We investigate the properties of trions in transition-metal dichalcogenides (TMDCs) monolayers using the Gaussian expansion method (GEM) adapted to two-dimensional systems. Excitons and trions in monolayer TMDCs with the chemical composition ${MX}_2$ in the 2H phase are studied systematically. We computed the associated exciton and trion binding energies. We find, in addition to the known $J=0$ trion, the existence of a bound state with orbital angular momentum $J=1$. The results for $J=0$ are benchmarked against existing calculations from the stochastic variational method (SVM) and quantum Monte Carlo (QMC). Furthermore, we give further insight on the trion internal structure and geometry through their probability-density distributions, accounting for the effects of different materials. We also show that GEM—widely used in studies of strongly interacting few-body systems—is well adapted to allow comprehensive and computationally efficient investigations of trions in layered materials. In addition, we systematically explore the effect of strain and the dielectric environment on the $J=1$ trion predictions, illustrated for the ${\mathrm{MoS}}_2$ monolayer.

We demonstrate that conductance anomalies can arise in a clean, adiabatic quantum point contact when a channel is partially transmitting. Even for a smooth barrier potential, backscattering induces Friedel oscillations that, via electron interactions, generate a singular correction to the conductance. This correction is maximized when the channel is half-open, resulting in a reduction of conductance. In addition, a magnetic field applied perpendicular to the spin-orbit axis modifies the single-particle spectrum, resulting in conductance oscillations via Fabry-Pérot-type interference, as well as a nonmonotonic field dependence of the anomaly. Our findings reveal a universal mechanism by which interactions modify the conductance of an ideal partially open channel and offer a possible explanation for the anomalous features observed in experiments.

While nonstabilizerness (“magic”) is a key resource for universal quantum computation, its behavior in many-body quantum systems, especially near criticality, remains poorly understood. We develop a spectral transfer-matrix framework for the stabilizer Rényi entropy (SRE) in infinite matrix product states, showing that its spectrum contains universal subleading information. In particular, we identify an SRE correlation length—distinct from the standard correlation length—which diverges at continuous phase transitions and governs the spatial response of the SRE to local perturbations. We derive exact SRE expressions for the bond dimension $\chi =2$ matrix product states “skeleton” of the cluster-Ising model, and we numerically probe its universal scaling along the ${\mathbb{Z}}_2$ critical lines in the phase diagram. These results demonstrate that nonstabilizerness captures signatures of criticality and local perturbations, providing a new lens on the interplay between computational resources and emergent phenomena in quantum many-body systems.

Infinite projected entangled-pair states (iPEPS) provide a powerful tensor network ansatz for two-dimensional quantum many-body systems in the thermodynamic limit. In this paper, we introduce an approach to accurately compute the energy variance of an iPEPS, enabling systematic extrapolations of the ground-state energy to the exact zero-variance limit. It is based on the contraction of a large cell of tensors using the corner transfer matrix renormalization group method to evaluate the correlator between pairs of local Hamiltonian terms. We show that the accuracy of this approach is substantially higher than that of previous methods and we demonstrate the usefulness of variance extrapolation for the Heisenberg model, for a free fermionic model, and for the Shastry-Sutherland model. Finally, we apply the approach to compute $\langle \langle {\mathcal{L}}^{†}\mathcal{L}\rangle \rangle$ for an open quantum system described by the Liouvillian $\mathcal{L}$ in order to assess the quality of the steady-state solution and to locate first-order phase transitions, using the dissipative quantum Ising model as an example.

