Phenomena in diverse contexts such as wetting, biological assembly, and manufacturing are attributed to the three-phase line tension. However, decades of line tension estimates based on contact angles of droplets controversially span 6 orders of magnitude, raising the question of which measurements are authoritative. Here, we show with experiments and calculations that contact angles fail to estimate line tension regardless of length scale, technique, and measurement quality. Line tension measurements based on contact angles are driven by two distinct and spurious mechanisms: body forces under ideal conditions, and data scatter under noisy conditions.

Defect engineering in two-dimensional semiconductors has been exploited to tune the optoelectronic properties and introduce new quantum states in the band gap. Chalcogen vacancies in transition metal dichalcogenides in particular have been found to strongly impact charge carrier concentration and mobility in 2D transistors as well as feature subgap emission and single-photon response. In this Letter, we investigate the layer-dependent charge-state lifetime of Se vacancies in ${\mathrm{WSe}}_2$. In one monolayer ${\mathrm{WSe}}_2$, we observe ultrafast charge transfer from the lowest unoccupied orbital of the top Se vacancy to the graphene substrate within $(1\pm 0.2)\mathrm{ps}$ measured via the current saturation in scanning tunneling approach curves. For Se vacancies decoupled by transition metal dichalcogenide (TMD) multilayers, we find a subexponential increase of the charge lifetime from $(62\pm 14)\mathrm{ps}$ in bilayer to a few nanoseconds in four-layer ${\mathrm{WSe}}_2$, alongside a reduction of the defect state binding energy. Additionally, we attribute the continuous suppression and energy shift of the $dI/dV$ in-gap defect state resonances at very close tip-sample distances to a current saturation effect. Our results provide a key measure of the layer-dependent charge transfer rate of chalcogen vacancies in TMDs.

The interplay between delocalization and repulsive interactions can cause electronic systems to undergo a Mott transition between a metal and an insulator. Here we use neural network hidden fermion determinantal states (HFDS) to uncover this transition in the disordered, fully connected Hubbard model. While dynamical mean-field theory (DMFT) provides exact solutions to physical observables of the model in the thermodynamic limit, our method allows us to directly access the wave function for finite system sizes well beyond the reach of exact diagonalization. We demonstrate how HFDS are able to obtain more accurate results in the metallic regime and in the vicinity of the transition than calculations based on a matrix product state (MPS) ansatz, for which the volume law of entanglement exhibited by the system is prohibitive. We use the HFDS method to calculate the energy and double occupancy, the quasiparticle weight and the energy gap and, importantly, the amplitudes of the wave function that provide a novel insight into this model. Our work paves the way for the study of strongly correlated electron systems with neural quantum states.

Recent experimental discovery of fractional Chern insulators at zero magnetic field in moiré superlattices has sparked intense interests in bringing Landau level physics to flat Chern bands. In twisted ${\mathrm{MoTe}}_2$ bilayers (${\mathrm{tMoTe}}_2$), recent theoretical and experimental studies have found three consecutive flat Chern bands at twist angle $\sim 2°$. In this Letter, we investigate whether higher Landau level physics can be found in these consecutive Chern bands. At twist angles 2.00° and 1.89°, we identify four consecutive $C=1$ bands for the $K$ valley in ${\mathrm{tMoTe}}_2$. By constructing Wannier functions directly from density functional theory (DFT) calculations, a six-orbital model is developed to describe the consecutive Chern bands, with the orbitals forming a honeycomb lattice. Exact diagonalization on top of Hartree-Fock calculations are carried out with the Wannier functions. Especially, when the second moiré miniband is half-filled, signatures of non-Abelian states are found. Our Wannier-based approach in modeling moiré superlattices is faithful to DFT wave functions and can serve as benchmarks for continuum models. The possibility of realizing non-Abelian anyons at zero magnetic field also opens up a new pathway for fault-tolerant quantum information processing.

We study the effect of geometric frustration on dilational mechanical metamaterial membranes. While shape frustrated elastic plates can only accommodate nonzero Gaussian curvature up to size scales that ultimately vanish with their elastic thickness, we show that frustrated metamembranes accumulate hyperbolic curvatures up to mesoscopic length scales that are ultimately independent of the size of their microscopic constituents. A continuum elastic theory and discrete numerical model describe the size-dependent shape and internal stresses of axisymmetric, trumpetlike frustrated metamembranes, revealing a nontrivial crossover to a much weaker power-law growth in elastic strain energy with size than in frustrated elastic membranes. We study a consequence of this for the self-limiting assembly thermodynamics of frustrated trumpets, showing a severalfold increase in the size range of self-limitation of metamembranes relative to elastic membranes.

