We directly observe and spatially map an optical analog of the Magnus effect, where intrinsic spin-orbit-like coupling of light generates a spin-dependent transverse displacement of the atom-light interaction profile for a ${}^{40}{\mathrm{Ca}}^{+}$ ion. Probed on a quadrupole transition using a tightly focused beam, we observe displacements of the maximum in the profile of the effective interaction by several 100 nm originating from intrinsic longitudinal electric field components beyond the paraxial approximation. The tight focus of the beam induces additional transverse polarization gradients, which we characterize through a phase-sensitive measurement and spatial maps for different beam configurations. The results establish the physical basis of polarization-gradient interactions relevant to optical tweezer-based quantum control.

State-dependent conformational changes play a central role in molecular dynamics, yet they are often difficult to observe or simulate due to their complexity and ultrafast nature. One alternative approach is to emulate such phenomena using quantum simulations with cold, trapped ions. In their electronic ground state, these ions form long-lived Wigner crystals. When excited to high-lying electronic Rydberg states, the ions experience a modified trapping potential, resulting in a strong coupling between their electronic and vibrational degrees of freedom. In an ion crystal, this vibronic coupling creates electronic state-dependent potential energy surfaces that can support distinct crystal structures—closely resembling the conformational changes of molecules driven by electronic excitations. Here, we present the first experimental observation of this effect, by laser coupling a single ion at the center of a three-ion crystal to a Rydberg state. By tuning the system close to a structural phase transition, the excitation induces a state-dependent conformational change, transforming the Wigner crystal from a linear to a zigzag configuration. This structural change leads to a strong hybridization between vibrational and electronic states, producing a clear spectroscopic signature in the Rydberg excitation. Our findings mark the first experimental step toward using Rydberg ions to create and study artificial molecular systems.

Open questions in collisionless plasma dissipation can be addressed using space-based observations in different astrophysical environments, with implications for both astrophysical and laboratory plasma systems. We study a low-$\beta$, highly imbalanced, sub-Alfvénic stream observed by Parker Solar Probe (PSP) to identify and distinguish between signatures of stochastic heating (SH) and resonant heating (RH) by parallel ion cyclotron waves ($\parallel$-ICWs). Prior work studying this stream [Trevor A. Bowen et al., Stochastic heating in the sub-Alfvénic solar wind, Phys. Rev. Lett. 135, 255201 (2025)] showed that the SH rate, accounting for intermittency, matched the amplitude of the local energy transfer (LET) rate, while the RH rate did not. This comparison relied on a number of assumptions regarding the nature of the diffusive process and the calculation of the LET rate. We introduce a novel technique of inverting the proton guiding center equation to empirically measure velocity-space diffusion coefficients using three-dimensional proton velocity distribution functions, from the ion electrostatic analyzer (the Solar Probe Analyzer for Ions) on PSP. Measured diffusion coefficients are used to determine phase-space heating rates, leading to a calculation of a fully kinetic heating rate independent of assumptions made in prior work. We show that scale-dependent analytic expressions for SH via noncoherent fluctuations match the empirical measurements from PSP data, provided that we account for intermittency in the heating calculation. In contrast, the derived heating rates for SH that accounts for the effects of the helicity barrier and heating rates for RH via $\parallel$-ICWs do not peak in the same region of velocity space as the empirical measurements, nor do they reach the required magnitude. Our approach provides novel methodology to uniquely identify and constrain heating processes in collisionless plasmas and shows evidence of a Fokker-Planck-like diffusive process in the near-Sun solar wind.

