Papers

Standard Pancharatnam-Berry and linear-birefringent media convert optical spin into orbital angular momentum (OAM) through an anisotropy director, a rank-two, headless field, and therefore obey the selection rule $\Delta\ell=2q$ per unit texture charge $q$. We show that a medium with geometric torsion, the continuum limit of a screw-dislocation array, can convert spin to OAM through the contortion of its material connection, which enters the effective paraxial dynamics as a rank-one vector field. The resulting selection rule is $\Delta\ell=q$. Its winding is fixed by geometry and symmetry, not by a Pancharatnam–Berry director, and the process conserves the screw charge $\tilde J_z=L_z+(q/2)\sigma_z$ while exchanging $(2-q)\hbar$ of angular momentum per converted photon with the defect lattice. Paraxial simulations confirm the rule: a circular Gaussian input develops a stable, topologically quantized $\ell=+q$ vortex in the reversed helicity, with $83\%$ conversion over three Rayleigh ranges and no fine-tuning. We propose a polarization-resolved photonic-lattice discriminator in which the slope of the measured OAM versus the independently written texture charge, one for torsion, two for birefringence, separates the two mechanisms.

We complete the phase diagram of the macroscopic Curie-Weiss magnet in a time-periodic external field, as a function of temperature and driving parameters. There is a regime (large enough driving amplitude and frequency, at low temperatures) where stable paramagnetic and ferromagnetic phases coexist. In particular, we present a new detailed analysis of the (nonequilibrium) specific heat, diverging at the same critical inverse temperature $\beta_c$ as the magnetic susceptibility. The new Curie temperature decreases with the driving, and we find critical exponent $\alpha=1$ for $\beta\downarrow \beta_c$, and $\alpha\simeq 0.86$ for $\beta\uparrow \beta_c$, even for small driving. A Floquet analysis shows the nature of the criticality, which is dynamical, with implications that remain unseen and are mostly impossible when the system is in thermal equilibrium.

It is known that a one-dimensional (1D) quantum walk gives a local space-time discretization of the massless Dirac equation with a single quasi-energy cone (no fermion doubling at low energies), keeping the fundamental symmetries (chiral and time-reversal) of the continuum theory. We show that the analogous 2D construction is fundamentally more fragile. Local two-band quantum walks can have an unpaired Dirac cone, but the protecting symmetries then cease to be ordinary on-site symmetries: They become non-symmorphic, involving half-lattice translations, and are broken by generic spatial inhomogeneities. In particular, we demonstrate that the 2D Dirac quantum walk based on the Ho-Chalker network model can be gapped by potential scattering, as is evidenced by the breakdown of reflectionless Klein tunneling. The symmorphic symmetry obstruction is sharp: If we allow for couplings that are no longer strictly finite-range but decay exponentially with distance, we can construct a 2D quantum walk with a single Dirac cone and on-site chiral and time-reversal symmetries.

Matrix Brownian motion provides a powerful framework for studying crossover ensembles in quantum chaos and quantum transport, as well as thermalization and information scrambling in many-body dynamics. Here, we develop a unified diagrammatic framework to characterize Brownian ensembles for orthogonal and symplectic random matrices, which describe systems with particle-hole symmetry. We compute polynomial averages up to fourth order and construct an orthogonally invariant interpolation for the disconnected $\mathrm{SO}^-(q)$ sector of the orthogonal group. We consider applications relating to the fields of quantum information, quantum chaos, and quantum transport.

The location of the neutron drip line in tin isotopes has important consequences for our fundamental understanding of nuclear structure and nuclear forces as well as for astrophysical nucleosynthesis. Performing high-precision ab initio calculations of even-even tin isotopes from $N=50$ to $N=126$ based on chiral two- and three-nucleon interactions, the predicted drip-line location is found to be highly sensitive to the employed nuclear interactions and to exhibit tension with recent energy-density-functional predictions. On the neutron-deficient side, results are consistent with extrapolated two-neutron separation energies constrained by recent Penning-trap mass measurements.

