetic energy is established using both Fourier analysis and a new exact physical-space flux relation in a simulated compressible turbulence. The subgrid scale (SGS) kinetic energy flux of the compressive mode is found to be significantly larger than that of the solenoid...

We show that transverse dispersion in flow through randomly packed monodisperse spheres (sphere diameter d) is a velocity-dependent superposition of three separable random processes—diffusion with coefficient D_r, intrinsic mechanical dispersion with dispersivity l_m=d/33 caused by advection on stream...

We develop an analytic formalism and derive new exact relations that express the short-time dispersion of fluid particles via the single-time velocity correlation functions in homogeneous isotropic and incompressible turbulence. The formalism establishes a bridge between single-time Eulerian and lon...

We characterize statistical properties of the flow field in developed turbulence using concepts from stochastic thermodynamics. On the basis of data from a free air-jet experiment, we demonstrate how the dynamic fluctuations induced by small-scale intermittency generate analogs of entropy-consuming ...

We propose a technique to form a single few-cycle attosecond pulse from vacuum ultraviolet or extreme ultraviolet radiation via resonant interaction with hydrogenlike atoms, irradiated by a high-intensity far-off-resonant laser field. The laser field strongly perturbs excited atomic energy levels vi...

Fully dynamic Stark effect visible spectroscopy was used for the first time to directly measure the local rf electric field in the boundary plasma near a high-power antenna in high-performance, magnetically confined, fusion energy experiment. The measurement was performed in the superconducting toka...

We experimentally demonstrate a notably enhanced acceleration of protons to high energy by relatively modest ultrashort laser pulses and structured dynamical plasma targets. Realized by special deposition of snow targets on sapphire substrates and using carefully planned prepulses, high proton yield...

The role of ions in the energy absorption of a short and ultraintense laser pulse and in the synchrotron radiation generated by accelerated electrons is revisited. For laser intensities above 10²²  W/cm² and plasma densities more than 10 times the critical density, the ion-to-electron mass ratio str...

We study the wave-breaking phenomenon of relativistic upper-hybrid (UH) oscillations in a cold magnetoplasma. For our purposes, we use the electron continuity and relativistic electron momentum equations, together with Maxwell’s equations, as well as introduce Lagrangian coordinates to obtain an exa...

Origami structures are mechanical metamaterials with properties that arise almost exclusively from the geometry of the constituent folds and the constraint of piecewise isometric deformations. Here we characterize the geometry and planar and nonplanar effective elastic response of a simple periodica...

We study the properties of dipolar fermions trapped in one-dimensional bichromatic optical lattices and show the existence of fractional topological states in the presence of strong dipole-dipole interactions. We find some interesting connections between fractional topological states in one-dimensio...

We demonstrate nonlinear metamaterial split ring resonators (SRRs) on GaAs at terahertz frequencies. For SRRs on doped GaAs films, incident terahertz radiation with peak fields of ∼20–160  kV/cm drives intervalley scattering. This reduces the carrier mobility and enhances the SRR LC response due to ...

We study the origin of efficiency roll-off (also called “efficiency droop”) in colloidal quantum-dot light-emitting diodes through the comparison of quantum-dot (QD) electroluminescence and photoluminescence. We find that an electric-field-induced decrease in QD luminescence efficiency—and not charg...

Phase IV of dense solid hydrogen has been identified by its infrared spectrum using high-pressure synchrotron radiation techniques. The spectrum exhibits a sharp vibron band at higher frequency and lower intensity than that for phase III, indicating the stability of molecular H₂ with decreased inter...

We study the crucial role played by the solid-state environment in determining the photon emission characteristics of a driven quantum dot. For resonant driving, we predict a phonon enhancement of the coherently emitted radiation field with increasing driving strength, in stark contrast to the conve...

Several scenarios for the realization of edge Majorana modes in quantum chain systems, spin chains, chains of Josephson junctions, and chains of coupled cavities in quantum optics, are considered. For all these systems excitations can be presented as superpositions of a spinless fermion and a hole, ...

Using resonant magnetic x-ray photon correlation spectroscopy, we show that the domains of a spiral antiferromagnet enter a jammed state at the onset of long-range order. We find that the slow thermal fluctuations of the domain walls exhibit a compressed exponential relaxation with an exponent of 1....

We study the Josephson current through a long ferromagnetic bilayer in the diffusive regime. For noncollinear magnetizations, we find that the current-phase relation is dominated by its second harmonic, which corresponds to the long-range coherent propagation of two triplet pairs of electrons.

A mesoscopic hybrid normal-metal–superconductor ring is characterized by a dense Andreev spectrum with a flux dependent minigap. To probe the dynamics of such a ring, we measure its linear response to a high frequency flux, in a wide frequency range, with a multimode superconducting resonator. We fi...

We study the three-dimensional topological insulators in the continuum by coupling spin-1/2 fermions to the Aharonov-Casher SU(2) gauge field. They exhibit flat Landau levels in which orbital angular momentum and spin are coupled with a fixed helicity. The three-dimensional lowest Landau level wave ...

Potassium-doped picene (K_xpicene) has recently been reported to be a superconductor at x=3 with critical temperatures up to 18 K. Here we study the electronic structure of K-doped picene films by photoelectron spectroscopy and ab initio density functional theory combined with dynamical mean-field th...

We study the influence of electron puddles created by doping of a 2D topological insulator on its helical edge conductance. A single puddle is modeled by a quantum dot tunnel coupled to the helical edge. It may lead to significant inelastic backscattering within the edge because of the long electron...

We study Bi₂Se₃ by polarization-dependent angle-resolved photoemission spectroscopy and density-functional theory slab calculations. We find that the surface state Dirac fermions are characterized by a layer-dependent entangled spin-orbital texture, which becomes apparent through quantum interferenc...

Many biological networks have to filter out useful information from a vast excess of spurious interactions. In this Letter, we use computational evolution to predict design features of networks processing ligand categorization. The important problem of early immune response is considered as a case s...

Photosynthesis is a biological process that involves the highly efficient transport of energy captured from the Sun to a reaction center, where conversion into useful biochemical energy takes place. Using a quantum description, Rebentrost et al. [ New J. Phys. 11 033003 (2009)] and Plenio and Huelg...