Suprathermal ion turbulent transport in magnetized plasmas is generally nondiffusive, ranging from subdiffusive to superdiffusive depending on the interplay of the turbulent structures and the suprathermal ion orbits. Here, we present time-resolved measurements of the cross-field suprathermal ion transport in a toroidal magnetized turbulent plasma. Measurements in the superdiffusive regime are characterized by a higher intermittency than in the subdiffusive regime. Using conditional averaging, we show that, when the transport is superdiffusive, suprathermal ions are transported by intermittent field-elongated turbulent structures that are radially propagating.

We present a study of two model liquids with different interaction potentials, exhibiting similar structure but significantly different dynamics at low temperatures. By evaluating the configurational entropy, we show that the differences in the dynamics of these systems can be understood in terms of their thermodynamic differences. Analyzing their structure, we demonstrate that differences in pair correlation functions between the two systems, through their contribution to the entropy, dominate the differences in their dynamics, and indeed overestimate the differences. Including the contribution of higher order structural correlations to the entropy leads to smaller estimates for the relaxation times, as well as smaller differences between the two studied systems.

The contributions of chain ends and branch points to surface segregation of long-branched chains in blends with linear chains have been studied using neutron reflectometry and surface-enhanced Raman spectroscopy for a series of novel, well-defined polystyrenes. A linear response theory accounting for the number and type of branch points and chain ends is consistent with surface excesses and composition profile decay lengths, and allows the first determination of branch point potentials. Surface excess is determined primarily by chain ends with branch points playing a secondary role.

We present a paradigm in constructing very stable, faceted nanotube and fullerene structures by laterally joining nanoribbons or patches of different planar phosphorene phases. Our ab initio density functional calculations indicate that these phases may form very stable, nonplanar joints. Unlike fullerenes and nanotubes obtained by deforming a single-phase planar monolayer at substantial energy penalty, we find faceted fullerenes and nanotubes to be nearly as stable as the planar single-phase monolayers. The resulting rich variety of polymorphs allows us to tune the electronic properties of phosphorene nanotubes and fullerenes not only by the chiral index but also by the combination of different phosphorene phases. In selected phosphorene nanotubes, a metal-insulator transition may be induced by strain or by changing the number of walls.

Our comprehensive study on ${\mathrm{EuFe}}_2{\mathrm{As}}_2$ reveals a dramatic reduction of magnetic detwinning fields compared to other $A{\mathrm{Fe}}_2{\mathrm{As}}_2$ ($A=\mathrm{Ba}$, Sr, Ca) iron pnictides by indirect magnetoelastic coupling of the ${\mathrm{Eu}}^{2+}$ ions. We find that only $\sim 0.1\mathrm{T}$ are sufficient for persistent detwinning below the local ${\mathrm{Eu}}^{2+}$ ordering; above $T_{\mathrm{Eu}}=19\mathrm{K}$, higher fields are necessary. Even after the field is switched off, a significant imbalance of twin domains remains constant up to the structural and electronic phase transition (190 K). This persistent detwinning provides the unique possibility to study the low temperature electronic in-plane anisotropy of iron pnictides without applying any symmetry-breaking external force.

We study proximity induced triplet superconductivity in a spin-orbit-coupled system, and show that the $\mathbf{d}$ vector of the induced triplet superconductivity undergoes precession that can be controlled by varying the relative strengths of Rashba and Dresselhaus spin-orbit couplings. In particular, a long-range spin-triplet helix is predicted when these two spin-orbit couplings have equal strengths. We also study the Josephson junction geometry and show that a transition between 0 and $\pi$ junctions can be induced by controlling the spin-orbit coupling with a gate voltage. An experimental setup is proposed to verify these effects. Conversely, the observation of these effects can serve as a direct confirmation of triplet superconductivity.

We report ${}^7\mathrm{Li}\text{−}\mathrm{NMR}$ studies on ${\mathrm{LiInCr}}_4{\mathrm{O}}_8$ and ${\mathrm{LiGaCr}}_4{\mathrm{O}}_8$, in which ${\mathrm{Cr}}^{3+}$ ions with spin $3/2$ form a breathing pyrochlore lattice, a network of tetrahedra with alternating sizes. In ${\mathrm{LiInCr}}_4{\mathrm{O}}_8$ with large alternation, the nuclear relaxation rate $1/T_1$ shows an activated temperature ($T$) dependence down to 18 K, indicating a singlet ground state with a spin gap. This behavior, however, is disrupted by an antiferromagnetic transition at 13 K, which is preceded by another, most likely structural, transition at 16 K. In contrast, ${\mathrm{LiGaCr}}_4{\mathrm{O}}_8$ with a small alternation shows no spin gap but exhibits a first-order antiferromagnetic transition over a distributed $T$ range 13–20 K. Nevertheless, $1/T_1$ of the paramagnetic phase diverges toward 13 K, indicating proximity to a second-order transition. The results indicate that ${\mathrm{LiGaCr}}_4{\mathrm{O}}_8$ is located in the vicinity of a tricritical point in the phase diagram.

