We report measurements of the spin torque efficiencies in perpendicularly magnetized $\mathrm{Pt}/\mathrm{Co}$ bilayers where the Pt resistivity ${\rho }_{\mathrm{Pt}}$ is strongly dependent on thickness $t_{\mathrm{Pt}}$. The dampinglike spin Hall torque efficiency per unit current density ${\xi }_{\mathrm{DL}}^j$ varies significantly with $t_{\mathrm{Pt}}$, exhibiting a peak value ${\xi }_{\mathrm{DL}}^j=0.12$ at $t_{\mathrm{Pt}}=2.8–3.9\mathrm{nm}$. In contrast, ${\xi }_{\mathrm{DL}}^j/{\rho }_{\mathrm{Pt}}$ increases monotonically with $t_{\mathrm{Pt}}$ and saturates for $t_{\mathrm{Pt}}>5\mathrm{nm}$, consistent with an intrinsic spin Hall effect mechanism, in which ${\xi }_{\mathrm{DL}}^j$ is enhanced by an increase in ${\rho }_{\mathrm{Pt}}$. Assuming the Elliott-Yafet spin scattering mechanism dominates, we estimate that the spin diffusion length ${\lambda }_s=(0.77\pm 0.08)\times {10}^{-15}\mathrm{\Omega }·{\mathrm{m}}^2/{\rho }_{\mathrm{Pt}}$.

We investigate the structural and electronic properties of nitrogen-doped epitaxial monolayer graphene and quasifreestanding monolayer graphene on $6H\text{−}\mathrm{SiC}(0001)$ by the normal incidence x-ray standing wave technique and by angle-resolved photoelectron spectroscopy supported by density functional theory simulations. With the location of various nitrogen species uniquely identified, we observe that for the same doping procedure, the graphene support, consisting of substrate and interface, strongly influences the structural as well as the electronic properties of the resulting doped graphene layer. Compared to epitaxial graphene, quasifreestanding graphene is found to contain fewer nitrogen dopants. However, this lack of dopants is compensated by the proximity of nitrogen atoms at the interface that yield a similar number of charge carriers in graphene.

Elastic scattering of electron vortex beams on magnetic materials leads to a weak magnetic contrast due to Zeeman interaction of orbital angular momentum of the beam with magnetic fields in the sample. The magnetic signal manifests itself as a redistribution of intensity in diffraction patterns due to a change of sign of the orbital angular momentum of the electron vortex beam. While in the atomic resolution regime the magnetic signal is most likely under the detection limits of present transmission electron microscopes, for electron probes with high orbital angular momenta, and correspondingly larger spatial extent, its detection is predicted to be feasible.

We present a formalism for calculating the Raman scattering intensity dependent on the polarization configuration for optically anisotropic crystals. It can be applied to crystals of arbitrary orientation and crystal symmetry measured in normal incidence backscattering geometry. The classical Raman tensor formalism cannot be used for optically anisotropic materials due to birefringence causing the polarization within the crystal to be depth dependent. We show that in the limit of averaging over a sufficiently large scattering depth, the observed Raman intensities converge and can be described by an effective Raman tensor given here. Full agreement with experimental results for uniaxial and biaxial crystals is demonstrated.

First-principles-based effective Hamiltonian simulations are used to reveal the hidden connection between topological defects (hedgehogs and antihedgehogs) and relaxor behavior. Such defects are discovered to predominantly lie at the border of polar nanoregions in both $\mathrm{Ba}({\mathrm{Zr}}_{0.5}{\mathrm{Ti}}_{0.5}){\mathrm{O}}_3$ (BZT) and $\mathrm{Pb}({\mathrm{Sc}}_{0.5}{\mathrm{Nb}}_{0.5}){\mathrm{O}}_3$ (PSN) systems, and the temperature dependency of their density allows us to distinguish between noncanonical (PSN) and canonical (BZT) relaxor behaviors (via the presence or absence of a crossing of a percolation threshold). This density also possesses an inflection point at precisely the temperature for which the dielectric response peaks. Moreover, hedgehogs and antihedgehogs are found to be mobile excitations, and the dynamical nature of their annihilation is demonstrated (using simple hydrodynamical arguments) to follows laws, such as those of Vogel-Fulcher and Arrhenius, that are characteristic of dipolar relaxation kinetics of relaxor ferroelectrics.

Non-Markovian master equations describe general open quantum systems when no approximation is made. We provide the exact closed master equation for the class of Gaussian, completely positive, trace preserving, non-Markovian dynamics. This very general result allows us to investigate a vast variety of physical systems. We show that the master equation for non-Markovian quantum Brownian motion is a particular case of our general result. Furthermore, we derive the master equation unraveled by a non-Markovian, dissipative stochastic Schrödinger equation, paving the way for the analysis of dissipative non-Markovian collapse models.

