Non-Hermitian systems with nonreciprocal hopping may display the non-Hermitian skin effect, where states under open boundary conditions localize exponentially at one edge of the system. This localization has been linked to spectral winding and topological gain, forming a bulk-boundary correspondence akin to the one relating edge modes to bulk topological invariants in topological insulators and superconductors. In this work, we establish a bulk-boundary correspondence for disordered Hatano-Nelson models. We relate the localization of states to spectral winding using the Lyapunov exponent and the Thouless formula. We identify two kinds of phase transitions and relate them to transport properties. Our framework is relevant to a broad class of 1D non-Hermitian models, opening alternative directions for disorder-resilient transport and quantum-enhanced sensing in photonic, optomechanical, and superconducting platforms.

We investigate quantum transport in aligned carbon nanotube (CNT) fibers fabricated via solution spinning, focusing on the roles of structural dimensionality and quantum interference effects. The fibers exhibit metallic behavior at high temperatures, with conductivity increasing monotonically as the temperature decreases from room temperature to $\sim 36\mathrm{K}$. Below this temperature, the conductivity gradually decreases with further cooling, signaling the onset of quantum conductance corrections associated with localization effects. Magnetoconductance measurements in both parallel and perpendicular magnetic fields exhibit pronounced positive corrections at low temperatures, consistent with weak localization (WL). To determine the effective dimensionality of electron transport, we analyzed the data using WL models in 1D, 2D, and 3D geometries. We found that while the 2D model can reproduce the field dependence, it lacks physical meaning in the context of our fiber architecture and requires an unphysical scaling factor to match the experimental magnitude. By contrast, we developed a hybrid $3\mathrm{D}+1\mathrm{D}$ WL framework that quantitatively captures both the field and temperature dependences using realistic coherence lengths and a temperature-dependent crossover parameter. Although this combined model also employs a scaling factor for magnitude correction, it yields a satisfactory fit, reflecting the hierarchical structure of CNT fibers in which transport occurs through quasi-1D bundles embedded in a 3D network. Our results establish a physically grounded model of phase-coherent transport in macroscopic CNT assemblies, providing insights into enhancing conductivity for flexible, lightweight power transmission applications.

We investigate from first principles a variety of low-dimensional open quantum spin systems based on magnetic nanographene structures that contain spin-1/2 and spin-1 triangulenes and/or olympicenes. These graphene nanostructures behave as localized spins and can be effectively described by a quantum bilinear-biquadratic Heisenberg Hamiltonian, for which we will compute the energy spectrum and the quantum numbers associated with the low-energy eigenstates. We propose the experimental realization of antiferromagnetic alternating spin chains using these graphene nanostructures, which result in ferrimagnetic systems whose ground state spin and degeneracy depend on the length of the chain. We identify a double degeneracy in the total spin quantum number $S$ of the first excited state in three-leg spin graphs (3-LSGs) and other heterospin nanostructures, which depends on both the number of sites and the spin species, and originates from the swapping transformation symmetry of the Hamiltonian. Numerical simulations indicate that this degeneracy remains largely robust for $N=7$ spin-1 3-LSGs under realistic perturbations present in experimental conditions.

We combine single-crystal neutron diffraction studies and Monte Carlo simulations to determine the spin structures and finite-temperature phase diagram of the spin-5/2 triangular-lattice antiferromagnet ${\mathrm{Na}}_2\mathrm{BaMn}{\left({\mathrm{PO}}_4\right)}_2$ in magnetic field. With the application of a magnetic field in two different directions, namely along the $c$ axis and in the $ab$ plane of the trigonal symmetry, we track the evolution of the spin structure through changes of the magnetic propagation vector. We account for these results with a minimal Heisenberg Hamiltonian that includes easy-axis anisotropy and weak, frustrated interlayer couplings in addition to intralayer exchange. Guided by representation analysis, we refine symmetry-allowed modes to the measured intensities and obtain the spin structures for all field-induced phases, which we compare quantitatively with simulated configurations. Taken together, our measurements and simulations show that frustrated interlayer exchange—rather than purely two-dimensional physics—organizes the unexpectedly rich field-induced phases of ${\mathrm{Na}}_2\mathrm{BaMn}{\left({\mathrm{PO}}_4\right)}_2$.