Enhanced experimental capabilities to control nonlocal and power-law decaying interactions are currently fueling intense research in the domain of quantum many-body physics. Compared to their counterparts with short-ranged interactions, long-range interacting systems display novel physics, such as nonlinear light cones for the propagation of information or inequivalent thermodynamic ensembles. In this work, we consider generic long-range open quantum systems in arbitrary dimensions and focus on the so-called strong long-range regime. We prove that in the thermodynamic limit local properties, captured by reduced quantum states, are described by an emergent noninteracting theory. Here, the dynamics factorizes and the individual constituents of the system evolve independently such that no correlations are generated over time. In this sense, long-range interacting systems are locally noninteracting. This has significant implications for their relaxation behavior, for instance, in relation to the emergence of long-lived quasistationary states or to the absence of thermalization.

Fock-state lattices, composed of photon number states with infinite Hilbert space, have emerged as a promising platform for simulating high-dimensional physics due to their potential to extend into arbitrarily high dimensions. Here, we demonstrate the construction of multidimensional Fock-state lattices using superconducting quantum circuits. By controlling artificial gauge fields within their internal structures, we investigate flux-induced extreme localization dynamics, such as Aharonov-Bohm caging, extending from 2D to 3D. We also explore the coherent interference of quantum superposition states, achieving extreme localization within specific subspaces assisted by quantum entanglement. Our findings pave the way for manipulating the behavior of a broad class of quantum states in higher-dimensional systems.

We propose schemes capable of measuring an arbitrary set of commutative logical Pauli operators in time independent of the number of operators. The only condition is commutativity, a fundamental requirement for simultaneous measurements in quantum mechanics. Quantum low-density parity check (qLDPC) codes show great promise for realizing fault-tolerant quantum computing. They are particularly significant for early fault-tolerant technologies as they can encode many logical qubits using relatively few physical qubits. By achieving simultaneous measurements of logical operators, our approaches enable fully parallelized quantum computing, thus minimizing computation time. Our schemes are applicable to any qLDPC codes and maintain the low density of parity checks while measuring multiple logical operators simultaneously. These results enhance the feasibility of applying early fault-tolerant technologies to practical problems.

Trapped atomic ions constitute one of the leading physical platforms for building the quantum repeater nodes to realize large-scale quantum networks. In a long-distance trapped-ion quantum network, it is essential to have crosstalk-free dual-type qubits: one type, called the communication qubit, to establish an entangling interface with telecom photons; and the other type, called the memory qubit, to store quantum information immune from photon scattering under entangling attempts. Here, we report the first experimental implementation of a telecom-compatible and crosstalk-free quantum network node based on two trapped ${}^{40}{\mathrm{Ca}}^{+}$ ions. The memory qubit is encoded on a long-lived metastable level to avoid crosstalk with the communication qubit encoded in another subspace of the same ion species, and a quantum wavelength conversion module is employed to generate heralded ion-photon entanglement over a 12 km fiber. Our work therefore constitutes an important step toward the realization of quantum repeaters and long-distance quantum networks.

Millicharged particles, proposed by various extensions of the standard model, can be created in pairs by high-energy photons within nuclear reactors and can interact electromagnetically with electrons in matter. Recently, the existence of a plasmon peak in the interaction cross section with silicon in the eV range was highlighted as a promising approach to enhance low-energy sensitivities. The CONNIE and Atucha-II reactor neutrino experiments utilize Skipper-CCD sensors, which enable the detection of interactions in the eV range. We present world-leading limits on the charge of millicharged particles within a mass range spanning 6 orders of magnitude, derived through a comprehensive analysis and the combination of data from both experiments.

A study of light $\mathrm{\Lambda }$ hypernuclei in chiral effective field theory is presented. For the first time, chiral $\mathrm{\Lambda }\text{NN}$ and $\mathrm{\Sigma }\mathrm{NN}$ three-body forces are included consistently. The calculations are performed within the no-core shell model. Results for the separation energies of the hypernuclei ${}_{\mathrm{\Lambda }}{}^3\mathrm{H}$, ${}_{\mathrm{\Lambda }}{}^4\mathrm{H}/{}_{\mathrm{\Lambda }}{}^4\mathrm{He}$, ${}_{\mathrm{\Lambda }}{}^5\mathrm{He}$, and ${}_{\mathrm{\Lambda }}{}^7\mathrm{Li}$ are given. It is found that the experimental values can be fairly well reproduced once hyperon-nucleon-nucleon three-body forces are taken into account.