We study a quasi-one-dimensional associating fluid composed of hard superellipses carrying two patches interacting through a directional Kern–Frenkel potential. Using the Transfer Operator Method, we show that the selective patch–patch association promotes horizontal alignment and chain formation at low-to-intermediate densities, whereas hard-core interaction favours vertical alignment without bonds at high densities. The competition between these two mechanisms drives a structural crossover upon compression from a horizontally aligned bonded chain structure to a completely unbonded, vertically aligned structure. While patchy ellipses undergo a tilted-to-vertical realignment, patchy rectangle-like superellipses exhibit a horizontal-to-vertical change. These structural changes manifest as a plateau in the equation of state. To capture these properties, we generalise Wertheim's first-order thermodynamic perturbation theory by introducing an orientation-dependent fraction of sites not in a bond. When combined with the Parsons–Lee hard-body theory, the orientationally resolved perturbation theory provides quantitatively reliable results for the structural properties and phase behaviour. Therefore, the generalised Wertheim theory together with Parsons-Lee theory can be suitable in higher dimensions, too.

We formulate the finite-frequency magnetic common-bath problem of two spin probes in a ferromagnetic planar cavity. The probes couple to the retarded magnetic Green tensor of the cavity, whose imaginary and real parts determine the collective decay rate \(\gamma_{12}\) and the coherent exchange coupling \(\Omega_{12}\), respectively. We evaluate these quantities for a finite-thickness scalar transverse-electric (TE) cavity channel formed by ferromagnetic films on nonmagnetic conducting substrates, using a Polder-type scalar permeability \(\mu_\perp(\omega,B)\) as the magnetic input. The normalization is fixed by the free-space magnetic-dipole decay rate. In the \(\omega\to0\) limit, the Green-tensor kernel reduces to the magnetostatic response, and the finite slab retains its static TE reflection amplitude. For a \(t=200\,\mathrm{nm}\) film with a representative Ni-like parameter set, the GHz transition of a spin probe at the mid-gap of a micron-scale cavity samples the spectral density of the body-assisted magnetic reservoir at millikelvin temperature. At the resonant bias, the cavity-induced contribution \(2|\delta\gamma_{12}^{(zz)}|\) to the collective linewidth splitting in the \(zz\) transition-moment projection is about two thirds of the local single-spin linewidth correction \(\delta\gamma_{11}^{(zz)}\) at \(\rho=3\,\mu\mathrm m\). Together, the linewidth splitting and collective Lamb shift probe the dissipative and dispersive finite-frequency response, respectively, while the shared Green-tensor normalization connects these observables to the static TE coupling-frequency shift.

Charge density wave (CDW) and superconductivity are both common in strongly interacting electron systems. While CDW order is ubiquitous in both quantum Hall systems and unconventional superconductors, superconductivity is generally suppressed by the strong magnetic fields required for Landau quantization. Here we investigate the intertwined CDW and superconducting phases of rhombohedral hexalayer graphene (R6G) in a large displacement field, which generates tunable flat band edges, and a strong magnetic field, which generates a manifold of nearly degenerate Landau levels. We find a series of integer quantum Hall effects with Hall conductance quantum numbers that deviate from nearby integer filling factors, an observation that can be explained only by CDW order that mixes many Landau levels. We also find a nearby superconducting phase stabilized by perpendicular magnetic fields and persists deep within the quantum Hall regime. This intertwinement provides new insight into superconductivity in R6G at zero magnetic field.

Thermodynamic integration (TI) is a widely used approach for computing free energies and phase diagrams. However, TI calculations driven by machine learning interatomic potentials (MLIPs) remain technically challenging because they require careful design of reversible integration paths and many closely related molecular dynamics (MD) tasks for each phase and state point. To address these challenges, we present dpti, an open-source Python package that automates TI workflows for phase diagram calculations with MLIPs. dpti connects reference systems with analytically known free energies to MLIP-described atomic and molecular solids and liquids through reversible integration paths. Given JSON input files, dpti generates and runs the required MD tasks, computes free energy contributions, estimates errors, and propagates coexistence points into phase boundaries. We demonstrate the usage of dpti with two examples driven by Deep Potential models: a silica phase diagram involving beta-quartz, coesite, and melt, and the ice Ih-liquid water phase boundary. dpti provides a useful tool for automated phase diagram calculations of materials modeled by MLIPs.