We investigate a hybrid modeling framework in which a quantum annealer is used to simulate magnetic interactions in molecular qubit lattices inspired by experimentally realizable systems. Using phthalocyanine assemblies as a structurally constrained prototype, we model a continuous deformation from a Lieb to a kagome lattice, revealing frustration-driven disorder and magnetic field-induced reordering in the spin structure. The goal is to show how a quantum annealer can operate as a physically instantiated, programmable platform to emulate experimentally relevant lattice deformations and produce observables in a manner analogous to an experimental measurement, enabling the characterization of magnetic arrangements beyond the reach of current molecular architectures. This surrogate modeling approach offers a pathway to explore and iteratively design tunable magnetic states in synthetic materials. The synthetic design, structural characterization, and quantum simulation framework established here defines a modular and scalable paradigm for probing the limits of engineered matter across chemistry, condensed matter, and quantum information science.

The magnetic spin Hall effect is a time-reversal-odd phenomenon in which spin current is induced by the charge current. In the presence of a spin-orbit coupling and/or noncolinear magnetism, however, spin current is not uniquely defined. Instead, we study an intrinsic response of spin to an electric field gradient that describes the spin accumulation at the boundaries of magnetic systems. We derive a generic formula expressed by Bloch wave functions and apply it to a minimal model for representative altermagnets, ${\mathrm{RuO}}_2$ and ${\mathrm{MnF}}_2$. Our results show that the intrinsic spin accumulation can be nonzero in magnetic insulators in sharp contrast to the magnetic spin Hall conductivity.

We investigate disorder-induced phase transitions in three-dimensional higher-order Weyl semimetals. Using the transfer matrix method to compute the localization length, we map out the global phase diagram. Remarkably, we uncover an emergent intermediate insulating phase separating the higher-order Weyl semimetal and diffusive metal regimes with increasing disorder strength, which is analogous to conventional Weyl semimetals but with a crucial distinction. While the intermediate phase manifests as a higher-order topological insulator in our system, it appears as a three-dimensional Chern insulator (3DCI) in standard Weyl semimetals. The existence of these insulating phases is intimately tied to interorbital disorder correlations: they persist for uncorrelated disorder but vanish when the disorder is magnetically correlated. Additionally, we reveal that the transition between Weyl and higher-order Weyl semimetal phases is mediated either by a 3DCI or by a hybrid Weyl semimetal phase hosting both conventional and higher-order Weyl points, depending crucially on the isotropy of hopping parameters.

Interactions in many-body systems are typically short-range and few-body. We investigate how such local interactions build up long-range and intrinsically multipartite entanglement by studying the $n$-partite Greenberger-Horne-Zeilinger $\left({\text{GHZ}}_n\right)$ entanglement in monitored random Clifford circuits, which is well-known for a measurement-induced transition between phases of volume-law and area-law (bipartite) entanglement. We obtain a series of results: (1) About 1.25 $|{\text{GHZ}}_3\rangle$ can be extracted from states in the volume-law phase. This value is remarkably universal, independent of both the measurement rate and partitioning details, until a phase transition (either measurement-induced or a newly identified partitioning-induced transition) is approached. (2) Dynamically, the creation (sometimes also the annihilation) of ${\text{GHZ}}_3$ entanglement occurs suddenly via dynamical phase transitions (DPTs). The critical points of these DPTs are governed by the entanglement speed $\left(v_E\right)$ of biaprtite entanglement. (3) In stark contrast to ${\text{GHZ}}_{n\le 3}$, ${\text{GHZ}}_{n\ge 4}$ entanglement is statistically significant only at the measurement-induced critical point, not in the bulk of the volume-law phase. Our results uncover a rich hierarchy of multipartite entanglement structures.

