Recently, artificial intelligence for science has made significant inroads into various fields of natural science research. In the field of quantum many-body computation, researchers have developed numerous ground-state solvers based on neural-network quantum states (NQSs), achieving ground-state energies with accuracy comparable to or surpassing traditional methods such as variational Monte Carlo methods, density matrix renormalization group, and quantum Monte Carlo methods. Here, we combine supervised learning, variational Monte Carlo (VMC) and the Lanczos method to develop a systematic approach to improving the NQSs of many-body systems, which we refer to as the NQS Lanczos method. The algorithm mainly consists of two parts: the supervised learning part and the VMC optimization part. Through supervised learning, the Lanczos states are represented by the NQSs. Through VMC, the NQSs are further optimized. We analyze the reasons for the underfitting problem and demonstrate how the NQS Lanczos method systematically improves the energy in the highly frustrated regime of the two-dimensional Heisenberg $J_1\text{−}{J}_2$ model. Compared to the existing method that combines the Lanczos method with the restricted Boltzmann machine, the primary advantage of the NQS Lanczos method is its linearly increasing computational cost.

Predicting interfacial electronic properties with quantitative accuracy is essential for the rational design of next-generation electronic and optoelectronic devices. We present a nonempirical screened-exchange dielectric-dependent range-separated hybrid (SE-DD-RSH) functional, in which the fraction of exact exchange is determined by the inverse macroscopic dielectric constant, and the range-separation parameter consistently accounts for both bulk and surface screening. This physically grounded framework removes the need for empirical tuning and provides a transferable description of bulk, surfaces, and interfaces. Benchmark calculations demonstrate that SE-DD-RSH yields band offsets and ionization potentials for semiconductor-semiconductor and semiconductor-oxide interfaces in excellent agreement with experiment and $GW$ theory. Furthermore, the computed surface band structures and optical spectra closely reproduce $GW$-BSE results, confirming the accuracy and robustness of the approach. Overall, SE-DD-RSH offers a computationally efficient and predictive first-principles route for modeling interfacial electronic and optical properties across diverse material systems.

Simulating the dynamics of quantum many-body systems with disorder is a fundamental challenge. In this work, we propose a general approach—the statistics-encoded tensor network (SeTN)—to study such systems. By encoding disorder into an auxiliary layer and averaging separately, SeTN restores translational invariance, enabling a well-defined transfer-matrix formulation. We derive a universal criterion, $n\gg {\alpha }^2{t}^2$, linking discretization $n$, disorder strength $\alpha$, and evolution duration $t$. This sets the resolution required for faithful disorder averaging and shows that encoding is most efficient in the weak-disorder, typically chaotic regime. Applied to the disordered transverse-field Ising model, SeTN shows that, over the numerically accessible time window, the spectral form factor is governed by the leading transfer-matrix eigenvalue, in contrast to the kicked Ising model. SeTN thus provides a novel framework for probing the disorder-driven dynamical phenomena in many-body quantum systems.

By using the zone-melting method, we have grown a series of narrow-gap, semiconducting single-crystalline ${\mathrm{Bi}}_{1-x}{\mathrm{Sb}}_x$ alloys ($0.09\le x\le 0.20$) with centimeter-scale single grains of uniform composition, and systematically investigated their thermoelectric properties. Due to the combination of a significant Seebeck coefficient and reduced thermal conductivity, the in-plane thermoelectric figure of merit $ZT$ achieved approximately 0.35 at 150 K. This $ZT$ value shows minimal variation—less than 30%—across the entire composition range. Furthermore, the $ZT$ value of the single-crystalline alloy reaches an outstanding 0.48 at 100 K when both electric current and heat flow are aligned with the direction of the $c$ axis. We establish a universal scaling relation between the energy gap and the temperature-dependent Seebeck coefficient for the entire series of alloys within their intrinsic semiconducting temperature range. This scaling relation indicates that the large Seebeck coefficient arises from the pronounced asymmetry in the conductivity and effective masses of the electron and hole bands.

We present a variational-empirical model describing the magnetic-field dependence of exciton energies in two-dimensional semiconductors. We focus on Rydberg excitons in monolayer transition metal dichalcogenides (${\mathrm{MoS}}_2, {\mathrm{MoSe}}_2, {\mathrm{MoTe}}_2, {\mathrm{WS}}_2$, and ${\mathrm{WSe}}_2$) encapsulated by hexagonal boron nitride. Using a variational parameter, the model yields exciton binding energies at zero magnetic field in reasonable agreement with experimental results from helicity-resolved magnetophotocurrent spectroscopy. Adding two empirical parameters, the model is able to predict the magnetic-field dependence of exciton energies. The model describes the diamagnetic shift and gives exciton radii as well as diamagnetic coefficients in reasonable agreement with experimental data from magneto-optical spectroscopy measurements.