Large-scale quadratic unconstrained binary optimization (QUBO) formulations of constrained combinatorial optimization problems often exceed the input-size limit of present Ising machines or suffer from degraded solution quality as the number of binary variables increases. Large neighborhood search (LNS) mitigates this difficulty by sequentially optimizing restricted subproblems, but the structural factors that distinguish subproblems beyond the number of binary variables remain insufficiently characterized. In this study, we examine vehicle routing problems and compare a construction based on the vehicle routes of the current solution, denoted by LNS-K, with a construction based on QUBO variables and constraint relations, denoted by LNS-Q, while controlling the number of binary variables in the subproblems. Under the tested conditions, LNS-K obtained shorter total distances than LNS-Q in the matched-size comparisons, and the position variance, a measure of the spatial spread of the selected customers, decreased during the iterations in LNS-K. These observations suggest that subproblem design for sequential optimization with Ising machines should consider not only subproblem size but also semantic and geometric structures inherited from the current solution.

Canonical quantization provides a systematic procedure for constructing quantum models from classical Hamiltonians. Here, we apply this principle to a fundamental computational primitive of machine learning: the neuron. Specifically, by viewing a neuron as a composition of an energy function and an activation function, we quantize this model by replacing the energy function with a quantum Hamiltonian and applying the activation function to it through matrix functional calculus. This results in an activation observable that can be measured on an input quantum state. We investigate the use of these quantized neurons for function approximation, where the objective is to learn an unknown observable from labeled quantum data. For this purpose, we develop hybrid quantum-classical algorithms for training and evaluation, including procedures for measuring the activation observable and estimating gradients of the squared loss error. Our algorithms for gradient estimation rely on basic primitives like classical random sampling, the Hadamard test, and Hamiltonian simulation, and those for measuring an activation observable rely on quantum algorithms known as the power of one qumode and Schroedingerization. Numerical experiments demonstrate that our quantized neurons exhibit enhanced expressive capabilities relative to corresponding classical neurons on representative learning tasks. Our work establishes canonical quantization as a principled framework for constructing quantum machine learning primitives and provides a foundation for developing neural architectures tailored to quantum data.

Dielectric elastomers exhibit rich electromechanical instabilities arising from the coupling between mechanical deformations and electric fields. A widely used approach for analyzing instabilities in dielectric elastomers is the Hessian stability criterion proposed by Zhao and Suo (2007), which identifies the onset of instability of a homogeneous deformation but does not determine how the deformation develops beyond the instability threshold. To address this problem, we investigate dielectric membranes subjected to uniaxial tension and an electric field. Starting from a three-dimensional nonlinear electroelastic formulation, we derive asymptotically consistent reduced models, including a membrane model and a plate model, using the variational-asymptotic method. A linear bifurcation analysis first shows that the Hessian stability criterion is equivalent to a zero-wavenumber bifurcation condition, thereby establishing a direct connection between energy-based stability analysis and bifurcation theory. A subsequent weakly nonlinear analysis demonstrates that the zero-wavenumber bifurcation gives rise to localized necking, manifested as inhomogeneous thinning of the membrane. The weakly nonlinear predictions are further validated by numerical simulations. Furthermore, for the plane-stress configuration considered here, the membrane model accurately captures both the onset of instability and the associated localization behavior, while bending effects remain small. These results identify the deformation associated with the Hessian instability and provide a framework for understanding electromechanical instabilities in dielectric membranes.

What distinguishes front from back? In physics, such directionality emerges only when an underlying symmetry is broken. Antiferromagnets that inherently break both space-inversion and time-reversal symmetries provide a striking example, exhibiting nonreciprocal optical responses that depend on the direction of light propagation. Beyond distinguishing antiferromagnetic domains, we show that this nonreciprocity can deterministically create them. Using mid-infrared light, we demonstrate deterministic switching of antiferromagnetic domains in the magnetoelectric antiferromagnet LiFePO4, where illumination from opposite sides selectively stabilizes opposite domain states. Remarkably, the switching persists over a broad wavelength range rather than being confined to a narrow transition-specific spectral region, overcoming the spectral and material constraints of resonance-based optical switching schemes. The broadband switching originates from the material's intrinsic nonreciprocity through optically generated heat currents. Our results establish nonreciprocity as a general principle for deterministically controlling symmetry-broken phases with light.