We report the observation of a phonon bottleneck effect impacting the thermal depopulation of photoexcited shallow defects in high-resistivity silicon. Using time-resolved terahertz (THz) spectroscopy, near-band-gap excitation produces a pronounced temporal delay in photoconductivity, indicating that a fraction of photogenerated charge carriers is temporarily trapped immediately after excitation. By analyzing the frequency-resolved complex photoconductivity as a function of pump-probe delay and photon energy, we attribute this delay to the presence of a localized shallow state situated approximately 40 meV from the band edge, which competes with silicon's indirect band-to-band absorption. The zero-order kinetic profile of the temporal delay, its invariance with respect to photon flux, and its temperature dependence collectively support the existence of a phonon bottleneck that hinders the thermal release of electrons from this shallow trap. this represents experimental evidence of a phonon bottleneck effect associated with the thermal activation of shallow traps in photoexcited silicon. These findings provide microscopic insight into carrier relaxation dynamics in silicon and highlight the significance of electron-phonon interactions in the ultrafast processes governing materials used in optoelectronic applications.

In this work, we show that the dispersion relation for the dynamical modes of dislocations (“dislons”) in solids is sensitive to the lattice symmetries. In particular, we show that, in the IR, the dislon dispersion relation develops a logarithmic dependence on momenta for approximately isotropic lattices, whereas for nonisotropic lattices, the linear term dominates. The renormalization group flows for dislocation tension are shown to be distinct for isotropic and anisotropic lattices.

We report the magnetic and transport properties of ${\mathrm{CeMn}}_{0.84}{\mathrm{Sb}}_2$ measured on single-crystal samples as well as the magnetic structures determined by neutron diffraction using a powder sample. The results of magnetic and transport measurements below room temperature show that ${\mathrm{CeMn}}_{0.84}{\mathrm{Sb}}_2$ exhibits metallic conduction and undergoes three magnetic transitions at $T_1,T_2$, and $T_3$, where $T_1>T_2>T_3$, indicating the existence of three distinct magnetic phases (I, II, and III). The magnetization and the magnetoresistance effect exhibit characteristic behaviors that can be ascribed to field-induced magnetic transitions. The results of powder neutron diffraction indicate the formation of antiferromagnetic orders with a propagation vector of (0, 0, 1/2) below $T_1$. Rietveld refinements reveal that the Mn moments align along the $c$ axis at 160 K (phase I) and cant toward the $ab$ plane at lower temperatures (phase II). With a further decrease in the temperature, both Mn and Ce moments order in phase III.

We investigate the phase diagram of a quantum mixed-spin $(1/2,1/2,1,1)$ Heisenberg tetramer chain featuring bond-alternating antiferromagnetic nearest-neighbor exchange interactions and single-ion anisotropy. This model exhibits a rich phase structure comprising three gapped phases: the antiferromagnetic, topological valence-bond-solid (TVBS), and the trivial nonmagnetic phases (TnM). We identify a multicritical Wess-Zumino-Witten $SU{\left(2\right)}_1$ point where two Ising critical lines merge, forming a higher-symmetry point that realizes conformal embedding on the lattice. Beyond this multicritical point, a Gaussian critical line emerges, determining the boundary between the TVBS and the TnM phases. Utilizing the tangential finite-size scaling method, we demonstrate the precision with which critical points and correlation length critical exponents can be extracted along this Gaussian line. Our results reveal rich critical phenomena induced by the interplay of bond-alternating exchange and anisotropic single-ion interactions in quantum many-body systems.

