Electric field–assisted sintering techniques demonstrate accelerated densification at lower temperatures than the conventional sintering methods. However, it is still debated whether the applied field and/or resulting currents are responsible for the densification enhancement. To distinguish the effects of an applied field from current flow, in situ scanning transmission electron microscopy experiments with soft agglomerates of partially stabilized yttria-doped zirconia particles are carried out. A new microelectromechanical system–based sample support is used to heat particle agglomerates while simultaneously exposing them to an externally applied noncontacting electric field. Under isothermal condition at $900°\mathrm{C}$, an electric field strength of $500\mathrm{V}/\mathrm{cm}$ shows a sudden threefold enhancement in the shrinkage of the agglomerates. The applied electrostatic potential lowers the activation energy for point defect formation within the space charge zone and therefore promotes consolidation. Obtaining similar magnitudes of shrinkage in the absence of any electric field requires a higher temperature and longer time.

We analyze incommensurate charge-density-wave (CDW) and pair-density-wave (PDW) orders with transferred momenta $(\pm Q,0)/(0,\pm Q)$ in underdoped cuprates within the spin-fermion model. Both orders appear due to an exchange of spin fluctuations before magnetic order develops. We argue that the ordered state with the lowest energy has nonzero CDW and PDW components with the same momentum. Such a state breaks $C_4$ lattice rotational symmetry, time-reversal symmetry, and mirror symmetries. We argue that the feedback from CDW/PDW order on fermionic dispersion is consistent with ARPES data. We discuss the interplay between the CDW/PDW order and $d_{x^2-y^2}$ superconductivity and make specific predictions for experiments.

We show that the interaction of the magnetic subsystem of a curved magnet with the magnet curvature results in the coupling of a topologically nontrivial magnetization pattern and topology of the object. The mechanism of this coupling is explored and illustrated by an example of a ferromagnetic Möbius ring, where a topologically induced domain wall appears as a ground state in the case of strong easy-normal anisotropy. For the Möbius geometry, the curvilinear form of the exchange interaction produces an additional effective Dzyaloshinskii-like term which leads to the coupling of the magnetochirality of the domain wall and chirality of the Möbius ring. Two types of domain walls are found, transversal and longitudinal, which are oriented across and along the Möbius ring, respectively. In both cases, the effect of magnetochirality symmetry breaking is established. The dependence of the ground state of the Möbius ring on its geometrical parameters and on the value of the easy-normal anisotropy is explored numerically.

The valence of individual europium atoms confined in carbon nanotubes is successfully measured by using core-level electron energy loss spectroscopy. Changes in the oxidation state at the atomic scale have been observed in Eu atomic chains exposed to oxygen. A transitory behavior has been identified where multiple atoms show a signal consistent with a sum of ${\mathrm{Eu}}^{2+}$ and ${\mathrm{Eu}}^{3+}$. This indicates that single atoms change their valence state multiple times during the reaction, suggesting that oxidation in confined spaces and with extra energy input (from the electron beam) might not be a simple one step electron transfer event.

A vertically shaken granular medium hosts a blade rotating around a fixed vertical axis, which acts as a mesorheological probe. At high densities, independently of the shaking intensity, the blade’s dynamics shows strong caging effects, marked by transient subdiffusion and a maximum in the velocity power density spectrum, at a resonant frequency $\sim 10\mathrm{Hz}$. Interpreting the data through a diffusing harmonic cage model allows us to retrieve the elastic constant of the granular medium and its collective diffusion coefficient. For high frequencies $f$, a tail $\sim 1/f$ in the velocity power density spectrum reveals nontrivial correlations in the intracage microdynamics. At very long times (larger than 10 s), a superdiffusive behavior emerges, ballistic in the most extreme cases. Consistently, the distribution of slow velocity inversion times $\tau$ displays a power-law decay, likely due to persistent collective fluctuations of the host medium.