We investigate surfaces of a $g$-wave altermagnet(AM) and show that they provide a platform for realizing $d$-wave altermagnetism and the associated spin-splitter functionality. Using the Kubo formalism applied to a minimal slab model, we evaluate the spin-splitter effect(SSE) by computing the spin conductivity corresponding to a transverse spin current induced by a longitudinal electric field. We find a finite SSE, absent in the bulk, that emerges from surface-induced $d$-wave altermagnetism. Strikingly, the sign pattern of the $d$-wave altermagnetism on both surfaces of the slab geometry is identical to each other, leading to additive contributions to SSE from the two surfaces, with a spin-splitter angle reaching up to 15 degrees. In addition, this response is intrinsically linked to an accompanying surface-induced weak ferromagnetism, which potentially enables control of altermagnetic domains via an external magnetic field and provides a route to optimize the SSE functionality. These results can be understood in terms of a bulk-boundary correspondence between surface states and bulk altermagnetic order parameters, where the magnetic multipolar character of the latter plays a central role. Our findings strongly suggest thin-film engineering as a viable strategy to functionalize non-$d$-wave AMs.

The field of hybrid superconductor-semiconductor quantum dots is advancing toward the development of functional devices that leverage the advantages of both types of materials. However, the inherent complexity of these devices demands a comprehensive theoretical framework for a complete understanding of their responses to external probes, readout and the dissipation arising from environmental coupling. We present a Lindblad-based linear response formalism that captures the multi-level nature of these devices, their probe-readout flexibility, and the non-unitary effects of finite-frequency response, including the so-called Sisyphus and Hermes dynamical susceptibilities. These arise from fluctuations in the rates and jump operators, and are hence absent in standard Kubo linear response treatments. We exemplify the framework using quantum dot-based Kitaev chain setups which are promising candidates for topologically protected Majorana-based parity qubits. Our results shed light onto the validity of the standard curvature-based approximation for fermionic parity and qubit readout, show that Hermes terms compensate decoherence in dispersive readout and implement important corrections beyond thermalized states.

In Rashba two-dimensional electron gases (2DEGs), charge-to-spin conversion via the Edelstein effect is conventionally limited to the transverse plane. Accessing longitudinal or out-of-plane pathways typically requires static magnetic fields or interface engineering, which cause stray fields and lack tunability. While dynamic circular or elliptical Floquet drives can also unlock these forbidden pathways, a simple Floquet linear drive cannot. Here, we propose an alternative approach: a chirped Floquet linear drive. The chirp induces in-plane Floquet-Zeeman fields and an odd-parity momentum drift, which simultaneously break rotational and time-reversal symmetries. This mechanism activates the forbidden Edelstein charge-to-spin conversions in Rashba 2DEGs. Experimentally accessible via programmable spatial light modulators or optical delay lines, this tunable chirped linear drive offers a broadly applicable route to spin-orbit torque switching and high-efficiency spintronics.

The superconductivity of CeRh$_2$As$_2$ has drawn attention due to its first-order transition in magnetic fields. At first glance, the multiple superconducting (SC) phases as well as the first-order transition appear consistent with the parity-switch scenario, which emphasizes the role of strong Rashba spin-orbit coupling enabled by the locally non-centrosymmetric crystal structure. However, experimental phase diagrams exhibit notable deviations from this simple picture: thermodynamic measurements reveal a nearly vertical phase boundary of the high-field SC phase despite the orbital depairing effect, while transport measurements show that the initial slope of the high-field SC phase is steeper than that of the low-field SC phase. Here, we show that these discrepancies can be understood by considering the combined effects of nonsymmorphic band structure and coexisting antiferromagnetic order. We demonstrate that the symmetry-enforced electronic structure around the Dirac node and type-II Van Hove saddle points near the X point in the Brillouin zone boundary becomes more anisotropic with increased interlayer hopping amplitude, and this anisotropic band structure naturally accounts for the anomalous initial slope of the odd-parity SC phase. Meanwhile, a phenomenological theory incorporating coexisting antiferromagnetism explains the nearly vertical thermodynamic phase boundary as a consequence of field-enhanced odd-parity superconductivity enabled by the over-suppression of Pauli depairing.