Two-dimensional van der Waals (vdW) moiré superlattices have provided a powerful knob to engineer a plethora of new quantum states. However, extending such moiré engineering to one-dimensional (1D) vdW systems has remained challenging. Here, we report the creation of moiré-engineered electronic insulating states in a new 1D moiré superlattice by crystallographically aligning an armchair single-walled carbon nanotube (SWNT) to a two-dimensional hexagonal boron nitride (hBN) substrate. Remarkably, we observe the emergence of pronounced insulating states at the charge neutrality point and at full and half moiré fillings in lattice-aligned armchair SWNT/hBN heterostructures using low-temperature electrical transport measurements. In strong contrast, armchair SWNT devices without hBN alignment do not show any of these insulating behaviors, which provides compelling evidence of a significant 1D moiré effect. Our density functional theory and tight-binding calculations reveal that synergetic nanotube partial flattening and in-plane lattice reconstruction at the 1D moiré interface expand the most stable AB’ stacking regions (carbon on top of boron) and open sizable band gaps at both the charge neutrality point and full moiré fillings at the single-particle level. Our one-body theory predicts no band gaps at half moiré fillings, suggesting that electron correlation and/or Peierls distortion may give rise to these emergent insulating behaviors in our 1D moiré systems. Our Letter establishes a new and definite moiré engineering route for 1D vdW materials and opens an exciting avenue for exploring interaction-driven quantum phases in 1D.

The topological magnet ${\text{MnBi}}_2{\text{Te}}_4$ (MBT), with gapped topological surface state, is an attractive platform for realizing quantum anomalous Hall and axion insulator states. However, the experimentally observed surface state gaps fail to meet theoretical predictions, although the exact mechanism behind the gap suppression has been debated. Recent theoretical studies suggest that intrinsic antisite defects push the topological surface state away from the MBT surface, closing its gap and making it less accessible to scanning probe experiments. Here, we report on the local effect of defects on the MBT surface states and demonstrate that high defect concentrations lead to a displacement of the surface states well into the MBT crystal, validating the theorized mechanism. The local and global influence of antisite defects on the topological surface states are studied with samples of varying defect densities by combining scanning tunneling microscopy, angle-resolved photoemission spectroscopy, and density functional theory. Our findings identify a combination of increased defect density and reduced defect spacing as the primary factors underlying the displacement of the surface states and suppression of surface gap, guiding further development of topological quantum materials.

The emergence of chirality in the charge density wave (CDW) phase of $1T\text{−}{\mathrm{TiSe}}_2$ has recently attracted significant attention, yet its microscopic origin remains debated. The prevailing interpretation attributes chirality to a relative phase shift between the charge density components. Here, using density functional theory and symmetry analysis, it is demonstrated that such phase-shifted states entail prohibitive energy costs, rendering them unlikely candidates for the ground state. Instead, a nearly degenerate metastable CDW phase stacking order with monoclinic symmetry is identified that naturally breaks mirror and inversion symmetries. The CDW in $1T\text{−}{\mathrm{TiSe}}_2$ possesses a dual physical nature: The electronic charge redistribution is intrinsically bond modulated, while the periodic lattice distortion is atom-centered transverse. This spatial separation allows a specific optical coupling mechanism where circularly polarized light breaks the energetic degeneracy between chiral domains. These results reconcile conflicting experimental observations, identifying the “spontaneous” chirality observed in local probes as a statistical distribution of CDW phase stacking domains while establishing the mechanism for macroscopic, light-induced gyrotropic order.

We study boundary criticality at the Nishimori multicritical point of the two-dimensional (2D) random-bond Ising model. Using tensor-network methods, we construct a family of microscopic boundary conditions that incorporates both boundary-spin rotation and boundary disorder. We identify three conformal boundary fixed points, corresponding to free, fixed, and random boundary conditions, and map out the boundary renormalization group flows among them. We extract the corresponding boundary conformal data, including the boundary entropies and the scaling dimensions of boundary primary operators, which characterize the boundary universality class. At the free boundary fixed point, we uncover the multifractal scaling of boundary-spin fields. We further complement the numerical results with a controlled renormalization group analysis. Finally, we connect the boundary conformal data to quantum error-correcting codes, establishing a bridge between boundary universality class and boundary decoding threshold.

