Multiterminal Josephson junctions (MTJJs), devices in which a normal metal is in contact with three or more superconducting leads, have been proposed as artificial analogs of topological crystals. The topological nature of MTJJs manifests as a modulation of the quasiparticle density of states (DOS) in the normal metal that may be probed by tunneling measurements. We show that one can reveal this modulation by measuring the resistance of diffusive MTJJs with normal contacts, which shows rich structure as a function of the phase differences $\{{\varphi }_i\}$. Our approach demonstrates a simple yet powerful technique for exploring topological effects in MTJJs.

We report spin-polarized scanning tunneling microscopy measurements of an Anderson impurity system in ${\mathrm{MoS}}_2$ mirror-twin boundaries, where both the quantum-confined impurity state and the Kondo resonance resulting from the interaction with the substrate are accessible. Using a spin-polarized tip, we observe magnetic-field-induced changes in the peak heights of the Anderson impurity states as well as in the magnetic-field-split Kondo resonance. Quantitative comparison with numerical renormalization group calculations provides evidence of the notable spin polarization of the spin-resolved impurity spectral function under the influence of a magnetic field. Moreover, we extract the field and temperature dependence of the impurity magnetization from the differential conductance measurements and demonstrate that this exhibits the universality and asymptotic freedom of the $S=1/2$ Kondo effect. This work shows that mirror-twin boundaries can be used as a testing ground for theoretical predictions on quantum impurity models.

We present an approach to detecting (linear) gravitational wave memory in a Galactic core-collapse supernova using current interferometers. Gravitational wave memory is an important prediction of general relativity that has yet to be confirmed. Our approach uses a combination of linear prediction filtering and matched filtering. We present the results of our approach on data from core-collapse supernova simulations that span a range of progenitor mass and metallicity. We are able to detect gravitational wave memory out to 10 kpc. We also present the false alarm probabilities assuming an on-source window compatible with the presence of a neutrino detection.

Dipole toroidal modes appear in many fields of physics. In nuclei, such a mode was predicted more than 50 years ago, but clear experimental evidence was lacking so far. Using a combination of high-resolution inelastic scattering experiments with photons, electrons, and protons, we identify for the first time candidates for toroidal dipole excitations in the nucleus ${}^{58}\mathrm{Ni}$ and demonstrate that transverse electron scattering form factors represent a relevant experimental observable to prove their nature.

Recent studies of wetting in a two-component square-gradient model of interfaces in a fluid mixture, showing three-phase bulk coexistence, have revealed some highly surprising features. Numerical results show that the density profile paths, which form a tricuspid shape in the density plane, have curious geometric properties, while conjectures for the analytical form of the surface tensions imply that nonwetting may persist up to the critical end points, contrary to the usual expectation of critical point wetting. Here, we solve the model exactly and show that the profile paths are conformally invariant quartic algebraic curves that change genus at the wetting transition. Being harmonic, the profile paths can be represented by an analytic function in the complex plane which then conformally maps the paths onto straight lines. Using this, we derive the conjectured form of the surface tensions and explain the geometrical properties of the tricuspid and its relation to the Neumann triangle for the contact angles. The exact solution confirms that critical point wetting is absent in this square-gradient model.

In contrast to the Dirac-cone materials in which the low-energy spectrum features a pseudospin-$1/2$ structure, Lieb and Dice lattices both host triply degenerate low-energy excitations. Here, we discuss moiré structures involving twisted bilayers of these lattices, which are shown to exhibit a tunable number of isolated flat bands near the Fermi level due to the bipartite nature of their structures. These flat bands remain isolated from the high-energy bands even in the presence of small higher-order terms and chiral-symmetry-breaking interlayer tunneling. At small twist angles, many isolated flat bands can be generated with a notable Berry curvature, which could provide a geometric contribution to the superfluid weight under a BCS-type pairing potential. Remarkably, the emergence of isolated flat bands is insensitive to the twist angle, so that fine-tuning of the twist angle in an experimental setup would not be required. Our study suggests a promising new and efficient avenue for exploring and engineering flat bands based on the twisted bilayer Lieb and Dice lattices.

For over a century, the Hall effect, a transverse effect under an out-of-plane magnetic field or magnetization, has been a cornerstone for magnetotransport studies and applications. Modern theoretical formulation based on the Berry curvature has revealed the potential that even an in-plane magnetic field can induce an anomalous Hall effect, but its experimental demonstration has remained difficult due to its potentially small magnitude and strict symmetry requirements. Here, we report observation of the in-plane anomalous Hall effect by measuring low-carrier density films of magnetic Weyl semimetal ${\mathrm{EuCd}}_2{\mathrm{Sb}}_2$. Anomalous Hall resistance exhibits distinct threefold rotational symmetry for changes in the in-plane field component, and this can be understood in terms of out-of-plane Weyl points splitting or orbital magnetization induced by the in-plane field, as also confirmed by model calculation. Our findings demonstrate the importance of the in-plane field to control the Hall effect, accelerating materials development and further exploration of various in-plane field-induced phenomena.

