Heat dissipation capability of laser gain media is critical for ensuring the performance and stability of high-power laser systems. However, the thermal transport mechanisms in these materials, particularly in rare-earth ion-doped laser crystals under high-power heating conditions, remain largely elusive. In this study, we employ molecular dynamics simulations combined with a neuroevolution machine learning potential to investigate the effects of temperature and Ce doping on thermal transport in alumina. Our simulations reveal a significant reduction in thermal conductivity under uniform elevated temperatures and finite Ce doping concentrations, providing quantitative insight into thermal transport in Ce-doped ${\mathrm{Al}}_2{\mathrm{O}}_3$ under conditions relevant to laser operation. Simulation results demonstrate that elevated temperature causes a broad-spectrum suppression of thermal transport, while Ce doping predominantly affects specific low-frequency acoustic phonon modes and a few optical modes. Further analysis uncovers a mode-selective phonon-dopant scattering mechanism, where resonant and polarization-dependent coupling leads to the selective suppression of distinct phonon modes. This mechanism is in sharp contrast with the conventional understanding of phonon-dopant scattering observed in typical crystals. These findings provide valuable insights into the atomic-level mechanisms governing heat dissipation in alumina laser crystal, thus paving the way for the design of laser materials with optimized thermal properties for high-power applications.

Nanoelectromechanical resonators provide an ideal platform for investigating the interplay between electron transport and nonlinear mechanical motion. Externally driven suspended carbon nanotubes, containing an electrostatically defined quantum dot, are especially promising. These devices possess two main sources of nonlinearity: the electromechanical coupling and the intrinsic contributions of the resonator that induce a Duffing-like nonlinear behavior. In this work, we observe the interplay between the two sources across different driving regimes. The main nonlinear feature we observe is the emergence of archlike resonances in the electronic transport when the resonator is strongly driven. We show that our model is in good agreement with our experimental electron transport measurements on a suspended carbon nanotube. This characterization paves the way for the exploration of nonlinear phenomena using mesoscopic electromechanical resonators.

We demonstrate a model-free data analysis framework that leverages escort-weighted Shannon entropy and several divergence matrices to detect phase transitions in scattering and imaging datasets. By establishing a connection between physical entropy and informational entropy, this approach provides a sensitive method for identifying phase transitions without a physical model or order parameter. We further show that pairwise divergence matrices, in particular, Kullback-Leibler divergence, Jeffrey divergence, Jensen-Shannon divergence, and difference Kullback-Leibler divergence, provide more comprehensive measures of statistical changes than scalar entropy alone. Our approach successfully detects the onset of both long- and short-range order in neutron and x-ray scattering data, as well as a nontrivial phase transition in magnetic skyrmion lattices observed through Lorentz-transition electron microscopy. These results establish a framework for fast, automated, model-free detection of physical order in experimental data with broad applications in materials science and condensed matter physics.

Understanding how frustration and symmetry breaking shape collective behavior is a central problem in quantum many-body systems. In this work, we investigate this problem in large one- and two-dimensional arrays of coupled Dicke models on a periodic lattice, where strong light-matter coupling gives rise to a superradiant phase and competition between neighboring order parameters induces spontaneous translational symmetry breaking. Such Dicke lattice models constitute a fundamentally new class of quantum many-body systems, as they simultaneously realize the thermodynamic limit associated with the lattice size and an intrinsic thermodynamic limit arising from collective on-site interactions with quantum emitters. We show that frustration drives photonic density-wave ordering, and that the resulting broken periodicity can be predicted from the excitation spectrum of the symmetric phase, without requiring computationally prohibitive thermodynamic energy minimization. Furthermore, we demonstrate that an emergent Nambu-Goldstone mode arises near the critical point in a one-dimensional chain despite the presence of only discrete symmetry, and uncover the mechanism that enables this otherwise forbidden gapless excitation. We also find quasiperiodic ordering in the superradiant phase, reminiscent of quasicrystals, and demonstrate that synthetic magnetic flux provides a powerful knob to control the nature of translational symmetry breaking. Our results establish a direction in quantum many-body physics where the coexistence of local and global thermodynamic limits gives rise to unconventional symmetry breaking and emergent collective behavior.

