We introduce a new class of functional correlated disordered materials, termed gyromorphs, which uniquely combine liquidlike translational disorder with quasi-long-range rotational order, induced by a ring of $G$ delta peaks in their structure factor. We generate gyromorphs in 2D and 3D by spectral optimization methods, verifying that they display strong discrete rotational order but no long-range translational order, while maintaining rotational isotropy at short range for sufficiently large $G$. Using a coupled dipoles approximation, we numerically show that these structures outperform quasicrystals, stealthy hyperuniformity, and Vogel spirals in the formation of low-index-contrast isotropic band gaps in 2D, for both scalar and vector waves, and open complete isotropic band gaps in 3D. This claim is further supported by analytical effective-medium theory and by numerical estimates of scattering mean-free paths. Finally, we introduce “polygyromorphs” with several rotational symmetries at different length scales (i.e., multiple rings of delta peaks), enabling the formation of multiple band gaps in a single structure, thereby paving the way for fine control over optical properties.

X-ray magnetic circular dichroism provides a means to identify ferromagnetic, chiral, and altermagnetic orders via their time-reversal-symmetry ($\mathcal{T}$) breaking. However, the symmetry properties that govern circular dichroism (CD) in resonant inelastic x-ray scattering (RIXS) remain poorly understood. We show that, due to the inherent irreversibility of the RIXS process, RIXS-CD does not require $\mathcal{T}$ breaking to be present, but reflects the change in unitary symmetries associated with magnetic ordering. Using the altermagnetic MnTe as a model system, we observe an azimuthal-angle dependent RIXS-CD signal in the magnon excitations. Our findings highlight the sensitivity of RIXS-CD to the relativistic symmetry in magnetic systems and its potential application as a probe of magnetic domains.

We study the effects of an orbital magnetic field on the Mott metal-insulator transition in the Hubbard-Hofstadter model. We demonstrate that sufficiently large magnetic fields induce a Mott insulator-to-metal phase transition supporting our claim with dynamical mean field theory (DMFT) numerical results. For both competing phases (metal and insulator) we observe a magnetic-field-induced metallization reflected in an enhancement of kinetic and potential energy. The kinetic energy of the Mott insulator increases due to the Aharonov-Bohm effect experienced by electrons virtually tunneling around an elementary plaquette which is, however, suppressed by strong correlations. The kinetic energy of the metallic phase, on the other hand, is more strongly affected by the magnetic field through a field-driven redistribution of spectral weight due to the formation of magnetic minibands. This leads to an increase of the kinetic energy which tends to stabilize the metallic state. Our theoretical results might be relevant for recent experimental studies on magnetic field driven insulator-to-metal transitions in strongly correlated materials such as ${\mathrm{VO}}_2$, $\lambda$-type organic conductors, and moiré multilayers.

Altermagnets are a new class of magnetic materials that are promising for spintronics technology. Here, it is shown that in altermagnets, the circular dichroism (CD) in resonant photoelectron diffraction (RPED) contains a time-reversal odd signal, which provides a direct probe of the sublattice magnetization. RPED calculations are performed for MnTe at the Mn ${\mathrm{L}}_{2,3}$-edge resonance, using a combination of atomic multiplet and multiple scattering theory. A large magnetic CD is found for light helicity parallel to the Néel vector. This signal has the same angular distribution as the difference between the structural RPED of the two magnetic sublattices and its amplitude is approximately proportional to the x-ray magnetic CD in absorption of a single sublattice, thus providing a direct probe of the local magnetic moments.

Active fluids can develop spontaneous flow instabilities and complex patterns. However, spatiotemporal control of active particles has remained challenging, despite its relevance in biological and applied contexts. Here, we harnessed phototaxis to steer millions of swimming “puller” Chlamydomonas reinhardtii algae to create active jets and control both pearling and buckling instabilities through the preferential orientation of the cells. Our experiments, supported by a full analytical model and simulations, confirm long-standing predictions that self-generated flows can lead to jet destabilization. Our results further indicate that pullers can behave analogously to pushers when their orientation is properly tuned, and demonstrate how light enables the efficient control of active fluids.