Direct imaging of transient electronic coherences in molecules has been challenging, with the potential to control electron motions and influence reaction outcomes. We propose a novel time-resolved vortex electron diffraction technique to spatially resolve transient electronic coherences in isolated molecules. By analyzing helical dichroism diffraction signals, the contribution of electronic populations cancels out, isolating the purely electronic coherence signals. This allows direct monitoring of the time evolution and decoherence of transient electronic coherences in molecules.

We introduce a quantum trajectory selector method capable of resolving individual quantum trajectories responsible for strong-field phenomena in real time, revealing the dependence of the electron dynamics on the ionization time. Using an attosecond extreme ultraviolet pulse train, we select the moment of ionization and measure the rates of rescattered electron emission and double ionization driven by a phase locked near IR (1.77 or $2.4\mathrm{\mu }\mathrm{m}$) field. We show that there is an intensity-dependent shift in the ionization time associated with double ionization, and we clock this shift as it varies by 250 as. The quantum trajectory selector provides a new attosecond paradigm for expanding our understanding of recollision-driven physics.

Spin rotation is central for the spin manipulation of lepton beams which, in turn, plays an important role in investigation of the properties of spin-polarized lepton beams and the examination of spin-dependent interactions. However, realization of compact and ultrafast spin rotation of lepton beams, between longitudinal and transverse polarizations, still faces significant challenges. Here, we put forward a novel method for ultrafast (picosecond timescale) spin rotation of a relativistic lepton beam via employing a moderate-intensity terahertz (THz) wave in a dielectric-lined waveguide (DLW). The lepton beam undergoes spin precession induced by the THz magnetic field. We find that optimizing the lepton velocity and THz phase velocity in the DLW can mitigate the impact of transverse Lorentz forces on the lepton beam and increase the precession frequency, thereby maintaining the beam quality and enhancing the efficiency of transverse-to-longitudinal spin rotation. The final polarization degree of the lepton beam exceeds 98%, and the energy spread can be improved significantly. Flexibility in adjusting the electromagnetic modes within the DLW adds further potential for spin manipulation and holds promise for advancing the development of spin-polarized particle beams, which has broad applications in materials science and atomic, nuclear, and high-energy physics.

Two-dimensional van der Waals materials, possessing a unique stacking degree of freedom, offer an alternative strategy for modulating their properties through interlayer sliding. Controlling the stacking order is crucial for tuning material properties and developing slidetronics-based devices. Here, using machine-learning potentials, we propose a mechanical bending approach to manipulate stacking orders and related properties in sliding ferroelectric h-BN, 3R-${\mathrm{MoS}}_2$, and nonferroelectric bilayer graphene. Our simulations predict the formation of irreversible kinks in bent bilayers, deviating from the expected arclike deformation. This kink formation arises from the interplay between bending energy and interlayer stacking energy. Notably, the bending-induced kink contains a ferroelectric topological domain wall that reverses the polarization of sliding ferroelectrics, a mechanism distinct from the conventional flexoelectric effect. This work proposes an exciting mechanical bending approach to dynamically manipulate the stacking order and associated optical, topological, ferroelectric, and magnetic properties in van der Waals layered materials.

Quantum point contacts (QPCs) are an essential component in mesoscopic devices. Here, we study the transmission of quantum Hall edge modes through a gate-defined QPC in monolayer graphene. We observe resonant tunneling peaks and a nonlinear conductance pattern characteristic of Coulomb-blockaded localized states. The in-plane electric polarizability reveals the states are localized at a classically unstable electrostatic saddle point. We explain this unexpected finding within a self-consistent Thomas-Fermi model, finding that localization of a zero-dimensional state at the saddle point is favored whenever the applied confinement potential is sufficiently soft compared to the Coulomb energy. Our results provide a direct demonstration of Coulomb-driven reconstruction at the boundary of a quantum Hall system.

We present first-principles theoretical calculations for the electronic stopping power (SP) of both protons and antiprotons in LiF. Our results show the presence of the Barkas effect: a higher stopping for positively charged particles than their negatively charged antiparticles. In contrast, a previous study has predicted an anti-Barkas effect (higher stopping for negative charges) at low velocity [Qi, Bruneval and Maliyov, Phys. Rev. Lett. 128, 043401 (2022)]. We explain this discrepancy by showing that this anti-Barkas effect appears for highly symmetric trajectories and disappears when considering trajectories that better reproduce the experimental setup. Our low-velocity results show that the SP of both protons and antiproton vanish for velocities under 0.1 a.u.