Nonreciprocal interactions have recently attracted growing interest in nonequilibrium physics. In particular, breaking action-reaction symmetry has been proposed as a mechanism for collective motion, yet controlled experimental realizations remain scarce. Here, we show that bidisperse colloidal suspensions driven by AC electric fields exhibit persistent active clusters sustained by nonreciprocal electrohydrodynamic interactions. Size-asymmetric particle pairs spontaneously self-propel due to imbalanced electrohydrodynamic attraction, producing clusters that continuously fragment and reorganize rather than coarsening into static aggregates as in monodisperse systems. Agent-based simulations reproduce the observed dynamics and identify nonreciprocal pair propulsion as the minimal ingredient for the persistent cluster dynamics. These results demonstrate that action-reaction symmetry breaking in electrohydrodynamic interactions can arrest coarsening and sustain dynamically reconfigurable collective states in dense colloidal suspensions.

We show that the orbital angular momentum (OAM) of electrons is dynamically induced by circularly polarized phonons. The induced OAM originates from the adiabatic evolution in which electrons acquire Berry phase formulated in terms of the Berry curvature encoded in phonon displacement space. By introducing a tight-binding model with $p$ orbitals on a honeycomb lattice, we show a microscopic picture that ionic rotations modulate orbital overlaps of electrons, and calculate the generated OAM, whose sign depends on phonon chirality. We then construct an effective model for valley phonons with different phonon pseudoangular momenta and identity their distinct intervalley-scattering channels. Our model obeys the selection rule between phonons and electrons with the orbital degree of freedom. Extending this framework to $d$-orbital electrons, our model is applied to describe the induced OAM in monolayer transition metal dichalcogenides. Our results reveal a direct orbital generation mechanism that emerges even in materials with weak spin-orbital coupling, opening a new promising way for orbitronics applications.

We theoretically investigate orbital accumulation driven by chiral phonons via orbital-dependent electron-lattice coupling. We derive a formula for the orbital accumulation induced by classical lattice dynamics or nonequilibrium phonons, emphasizing the rectified second-order response of the orbital moment to lattice displacement. We show that chiral phonons primarily couple to orbital quadrupole moments and that static orbital dipole accumulation can be generated at second order in the lattice displacement. Our Letter provides a useful method for generating orbital accumulation without using spin-orbit interactions and suggests a strategy to boost its magnitude by harnessing band structure hot spots associated with orbital degeneracy.

The primordial power spectrum of matter density perturbations contains highly valuable information about new fundamental physics, in particular cosmological inflation, but is only very weakly constrained observationally for small cosmological scales $k\gtrsim 3{\mathrm{Mpc}}^{-1}$. We derive novel constraints, ${\mathcal{P}}_{\mathcal{R}}(k)\lesssim 5\times {10}^{-6}$ over a large range of such scales, from the formation of ultracompact minihalos in the early universe. Unlike most existing constraints of this type, our results do not rest on the assumption that dark matter can annihilate into ordinary matter.

The first search for the lepton-flavor violating decays $B^{+}\to {\pi }^{+}{\mu }^{\pm }{e}^{\mp }$ in proton-proton collisions is presented, using data collected by the LHCb experiment between 2011 and 2018, corresponding to an integrated luminosity of $9{\mathrm{fb}}^{-1}$. No significant signal is observed and an upper limit on the branching fraction is set at $\mathcal{B}(B^{+}\to {\pi }^{+}{\mu }^{\pm }{e}^{\mp })<1.8\times {10}^{-9}$ at the 90% confidence level, 2 orders of magnitude more restrictive than the most stringent upper limit to date. This is the first constraint on lepton-flavor violating $b\to d$ quark transitions at the LHC and also sets the most stringent upper limits to date on $b\to d{\mu }^{\pm }{e}^{\mp }$ transitions. Limits on left-handed and scalar scenarios beyond the standard model are also reported.