Elastic waves propagating in magnetic materials with significant coupling between spins and strains are able to efficiently generate coherent magnons, which represent advantageous signal carriers for information processing devices. Such strain-driven excitation of spin waves is especially important for antiferromagnets, where magnon frequencies can reach the terahertz (THz) range, thus enabling ultrafast data processing. Here, we report the micromagnetoelastic modeling of the spin dynamics arising in single-crystalline NiO films and NiO/Pt bilayers traversed by monochromatic longitudinal and transverse elastic waves, which can be generated by an attached optomechanical transducer. The strong magnetoelastic interaction inherent in this collinear antiferromagnet is described using the magnetoelastic energy density written in terms of the Néel-vector direction cosines. The simulations show that a monochromatic elastic wave propagating across the (001)-oriented NiO film creates a “forced” antiferromagnetic spin wave with the length and velocity controlled by the driving strain wave at any frequency of the latter. In addition, a “free” spin wave compatible with the dispersion of antiferromagnetic magnons is generated at the NiO surface. This wave is evanescent at excitation frequencies $\nu$ below the frequency ${\nu }_{\text{AFMR}}$ of the antiferromagnetic resonance, but it becomes propagating at $\nu >{\nu }_{\text{AFMR}}$. As the upper branch of the antiferromagnetic dispersion curve crosses the dispersion of longitudinal elastic waves, magnetoelastic waves with frequencies close to the crossing-point frequency can be generated in NiO as well. Performing the modeling of the NiO/Pt bilayer, we also determine the oscillating spin current created in Pt by the correlated precession of sublattice magnetizations in NiO. It is shown that the acoustically excited NiO can efficiently generate a spin current with a THz frequency, which gives rise to an alternating charge current in the Pt film and a THz electromagnetic wave above its free surface. Our theoretical results provide useful information for the development of energy-efficient magnon generators, spin injectors, and emitters of THz electromagnetic waves based on dynamically strained antiferromagnets.

The spontaneous breaking of noninvertible symmetries can lead to exotic phenomena such as the coexistence of order and disorder. Here, we explore second-order phase transitions in one-dimensional spin chains between two phases that correspond to distinct patterns of noninvertible symmetry breaking. The critical point shares several features with well-understood examples of deconfined quantum critical points, such as enlarged symmetry and identical exponents for the two order parameters participating in the transition. Interestingly, such deconfined transitions involving noninvertible symmetries allow one to construct a whole family of similar critical points by gauging spin-flip symmetries. By employing gauging and bosonization, we characterize the phase diagram of our model in the vicinity of the critical point. We also explore proximate phases and phase transitions in related models, including a deconfined quantum critical point between invertible order parameters that is enforced by a noninvertible symmetry.

Electronic topological transitions (ETTs) are characterized by abrupt changes in Fermi-surface topology, which can lead to pronounced anomalies in the physical properties of transition metals under high pressure-temperature ($P-T$) conditions. Zinc (Zn), a group-IIB transition metal with a fully occupied $3d$ shell and a highly anisotropic hexagonal structure, has been proposed to undergo a Lifshitz-type ETT at ∼6–10 GPa. However, its existence and thermodynamic characteristics at high P-T remained unresolved. Here, we investigate the longitudinal sound velocity of Zn up to ∼11 GPa and the electrical resistivity up to ∼20 GPa and ∼430 K under shock compression, using the reverse-impact configuration and four-probe technique, respectively. The sound velocity evolves smoothly with pressure across the investigated range, with no detectable elastic or structural anomalies. In contrast, the electrical resistivity exhibits a notable slope change at 14(1) GPa, followed by a steeper pressure dependence. This anomaly aligns with the pressure-induced ETT identified in static compression studies, but occurs at a higher critical pressure under shock loading. This shift highlights the influence of shock-elevated temperature and dynamic compression in delaying the onset of the transition. The more rapid increase in resistivity within the ETT is attributed to Fermi-surface reconstruction, which modifies band curvature, carrier effective mass, and scattering rates. These results provide strong experimental evidence for the ETT in Zn under high $P-T$ conditions, and demonstrate that dynamic resistivity measurements serve as a sensitive probe of subtle electronic transitions in transition metals.

Motivated by the newly discovered Co-based superconductor ${\mathrm{Na}}_2{\mathrm{CoSe}}_2\mathrm{O}$, we performed systematic calculations of its electronic band structures using the density functional theory plus the dynamical mean-field theory approaches. Our comparative studies reveal the weakly correlated and itinerant nature of the Co $3d$ electrons and show no sign of fluctuating local moments as expected in many other unconventional superconductors, although the Co $e_g$ orbitals are close to half filling. These suggest that ${\mathrm{Na}}_2{\mathrm{CoSe}}_2\mathrm{O}$ is a normal paramagnetic metal and its superconductivity might not be of strongly correlated nature, contrary to the initial speculation. We suggest future investigations of electron-phonon interactions to clarify its pairing mechanism.