We study the correlated ground states of twisted mono-bilayer graphene with and without proximity-induced spin-orbit coupling (SOC) from a transition-metal dichalcogenide layer placed on top. We perform self-consistent Hartree-Fock calculations that allow the variational space to include multi-$Q$ translational-symmetry-broken states for all integer and half-integer fillings of the conduction bands, where signatures of correlated, topological states have been reported experimentally. We find interaction-induced insulators that retain moiré translational symmetry at integer fillings, but that break this symmetry at half-integer fillings. We argue that translational symmetry breaking arises from half-filled polarized bands, even when SOC is present. Yet, we find that small SOC can already crucially affect the spin nature of correlated states. Generally, Ising SOC favors out-of-plane spin polarization and spin-valley locking, while Rashba SOC favors in-plane spin order. If only one of these two terms is present, we find that, depending on the type of SOC, it drives a transition from a tetrahedal antiferromagnet to either a coplanar, noncoplanar, or collinear spin-density wave state for half-integer fillings. The frustration associated with the simultaneous presence of both types of SOC can induce chiral, noncoplanar order in parameter ranges where the ground state in the absence of SOC is collinear.

Secure, repeatable access to information stored in deep electron traps remains the central barrier to realizing the full potential of electron-trapping phosphors in next-generation optical memory. Existing readout methods typically rely on destructive thermal or nonselective optical stimulation, which limits repeated access and compromises data integrity. Here, we introduce photonically engineered trap transfer (PETT), a heat-free, nonvolatile approach enabling selective data extraction from deep traps. A specially designed garnet phosphor, $\mathrm{G}{\mathrm{d}}_3\mathrm{G}{\mathrm{a}}_5{\mathrm{O}}_{12}$ codoped with $\mathrm{C}{\mathrm{r}}^{3+}$ and $\mathrm{E}{\mathrm{u}}^{3+}$, serves as the storage medium, with $\mathrm{C}{\mathrm{r}}^{3+}$ acting as the luminescent center and $\mathrm{E}{\mathrm{u}}^{3+}$ engineering a hierarchical trap landscape. Data writing is achieved through an up-conversion charging process that embeds data within 0.01 s. In the PETT readout, visible light transfers electrons from deep to shallow traps; subsequent infrared stimulation releases them, producing a detectable luminescence signal. Kinetic modeling of the PETT process describes the time evolution of the shallow-trap population and reveals its characteristic rise-and-decay behavior. This method provides a reliable, selective, and repeatable route to data retrieval and establishes a robust physical framework for secure, multilevel, rewritable optical memory.

Altermagnetism has emerged as a promising ingredient for realizing nontrivial Josephson phases but so far explored in single Josephson junctions. In this work, we consider the coherent coupling of two Josephson junctions with spin-singlet $s$-wave superconductivity and demonstrate that $d$-wave altermagnetism gives rise to spin-polarized Andreev molecules due to the hybridization of Andreev bound states of each junction when the coupling is weak. Interestingly, these spin-polarized Andreev molecules induce anomalous nonlocal Josephson effect, where the current flow across one Josephson junction due to phase changes across the other junction develops $0-\pi$ and ${\varphi }_0$ transitions originating from altermagnetism. Furthermore, the nonlocal Josephson current carried by spin-polarized Andreev molecules exhibits nonreciprocal critical currents, enabling a nonlocal Josephson diode effect whose polarity is tunable by the altermagnetic strength and right phase. Our findings put forward altermagnetism as a promising arena for designing nonlocal spin Josephson phenomena.

It is generally argued that Mermin-Wagner theorem excludes the possibility of long-range order in two-dimensional bosonic systems at nonzero temperatures. In contrast, we show here that generic bilayer semiconductors could demonstrate true Bose-Einstein condensation of interlayer excitons. We find that the key requirements include (1) reduction of the interlayer band gap using an applied electric field so that excitons spontaneously appear in the ground state, (2) band structure that allows for long-range electron-hole exchange interaction, and (3) a finite magnetic field. When these conditions are fulfilled, superfluidity and ferroelectric order can coexist in two-dimensional excitonic insulators. Our results provide an example where coupling to the vacuum electromagnetic near field leads to a finite temperature second-order phase transition.

