In this work, we propose a one-dimensional $t\text{−}J\text{−}K\text{−}U$ model, where itinerant spin-1/2 fermions are coupled to a spin-1/2 Heisenberg chain via a Kondo interaction $J_k$. Depending on the sign of $J_k$, the system realizes either a high-spin or low-spin ground state. Using the density matrix renormalization group (DMRG) calculations, we demonstrate the emergence of a pairing density wave (PDW) with wave vector $Q=\pi$ in this model. In the low-spin state, the ground state of the system is identified as a Luther-Emery liquid. In the high-spin state, superconducting pairing correlations are suppressed, and a quasi-long-range (QLR) spin density wave (SDW) emerges. In addition to the Kondo coupling $J_K$, strong correlations among the itinerant electrons also play a significant role in stabilizing these density wave orders. We suggest that this model may be realized in a ${\mathrm{Ni}}^{2+}$ chain with Ni in the $d^8$ configurations. Although superconductivity has not yet been observed in these materials, charge and spin ordering phenomena have been widely reported. Our results provide a potential pairing mechanism, indicating the possible existence of these intertwined orders in nickelates.

We investigate the localization properties of non-Hermitian bound states in the nonreciprocal two-particle Hubbard model. Remarkably, under the conditions of finite-size truncation, non-Hermitian skin effect (NHSE), bound-state localization (BSL), and topological edge localization will compete with each other, giving rise to diverse density profiles. When BSL and NHSE favor different direction of localization, bound states can either be destroyed or survive depending on the strength of nonreciprocal tunneling and two-particle interaction. For the unbound scattering states, unlike the exponential localization predicted by the Hatano-Nelson model, interaction can get the total localization split into multiple centers. Meanwhile, apart from non-Hermitian bound states out of continuum, non-Hermitian bound states in continuum can also be achieved as a by-product of the multiple independent tunneling factors. Besides, we not only consider the bosonic but also the fermionic interacting model, where in the latter case, localization properties are greatly enriched by the configuration space boundary caused by Pauli exclusion rule, and the non-Hermitian near-bound states are proposed. Finally, to achieve nontrivial topology, we include terms taking the form of two-photon tunneling, and the competition among all three localization mechanisms is analyzed via the transfer matrix approach, where the unique phenomenon, NHSE oriented by two-particle interaction, is demonstrated.

The realization of a Weyl semimetal hosting a minimal single pair of Weyl points (WPs) is a long-standing goal for fundamental studies of chiral fermions, yet remains elusive in nonmagnetic electronic materials. Here, through first-principles calculations and symmetry analysis, we propose a stable, all-${\mathit{sp}}^2$ hybridized three-dimensional carbon allotrope, $\mathrm{HSRDC}\text{−}{\mathrm{C}}_{28}$. Crucially, its low-energy bands host exactly one pair of WPs at the time-reversal-invariant momenta $\mathrm{\Gamma }$ and M, carrying topological charge $C=\pm 2$, with the sign of the charge tied to the structural chirality. These WPs exhibit characteristic anisotropic dispersions, linear along the $C_4$-rotation axis and quadratic in the plane perpendicular to this axis, and are protected by $C_4$-rotation and time-reversal symmetries. The calculated surface states exhibit ultralong double-Fermi arcs connecting the projections of $\mathrm{\Gamma }$ and M, spanning the entire surface Brillouin zone and providing unambiguous signatures for experimental verification. Our work not only expands the landscape of topological quantum states but also offers a nonmagnetic electronic platform for exploring the physics associated with minimal double-Weyl fermions.

High-pressure, high-temperature synthesis is a valuable technique for the investigation of binary systems because it enables the stabilization of new phases that are metastable at ambient pressure and temperature. Because of its low bulk modulus, the atomic radius of Mg undergoes a large shrinkage above the GPa range, which can lead to the stabilization of potential new structures with other transition-metal (TM) elements. The present study reports on the synthesis and characterization of a Mg–Fe intermetallic phase in aser-heated diamond anvil cells (LH-DAC) on the ID27 beamline of the ESRF, above $1200{}^{\circ }\mathrm{C}$ and from 30 GPa to 60 GPa. The compound crystallizes in the cubic $P{4}_{1}32$ space group with $\beta$-Mn structure as a prototype (Strukturbericht designation $A13$). Several isobaric heating experiments as well as a temperature-controlled decompression were performed on this $A13$ phase, observed to be stable in two different compositions of Fe–Mg samples obtained by physical vapor deposition (PVD) (48 at.% Mg and 68 at.% Mg). Additional first-principles calculations on ordered and disordered phases were also performed to support the experimental work. A thermal equation of state of the $A13-{\mathrm{Fe}}_2{\mathrm{Mg}}_3$ phase is proposed, as well as a diagrammatic interpretation, taking into account the experimental results with the corresponding binary phase diagrams on the Mg-rich side.