An obstacle to utilizing the entangled photons nowadays is the low efficiency of their creation. As a solution, we consider the generation of coherent photons using coupled graphene quantum dot (GQD) lasers activated with a short voltage pulse. To illustrate the method, we analyze the terahertz (THz) sensing with undetected photons. The simulation results suggest that the GQD setup offers attractive advantages compared to the former approaches. They are (i) generation efficiency is improved by 3 to 4 orders of magnitude, (ii) easier frequency tunability, and (iii) the room temperature performance.

By analyzing the spin-group symmetry of magnons, we establish two generalized Onsager's relations in the magnon thermal Hall effect, which reveals the rich and complicated structures of the magnon Berry curvature in the parameter space of different types of the exchange coupling. As an important consequence, we find that the diagonal and off-diagonal part of the symmetric anisotropic exchange coupling together can support the planar magnon thermal Hall effect without the DM interaction. This removes the local inversion-symmetry-breaking condition for generating the magnon thermal Hall effect. Moreover, we predict an exotic phenomenon that the thermal conductivity exhibits angular dependence with respect to the in-plane magnetization. Our work lays the ground for decoding the coupling between magnon transport and different types of exchange interactions.

In ultrathin ferromagnetic films sandwiched between two distinct heavy metal layers or between a heavy metal and an oxide layer, the Dzyaloshinskii-Moriya interaction (DMI) is of interfacial origin. Its chirality and strength are determined by the properties of the adjacent heavy metals and the degree of oxidation at the interfaces. Here, we demonstrate that the DMI chirality can change solely with variations in the thickness of the ferromagnetic layer—an effect that has not been experimentally studied in details or explained until now. Our experimental observation in the trilayer system Ta/FeCoB/TaOx is supported by ab initio calculations: they reveal that variations in orbital filling and interatomic distances at the interface, driven by the structural relaxations in the ultrathin regime, lead to an inversion of DMI chirality. We hence propose a new degree of freedom to tune DMI chirality and the associated chiral spin textures by tailoring crystal structure, e.g., using strain or surface acoustic waves.

The proximity effect in thin-film superconductor (S)/magnet heterostructures with different types of magnets including ferromagnets, antiferromagnets, and altermagnets is widely considered in the framework of an effective model, where the heterostructure is replaced by a homogeneous superconductor in the presence of a homogeneous exchange field $h_{\mathrm{eff}}$ of a corresponding type. Here we study the extent to which such a model is actually applicable to ballistic thin-film superconductor/magnetic heterostructures. In particular, a comparative analysis of thin-film superconductor/magnetic metal and superconductor/magnetic insulator heterostructures is performed. Metallic and insulating ferromagnets (FM, FI) and altermagnets (AM, AI) are considered. It is shown that in the S/FI and S/AI heterostructures the the proximity effect creates a well-defined spin splitting of the electronic spectra in the S layer. Thus, they are well described by the effective model. At the same time, the proximity effect in S/FM and S/AM heterostructures also creates a spin splitting of the spectra of the S layer, but it has a chaotic spectral and spatial distribution and unpredictable amplitude and, in general, cannot be detected via the spin splitting of the superconducting density of states. Thus, the effective model is not applicable to such heterostructures. Nevertheless, we demonstrate that they support well-pronounced triplet correlations and, thus, can be used for spintronics applications.

The interplay between bulk properties and boundary conditions in one-dimensional quantum systems gives rise to many intriguing phenomena. These include the emergence of zero-energy modes which are of significant interest to a variety of fields. In this work we investigate the presence of such zero modes in cases where the boundary conditions are dynamical and arise due to the coupling to some quantum degrees of freedom. In particular, we study a one-dimensional spin-singlet superconductor, modeled by the Gross-Neveu field theory, coupled to spin-$\frac{1}{2}$ magnetic impurities at its boundaries via a spin-exchange interaction. We solve the model exactly for arbitrary values of the bulk and the impurity coupling strengths using nested coordinate Bethe ansatz and show that the system exhibits a rich boundary phase structure. For a range of couplings, the low-energy degrees of freedom form irreducible representations of the supersymmetric $\text{spl}(2,1)\otimes \text{spl}(2,1)$ algebra which become degenerate at a specific point, indicating the emergence of supersymmetry in the low-energy boundary degrees of freedom. We show that at the supersymmetric point there exist exact zero-energy modes that map one ground state with the other. We express these in terms of the generators of the algebra.