The sensitivity of low-dimensional superconductors to fluctuations gives rise to emergent behaviors beyond the conventional Bardeen-Cooper-Schrieffer framework. Anisotropy is one such manifestation often linked to spatially modulated electronic responses and unconventional pairing mechanisms. Pronounced in-plane anisotropy recently reported at ${\mathrm{KTaO}}_3$-based oxide interfaces has been interpreted as indicative of a stripelike superconducting texture, yet its microscopic origin and formation pathway remain unresolved. Here, we show that disorder in MgO/${\mathrm{KTaO}}_3$(111) heterostructures broadens the superconducting transition and reveals transport signatures suggesting a percolative evolution from localized superconducting coherence to a stripelike texture. The stripe width extracted from vortex-dynamical responses is comparable to the spin precession length, suggesting a self-organized modulation influenced by spin-orbit coupling and reduced lattice symmetry. These results highlight disorder as a tuning parameter for superconductivity in two-dimensional quantum materials.

We propose an alternative to the infinite density-matrix renormalization approach for accessing quantum many-body states within a finite-size calculation that faithfully mimics the thermodynamic limit. Our method constructs environment-matrix-product operators (environment-MPOs) representing the Hamiltonian of semi-infinite regions surrounding the target system. Starting from the finite-size ground-state matrix-product state, we contract its Hamiltonian representation to generate effective environment-MPOs, which are then attached to a renewed finite system in a recursive manner. This iterative embedding drives the system toward a bulklike state with negligible finite-size effects. The scheme requires no assumption of homogeneity and is applied to random-singlet state realized under quenched bond randomness, as well as to the real-time dynamics simulations where the boundary reflections of quasiparticles are efficiently delayed.

Intrinsic two-dimensional magnets serve as a good platform to explore collective, charge-neutral, and low-energy excitations. Distinguishing their crucial role in the experimental aspect remains a challenge for decades. Here, we study the thermal transport in honeycomb antiferromagnet ${\mathrm{MnPS}}_3$ with $T_{\mathrm{N}}=78$ K down to very low temperatures ($<0.01T_{\mathrm{N}}$). At high temperatures ($>0.1T_{\mathrm{N}}$), the field dependence of the thermal Hall conductivity exhibits a linear phonon Hall effect and a peak associated with the spin-flop transition due to a strong spin-lattice coupling, well reproducing the previous report [Phys. Rev. B 110, 165147 (2024)]. Notably, below 2 K, we find that the field dependence of the thermal Hall conductivity exhibits sign reversals within the spin-flop phase, at which the field dependence of the longitudinal thermal conductivity also shows multiple valleys. We suggest that these anomalies are caused by the redistribution of Berry curvature in magnon bands, demonstrating the superior performance of the thermal Hall measurements to detect the Berry curvature distributions in magnetic insulators.

We investigate Coulomb drag in a system of two capacitively coupled superconducting nanowires. In this context, drag refers to the appearance of a stationary voltage in the passive wire in response to a current bias applied to the active one. Quantum phase slips in the biased wire generate voltage fluctuations that can be transmitted to the other. Using perturbative and semiclassical approaches, we show that when both wires are superconducting the induced voltage vanishes due to exact cancellation of plasmon contributions. By contrast, when the second wire is tuned below the superconductor-insulator transition and develops a mass gap, this cancellation is lifted and a finite drag voltage emerges. The drag coefficient exhibits a crossover from weak drag in short wires to a maximal value set by the mutual capacitance in long wires. A semiclassical picture of voltage pulse propagation clarifies the physical origin of the effect: The mass term synchronizes plasmon modes and prevents complete cancellation of induced signals. Our results establish a mechanism of mass-induced Coulomb drag in low-dimensional superconductors and suggest different routes for probing nonlocal transport near quantum criticality.

In conducting films subjected to an out-of-plane magnetic field, electron motion along the field direction gives rise to conductance oscillations periodic in field intensity—a phenomenon known as Sondheimer oscillations. Traditionally, these oscillations were understood within the semiclassical framework of kinetic theory. However, their behavior in the quantum regime (i.e., at strong fields and weak disorder) remains unclear, particularly due to potential interference with quantum Shubnikov-de Haas magneto-oscillations. In this work, we develop a comprehensive theory of quantum magnetoconductivity oscillations in metallic films of finite thickness, fully capturing the interplay between the Sondheimer and Shubnikov-de Haas effects beyond the semiclassical limit. By treating surface scattering, in-plane Landau quantization, and dimensional confinement along the magnetic field direction on equal footing, we reveal an intricate hierarchy of oscillation patterns and characterize how their amplitudes and frequencies depend on various physical parameters. Our results pave the way for systematic characterization of thin metallic films with boundary-dominated transport properties.