We investigate a stochastic search process in one dimension under the competing roles of mortality, redundancy, and diversity of the searchers. This picture represents a toy model for the fertilization of an oocyte by sperm. A population of $N$ independent and mortal diffusing searchers all start at $x=L$ and attempt to reach the target at $x=0$. When mortality is irrelevant, the search time scales as ${\tau }_D/\ln N$ for $\ln N\gg 1$, where ${\tau }_D\sim L^2/D$ is the diffusive time scale. Conversely, when the mortality rate $\mu$ of the searchers is sufficiently large, the search time scales as $\sqrt{{\tau }_D/\mu }$, independent of $N$. When searchers have distinct and high mortalities, a subpopulation with a nontrivial optimal diffusivity is most likely to reach the target. We also discuss the effect of chemotaxis on the search time and its fluctuations.

We examine the influence of the shape of dynamical heterogeneities on the Stokes-Einstein (SE) and Stokes-Einstein-Debye (SED) relations in quasi-two-dimensional suspensions of colloidal ellipsoids. For ellipsoids with repulsive interactions, both SE and SED relations are violated at all area fractions. On approaching the glass transition, however, the extent to which this violation occurs changes beyond a crossover area fraction. Quite remarkably, we find that it is not just the presence of dynamical heterogeneities but their change in the shape from stringlike to compact that coincides with this crossover. On introducing a suitable short-range depletion attraction between the ellipsoids, associated with the lack of morphological evolution of dynamical heterogeneities, the extent to which the SE and SED relations are violated remains unchanged even for deep supercooling.

We demonstrate that a microfabricated bump array can concentrate genomic-length DNA molecules efficiently at continuous, high flow velocities, up to $40\mu \mathrm{m}/\mathrm{s}$, if the single-molecule DNA globule has a sufficiently large shear modulus. Increase in the shear modulus is accomplished by compacting the DNA molecules to minimal coil size using polyethylene glycol (PEG) derived depletion forces. We map out the sweet spot, where concentration occurs, as a function of PEG concentration and flow speed using a combination of theoretical analysis and experiment. Purification of DNA from enzymatic reactions for next-generation DNA-sequencing libraries will be an important application of this development.

A projective measurement of energy (PME) on a quantum system is a quantum measurement determined by the Hamiltonian of the system. PME protocols exist when the Hamiltonian is given in advance. Unknown Hamiltonians can be identified by quantum tomography, but the time cost to achieve a given accuracy increases exponentially with the size of the quantum system. In this Letter, we improve the time cost by adapting quantum phase estimation, an algorithm designed for computational problems, to measurements on physical systems. We present a PME protocol without quantum tomography for Hamiltonians whose dimension and energy scale are given but which are otherwise unknown. Our protocol implements a PME to arbitrary accuracy without any dimension dependence on its time cost. We also show that another computational quantum algorithm may be used for efficient estimation of the energy scale. These algorithms show that computational quantum algorithms, with suitable modifications, have applications beyond their original context.

We present the first realization of a “twin Higgs” model as a holographic composite Higgs model. Uniquely among composite Higgs models, the Higgs potential is protected by a new standard model (SM) singlet elementary “mirror” sector at the sigma model scale $f$ and not by the composite states at $m_{\mathrm{KK}}$, naturally allowing for $m_{\mathrm{KK}}$ beyond the LHC reach. As a result, naturalness in our model cannot be constrained by the LHC, but may be probed by precision Higgs measurements at future lepton colliders, and by direct searches for Kaluza-Klein excitations at a 100 TeV collider.

The double-differential cross sections of promptly produced $J/\psi$ and $\psi (2S)$ mesons are measured in $pp$ collisions at $\sqrt{s}=7\mathrm{TeV}$, as a function of transverse momentum $p_T$ and absolute rapidity $|y|$. The analysis uses $J/\psi$ and $\psi (2S)$ dimuon samples collected by the CMS experiment, corresponding to integrated luminosities of 4.55 and $4.90{\mathrm{fb}}^{-1}$, respectively. The results are based on a two-dimensional analysis of the dimuon invariant mass and decay length, and extend to $p_T=120$ and 100 GeV for the $J/\psi$ and $\psi (2S)$, respectively, when integrated over the interval $|y|<1.2$. The ratio of the $\psi (2S)$ to $J/\psi$ cross sections is also reported for $|y|<1.2$, over the range $10<p_T<100\mathrm{GeV}$. These are the highest $p_T$ values for which the cross sections and ratio have been measured.