The antiferromagnetic structure of ${\mathrm{Yb}}_3{\mathrm{Ga}}_5{\mathrm{O}}_{12}$ is identified by neutron diffraction experiments below the previously known transition at $T_{\lambda }=54\mathrm{mK}$. The magnetic propagation vector is found to be $\mathbf{k}=(1/2,1/2,0)$, an unusual wave vector in the garnet structure. The associated complex magnetic structure highlights the role of exchange interactions in a nearly isotropic system dominated by dipolar interactions and finds echoes with exotic structures theoretically proposed. Reduced values of the ordered moments may indicate significant quantum fluctuations in this effective spin-$1/2$ geometrically frustrated magnet.

Stable ${}^{205}\mathrm{Tl}$ ions have the lowest known energy threshold for capturing electron neutrinos (${\nu }_e$) of $E_{{\nu }_e}\ge 50.6\mathrm{keV}$. The Lorandite Experiment (LOREX), proposed in the 1980s, aims at obtaining the longtime averaged solar neutrino flux by utilizing natural deposits of Tl-bearing lorandite ores. To determine the ${\nu }_e$ capture cross section, it is required to know the strength of the weak transition connecting the ground state of ${}^{205}\mathrm{Tl}$ and the 2.3 keV first excited state in ${}^{205}\mathrm{Pb}$. The only way to experimentally address this transition is to measure the bound-state beta decay (${\beta }_b$) of fully ionized ${}^{205}{\mathrm{Tl}}^{81+}$ ions. After three decades of meticulous preparation, the half-life of the ${\beta }_b$ decay of ${}^{205}{\mathrm{Tl}}^{81+}$ has been measured to be ${291}_{-27}^{+33}\mathrm{days}$ using the Experimental Storage Ring (ESR) at GSI, Darmstadt. The longer measured half-life compared to theoretical estimates reduces the expected signal-to-noise ratio in the LOREX, thus challenging its feasibility.

We experimentally study the evolution of the magnetic moment $m$ and exchange interaction $J$ as a function of hydrostatic pressure in the zero-field helimagnetic phase of the strongly correlated electron system MnSi. The suppression of magnetic order at $\approx 1.5\mathrm{GPa}$ is shown to arise from the $J$ collapse and not from a quantum fluctuations induced reduction of $m$. Our work provides benchmarks for first principles theories that are challenged by the presence of strong correlations and the possible role of Hund’s coupling. In addition, our experimental data are consistent with a reorientation of the magnetic propagation wave vector recently evidenced above $\approx 1.2\mathrm{GPa}$. This result calls for a thorough investigation of the crystal structure in this pressure range.

Canard cascading (CC) is observed in dynamical networks with global adaptive coupling. It is a slow-fast phenomenon characterized by a recurrent sequence of fast transitions between distinct and slowly evolving quasistationary states. In this Letter, we uncover the dynamical mechanisms behind CC, using an illustrative example of globally and adaptively coupled semiconductor lasers, where CC represents sequential switching on and off the lasers. First, we show that CC is a robust and truly adaptive network effect that is scalable with network size and does not occur without adaptation. Second, we uncover multiple saddle slow manifolds (unstable quasistationary states) linked by heteroclinic orbits (fast transitions) in the phase space of the system. This allows us to identify CC with a novel heteroclinic canard orbit that organizes different unstable quasistationary states into an intricate slow-fast limit cycle. Although individual quasistationary states are unstable (saddles), the CC cycle as a whole is attractive and robust to parameter changes.

A novel method of ultrafast electron diffraction for the study of structural dynamics at surfaces is presented. The probing electron pulse is generated in the immediate vicinity of the surface by photoemission of low-energy electrons from the sample substrate. This limits the propagation distance of the electron pulse before diffraction to a few nanometers and thus minimizes pulse broadening effects due to space charge and dispersion. The experimentally proven time resolution of $\approx 100\mathrm{fs}$ exceeds reported values of conventional ultrafast low-energy electron diffraction by a factor of 10.

We demonstrate a mechanical crystal with an optically programmable defect mode. By applying an optical spring to a single unit cell of a phononic crystal membrane, we smoothly transfer a single mechanical mode into the band gap, thereby localizing its spatial profile from one spanning the entire crystal to one confined within a few unit cells. This localization is evidenced by an enhanced mechanical frequency shift commensurate with a 37-fold reduction in the mode’s participating mass. This fast, reversible, all-optical control represents a qualitatively new way to engineer mechanical defects, advantageously with in situ reconfigurability.

The precise control of complex reactions is critical for biological processes, yet our inability to design for specific outcomes limits the development of synthetic analogs. Here, we leverage differentiable simulators to design nontrivial reaction pathways in colloidal assemblies. By optimizing over external structures, we achieve controlled disassembly and particle release from colloidal shells. Lastly, we characterize the role of configurational entropy in the structure via both forward calculations and optimization, inspiring new parameterizations of designed colloidal reactions.