We propose the superconducting diode effect (SDE) in a planar $s$-wave/$d$-wave/$s$-wave Josephson junction as a direct phase-sensitive probe of the $d$-wave pairing function in high-$T_c$ superconductors. Asymmetric interface coupling breaks inversion symmetry and induces a spontaneous $\pm \pi /2$ phase difference, thereby breaking time-reversal symmetry without a magnetic field. In this TRS-broken state, the SDE emerges when single-Cooper-pair tunneling is enabled at the s-d interfaces, with its polarity and efficiency controllable by rotating the $d$-wave crystallographic orientation or perturbing its intrinsic $C_4$ symmetry. Our results reveal a robust link between nonreciprocal Josephson transport and pairing symmetry, demonstrating the SDE as a powerful diagnostic tool for high-$T_c$ superconductors and a tunable element for superconducting electronics.

Deterministic quasiperiodicity in quantum systems has long been associated with localization, criticality, or glassy behavior, and has therefore been believed to suppress long-range order rather than stabilize it. Here, we demonstrate the opposite: quasiperiodicity in interactions—without any quasiperiodic potential, disorder, or geometric modulation—can generate coherent, ordered quantum phases. We study hard-core bosons in one dimension with quasiperiodic long-range interactions, $V_{ij}=V_{0}cos\left(\pi \alpha i\right)cos\left(\pi \alpha j\right)$, where $\alpha =(\sqrt{5}-1)/2$ is the inverse golden ratio. Using large-scale path-integral quantum Monte Carlo simulations, we uncover thermodynamically stable incompressible plateaus at irrational densities tied to Fibonacci ratios. These plateaus exhibit sharp incommensurate Bragg peaks, signaling an emergent quasisolid with long-range quasicrystalline density order. More strikingly, at nearby fillings and interaction strengths, we identify a quasisupersolid phase that supports both Fibonacci density ordering and finite superfluid density—demonstrating that interaction-induced quasiperiodicity can stabilize supersolid coherence. Our results establish a mechanism for realizing ordered quasicrystalline quantum matter, and suggest possible routes toward implementation in engineered platforms such as multimode cavity-QED systems, programmable Rydberg arrays, and trapped-ion quantum simulators.

Nonlinear exceptional points (NEPs), an emerging class of spectral singularities, are expected to address the challenges of noise divergence and complicated parameter tuning in linear EPs, attracting intense theoretical and experimental interest. Recently, however, it has been argued that the interplay between noise and nonlinearity degrades NEPs and thereby limits the performance of NEP-based applications, especially sensing. Here, we develop a rigorous framework to characterize this interplay and demonstrate the superior advantages of NEP. Taking NEP-based sensors—the most noise-affected case—as a representative example, we show that their signal-to-noise ratio (SNR), the core figure of merit, can be significantly enhanced at NEPs owing to a hidden nonlinear feedback mechanism. Our results advance the theoretical understanding of noise in nonlinear systems, resolve the ongoing debate on the SNR of NEP-based sensors, and take essential steps toward the practical realization of diverse NEP-related applications.