Quantum mechanics suggests a persistent lattice vibration even at zero temperature; however, this elusive zero-point motion is difficult to measure for further analyses and exploitations. Here, we have performed near-resonant excitations on single perovskite ${\mathrm{CsPbI}}_3$ nanocrystals (NCs) at cryogenic temperatures, showing that pronounced up-converted photoluminescence (UC-PL) still takes place even at $\sim 4\mathrm{K}$ despite the vanishing phonon-assisted absorption. This surprising result can be explained in terms of a dynamic electric field caused by the zero-point motion of polar optical phonons, which gives rise to an absorption tail as in the Franz-Keldysh electroabsorption process. Furthermore, laser cooling is demonstrated in the $\sim 4\mathrm{K}$ UC-PL process of a single ${\mathrm{CsPbI}}_3$ NC, which opens a novel research avenue for the realization of even lower temperatures beyond the limit set forth by the helium-based cryostat.

Superconducting quantum computers leverage superconducting qubits, systems with well-defined energy levels, the spacing of which is determined by the properties of embedded Josephson junctions. Indeterminacy of Josephson junction manufacturing limits large-scale superconducting circuits; however, junction-by-junction tuning affords the possibility of an order of magnitude improvement of determinacy—although the origin of this tuning effect is uncertain. Understanding how tuning techniques may physically modify the tunnel barrier of a Josephson junction is important and will enable these techniques to be optimized. We develop a model of junction tuning based on depinning theory to interpret a phase diagram of the tuning rate. We extract the dependence on temperature, time-varying voltages, and oscillation frequency. Comparing the effect of junction tuning on room-temperature $I\text{−}V$’s, electrical breakdown, and frequency of higher-energy levels of transmon qubits indicates that the tuning process leaves the barrier thickness unchanged but modifies its composition.

Despite its tiny net magnetization, the antiferromagnetic (AFM) van der Waals material ${\mathrm{Co}}_{1/3}{\mathrm{NbS}}_2$ exhibits a large transverse Hall conductivity ${\sigma }_{xy}$ even at zero applied magnetic field, which arises, as recently shown, from the topological nature of its noncoplanar “tetrahedral” AFM order. This triple-$\mathbf{q}$ magnetic order can be regarded as the short-length-scale limit of a magnetic skyrmion lattice and has an intrinsic spin chirality. Here, we show, using optical wavelengths spanning the ultraviolet to infrared (400–1000 nm), that magnetic circular dichroism provides an incisive optical probe of the topological AFM order in ${\mathrm{Co}}_{1/3}{\mathrm{NbS}}_2$. Measurements as a continuous function of photon energy are directly compared with first-principles calculations, revealing the influence of the underlying quantum geometry on optical conductivity. Leveraging the power and flexibility of optical methods, we use scanning magnetic circular dichroism microscopy to directly image chiral AFM domains and demonstrate writing of chiral AFM domains.

Thermal Hall effect (THE) in insulators is a remarkable phenomenon that arises from the motion of chargeless quasiparticles under a magnetic field. While magnons or various exotic excitations were considered as the origin of THE in some magnetic materials, there is more and more evidence suggesting that phonons play a significant role. However, the mechanism behind phonon THE is still unknown. Here we report the observation of THE, including planar THE, in a broad range of nonmagnetic insulators and semiconductors: ${\mathrm{SrTiO}}_3$, ${\mathrm{SiO}}_2$ (quartz), MgO, ${\mathrm{MgAl}}_2{\mathrm{O}}_4$, Si, and Ge. While the presence of antiferrodistortive domains in ${\mathrm{SrTiO}}_3$ and chiral structure in ${\mathrm{SiO}}_2$ may complicate the interpretation of THE, the striking observations of THE in trivial insulators MgO and ${\mathrm{MgAl}}_2{\mathrm{O}}_4$, as well as in high-purity intrinsic semiconductors Si and Ge, demonstrate that phonon THE is a universal property of crystals. Without other effects on phonons such as from magnons, this universal phonon THE is characterized by a scaling behavior of $|{\kappa }_{xy}|\sim {\kappa }_{xx}^2$. Our results experimentally discover a fundamental physics of phonons in the magnetic field, which should come from the direct coupling between atom vibrations and the field. Starting from this universal phonon THE in crystals, previous interpretations of THE in magnetic or nonmagnetic materials need to be reconsidered.