The conformation of polyelectrolyte (PE) brushes is highly sensitive to external conditions, particularly salt concentration and ion-specific effects. As salt concentration increases, PE brushes transition from an osmotic brush regime at low salt ($H \propto c_\mathrm{s}^{0}$) to a salted brush regime at high salt ($H \propto c_\mathrm{s}^{-1/3}$). However, deviations from this ideal scaling behavior are frequently observed in molecular simulations. In this work, we employ coarse-grained molecular dynamics simulations to systematically investigate how the sizes of counterions and co-ions affect the structural evolution and scaling behavior of PE brushes over a broad range of salt concentrations. Our results show that counterion size plays a dominant role in regulating ion penetration and coordination with PE monomers. At low salt concentration, smaller counterions penetrate more easily into the brush, leading to enhanced local charge compensation and stronger brush collapse. At high salt concentration, however, the brush height becomes largely insensitive to counterion size, while deviations from the classical scaling relation emerge. On the other hand, co-ion size mainly affects the system indirectly by modifying ion distributions and the local electrostatic environment. Smaller co-ions weaken local charge compensation and suppress brush collapse, with this effect becoming more pronounced at high salt concentration. When the sizes of counterions and co-ions are reduced simultaneously, the system exhibits a coupled response. Collectively, this work provides a microscopic understanding of how ion size and salt concentration jointly govern the structural response of PE brushes and the emergence of non-classical scaling behavior in realistic solution environments.

Raman spectroscopic imaging has emerged as a potent tool due to its non-invasive nature and capability for chemical composition analysis. Line-scan Raman spectroscopy accelerates imaging speed by two orders of magnitude compared to point detection Raman methods. However, further enhancements in imaging speed were constrained by the readout speed of typically used charge-coupled device (CCD) spectroscopic detectors. We developed an ultra-fast line-scan Raman imaging technique based on recently available complementary metal-oxide-semiconductor (CMOS) detectors with low cost and read noise, and fast readout during exposure combined with a global shutter. Employing a high-efficiency transmissiongrating imaging spectrometer, we demonstrate imaging speeds up to two orders of magnitude faster than traditional line scan Raman imaging techniques and up to four orders of magnitude faster than point scan Raman methods, achieving Raman imaging up to 80 kHz spectral rate. We demonstrate that this technology is applicable to a variety of samples, including microplastics, biological cells, and tablets, creating images in an extremely short time frame, showcasing exceptional detection capabilities and the ability to reveal detailed information.

In advanced complementary metal-oxide-semiconductor (CMOS) quantum chips, compact gate stacks make it difficult to connect lithographic geometry, electrostatic confinement and many-electron spin filling in one transparent model. This connection is central to design-technology co-optimization (DTCO). Here we develop a reduced-order analytical framework for asymmetric multigate silicon quantum-dot devices. Its electrostatic core, the Poisson-kernel coupled-interface Green-function (PK-GF) model, agrees with an independent finite-volume solution at the millivolt scale for the matched two-dimensional problem, without fitting to that solution. We then pass the gate-derived confinement, rather than a harmonic or fitted potential, to a spin-valley many-body calculation for a jellybean quantum dot with N = 2-17 electrons at B = 5 T. The unrestricted Hartree-Fock (UHF) solution supports occupation-dependent, Wigner-molecule-like charge localization but likely overestimates spin polarization. Complete active-space configuration interaction (CASCI) supports a low-spin branch within the tested active spaces, which aligns with the experiments. The workflow therefore connects CMOS layout, device electrostatics, and potential-determined quantum observables, providing an auditable modelling layer for CMOS-based qubit design and DTCO.

We show that, by using suitable protocols for a non-interacting condensate in a driven double-well, one can achieve controlled rotations about arbitrary axes in the equatorial plane of the Bloch sphere, composed with fast rotations about the $z$-axis. Specifically, we investigate the dynamics induced by a spatially linear time-periodic potential, by means of numerical simulations. We also provide an explicit two-level model that accurately captures the microscopic evolution of the driven system, with the full time-dependent evolution operator obtained using a Floquet-based approach. The analysis is carried out using as a reference a recently realized experimental platform consisting of arrays of double-well potentials based on Beat-Note Superlattices, to which the proposed control scheme is directly applicable.