Sulfur and selenium demonstrate one of the most complex behavior under high pressure among all elements of the periodic table. Despite being known to form interchalcogens, the properties of these compounds have not been widely explored in the dense state. Through a series of diamond anvil experiments combined with x-ray diffraction, optical spectroscopy, and electrical resistance measurements, we explore the properties of selenium disulfide $\left({\mathrm{SeS}}_2\right)$ up to pressures of 150 GPa. At ambient pressure, ${\mathrm{SeS}}_2\text{−}\mathrm{I}$ represents a substitutional solid solution of S and Se atoms, forming an eight-membered molecular ring arrangement analogous to $\gamma$-S. The band gap of ${\mathrm{SeS}}_2\text{−}\mathrm{I}$ rapidly closes upon compression, and above 27 GPa, there is a transformation to a metallic tetragonal phase $\left({\mathrm{SeS}}_2\text{−}\mathrm{III}\right)$, in which atoms form square helical chains. Upon further compression, we observe a phase sequence from incommensurate modulated ${\mathrm{SeS}}_2\text{−}\mathrm{IV}$ above 59 GPa, transforming to rhombohedral ${\mathrm{SeS}}_2\text{−}\mathrm{V}$ by 116 GPa.

The layered van der Waals ${\mathrm{Fe}}_5{\mathrm{GeTe}}_2$ (F5GT) compound exhibits room-temperature ferromagnetism, making it a promising candidate for technological applications. In our study, combined temperature, wavelength, and polarization-dependent Raman measurements, along with ab initio calculations reveal important aspects of lattice dynamics and electron–phonon interactions. The angle-resolved Raman intensity under linear polarization configurations exhibits a strong tilt in the laboratory coordinate system, indicating the existence of anisotropic electron–phonon coupling. The temperature evolution of this anisotropy is discussed by extracting the phase factor of the Raman tensor elements from the angle-resolved intensity measured at different temperatures, also uncovering a spin–orbit coupling–mediated electron–phonon response in F5GT. The thermal evolution of electron–phonon coupling is also examined by measuring the temperature dependence of the Fano parameter of the asymmetric peak in the Raman spectra, while wavelength-dependent measurements establish the role of optical resonance in enhancing the anisotropic interaction. Finally, the threefold rotational symmetry guarantees the existence of chiral phonons. We present direct spectroscopic evidence for these chiral vibrational modes through cross-circularly polarized Raman measurements, complemented by theoretical calculations of phonon circular polarization. Together, these results identify F5GT as an ideal platform for investigating emergent couplings among lattice, electronic, and magnetic degrees of freedom and for advancing the understanding of chiral phonons in magnetic van der Waals materials.

Among the fundamental symmetry classes of quantum chaotic systems in Dyson's threefold way, the symplectic class is rarely observed in nature. Characterized by the strongest possible level repulsion in the energy spectrum, the symplectic symmetry class also implies a double (Kramers) degeneracy of levels. Studying the spectral statistics of three quantum particles (identical bosons or mass-imbalanced fermions) in a harmonic trap, we find numerical evidence for strong level repulsion in the regime of weak contact interactions. While the statistical indicators are consistent with quantum chaos in systems with symplectic symmetry, the absence of Kramers degeneracy rules out this symmetry. In the strongly interacting unitary limit either Poissonian or stick statistics are observed (depending on commensurability of the mass ratio) indicating regular dynamics. The transition between the regular and chaotic regimes as a function of interaction strength is well described by the Rosenzweig-Porter model. The system can be realized with cold neutral atoms in microtraps or in optical lattices.

The coherent mobility of doublons, arising from second-order virtual dissociation-recombination processes, fundamentally limits their use as information carriers in the strongly interacting Bose-Hubbard model. We propose a disorder-free suppression mechanism by introducing an optimized nearest-neighbor pair-hopping term that destructively interferes with the dominant virtual hopping channel. Using the third-order Schrieffer-Wolff transformation, we derive an analytical optimal condition that accounts for lattice geometry corrections. Numerical simulations demonstrate that this optimized scheme achieves near-complete dynamical arrest and entanglement preservation in one-dimensional chains, while in two-dimensional square lattices, it significantly suppresses ballistic spreading yet permits a slow residual expansion. Furthermore, in the many-body regime, finite-size scaling analysis identifies the observed long-lived density-wave order as a prethermal plateau emerging from the dramatic separation of microscopic and thermalization timescales.