We present the first successful trapping of single erbium atoms in an array of optical tweezers. Using a single narrow-line optical transition, we achieve deep cooling for direct tweezer loading, pairwise ejection, and continuous imaging without additional recoil suppression techniques. Our tweezer wavelength choice enables us to reach the magic trapping condition by tuning the ellipticity of the trapping light. Additionally, we implement an ultrafast high-fidelity fluorescence imaging scheme using a broad transition, allowing time-resolved study of the tweezer population dynamics from many to single atoms during light-assisted collisions. In particular, we extract a pair-ejection rate that qualitatively agrees with the semiclassical predictions by the Gallagher-Pritchard model. This Letter represents a promising starting point for the exploration of erbium as a powerful resource for quantum simulation in optical tweezers.

Colloidal gels are prime examples of functional materials exhibiting disordered, amorphous, yet metastable forms. They maintain stability through short-range attractive forces and their material properties are tunable by external forces. Combining persistent homology analyses and simulations of three-dimensional colloidal gels doped with active particles, we reveal novel dynamically evolving structures of colloidal gels. Specifically, we show that the local injection of energy by active dopants can lead to highly porous, yet compact gel structures that can significantly affect the transport of active particles within the modified colloidal gel. We further show how passive interfaces play a topologically significant role in interacting with active particles in 3D. The results open the door to an unexplored prospect of forming a wide variety of compact but highly heterogeneous and percolated porous media through active doping of 3D passive matter, with diverse implications in designing new functional materials for active ground remediation.

Owing to their rapid cooling rate and hence loss-limited propagation distance, cosmic-ray electrons and positrons (CRe) at very high energies probe local cosmic-ray accelerators and provide constraints on exotic production mechanisms such as annihilation of dark matter particles. We present a high-statistics measurement of the spectrum of CRe candidate events from 0.3 to 40 TeV with the High Energy Stereoscopic System, covering 2 orders of magnitude in energy and reaching a proton rejection power of better than ${10}^4$. The measured spectrum is well described by a broken power law, with a break around 1 TeV, where the spectral index increases from ${\mathrm{\Gamma }}_1=3.25\pm 0.02(\mathrm{stat})\pm 0.2(\mathrm{sys})$ to ${\mathrm{\Gamma }}_2=4.49\pm 0.04(\mathrm{stat})\pm 0.2(\mathrm{sys})$. Apart from the break, the spectrum is featureless. The absence of distinct signatures at multi-TeV energies imposes constraints on the presence of nearby CRe accelerators and the local CRe propagation mechanisms.

In space plasmas, large-amplitude Alfvén waves can drive compressive perturbations, accelerate ion beams, and lead to plasma heating and the excitation of ion acoustic waves at kinetic scales. This energy channeling from fluid to kinetic scales represents a complementary path to the classical turbulent cascade. Here, we present observational and computational evidence to validate this hypothesis by simultaneously resolving the fluid-scale Alfvén waves, kinetic-scale ion acoustic waves, and their imprints on ion velocity distributions in the Earth’s magnetopause boundary layer. We show that two coexisting compressive modes, driven by the magnetic pressure gradients of Alfvén waves, not only accelerate the ion tail population to the Alfvén velocity, but also heat the ion core population near the ion acoustic velocity and generate Debye-scale ion acoustic waves. Thus, Alfvén-acoustic energy channeling emerges as a viable mechanism for plasma heating near plasma boundaries where large-amplitude Alfvén waves are present.

The precision of currents in Markov networks is bounded by dissipation via the so-called thermodynamic uncertainty relation (TUR). In our Letter, we demonstrate a similar inequality that bounds the precision of the static current response to perturbations of kinetic barriers. Perturbations of such type, which affect only the system kinetics but not the thermodynamic forces, are highly important in biochemistry and nanoelectronics. We prove that our inequality cannot be derived from the standard TUR. Instead, it implies the standard TUR and provides an even tighter bound for dissipation. We also provide a procedure for obtaining the optimal response precision for a given model.

Nickel and nitrogen co-doped carbon (Ni-N-C) catalysts are attracting attention due to their exceptionally high performance in the electrocatalytic reduction of ${\mathrm{CO}}_2({\mathrm{CO}}_2\mathrm{RR})$ to CO. However, the direct experimental insight into the working mechanism of these catalysts is missing, hindering our fundamental understanding and their further improvement. This work sheds light on the nature of adsorbates forming under ${\mathrm{CO}}_2\mathrm{RR}$ at singly dispersed Ni sites. In particular, operando high energy resolution fluorescence detected x-ray absorption near edge structure (HERFD-XANES) at the Ni $K$-edge together with valence-to-core x-ray emission spectroscopy (vtc-XES) and x-ray absorption (XAS) at the Ni $L_3$-edge were employed to unveil the structure and electronic properties of the reaction intermediates. These techniques, coupled with unsupervised and supervised machine learning methodologies and density functional theory, enabled a comprehensive characterization of the local atomistic and electronic structure of the working Ni-N-C catalysts. Specifically, we were able to distinguish between the structural and electronic changes of the Ni sites associated with the ${\mathrm{CO}}_2\mathrm{RR}$ functionality from the effect of radiation-induced damage, providing direct insight into the bond formation between the Ni centers and ${\mathrm{CO}}_2\mathrm{RR}$ intermediates such as CO adsorbates.