The precise quantification of fusion suppression in heavy-projectile induced reactions is obscured by dominant noncompound processes, limited data, and uncertain models. Mass-total kinetic energy (MTKE) distributions for the reaction ${}^{54}\mathrm{Cr}+{}^{209}\mathrm{Bi}$ were measured at three beam energies, $E_{\mathrm{beam}}=261$, 271, and 278 MeV. The fission fragments were detected using the newly developed TOSCA spectrometer setup. This Letter reveals, for the first time, two asymmetric mass modes at $\sim 80\mathrm{u}$ (complementary $\sim 183\mathrm{u}$), and $\sim 105$ u (complementary $\sim 158\mathrm{u}$), likely associated with the spherical $N=50$ shell and the deformed $Z\approx 42/N\approx 94$ shells, respectively. At the lowest energy, the symmetric mode exhibits a narrow, super-short-like width and high correlated TKE caused likely by $Z=50$, $N=82$ shells. The fusion probability (${\mathrm{P}}_{\mathrm{CN}}$) from multi-Gaussian fits to gated mass (and TKE) distributions using a refined tail-subtraction approach to remove the quasifission background remains robust despite model dependence. $P_{\mathrm{CN}}$ peaks near the barrier and decreases on either side, with a slower decrease at the above-barrier energy, differing from the sub-barrier fusion enhancement reported in [Phys. Rev. Lett. 122, 232503 (2019)] and indicating an open question for further study.

Lagrangian measurements of tracer particle dispersion in stratified turbulence are presented from a large-scale experiment achieving both high buoyancy Reynolds numbers and low Froude numbers—a regime characteristic of oceanic conditions. Stratification has a pronounced effect on the vertical particle dispersion, which is observed to be constrained to distances on the order of the buoyancy scale $w_{\mathrm{std}}/N$, where $w_{\mathrm{std}}$ is the standard deviation of the vertical velocity and $N$ is the Brunt-Väisälä frequency. As expected in strongly nonlinear, stratified turbulence, the frequency spectrum of the Lagrangian velocity becomes isotropic at frequencies higher than $N$. The spectral decay follows a $1/f^3$ scaling, which contrasts with the $1/f^2$ behavior typical of homogeneous isotropic turbulence. At time scales corresponding to internal waves, the statistics of velocity increments remain Gaussian, consistent with the weakly nonlinear regime of wave turbulence. At smaller scales, however, the flow exhibits strongly non-Gaussian statistics, indicative of fully nonlinear turbulent dynamics driven by wave breaking.

Elemental superconductors serve as essential model systems because their compositional simplicity enables fundamental mechanisms to be probed with minimal extrinsic complexity. Their superconducting transition temperatures ($T_{\mathrm{c}}$), however, are generally low, with the notable exception of scandium, which reaches 36 K at 260 GPa—the highest $T_{\mathrm{c}}$ reported for any elemental material. Although bulk boron is semiconducting at ambient pressure, two-dimensional boron monolayers (borophenes) exhibit rich structural polymorphism, and several phases are predicted to be superconducting with $T_{\mathrm{c}}$ values of 3.7–27.6 K, limited by relatively weak electron-phonon coupling. Here, we show that borophene bilayers, stabilized by interlayer B-B bonds, unexpectedly enhance the electronic density of states near the Fermi level and promote cooperative electron-phonon interactions, in which $p_{\text{x},\text{y}}$ states couple to in-plane phonons and $p_{\text{z}}$ states to out-of-plane modes. A high-throughput search of more than 9000 bilayer configurations identifies an $AA$-stacked, low-energy $v_{1/7}$ structure with $T_{\mathrm{c}}\approx 68\mathrm{K}$, setting a new record for elemental superconductivity.

We investigate Bloch oscillations in a lattice system featuring a momentum gap ($k$ gap), where in-gap modes exhibit exponential growth or decay. We demonstrate that the interplay of $k$-gap amplification, attenuation, and interband interference gives rise to a critical regime, where the wave packet alternates between the growing and decaying channels, forming a period-doubled oscillation with globally stable intensity under critical driving—a phenomenon we term self-balanced Bloch oscillations. This self-balance arises from phase-accumulation-dependent selection of the $k$-gap channels during band traversal, as confirmed by numerical simulations and spectral analysis. This mechanism, broadly applicable to $k$-gap-engineered systems, not only enables intrinsic stabilization beyond mere amplification but also offers a powerful route for controlling wave propagation in time-varying media and non-Hermitian physics.