We consider a generalization of the XXZ model on the sawtooth spin chain with Dzyaloshinskii-Moriya interactions in which all exchange constants (symmetric, antisymmetric, and axial anisotropy) are different for the three different bonds of each triangle. We derive and resolve algebraic constraints on the exchange constants ensuring the appearance of a flat band in the one-magnon spectrum. The properties of the corresponding flat magnon bands and localized magnon states are analyzed. We further construct the mapping of the flat-band conditions for the Dzyaloshinskii-Moriya constants onto the Katsura-Nagaosa-Balatsky parameters. Based on the mapping, the possibility of the electric-field-driven flat bands with the aid of the magnetoelectric coupling is examined.

We investigate a generalized Aubry-André-Harper (AAH) model with non-reciprocal hopping and power-law quasiperiodic potentials $V\left(i\right)=V{[cos\left(2\pi \beta i\right)]}^p$. Our study reveals that the interplay between nonreciprocity, quasiperiodicity, and the power-law exponent $p$ gives rise to a variety of phase transitions and localization phenomena. In the Hermitian case, the system undergoes a direct transition from extended to localized phases for $p=1,2$, while for $p\ge 3$, an intermediate mixed phase emerges, characterized by the coexistence of extended and localized states and the presence of mobility edges. Importantly, we find that prominent high-IPR states associated with well-resolved spectral gaps appear at specific energy levels, whose positions are captured by the relation $x_n=n\beta -\lfloor n\beta \rfloor$, for low-order $n$. In the non-Hermitian regime, the energy spectrum becomes complex and the $\mathcal{PT}$ transition coincides with the extended-to-localized phase boundary for $p=1,2$, whereas for $p\ge 3, \mathcal{PT}$-symmetry breaking occurs at the mixed-to-localized phase transition. This work reveals how power-law quasiperiodic potentials and nonreciprocal hopping govern phase transitions, providing new insight into localization phenomena of quasiperiodic systems.

Computational simulations are an important tool for understanding the magnetic properties of nanostructures that complement both experimental and analytical techniques. Among the different numerical techniques, micromagnetism offers tools for large systems; however, it presents difficulties when dealing with finite temperature and disorder at the atomic scale. Conversely, discrete-scale models, such as Monte Carlo, despite allowing temperature and disorder to be considered, are often computationally prohibitive. A promising solution is the scaling method that reduces the computational cost by simulating a smaller equivalent system with rescaled interactions. Traditional scaling of the exchange constant introduces complexities when handling temperature, external fields, and certain energy contributions, such as the Dzyaloshinskii-Moriya interaction (DMI). Therefore, in this paper, we revisit the scaling technique from a different perspective, proposing a change in the lattice constant instead of the exchange parameter. This approach offers simpler parametrization, naturally incorporates the DMI, and avoids the still unclear scaling of temperature and external fields. Our approach aims to provide a simpler and more robust tool for investigating a wide range of phenomena in nanostructured magnetic systems, including antiferromagnetic and complex interactions.

The spin Hall effect (SHE), a key mechanism for generating spin currents, is typically uniform in bulk materials. In topological materials, however, the layer degree of freedom offers a novel avenue to control spin transport. Here, we demonstrate a layer-resolved SHE in the intrinsic antiferromagnetic topological insulator $\mathrm{Mn}{\mathrm{Bi}}_2{\mathrm{Te}}_4$. Using first-principles calculations and linear response theory, we reveal that the surface layers exhibit a spin Hall conductivity opposite in sign to that of the inner layers. This unusual layer selectivity stems from an abrupt change of the axion angle at the surface, which inverts the spin current direction while preserving the spin polarization alignment between the surface and subsurface layers with antiferromagnetic coupling. Our work establishes layer engineering as a powerful tool for manipulating spin currents and opens avenues for designing layer-resolved spintronic devices.