The temperature-induced γ-α isostructural metal-metal transition in Ce is fundamentally intriguing and provides a rare case for in-depth exploration of strongly correlated $f$-electron systems. However, the transition has yet to be well understood, with many ambiguities regarding the associated structural, electronic, and magnetic properties. In this work, we present a comprehensive study of this transition using combined state-of-the-art low-temperature x-ray diffraction and electrical and magnetic transport measurements. The reversible γ-α transition in Ce is confirmed to be coupled with a metal-to-metal crossover, which is primarily driven by the $4f$-electron instability with the involvement of intricate lattice-charge interactions. The forward $\gamma \to \alpha$ transition is found to be kinetically incomplete, and both phases coexist in a wide temperature range. An unusual ferromagnetic state is identified in γ-Ce, likely due to an indirect magnetic exchange between the localized $4f$ moments mediated by the itinerant $5d6s$ electrons (i.e., the Ruderman-Kittel-Kasuya-Yosida effect). Based on our results, the previously misassigned hexagonal “β-Ce” is excluded, and the ground state of γ-Ce is determined to be antiferromagnetic. These findings not only unravel long-standing ambiguities in Ce but also provide powerful insights into the mechanism underlying its γ-α transition.

We discuss a quantum typicality approach to examine systems composed of two subsystems at different temperatures. While dynamical quantum typicality is usually used to simulate high-temperature dynamics, we also investigate low-temperature dynamics using the method. To test our method, we investigate the energy current between subsystems at different temperatures in various paradigmatic spin-1/2 chains, specifically the XX chain, the critical transverse-field Ising chain, and the XXZ chain. We compare our numerics to existing analytical results and find a convincing agreement for the energy current in the steady state for all considered models and temperatures.

In this study, we propose an alternative route to realizing topological superconductivity (TSC). Our approach targets a new class of correlated noncentrosymmetric materials that host two spin-split Fermi surfaces due to spin-orbital intertwined effects. By investigating the superconducting pairings based on two-orbital Rashba-Hubbard model on a square lattice within a spin-fluctuation-mediated pairing framework, we find that, depending on model parameters, the leading superconducting state belongs to the $A_1\left(S_{\pm }\right)$, $B_2$, or $B_2\left(d_{\pm }\right)$ irreducible representations (IRs) of the $C_{4v}$ point group. Notably, the $A_1\left(S_{\pm }\right)$ state features a sign-changed gap between the two spin-split Fermi surfaces and exhibits two key characteristics: (i) it is a parity-mixed state, with the ratio of even-parity to odd-parity components tunable via the Rashba spin-orbit coupling (RSOC) strength and onsite orbital-dependent potential; (ii) it is a fully gapped TSC, characterized by a $Z_2$ topological invariant. When RSOC is strong, the $B_2\left(d_{\pm }\right)$ state can emerge and exhibits both parity-mixed and nodal TSC features. Further analysis reveals that the fully gapped TSC can be predominated by spin-singlet, despite the presence of the spin-triplet components. This distinguishes our case from single-orbital noncentrosymmetric materials, where TSC arises from $p$-wave or $f$-wave spin-triplet pairing. In those systems, the Fermi level must be tuned near a van Hove singularity to enhance ferromagnetic fluctuations that drive the spin-triplet pairing. These distinctions enhance the experimental feasibility of our model.

We solve the one-dimensional massive Thirring model or, equivalently, the sine-Gordon model in the repulsive regime with general Dirichlet boundary conditions, which are characterized by two boundary fields ${\varphi }_{L,R}$ associated with the left and right boundaries, respectively. In the presence of these boundary fields, which explicitly break the charge conjugation symmetry, the system exhibits a duality symmetry which changes the sign of the mass parameter $m_0$ and shifts the values of the boundary fields by ${\varphi }_{L,R}\to {\varphi }_{L,R}+\pi$. When the mass parameter $m_0<0$ and the boundary fields ${\varphi }_{L,R}=0$ or, equivalently, due to duality symmetry, when the mass parameter $m_0>0$ and the boundary fields ${\varphi }_{L,R}=\pi$, the system is at a trivial point. Here, the ground state is unique just as in the case of periodic boundary conditions. In contrast, when the mass parameter $m_0<0$ and the boundary fields ${\varphi }_{L,R}=\pi$ and, equivalently, due to the duality symmetry, when the mass parameter $m_0>0$ and the boundary fields ${\varphi }_{L,R}=0$, the system is at a topological point where it exhibits a symmetry protected topological phase, which is characterized by the existence of zero energy bound states at both boundaries. As a result, the system exhibits a twofold degenerate ground state in each fermionic parity sector and an emergent boundary Hilbert space. For a given value of the mass parameter $m_0$, we find that the bound state structure and the structure of the boundary Hilbert space remains intact even if the boundary fields take values way from the special values corresponding to the topological and trivial points, provided these values are less than certain critical values. We refer to these regions around the trivial and topological points as the trivial and midgap phases, respectively. We find that the critical values depend on the strength of the interactions in the bulk, which is characterized by the Luttinger parameter $\beta$. Hence, we show that the stability of the SPT and trivial phases depends on the interplay of the symmetry breaking boundary field values and the bulk interaction strength.