We predict the spontaneous modulated emission from a pair of exciton-polariton condensates due to coherent (Josephson) and dissipative coupling. We show that strong polariton-polariton interaction generates complex dynamics in the weak-lasing domain way beyond Hopf bifurcations. As a result, the exciton-polariton condensates exhibit self-induced oscillations and emit an equidistant frequency comb light spectrum. A plethora of possible emission spectra with asymmetric peak distributions appears due to spontaneously broken time-reversal symmetry. The lasing dynamics is affected by the shot noise arising from the influx of polaritons. That results in a complex inhomogeneous line broadening.

We present an all-laser-driven, energy-tunable, and quasimonochromatic x-ray source based on Thomson scattering from laser-wakefield-accelerated electrons. One part of the laser beam was used to drive a few-fs bunch of quasimonoenergetic electrons, while the remainder was backscattered off the bunch at weakly relativistic intensity. When the electron energy was tuned from 17–50 MeV, narrow x-ray spectra peaking at 5–42 keV were recorded with high resolution, revealing nonlinear features. We present a large set of measurements showing the stability and practicality of our source.

We show that the specific heat of incommensurately modulated crystals with broken translational periodicity presents similar features at low temperatures to those of amorphous and glass materials. Here we demonstrate that the excess to the constant $C_p(T)/T^3$ law (or Debye limit) is made up of an upturn below 1 K and of a broad bump at $T\approx 10\mathrm{K}$ that directly originates from the gapped phase and amplitude modes of the incommensurate structure. We argue that the low-energy dynamics of incommensurate systems constitute a plausible simplification of the landscape of interactions present in glasses, giving rise to their low-temperature anomalies.

A microscopic formalism to calculate thermal transport coefficients is presented based on a thermal vector potential, whose time derivative is related to a thermal force. The formalism is free from the unphysical divergences reported to arise when Luttinger’s formalism is applied naively, because the equilibrium (“diamagnetic”) currents are treated consistently. The mathematical structure for the thermal transport coefficients is shown to be identical with that for the electric ones if the electric charge is replaced by the energy. The results indicate that the thermal vector potential couples to the energy current via the minimal coupling.

New results are reported from a measurement of ${\pi }^0$ electroproduction near threshold using the $p(e,e^{\prime }p){\pi }^0$ reaction. The experiment was designed to determine precisely the energy dependence of $s$- and $p$-wave electromagnetic multipoles as a stringent test of the predictions of chiral perturbation theory (ChPT). The data were taken with an electron beam energy of 1192 MeV using a two-spectrometer setup in Hall A at Jefferson Lab. For the first time, complete coverage of the ${\varphi }_{\pi }^{*}$ and ${\theta }_{\pi }^{*}$ angles in the $p{\pi }^0$ center of mass was obtained for invariant energies above threshold from 0.5 up to 15 MeV. The 4-momentum transfer $Q^2$ coverage ranges from 0.05 to $0.155(\mathrm{GeV}/c{)}^2$ in fine steps. A simple phenomenological analysis of our data shows strong disagreement with $p$-wave predictions from ChPT for $Q^2>0.07(\mathrm{GeV}/c{)}^2$, while the $s$-wave predictions are in reasonable agreement.

We study the orbital angular momentum (OAM) $L_z$ in two-dimensional chiral $(p_x+i{p}_y{)}^{\nu }$-wave superfluids (SFs) of $N$ fermions on a disk at zero temperature, in terms of spectral asymmetry and spectral flow. It is shown that $L_z=\nu N/2$ for any integer $\nu$, in the Bose-Einstein condensation regime. In contrast, in the BCS limit, while the OAM is $L_z=N/2$ for the $p+ip$-wave SF, for chiral SFs with $\nu \ge 2$, the OAM is remarkably suppressed as $L_z=N\times O({\mathrm{\Delta }}_0/{ϵ}_F)\ll N$, where ${\mathrm{\Delta }}_0$ is the gap amplitude and ${ϵ}_F$ is the Fermi energy. We demonstrate that the difference between the $p+ip$-wave SF and the other chiral SFs in the BCS regimes originates from the nature of edge modes and related depairing effects.