We report on ab initio no-core shell model calculations of the mirror $\mathrm{\Lambda }$ hypernuclei ${}_{\mathrm{\Lambda }}{}^4\mathrm{H}$ and ${}_{\mathrm{\Lambda }}{}^4\mathrm{He}$, using the Bonn-Jülich leading-order chiral effective field theory hyperon-nucleon potentials plus a charge symmetry breaking $\mathrm{\Lambda }-{\mathrm{\Sigma }}^0$ mixing vertex. In addition to reproducing rather well the $0_{\mathrm{g}.\mathrm{s}.}^{+}$ and $1_{\mathrm{exc}}^{+}$ binding energies, these four-body calculations demonstrate for the first time that the observed charge symmetry breaking splitting of mirror levels, reaching hundreds of keV for $0_{\mathrm{g}.\mathrm{s}.}^{+}$, can be reproduced using realistic theoretical interaction models, although with a non-negligible momentum cutoff dependence. Our results are discussed in relation to recent measurements of the ${}_{\mathrm{\Lambda }}{}^4\mathrm{H}(0_{\mathrm{g}.\mathrm{s}.}^{+})$ binding energy at the Mainz Microtron [A. Esser et al. (A1 Collaboration), Phys. Rev. Lett. 114, 232501 (2015)] and the ${}_{\mathrm{\Lambda }}{}^4\mathrm{He}(1_{\mathrm{exc}}^{+})$ excitation energy [T.O. Yamamoto et al. (J-PARC E13 Collaboration), Phys. Rev. Lett. 115, 222501 (2015)].

The lifetimes of the first excited $2^{+}$ and $4^{+}$ states in ${}^{72}\mathrm{Ni}$ were measured at the National Superconducting Cyclotron Laboratory with the recoil-distance Doppler-shift method, a model-independent probe to obtain the reduced transition probability. Excited states in ${}^{72}\mathrm{Ni}$ were populated by the one-proton knockout reaction of an intermediate energy ${}^{73}\mathrm{Cu}$ beam. $\gamma$-ray-recoil coincidences were detected with the $\gamma$-ray tracking array GRETINA and the S800 spectrograph. Our results provide evidence of enhanced transition probability $B(E2;2^{+}\to 0^{+})$ as compared to ${}^{68}\mathrm{Ni}$, but do not confirm the trend of large $B(E2)$ values reported in the neighboring isotope ${}^{70}\mathrm{Ni}$ obtained from Coulomb excitation measurement. The results are compared to shell model calculations. The lifetime obtained for the excited $4_1^{+}$ state is consistent with models showing decay of a seniority $\nu =4$, $4^{+}$ state, which is consistent with the disappearance of the $8^{+}$ isomer in ${}^{72}\mathrm{Ni}$.

It is found that identical bosons (fermions) show a generalized bunching (antibunching) property in linear networks: the absolute maximum (minimum) of the probability that all $N$ input particles are detected in a subset of $\mathcal{K}$ output modes of any nontrivial linear $M$-mode network is attained only by completely indistinguishable bosons (fermions). For fermions $\mathcal{K}$ is arbitrary; for bosons it is either (i) arbitrary for only classically correlated bosons or (ii) satisfies $\mathcal{K}\ge N$ (or $\mathcal{K}=1$) for arbitrary input states of $N$ particles. The generalized bunching allows us to certify in a polynomial in $N$ number of runs that a physical device realizing boson sampling with an arbitrary network operates in the regime of full quantum coherence compatible only with completely indistinguishable bosons. The protocol needs only polynomial classical computations for the standard boson sampling, whereas an analytic formula is available for the scattershot version.

Complex (dusty) plasmas allow experimental studies of various physical processes occurring in classical liquids and solids by directly observing individual microparticles. A major problem is that the interaction between microparticles is generally not molecularlike. In this Letter, we propose how to achieve a molecularlike interaction potential in laboratory 2D complex plasmas. We argue that this principal aim can be achieved by using relatively small microparticles and properly adjusting discharge parameters. If experimentally confirmed, this will make it possible to employ complex plasmas as a model system with an interaction potential resembling that of conventional liquids.

We report time-of-flight measurements on electrons traveling in quantum Hall edge states. Hot-electron wave packets are emitted one per cycle into edge states formed along a depleted sample boundary. The electron arrival time is detected by driving a detector barrier with a square wave that acts as a shutter. By adding an extra path using a deflection barrier, we measure a delay in the arrival time, from which the edge-state velocity $v$ is deduced. We find that $v$ follows $1/B$ dependence, in good agreement with the $\overrightarrow{E}\times \overrightarrow{B}$ drift. The edge potential is estimated from the energy dependence of $v$ using a harmonic approximation.

We theoretically investigate effects of quantum fluctuations on superfluid spin transport through easy-plane quantum antiferromagnetic spin chains in the large-spin limit. Quantum fluctuations result in the decaying spin supercurrent by unwinding the magnetic order parameter within the easy plane, which is referred to as phase slips. We show that the topological term in the nonlinear sigma model for the spin chains qualitatively differentiates the decaying rate of the spin supercurrent between the integer versus half-odd-integer spin chains. An experimental setup for a magnetoelectric circuit is proposed, in which the dependence of the decaying rate on constituent spins can be verified by measuring the nonlocal magnetoresistance.

Lateral inhibition represents a well-studied example of biology’s ability to self-organize multicellular spatial patterns with single-cell precision. Despite established biochemical mechanisms for lateral inhibition (e.g., Delta-Notch), it remains unclear how cell-cell signaling delays inherent to these mechanisms affect patterning outcomes. We investigate a compact model of lateral inhibition highlighting these delays and find, remarkably, that long delays can ensure defect-free patterning. This effect is underscored by an interplay with synchronous oscillations, cis interactions, and signaling strength. Our results suggest that signaling delays, though previously posited as a source of developmental defects, may in fact be a general regulatory knob for tuning developmental robustness.