Fragility characterizes how rapidly a glass-forming liquid slows down upon supercooling, but whether strong and fragile behaviors arise from the same microscopic relaxation mechanism remains unclear. Here, we address this question using a density-tunable soft-repulsive binary mixture spanning distinct fragility regimes and analyze particle jump dynamics within the framework of dynamic disorder. Across these regimes, we show that increasing fragility leads to progressively broader cage-lifetime distributions and increasingly non-exponential survival probabilities, revealing non-Poisson cage-to-jump statistics governed by fluctuating jump rates and slowly evolving structural variables. To characterize their structural origin, we first identify the neighbor ranks most strongly coupled to jump motion using Kullback-Leibler divergence and Pearson correlation analyses. We then introduce a structural slowness parameter that combines these neighbor-distance fluctuations into a reduced slow coordinate for constructing the slow-fluctuation survival probability. A comparison with the actual survival probability shows that localized neighbor-distance fluctuations control the jump rate in the strong regime, whereas extended neighbor rearrangements become relevant in the intermediate and fragile regimes, increasing the effective dimensionality of the slow-variable space. In the fragile regime, distance-based descriptors alone become insufficient at the lowest temperature, where the Voronoi free volume captures additional cage-volume fluctuations in the rate-controlling slow variable. Point-to-set correlations grow with fragility, but the spatial extent of the slow variables exceeds the point-to-set length. These results show that fragility changes the structural bottleneck for microscopic rate fluctuations, linking dynamic disorder and multidimensional slow variables.

We study the inverse problem of classical density functional theory for inhomogeneous fluids: finding the wall potential that produces a constant equilibrium density profile, i.e., a perfectly flat density distribution in the accessible region adjacent to a substrate. Within Rosenfeld's fundamental measure theory, we solve this problem for a one-component fluid in planar, spherical, and cylindrical geometries, considering both a hard-sphere fluid and a fluid with an additional truncated Lennard-Jones attraction treated at the mean-field level. Explicit analytical expressions are obtained for planar walls, while spherical walls also admit an analytical treatment in a more cumbersome form. The cylindrical case is treated numerically. The construction provides an explicit microscopic realization of structure-cancelling wall fields, related to flat-profile conditions that occur under special matching conditions in interfacial theories of wetting and drying. The theory also yields a compact collection of formulae for weighted densities and one-body direct correlation functions in the three fundamental geometries, providing useful reference expressions for density-functional implementations. The resulting analytic wall potentials are validated in independent density functional calculations, which confirm that the prescribed flat profiles are recovered within numerical accuracy.

We systematically investigated the magnetic, dielectric, and MD properties of BaFe12-xMexO19 ceramics prepared by a solid-state reaction method. The Ga3+ cations with a smaller radius preferentially substitute the Fe3+ ions in FeO6 octahedra while the In3+ cations with a larger radius tend to replace the Fe3+ ions in FeO5 bipyramids of R blocks, inducing different physical characteristics. The pure BaFe12O19 and Ga-doped samples show ferrimagnetism in the temperature range from 10 K to 300 K. The In-doped samples exhibit a transition from non-collinear magnetism to collinear ferrimagnetism. The dielectric decrease of pure BaFe12O19 at around 10-175 K is attributed to the quantum paraelectric state, and the shoulder peaks of loss at about 140-200 K are from electron hopping. The dipole glass state is responsible for the dielectric peak of Ga-doped samples at around 20-40 K. The dielectric increase and plateau of In-doped samples are mainly ascribed to the electron hopping at low temperatures. Their dielectric properties at high temperatures are all attributed to the interfacial polarization caused by the Maxwell-Wagner effect. The MD effect also has different origins for the various samples at low temperatures. For the pure BaFe12O19, the negative MD effect at extremely low temperatures and the positive MD effect after warming are ascribed to spin-phonon coupling and field-dependent electron hopping, respectively. The positive MD effect in Ga-doped hexaferrites results from the field-dependent electric dipoles inside FeO5 bipyramids. For the In-doped samples, the negative MD effect and subsequent transformation to the positive MD effect originate from the field-dependent non-collinear spin ordering and electron hopping, respectively. The MD effect at high temperatures is attributed to the combination of magnetoresistance and Maxwell-Wagner effects.