Electron correlation and electron-lattice interactions are two fundamental aspects of condensed-matter physics, which, combined with nonbound interstitial anionic electrons, can give rise to abundant physical phenomena. In this work, we combined crystal structure prediction with first-principles calculations to explore alkaline-earth halides as potential hosts of exotic electrides and physical properties. We identified nine unconventional stoichiometric phases, among which four exhibit pronounced electride characteristics. In particular, the $P\text{−}6m2$ CaI phase adopts a hexagonal structure, where interstitial electrons are localized within the calcium honeycomb layers. The strong interstitial-electron correlations drive a Mott metal-insulator transition, with an antiferromagnetic ground state. For the ${\mathrm{Ca}}_3\mathrm{I}$ compound, strong interactions between interstitial electrons and adjacent calcium lattices promote a structural transformation from the $P{6}_3/mmc$ to the Cmcm phase, accompanied by the emergence of superconductivity with a transition temperature of 7.1 K at 70 GPa. Moreover, a metastable $P4/mmm {\mathrm{Ca}}_3\mathrm{I}$ electride is also predicted to exhibit superconductivity with a transition temperature of approximately 6.9 K. These findings highlight that interstitial electrons located near the Fermi level can induce strong electron correlations and enhance electron-phonon coupling, thereby giving rise to a rich spectrum of physical behaviors, including superconductivity and magnetism.

We report on all-optical generation and detection of high-frequency (up to $\sim 30$ GHz) surface acoustic waves (SAWs) in GaAs/AlGaAs heterostructures with short-period Au gratings on top. A highly sensitive method for SAW detection is demonstrated using a polarization-resolved pump-probe technique that exploits the narrow exciton resonance in high-quality GaAs. The elastic strain of the SAW modulates the exciton energy in the time domain. As a result, even a small deformation produces a noticeable change in the dielectric function at the detection wavelength leading to an order of magnitude increase in the detection sensitivity as compared to off-resonant conditions. A theoretical model is developed that considers two detection schemes: one accounting for probe light diffraction and one corresponding to a nondiffractive situation.

Quantum Hall edge channels partition electric charge over $N$ chiral (unidirectional) modes. Intermode scattering leads to partition noise, observed in graphene p-n junctions. While inelastic scattering suppresses this noise by averaging out fluctuations, we show that pure (quasielastic) dephasing may enhance the partition noise. The noise power increases by up to 50% for two modes, with a general enhancement factor of $1+1/N$ in the strong-dephasing limit. This counterintuitive effect is explained in the framework of monitored quantum transport, arising from the self-averaging of quantum trajectories.

Crystalline topological insulator nanowires with a magnetic flux threaded through their cross section display Aharanov-Bohm conductance oscillations. A characteristic of these oscillations is the perfectly transmitted mode present at certain values of the magnetic flux, due to the appearance of an effective time-reversal symmetry combined with the topological origin of the nanowire surface states. In contrast, amorphous nanowires display a varying cross section along the wire axis that breaks the effective time-reversal symmetry. In this work, we use transport calculations to study the stability of the Aharanov-Bohm oscillations and the perfectly transmitted mode in amorphous topological nanowires. We observe that at low energies and up to moderate amorphicity the transport is dominated, as in the crystalline case, by the presence of a perfectly transmitted mode. In an amorphous nanowire the perfectly transmitted mode is protected by chiral symmetry or, in its absence, by a statistical time-reversal symmetry. At high amorphicities the Aharanov-Bohm oscillations disappear and the conductance is dominated by nonquantized resonant peaks. We identify these resonances as bound states and relate their appearance to a topological phase transition that brings the nanowires into a trivial insulating phase.