Non-Hermitian physics has drawn tremendous attention in both fundamental physics and potential applications. Recent progress has witnessed a surge of research on non-Hermitian skin effects (NHSEs), where wave dynamics exhibits unconventional behaviors like non-Hermitian amplifications/attenuations, sticky effects, and edge bursts. In previous studies, the dynamics of NHSEs was often treated as the propagation of a single wavepacket. Here, we provide a novel perspective by exploring the multiwavepacket dynamics of NHSEs. This is realized by introducing nonreciprocal long-range couplings into the non-Hermitian Hatano-Nelson (HN) model. It is shown that by tuning the coupling strengths based on the periodic boundary condition (PBC) spectrum, the emergence, number, propagation directions, and intensities of multiple wavepackets in the bulk can be effectively controlled. Based on the open boundary condition (OBC) spectrum, the full temporal evolution and physical origins of the non-Hermitian wavepackets can be exactly captured. The PBC and OBC spectra complement each other, enabling both flexible manipulation and rigorous interpretation of multiple wavepackets, forming a complete theoretical framework for NHSE multiwavepacket dynamics. Furthermore, beyond using the stationary spectrum to understand and control multiwavepacket dynamics, we elucidate the time-dependent excitation methods for manipulating the relative intensity of different wavepackets in systems with and without loss. In particular, we identify the crucial role of the real part of the excitation frequency in selectively exciting different wavepackets. Our results reveal the rich dynamic properties of NHSEs and offer new insights for non-Hermitian wave manipulations in both spatial and temporal domains.

The production and evolution of radiation damage constitute a complex, multiscale process involving a wide range of physical mechanisms. Since electronic stopping represents the primary channel for energy dissipation by high-energy ions, it can be reasonably inferred that electrons play a significant role in high-energy irradiation damage cascades. This fundamental perspective, however, has largely overlooked the role of electronic effects in the regime of low-energy radiation damage. Moreover, the scarcity of reliable electronic stopping data for low-energy ions further hinders the investigation of electronic effects in low-energy radiation damage. This research combines real-time time-dependent density functional theory for electron dynamics with molecular dynamics simulations of collision cascades to examine the multiscale characteristics of irradiation damage. The basic molecular dynamics model, along with its extensions, the electronic energy loss model and the two-temperature model, are employed to explore the roles of electronic stopping and electron-phonon coupling during the collision cascade and in the resulting defects surviving. We show the respective roles of electronic stopping and electron-phonon coupling in shaping the defects produced by low-energy irradiation damage.

The pursuit of high-speed, low-power spintronic devices has driven extensive research into the anomalous Hall effect (AHE) in antiferromagnets. Concurrently, the topological Hall effect (THE), a hallmark of chiral spin textures, has emerged as a critical probe of nontrivial magnetism. Here, we report the synthesis and physical properties of ${\mathrm{V}}_{1/4}{\mathrm{NbSe}}_2$, a centrosymmetric van der Waals antiferromagnet with a $2\times 2$ superlattice structure. It exhibits two successive antiferromagnetic (AFM) transitions: a paramagnetic-to-AFM1 transition at $T_N$ = 14.7 K, followed by an AFM1-to-AFM2 transition below $T_t\approx$ 6.4 K. Magnetic characterization reveals dominant AFM interactions, weak magnetocrystalline anisotropy, and nonlinear magnetization suggestive of a spin-flop-like transition. Electrical transport demonstrates coexisting AHE and THE phenomena. The AHE, which is likely dominated by the intrinsic mechanism, peaks near $T_N$ with a conductivity of $\sim 160$ ${\mathrm{\Omega }}^{-1}{\mathrm{cm}}^{-1}$. Notably, the THE emerges exclusively within the AFM2 phase, suggesting its origin of a field-induced nonzero scalar spin chirality. Magnetoresistance exhibits butterfly-shaped hysteresis loops stemming from spin-dependent electron scattering. These phenomena collectively point to an intricate magnetic ground state in the absence of Dzyaloshinskii-Moriya interaction, warranting further investigation to unravel the underlying spin configuration.