The van der Waals transition metal dichalcogenide ${\mathrm{NiTe}}_2$ is investigated through soft x-ray photoelectron and absorption spectroscopy combined with density functional plus dynamical mean-field theory. We derive an electronic configuration of $d^9$ for the Ni ions with some admixture of $d^8$ and $d^{10}$, yielding an average $3d$ occupation of about 8.9. Despite the $d$ shell being open with non-negligible hole concentrations, calculations reveal the absence of local moments, thereby explaining the Pauli paramagnetic behavior as observed in magnetic susceptibility measurements. This behavior is unusual, particularly given that many Ni-based compounds exhibit strong electron correlations. We ascribe the silencing of correlation effects in this material to the fact that without the Ni–Te hybridization, the Ni would have the nonmagnetic full $d^{10}$ configuration, and that the Ni bands that get partially unfilled due to hybridization are extremely broad, making the holes “bandlike” or “highly delocalized”. The large Hubbard $U$ interaction does not become operative in this material.

Recent advancements in topological analysis offer a powerful way to classify how phases of nonlinear bosonic resonators organize. These tools are rooted in the Morse-Smale flow topology framework, where a graph-based construction describes how steady-state solutions are arranged in phase space. This construction remains incomplete as self-sustained oscillations in the form of limit cycles can impact the global connectivity of phase-space flows and the corresponding Morse-Smale topological classification. In this work, we extend the bosonic classification scheme to include limit cycles as fundamental topological elements. We illustrate the approach with a minimal nonlinear Van der Pol resonator model, where limit cycles coexist with steady-state solutions. Our results provide a unified topological description of stationary and time-periodic phases in nonlinear bosonic systems, with direct relevance to photonic, superconducting, and optomechanical platforms. Our findings raise fundamental questions regarding synchronization and the extension of flow topology to the quantum regime.

FeGe is the only known kagome metal hosting the coexistence of long-range magnetic order and charge-density-wave (CDW) order, making it an exceptional platform for studying spin-charge-lattice entanglement. Despite extensive experimental and theoretical efforts, the microscopic origin of the CDW in FeGe remains under active debate. In this work, we reveal how in-plane tensile strain reshapes the hierarchy of competing CDW orders in the antiferromagnetic kagome metal FeGe. First-principles phonon calculations uncover two Kohn-anomaly-induced incommensurate CDWs under strain, while slight electron correlations suppress these modes and instead lead to unconventional correlation-driven CDW phases. Notably, a previously unreported fully dimerized $\sqrt{3}\times \sqrt{3}\times 2$ CDW emerges from the softened H-point phonon mode. Total-energy analyses establish a strain-induced phase transition sequence: $2\times 2\times 2\to \sqrt{3}\times \sqrt{3}\times 2\to$ fully dimerized $\sqrt{3}\times \sqrt{3}\times 2$ at strains of $\sim 0.6\%$ and $\sim 2.4\%$, respectively, while a small U = 0.2 eV will reduce the required strain to $\sim 0.2\%$ and $\sim 1.8\%$, respectively. These results demonstrate the coexistence of electron-phonon-driven and correlation-driven CDW mechanisms, positioning strained FeGe as a powerful platform for probing strongly coupled spin-charge-lattice entanglement in correlated magnetic kagome systems.

We investigate the nature of the excitations captured by the dynamical response of XYZ triangular spin-1/2 ladders. We complement experimental inelastic neutron scattering results on the compound ${\mathrm{Cs}}_2{\mathrm{CoBr}}_4$ with numerically exact simulations based on time-dependent matrix product state methods. Our results show that bound states of spinon excitations can arise in XYZ beyond the requirement of strong Ising anisotropies. We analyze the role of the frustrated triangular couplings on the excitations giving rise to the spin dynamical structure factor and show how the features of the bound states manifest themselves in the different polarization channels.

We theoretically investigate the collisions between ultracold polar molecules in the presence of two lasers ensuring a Raman resonant transition on individual molecules to suppress photon scattering, taking the example of bosonic ${}^{23}\mathrm{Na}{}^{39}\mathrm{K}$ molecules. By varying laser detunings and intensities, we enable a repulsive long-range interaction potential between molecules. After solving a set of coupled Schrödinger equations with the Hamiltonian written in the basis of laser-dressed states of the molecule pair at infinite distance, we identify quasiresonant conditions under which elastic collisions are favored over inelastic and reactive ones, by a factor of about 2, thus demonstrating a promising pathway for efficient two-photon optical shielding of ultracold molecular collisions. The results are analyzed in terms of scattering length of the colliding laser-dressed molecules, which exhibit prominent resonances assigned to the interaction of the entrance channel with other specific channels, consistent with the existence of a quasibound level of the long-range molecular pair induced by the lasers.