Twisted magnetic van der Waals materials offer a promising route for multiferroic engineering, yet modeling large-scale moiré superlattices remains challenging. Leveraging a newly developed SpinGNN++ framework that effectively handles spin-lattice coupled systems, we develop a comprehensive interatomic machine learning potential and apply it to twisted bilayer ${\mathrm{NiI}}_2$. Structural relaxation introduces moiré-periodic “bumps” that modulate the interlayer spacing by about 0.55 Å and in-plane ionic shifts up to 0.48 Å. Concurrently, our machine learning potential, which faithfully captures all key spin interactions, produces reliable magnetic configurations; combined with the more accurate generalized Katsura-Nagaosa-Balatsky mechanism, it delivers precise spin-driven polarization. For twist angles $1.89°\le \theta \le 2.45°$, both mechanisms become prominent, yielding rich polarization textures that combine ionic out-of-plane dipoles with purely electronic in-plane domains. In the rigid (unrelaxed) bilayer, skyrmions are absent; lattice relaxation is thus essential for generating polar-magnetic topologies. In contrast, near $\theta \approx 60°$, stacking-dependent ferroelectric displacements dominate, giving rise to polar meron-antimeron networks. These results reveal cooperative ionic and spin-driven ferroelectricity in twisted bilayer ${\mathrm{NiI}}_2$, positioning twisted van der Waals magnets as adaptable platforms for tunable multiferroic devices.

The quantum anomalous Hall (QAH) effect holds fundamental importance in topological physics and technological promise for electronics. It is generally believed that the QAH effect can only be realized in insulators. In this Letter, we theoretically demonstrate that the QAH effect can also be realized in metallic systems, representing a phase distinct from the conventional QAH phase in insulators. This phase is characterized by the coexistence of chiral edge channels and isotropic bulk conduction channels without a bulk energy gap. Notably, in a six-terminal Hall bar, our calculations show that, the quantized Hall conductivity and nonzero longitudinal conductivity can emerge due to dephasing, despite the Hall resistivity itself never becoming quantized. Furthermore, the quantized Hall conductivity exhibits remarkable robustness against disorder. Our findings not only extend the range of materials capable of hosting the QAH effect from insulators to metals, but also provide insights that may pave the way for the experimental realization of the QAH effect at elevated temperatures.

We probe the spectrum of elementary excitations in ${\mathrm{SrIrO}}_3$ by using heterostructured [$({\mathrm{SrIrO}}_3{)}_m/({\mathrm{SrTiO}}_3{)}_l$] samples to approach the bulk limit. Our resonant inelastic x-ray scattering (RIXS) measurements at the Ir $L_3$ edge reveal a robust low-lying collective magnetic mode with an antiferromagnetic (AFM) dispersion similar to the insulators ${\mathrm{Sr}}_2{\mathrm{IrO}}_4$ and ${\mathrm{Sr}}_3{\text{Ir}}_2{\mathrm{O}}_7$, albeit with a large gap and much larger linewidth. At higher energies we find the spin-orbit exciton, also strongly broadened, but with an inverted dispersion and doubled periodicity that are controlled by the charge hopping. These results demonstrate that the AFM paramagnon persists, somewhat counterintuitively, far into the metallic regime of the insulator-metal transition driven by the degree of confinement in the heterostructure. We conclude that these two excitations, which are contrasting but coexisting hallmarks of strong AFM pseudospin and charge fluctuations in a spin-orbit-coupled Mott-Slater material, are properties intrinsic to the ground state of semimetallic perovskite ${\mathrm{SrIrO}}_3$.

Assuming the existence of an axionlike particle (ALP), beams of relativistic particles emit fluxes of quasireal ALPs, analogous to the photon fluxes described by Weizsäcker-Williams-type approximations. Consequently, ALP-ALP and ALP-photon collisions can occur at the LHC. We initiate the study of the LHC as an ALP collider, and show that ALP collisions provide competitive probes of certain ALP couplings. We show that ALP fluxes from heavy ions are suppressed relative to those from protons, unlike their photon counterpart. As a result, the most likely processes are ALP-photon collisions occurring in the proton-ion ($p\mathrm{A}$) ultraperipheral collisions. Using our implementation of ALP fluxes in simulation tools, we show that ALP-photon collisions in $p\mathrm{Pb}$ efficiently probe ALP couplings to third generation fermions. LHC data with realistic $p\mathrm{Pb}$ luminosity can constrain the product of ALP couplings to nucleons and top quarks at the level of $O(0.01{\mathrm{TeV}}^{-1})$. Notably, ALP-photon collisions naturally provide the leading probe of ALP flavor-violating couplings to the top quark. We suggest that the 2016 $p\mathrm{Pb}$ dataset collected at CMS, ATLAS, and LHCb should be explored for evidence of such collisions.

Disordered systems generically exhibit aging and a glass transition. Previous studies have long suggested that nonreciprocity tends to destroy glassiness. Here, we show that this is not always the case using a bipartite spherical Sherrington-Kirkpatrick model that describes the antagonistic coupling between two identical complex agents modeled as macroscopic spin glasses. Our dynamical mean-field theory calculations reveal an exceptional-point-mediated transition from a static disorder phase to an oscillating amorphous phase as well as nonreciprocal aging with slow dynamics and oscillations.