Precise control of emergent magnetic monopoles in artificial spin ice is pivotal for topological spin-based circuitry. We model a square-ice lattice on a “rotating squares” kirigami scaffold, so a single mechanical rotation angle $\theta$ reprograms dipolar couplings. Monte Carlo simulations and analytic results show $\theta$ not only drives a specific type of Dirac string tension through zero, reverses bound monopole motion, but also slows down and collimates the collective motion of multiple monopoles along nearly straight strings. The cut-and-fold design is based on a geometric principle that is inherently scale- and material-independent, offering a versatile route to reconfigurable ‘‘magnetricity’’ devices; the specific magnetic functionality, however, is determined by the chosen material and dimensions.

We propose a disorder-free one-dimensional single-particle Hamiltonian hosting an exact mobility edge (ME), placing the system outside the assumptions of no-go theorems regarding unbounded potentials. By applying a linear Stark potential selectively to one sublattice of a dimerized chain, we generate an effective Hamiltonian with unbounded, staggered hopping amplitudes. The unbounded nature of the hopping places the model outside the scope of the Simon-Spencer theorem, while the staggered scaling allows it to evade broader constraints on Jacobi matrices. We analytically derive the bulk spectrum in reciprocal space, identifying a sharp ME where the energy magnitude equals the intercell hopping strength. This edge separates a continuum of extended states from two distinct localized branches: a standard unbounded Wannier-Stark ladder and an anomalous bounded branch accumulating at the ME. The existence of extended states is supported by finite-size scaling of the inverse participation ratio up to system sizes $L\sim {10}^9$. Furthermore, we propose an experimental realization using photonic frequency synthetic dimensions. Our numerical results indicate that the ME is robust against potential experimental imperfections, including frequency detuning errors and photon loss, establishing a practical path for observing MEs in disorder-free systems.

The existence of Anderson localization, characterized by vanishing diffusion due to strong disorder, has been demonstrated in numerous ways. A systematic approach based on the Anderson quantum model of the Fermi gas in random lattices that can describe both diffusive and localized regimes has not yet been fully established. We build on a recent publication [V. Janiš, New J. Phys. 27, 073503 (2025)] and present a microscopic theory of disordered electrons that covers both the metallic phase with extended Bloch waves and the localized phase, where a propagating particle forms a quantum bound state with the hole left behind at the origin. The general theory provides a framework for constructing controlled approximations to one- and two-particle Green functions that satisfy the necessary conservation laws and causality requirements across the full range of disorder strength. It is used explicitly to derive a local, mean-field-like approximation for the two-particle irreducible vertices, enabling quantitative analysis of the solution's dynamic properties in both metallic and localized phases, including critical behavior at the mobility edge. A new instability line for the dynamical electron-hole correlation function of the metallic phase is introduced.

Many new families of quasicrystal-forming magnetic alloys have been synthesized and studied in recent years. For small changes of composition, the alloys can go from quasiperiodic to periodic (approximant crystals) while conserving most of the local atomic environments. Experiments show that many of the periodic approximants order at low temperatures, with clear signatures of ferromagnetic or antiferromagnetic transitions, and also in some cases undergo nonequilibrium spin glass transitions. In contrast, the quasicrystals are mostly found to be spin glasses. Systematically studying these alloys could help elucidate the role played by quasiperiodicity in (de)stabilizing long-range magnetic order. In this work, we study cluster spin models with the aim of understanding the mechanisms behind various types of long-range magnetic ordering in approximants and quasicrystals. These models embody key features of real systems, and to some extent are analytically tractable, both for periodic and quasiperiodic cases. For the quasicrystal, we describe two possible types of ordered magnetic phases in frustrated regions of the phase diagram. Our results should serve to motivate more detailed numerical explorations of such models so as to gain a better understanding of magnetic phases in quasicrystalline systems.

We investigate a hybrid device consisting of two quantum dots placed between a BCS superconductor and a semiconductor with a strong spin-orbit interaction. Assuming charge tunneling between quantum dots through spin-flip processes, we study the molecular Andreev bound states appearing in the proximized quantum dots. We show that the spin-orbit coupling splits a pair of the Andreev states into four in-gap quasiparticles. For the appropriate set of model parameters, two of these internal quasiparticle states merge, forming the zero-energy state. Under such circumstances, we obtain fully spin-polarized versions of the Majorana quasiparticles, localized on different quantum dots. This happens solely when the spin-orbit interaction is equally strong to the magnitude of crossed Andreev reflections, i.e., in the sweet spot. Otherwise, these processes are competitive, as can be observed in changes of the expectation values of the corresponding order parameters. We analyze signatures of such competition manifested under the nonequilibrium conditions for various configurations of the bias voltage. In particular, for the symmetric bias voltage between the normal electrodes and the Cooper pair splitter bias configuration, we reveal duality in the transport properties. Charge transport through the zero-energy state at the sweet spot is contributed by perfectly entangled crossed Andreev reflections with an (almost) ideal transmission. Transport studies would thus enable empirical detection of the molecular quasiparticle states and the efficiency of dissipation processes caused by the external normal electrodes.