Soft lattices combined with strong electron-phonon coupling in metal halide perovskites result in a complex interplay between electronic and lattice degrees of freedom. This interplay complicates the interpretation of time-resolved excitation spectra like pump-probe spectra. Here, we develop a first-principles approach that combines a nonequilibrium extension of the Bethe-Salpeter equation with ab initio molecular dynamics to resolve the origin of transient absorption. This approach can quantitatively disentangle electronic and thermal lattice contributions across femtosecond-to-picosecond timescales. Exemplified with \ce{CH3NH3PbBr3}, we find that on the femtosecond scale, both X-ray and optical transient absorption spectra are dominated by electronic contributions: Photoinduced Coulomb screening weakens the effective electron-hole interaction and blueshifts the excitonic resonances, whereas Pauli blocking is negligible. On the picosecond scale, thermal lattice contributions become essential, with distinct mechanisms dominating different spectral regions: Lattice vibrations lead to spectral redistribution in the X-ray transient absorption spectrum, whereas lattice expansion blueshifts the optical transient absorption spectrum.

Understanding how nanoconfinement alters the dynamics of glass-forming aqueous electrolytes is essential for clarifying the interplay among ionic hydration, hydrogen-bond structure, and interfacial effects. Here, LiCl.6H2O was investigated in the bulk and under confinement in SBA-15 mesoporous silica with an average pore diameter of 8 nm. Differential scanning calorimetry, Raman spectroscopy, quasielastic neutron scattering, 1 H spin-lattice relaxation, and pulsed-fieldgradient NMR were combined to probe thermal behavior, hydrogen-bond structure, local mobility, and translational transport over complementary time and length scales. The calorimetric results show that LiCl.6H2O remains glass-forming under confinement, while its thermal signature of the glass transition becomes slightly broader and shifted upward relative to the bulk. Raman spectra in the O-H stretching region indicate that the concentrated LiCl solution possesses a weakened and less tetrahedrally connected hydrogen-bond network compared with bulk water. On the subnanosecond timescale, elastic fixed-window analysis reveals reduced mean-squared displacements under confinement, demonstrating suppressed motional amplitudes inside the pores. Inelastic fixed-window neutron scattering scans analyzed within a jump-diffusion framework yield lower effective translational diffusion coefficients and longer residence times for the confined liquid, indicating that confinement mainly hinders translational escape from transient local environments. 1 H relaxometry further shows that confinement broadens the distribution of local proton fluctuation times, while PFG-NMR confirms that the measured long-range water mobility in bulk LiCl.6H2O solution is reduced relative to bulk water. While the present data do not resolve distinct interfacial and pore-centered populations in confined LiCl.6H2O, its dynamics are markedly altered across timescales, from the glassy to the liquid state, resulting in slower, spatially constrained, and more heterogeneous motions.

Tetrahydrofuran (THF) is a benchmark guest for probing clathrate hydrate thermodynamics because a stoichiometric aqueous solution (THF.17H2O) forms structure-II (sII) hydrate at ambient pressure with a well-defined dissociation temperature. Here, we combine differential scanning calorimetry (DSC) and wide-angle X-ray scattering (WAXS) in bulk and confined media to resolve how composition, pore filling, and cooling rate govern hydrate formation in SBA-15 mesoporous silica. Bulk DSC establishes mass-balanced enthalpies for ice and sII hydrate and confirms reversible dissociation/melting temperatures. In confinement, the heating traces separate into a Gibbs-Thomson depressed ice melt (= -14.7 $\pm$ 0.2 {\textdegree}C), an in-pore hydrate dissociation (= -13.2 $\pm$ 0.2 {\textdegree}C). Confined hydrate appears only when two criteria are met: near-percolating filling ($\phi$ = 1.0 -1.1 cm3/g) and sufficient THF ($\ge$ 1:16 mol:mol). Cooling-rate experiments (1.0 vs 0.5 {\textdegree}C/min) demonstrate that slower precooling increases the confined-hydrate fraction and reduces confined ice without shifting equilibrium temperatures: at $\phi$ = 1.1, the hydrate enthalpy rises by ~60% at 1:11 and ~54% at 1:14, but by $\le$ 17% at 1:16. Temperature-cycling tests show invariant reheating peak positions, indicating that capillarity and composition, rather than kinetic history, fix the liquidus and dissociation temperatures. WAXS indicates that the phase formed in pores is crystallographically identical to bulk sII. Finally, the variation of melting points ($\Delta$T___) plotted against inverse pore radius follows the Gibbs-Thomson law for both ice melting and hydrate dissociation, quantitatively linking the observed shifts to crystalline size and clarifying how confinement, cooling rate, and composition govern the competition between hydrate formation and water crystallization.