Terahertz near fields of gold metamaterials resonant at a frequency of 0.88 THz allow us to enter an extreme limit of nonperturbative ultrafast terahertz electronics: Fields reaching a ponderomotive energy in the keV range are exploited to drive nondestructive, quasistatic interband tunneling and impact ionization in undoped bulk GaAs, injecting electron-hole plasmas with densities in excess of ${10}^{19}{\mathrm{cm}}^{-3}$. This process causes bright luminescence at energies up to 0.5 eV above the band gap and induces a complete switch-off of the metamaterial resonance accompanied by self-amplitude-modulation of transmitted few-cycle terahertz transients. Our results pave the way towards highly nonlinear terahertz optics and optoelectronic nanocircuitry with subpicosecond switching times.

We study the basic mechanisms allowing light to photoswitch at the molecular scale a spin-crossover material from a low- to a high-spin state. Combined femtosecond x-ray absorption performed at LCLS X-FEL and optical spectroscopy reveal that the structural stabilization of the photoinduced high-spin state results from a two step structural trapping. Molecular breathing vibrations are first activated and rapidly damped as part of the energy is sequentially transferred to molecular bending vibrations. During the photoswitching, the system follows a curved trajectory on the potential energy surface.

The nonlinear decay of propagating spin waves in the low-Gilbert-damping Heusler film ${\mathrm{Co}}_2{\mathrm{Mn}}_{0.6}{\mathrm{Fe}}_{0.4}\mathrm{Si}$ is reported. Here, two initial magnons with frequency $f_0$ scatter into two secondary magnons with frequencies $f_1$ and $f_2$. The most remarkable observation is that $f_1$ stays fixed if $f_0$ is changed. This indicates, that the $f_1$ magnon mode has the lowest instability threshold, which, however, cannot be understood if only Gilbert damping is present. We show that the observed behavior is caused by interaction of the magnon modes $f_1$ and $f_2$ with the thermal magnon bath. This evidences a significant contribution of the intrinsic magnon-magnon scattering mechanisms to the magnetic damping in high-quality Heusler compounds.

Using a combination of Boltzmann’s equation and virial expansion, we study the effect of three-body losses and interactions on the momentum distribution of a homogeneous unitary Bose gas in the dilute limit where quantum correlations are negligible. The comparison of our results to the recent measurement made at JILA on a unitary gas of ${}^{85}\mathrm{Rb}$ allows us to determine an experimental fugacity $z=0.5(1)$.

We derive robust constraints on primordial non-Gaussianity (PNG) using the clustering of 800 000 photometric quasars from the Sloan Digital Sky Survey in the redshift range $0.5<z<3.5$. These measurements rely on the novel technique of extended mode projection to control the impact of spatially varying systematics in a robust fashion, making use of blind analysis techniques. This allows the accurate measurement of quasar halo bias at the largest scales, while discarding as little as possible of the data. The standard local-type PNG parameters $f_{\mathrm{NL}}$ and $g_{\mathrm{NL}}$ both imprint a $k^{-2}$ scale-dependent effect in the bias. Constraining these individually, we obtain $-49<f_{\mathrm{NL}}<31$ and $-2.7\times 10^5<g_{\mathrm{NL}}<1.9\times 10^5$, while their joint constraints lead to $-105<f_{\mathrm{NL}}<72$ and $-4.0\times 10^5<g_{\mathrm{NL}}<4.9\times 10^5$ (all at 95% C.L.). Introducing a running parameter $n_{f_{\mathrm{NL}}}$ to constrain $b(k)\propto k^{-2+n_{f_{\mathrm{NL}}}}$ and a generalized PNG amplitude ${\tilde{f}}_{\mathrm{NL}}$, we obtain $-45.5\exp (3.7n_{f_{\mathrm{NL}}})<{\tilde{f}}_{\mathrm{NL}}<34.4\exp (3.3n_{f_{\mathrm{NL}}})$ at 95% C.L. These results incorporate uncertainties in the cosmological parameters, redshift distributions, shot noise, and the bias prescription used to relate the quasar clustering to the underlying dark matter. These are the strongest constraints obtained to date on PNG using a single population of large-scale structure tracers, and are already at the level of pre-Planck constraints from the cosmic microwave background. A conservative forecast for a Large Synoptic Survey Telescope (LSST)-like survey incorporating mode projection yields $\sigma (f_{\mathrm{NL}})\sim 5$—competitive with the Planck result—highlighting the power of upcoming large scale structure surveys to probe the initial conditions of the Universe.