Bosonization describes Fermi surface dynamics in terms of a collective field that lives on a part of phase space. While sensible semiclassically, the challenge of treating such a field quantum mechanically has prevented bosonization from providing as powerful a nonperturbative tool as in one dimension. We show that general Fermi surfaces can be exactly described by a particular $N\to \infty$ limit of a $U{\left(N\right)}_1$ Wess-Zumino-Witten model, with a tower of irrelevant corrections. This matrix-valued description encodes the noncommutative nature of phase space, and its (solvable) strongly coupled dynamics resolves the naive overcounting of degrees of freedom of the collective field without the need to cut the Fermi surface into patches. This approach furthermore provides a quantitative tool to study power-law corrections to Fermi surface dynamics.

The clock speed of topological quantum computers based on Majorana zero mode (MZM)-supporting nanoscale devices is limited by the time taken for electrons to traverse the device. We employ the time-dependent Landauer-Büttiker transport theory for current cross-lead correlations in a superconducting nanowire junction hosting MZMs. From the time-dependent quantum noise, we are able to extract traversal times for electrons crossing the system. After demonstrating a linear scaling of traversal times with nanowire length, we present a heuristic formula for the traversal times which accurately captures their behavior. We then connect our framework to a proposed experimental verification of this discriminant between spurious and genuine MZMs utilizing time-resolved transport measurements.

We develop a quantum kinetic theory of two-dimensional electron gases in which exchange is treated self-consistently at the Hartree-Fock level and enters as a nonlocal, momentum-dependent field in phase space. By starting from the Coulomb Hamiltonian, we derive a Hartree-Fock-Wigner equation for the electronic Wigner function and obtain a closed fluid model with exchange-corrected pressure, force, and current. For a single layer, we show that exchange renormalizes the Fermi velocity and can drive a long-wavelength plasmonic instability at low densities. In coupled layers, the same framework predicts acoustic-optical mode coupling and an instability forming long-lived charge-imbalance patterns that are not predicted by classical Vlasov and Boltzmann models. Finally, we apply the kinetic model to the Coulomb drag problem and show how exchange substantially enhances the drag resistivity in dilute GaAs double wells, quantitatively matching experimental observations.

We investigated the local magnetism of the organic conductor $\kappa \text{−}{\left(\mathrm{ET}\right)}_2\mathrm{Hg}{\left(\mathrm{SCN}\right)}_2\mathrm{Cl}$ with a quasitriangular lattice of weakly dimerized molecules through ${}^{13}\mathrm{C}$ nuclear magnetic resonance (NMR) spectroscopy. The NMR spectra and nuclear relaxation show that charge disproportionation occurs, associated with the metal-insulator transition at 31 K. The relaxation rate indicates that the paramagnetic spins in the insulating phase undergo a transition into a spin-singlet ground state with the emergence of orphan spins, a possible valence-bond-glass state. The present results are in high contrast to the spin-cluster paramagnetism of the electric dipole-liquid candidate $\kappa \text{−}{\left(\mathrm{ET}\right)}_2\mathrm{Hg}{\left(\mathrm{SCN}\right)}_2\mathrm{Br}$, having nearly identical material parameters. This fact indicates that these two systems are on the verge between distinct phases in both charge and spin degrees of freedom; a spin-singlet charge-ordered state versus a spin-active Mott insulating state, competing with each other on a triangular lattice of dimerized sites.

The coupling of magnons and plasmons offers a promising avenue for hybrid quantum systems, facilitating coherent energy and information transfer between magnetic and charge excitations. However, existing mechanisms often depend on spin-orbit coupling or temperature-activated processes, limiting their robustness for low-temperature quantum technologies. Here, we propose a coupling mechanism between plasmons and the two-magnon continuum in antiferromagnetic insulators, which operates at zero temperature and does not require spin-orbit coupling. Using a model system consisting of a two-dimensional electron gas on an insulating antiferromagnetic substrate, we show that the electric field of the plasmons interacts with the magnetically mediated electric polarization in the antiferromagnet, arising from bonds with broken inversion symmetry. This interaction enables a strong coupling to the spin-conserving two-magnon continuum, allowing for efficient hybridization and reaching the ultrastrong coupling regime.