We study dynamical correlations of interacting hard-core anyons on a one-dimensional lattice at infinite temperature. This is a setting in which the many-body spectrum is independent of the statistical phase $\theta$, while dynamical correlators remain sensitive to $\theta$ through nonlocal Jordan-Wigner strings. We compute single-particle Green's functions, spectral functions, and density-density correlators, thereby separating the effects of fractional statistics on one-body coherence from those on density transport in a maximally mixed ensemble. In the noninteracting case $V=0$, high-temperature averaging leads to inversion-symmetric Green's functions for all $\theta$ despite the presence of anyonic strings. Finite nearest-neighbor interactions $V$ generate, however, a pronounced left-right asymmetry in the Green's functions for $0<\theta <\pi$, with the strongest chirality appearing at intermediate couplings $V\sim J$ where interactions and hopping compete most effectively. In this regime, the Green's function decays exponentially in time with a statistical-angle-dependent decay rate. At strong coupling, the dynamics crosses over to an atomic-limit regime in which the dependence on $\theta$ is reduced. Here, the Green's function decays universally as $t^{-1}$ and the corresponding spectral function displays a three-band structure. In contrast, density-density correlations are insensitive to statistics and recover the known infinite-temperature transport regimes of the XXZ chain, including ballistic, superdiffusive, and diffusive behaviors. These results identify dynamical correlation functions as direct probes of fractional statistics in high-entropy quantum systems.

We show that Andreev spin qubits can be realized in a Josephson junction based on the helical edge states of a two-dimensional topological insulator (quantum spin Hall system) proximized by superconducting films, in the presence of magnetic doping. We demonstrate that the electric dipole transitions between the Andreev spin states induced by the magnetic doping can be harnessed to manipulate the Andreev spin qubit by microwave radiation pulses, without applying an external Zeeman field or invoking ancillary states. We numerically simulate the realization of not and Hadamard quantum logic gates, and discuss implementations in realistic setups.

Crosstalk between qubits fundamentally limits the scalability of quantum processors, necessitating physics-based models that can handle the complexity of large qubit arrays. Here, we develop a comprehensive theoretical and experimental framework that captures residual interactions between both adjacent and nonadjacent qubits in fixed-frequency transmon lattices. The model integrates the combined effects of exponential localization in banded capacitance matrices, suppression of virtual couplings through detuning products across intermediate modes, and evanescent decay of below-cutoff electromagnetic fields, yielding predictive scaling relations for coupling strength as a function of spatial separation and spectral detuning. Experimental characterization of a $4\times 4$ superconducting qubit lattice with inductive shunt pillars reveals exponential spatial decay and frequency-dependent suppression consistent with theoretical predictions, achieving quantitative agreement for all nearest-neighbor couplings across the $4–6\mathrm{GHz}$ operating range. Our results show that standard dispersive Hamiltonian approximations systematically overestimate long-range coupling when spatial and spectral dependencies are neglected; these errors propagate into circuit simulation and design strategies. Our framework provides design guidance for crosstalk mitigation in larger-scale quantum processors under realistic fabrication constraints, addressing a bottleneck in scalability.

Carriers in flat bands (FBs) possess high effective masses and are predicted to exhibit unconventional transport properties. The study of the photocarrier dynamics in FBs is of fundamental importance for understanding many-body interactions and the emergence of exotic quantum phenomena. $1\mathrm{T}\text{−}\mathrm{Ti}{\mathrm{S}}_2$, a layered transition-metal dichalcogenide featuring a quasiflat band near the Fermi level, provides an ideal platform for investigating nonequilibrium carrier dynamics in electronic flat-band systems. Here, we employed transient absorption microscopy to uncover a picosecond, quasi-flat-band-mediated bimolecular recombination of photoexcited electrons and holes confined within the flat-band states in the 80–295 K experimental window. In addition, the launch of coherent acoustic phonons in ${\mathrm{TiS}}_2$ crystals at 45 GHz is demonstrated, from which sound velocity and Young's modulus are determined to be 4.39 $\text{km}{\text{s}}^{-1}$ and 62 GPa, agreeing well with the prediction from the first-principles calculation. The present study provides microscopic insight into ultrafast energy relaxation and the associated phonon generation in layered materials.