We experimentally demonstrate the noiseless teleportation of a single photon by conditioning on quadrature Bell measurement results near the origin in phase space and thereby circumventing the photon loss that otherwise occurs even in optimal gain-tuned continuous-variable quantum teleportation. In general, thanks to this loss suppression, the noiseless conditional teleportation can preserve the negativity of the Wigner function for an arbitrary pure input state and an arbitrary pure entangled resource state. In our experiment, the positive value of the Wigner function at the origin for the unconditional output state, $W(0,0)=0.015\pm 0.001$, becomes clearly negative after conditioning, $W(0,0)=-0.025\pm 0.005$, illustrating the advantage of noiseless conditional teleportation.

We introduce and experimentally explore the concept of the non-Gaussian depth of single-photon states with a positive Wigner function. The depth measures the robustness of a single-photon state against optical losses. The directly witnessed quantum non-Gaussianity withstands significant attenuation, exhibiting a depth of 18 dB, while the nonclassicality remains unchanged. Quantum non-Gaussian depth is an experimentally approachable quantity that is much more robust than the negativity of the Wigner function. Furthermore, we use it to reveal significant differences between otherwise strongly nonclassical single-photon sources.

We report on the generation of a narrow divergence (${\theta }_{\gamma }<2.5\mathrm{mrad}$), multi-MeV ($E_{\max }\approx 18\mathrm{MeV}$) and ultrahigh peak brilliance ($>1.8\times {10}^{20}\mathrm{photons}{\mathrm{s}}^{-1}{\mathrm{mm}}^{-2}{\mathrm{mrad}}^{-2}$ 0.1% BW) $\gamma$-ray beam from the scattering of an ultrarelativistic laser-wakefield accelerated electron beam in the field of a relativistically intense laser (dimensionless amplitude $a_0\approx 2$). The spectrum of the generated $\gamma$-ray beam is measured, with MeV resolution, seamlessly from 6 to 18 MeV, giving clear evidence of the onset of nonlinear relativistic Thomson scattering. To the best of our knowledge, this photon source has the highest peak brilliance in the multi-MeV regime ever reported in the literature.

Recently, the family of high-resolution scanning probe imaging techniques using decorated tips has been complemented by a method based on inelastic electron tunneling spectroscopy (IETS). The new technique resolves the inner structure of organic molecules by mapping the vibrational energy of a single carbon monoxide (CO) molecule positioned at the apex of a scanning tunneling microscope (STM) tip. Here, we explain high-resolution IETS imaging by extending a model developed earlier for STM and atomic force microscopy (AFM) imaging with decorated tips. In particular, we show that the tip decorated with CO acts as a nanoscale sensor that changes the energy of its frustrated translation mode in response to changes of the local curvature of the surface potential. In addition, we show that high resolution AFM, STM, and IETS-STM images can deliver information about the charge distribution within molecules deposited on a surface. To demonstrate this, we extend our mechanical model by taking into account electrostatic forces acting on the decorated tip in the surface Hartree potential.

We report the experimental observation and control of space and time-resolved light-matter Rabi oscillations in a microcavity. Our setup precision and the system coherence are so high that coherent control can be implemented with amplification or switching off of the oscillations and even erasing of the polariton density by optical pulses. The data are reproduced by a quantum optical model with excellent accuracy, providing new insights on the key components that rule the polariton dynamics.

Silicon nitride (SiN) micro- and nanomechanical resonators have attracted a lot of attention in various research fields due to their exceptionally high quality factors ($Q\mathrm{s}$). Despite their popularity, the origin of the limiting loss mechanisms in these structures has remained controversial. In this Letter we propose an analytical model combining acoustic radiation loss with intrinsic loss. The model accurately predicts the resulting mode-dependent $Q\mathrm{s}$ of low-stress silicon-rich and high-stress stoichiometric SiN membranes. The large acoustic mismatch of the low-stress membrane to the substrate seems to minimize radiation loss and $Q\mathrm{s}$ of higher modes ($n\wedge m\ge 3$) are limited by intrinsic losses. The study of these intrinsic losses in low-stress membranes reveals a linear dependence with the membrane thickness. This finding was confirmed by comparing the intrinsic dissipation of arbitrary (membranes, strings, and cantilevers) SiN resonators extracted from literature, suggesting surface loss as ubiquitous damping mechanism in thin SiN resonators with $Q_{\text{surf}}=\beta h$ and $\beta =6\times {10}^{10}\pm 4\times {10}^{10}{\mathrm{m}}^{-1}$. Based on the intrinsic loss the maximal achievable $Q\mathrm{s}$ and $Qf$ products for SiN membranes and strings are outlined.