Counterdiabatic (CD) driving has the potential to speed up adiabatic quantum state preparation by suppressing unwanted excitations. However, existing approaches either require intractable classical computations or are based on approximations that do not have performance guarantees. We propose and analyze a nonvariational, system-agnostic CD expansion method and analytically show that it converges exponentially quickly in the expansion order. In finite systems, the required resources scale inversely with the spectral gap, which we argue is asymptotically optimal. To extend our method to the thermodynamic limit and suppress errors stemming from high-frequency transitions, we leverage finite-time adiabatic protocols. In particular, we show that a time determined by the quantum speed limit is sufficient to prepare the desired ground state, without the need to optimize the adiabatic trajectory. Numerical tests of our method on the quantum Ising chain show that our method can outperform state-of-the-art variational CD approaches.

We generalize Landauer’s theory of ballistic transport in a one-dimensional (1D) conductor to situations where charge carrier injection and extraction are not any more confined to electrodes at either end of the channel, but may occur along its whole length. This type of distributed injection is expected to occur from the two-dimensional (2D) bulk of, e.g., a quantum spin (or anomalous) Hall insulator to its topologically protected edge states. We apply our conceptual solution to the case of two metal electrodes contacting the 2D bulk, enabling us to derive criteria that discriminate ballistic from resistive edge channels in multiterminal transport experiments.

We show that interacting electrons in a flat Chern band can form, in addition to fractional Chern insulators, a chiral $f$-wave topological superconductor that hosts neutral Majorana fermion edge modes. Superconductivity emerges from an interaction-induced metallic state that exhibits anomalous Hall effect, as observed in rhombohedral graphene and near the $\nu =\frac{2}{3}$ fractional Chern insulator in twisted transition metal dichalcogenides.

In strong magnetic fields beyond 100 T, the significant Zeeman energy competes with the lattice interactions, where a considerable magnetostriction is expected. However, the microscopic observation of the magnetostriction above 100 T has been hindered due to the short pulse duration of microseconds and the coil’s destruction. Here, we report the observation of the giant and anisotropic magnetostriction of $\sim 1\%$ at 110 T in the spin-controlled crystal $\beta \text{−}{\mathrm{O}}_2$ by combining the single-shot diffraction of an x-ray free-electron laser (XFEL) and the newly developed portable 100 T generator (PINK-02). The soft and anisotropic response of $\beta \text{−}{\mathrm{O}}_2$ should originate in the competing van der Waals force and exchange interaction and also the frustration of spin and lattice on the triangular network. The XFEL experiment above 100 T using PINK-02 enables microscopic investigations on materials’ properties at high magnetic fields, providing insights into how spins contribute to the stability of crystal structures.

Acoustic forces occurring in resonant microfluidic chambers allow the handling of micrometer-sized particles. Trapping of nanoparticles has been shown for high particle concentrations and after preseeding the chamber with larger particles. We show that the trapping mechanism is due to synergy between hydrodynamic shielding and acoustic forces. Acoustic interactions are significant only when seed particles are involved and are negligible when trapping monodisperse particles. Density-selective nanoparticle trapping is suggested based on the numerical results.

The GW170817 neutron star merger event and the PREX-2 experiment probing neutron skin thickness provide crucial clues for understanding the nuclear equation of state (EoS). However, an apparent inconsistency exists between the tidal polarizability ${\mathrm{\Lambda }}^{1.4}$ inferred from GW170817 and the neutron skin thickness $R_{\mathrm{np}}^{208}$ of ${}^{208}\mathrm{Pb}$ measured by PREX-2, based on relativistic energy density functionals (EDFs). This Letter employs both relativistic and nonrelativistic EDFs to identify a multipole correlation involving ${\mathrm{\Lambda }}^{1.4}$, $R_{\mathrm{np}}^{208}$, and the symmetry energy curvature $K_{\mathrm{sym}}$ at saturation density. We demonstrate the essential role of $K_{\mathrm{sym}}$ in reconciling the conflicting ${\mathrm{\Lambda }}^{1.4}\text{−}{R}_{\mathrm{np}}^{208}$ correlations derived from nonrelativistic versus relativistic EDFs and in resolving the discrepancy between the GW170817 and PREX-2 data constraints. Furthermore, we obtain a joint constraint on $K_{\mathrm{sym}}$ from these datasets, providing a vital constraint on the symmetry energy of the nuclear EoS.