The anomalous Hall effect in antiferromagnetic metals has attracted considerable attention. Most known realizations involve itinerant $d$ electrons that simultaneously mediate charge transport and magnetic order. Here, we focus on $f$-electron materials, where localized magnetic moments and conduction electrons are hosted in different orbitals. We develop a theoretical framework to describe the impact of localized antiferromagnetic order on itinerant electrons. Applying this approach to the recently discovered $4f$ antiferromagnetic metal $\mathrm{Ce}_{2}\mathrm{Cu}\mathrm{Ge}_{6}$, we identify the origin of both the intrinsic anomalous Hall conductivity and the spin splitting of the energy bands as spin-dependent intersite hopping induced by nonlocal Kondo exchange coupling, rather than a Zeeman-type effective field acting locally on the conduction electrons.

Altermagnets exhibit momentum-dependent spin splitting without net magnetization, providing a unique platform where magnetic order, electronic structure and lattice dynamics intertwine. Here, using first-principles calculations, we demonstrate that the prototypical altermagnets CrSb and MnTe host locally chiral phonon modes carrying finite phonon angular momentum with a six-lobes $f$-wave texture in momentum space. Our results show that the chiral lattice motion originates from the pnictogen/chalcogen sublattice, while the altermagnetic spin splitting is generated by the magnetic transition-metal atoms, indicating that chiral lattice dynamics and altermagnetic electronic states originate from different atomic sublattices of the same crystal. In pristine compounds, at each valley, inversion symmetry suppresses the net phonon angular momentum despite local circular atomic motion. We further demonstrate that isoelectronic symmetry lowering induced by chemical substitution lifts this cancellation and generates finite valley phonon chirality, while keeping the altermagnetic nature of the compounds intact. Most importantly, we reveal that chiral phonons couple to momentum-dependent spin-split electronic bands through momentum-dependent electron-phonon interaction, producing characteristic modifications of the electronic structure, possibly accessible by photoemission experiments. Our results establish altermagnets as a promising platform for chiral phononics and spin-selective lattice control.

Finite quantum environments can relax local probes without acting as canonical baths. We study this distinction for a probe qubit coupled to a programmable bath of ($N$) qubits under excitation-number-conserving dynamics. The conserved charge partitions the Hilbert space into sectors. We characterize probe-level bath emergence using the sector-resolved late-time population ($p_e^{(q)}$), the sector-memory variance ($M_N$), and a global Gibbs-fit error ($\Delta_G^{\mathrm{global}}$). Exact simulations with Haar-random pure states in each complete fixed-charge sector yield sector-dependent populations close to the maximally mixed-sector benchmark ($p_e^{(q)}=q/(N+1)$), producing a nonzero Gibbs obstruction. We then construct charge-preserving Floquet circuits using ($R_z$) phases and ($XX+YY$) exchange gates, validate them with ideal and noisy Qiskit simulations, and implement finite-depth experiments on IBM Fez. For ($N=4$) and ($\epsilon=0$), the hardware data give ($M_N \simeq 0.044$), ($\Delta_G^{\mathrm{global}} \simeq 0.558$), and charge preservation near 0.90 after readout mitigation. A paired symmetry-breaking scan using bath ($R_x(\epsilon)$) rotations reduces both diagnostics while increasing charge leakage, but does not erase sector ordering over the accessible depths. These results show that equilibration within constrained sectors is insufficient to produce a single sector-independent Gibbs state for the probe.