We report a Cu $K$-edge resonant inelastic x-ray scattering (RIXS) study of spin excitations in the $S=1/2$ antiferromagnetic chain system ${\mathrm{Sr}}_2{\mathrm{CuO}}_3$. The spectral weight observed below the charge-transfer gap appears in two-spinon continuum, indicating the fractionalization of a spin-conserving ($\mathrm{\Delta }S=0$) magnetic excitation into two-spinon states. The intensity of these excitations reaches a maximum near the midpoint between the center and the boundary of the Brillouin zone, and decreases toward the zone boundary; this behavior contrasts with that of the spin-flip ($\mathrm{\Delta }S=1$) excitations typically observed via inelastic neutron scattering or Cu $L_3$-edge RIXS. The momentum dependence of the intensity is described by the spin-exchange dynamical structure factor. A phenomenological analysis of the symmetry between the polarization and the $d$ orbital explains the resonance condition for the two-spinon excitations.

Spatially modulated symmetries are one of the new types of symmetries the symmetry actions of which are position dependent. Yet exotic phases resulting from these spatially modulated symmetries are not fully understood and classified. In this work, we systematically classify one-dimensional bosonic symmetry-protected topological phases of multipole symmetries by employing the matrix product state formalism. The symmetry action induces projective representations at the ends of an open chain, which we identify via group cohomology. In particular, for $r$-pole symmetries—for instance, $r=0$ (global), 1 (dipole), and 2 (quadrupole)—the classification is determined by distinct components of second cohomology groups that encode the boundary projective representations.

Lead-free halide double perovskites $A_{2}M\left(\mathrm{I}\right)M\left(\mathrm{III}\right)X_6$ have garnered significant attention in the past decade as promising alternatives to $\mathrm{CsPb}{X}_3$ perovskites, addressing concerns related to lead toxicity and material instability. In this work, we employ a trivalent metal cation transmutation strategy to design a series of inorganic Pb-free halide double perovskites ${\mathrm{Cs}}_2\mathrm{Ag}M\left(\mathrm{III}\right){\mathrm{Cl}}_6$ and perform a comprehensive investigation into their potential for applications in optoelectronic devices. Our first-principles calculations, rooted in density functional theory, demonstrate that these materials possess a face-centered cubic lattice structure while showcasing remarkable thermodynamic, dynamical, and mechanical stability. The $G_0{W}_0$@PBE electronic band gap ranges from 1.47 to 6.20 eV, while the Bethe-Salpeter equation (BSE) indicates strong optical absorption spanning near-infrared to ultraviolet regions for these compounds. Furthermore, the excitonic properties suggest that these perovskites exhibit intermediate exciton binding energies (0.17 to 0.60 eV) and generally longer exciton lifetimes, except for the materials with $M$(III) = Sc, Y, Tb, and Lu. The Fröhlich model indicates that these materials exhibit intermediate to strong carrier-phonon interactions, with hole-phonon coupling more prominent than electron-phonon coupling. Interestingly, the charge-separated polaronic states are found to be less stable than the bound exciton states, with higher polaron mobility for electrons ($4.92–29.03{\mathrm{cm}}^2{\mathrm{V}}^{-1}{\mathrm{s}}^{-1}$) than for holes ($0.56–8.69{\mathrm{cm}}^2{\mathrm{V}}^{-1}{\mathrm{s}}^{-1}$) in these materials. Overall, our study demonstrates that trivalent metal cation transmutation in ${\mathrm{Cs}}_2\mathrm{Ag}M\left(\mathrm{III}\right){\mathrm{Cl}}_6$ enables the creation of stable and lead-free halide double perovskites with exceptional, tunable optoelectronic properties, making them ideal for flexible optoelectronic applications.