Papers

A detailed study of emission wavelength tailoring of GaSb-based QDs formed by InGaSb-filling of droplet-etched nanoholes in AlGaSb is presented. The study shows that the emission wavelength can be modified from 1.48 um to the center of the telecom C-band at 1.55 mm by independently varying the QD composition and size. More specifically, the optical transition energy shifts linearly as a function of In-content of the QD material at a rate of -4.4 meV/In-percentage, and with the number of monolayers (ML) of material used for filling the nanoholes, at -2.0 meV/ML. These experimentally observed energy shifts are well predicted by simulations yielding rates of -4.3 meV/In-percentage and -2.1 meV/ML, respectively. For the simulation, a uniform In composition, low intermixing, and microscopically measured QD geometry is considered. Additionally, excellent ensemble QD uniformity, with unprecedented inhomogeneous broadening well-below 7 meV across all samples is demonstrated. Finally, photoluminescence of single-QDs reveals narrow excitonic emission lines of 13.8+/-6.7 ueV and low fine-structure splitting values reaching <10 ueV. These results identify GaSb-based LDE QDs as a tunable telecom platform for scaling quantum-photonic applications over long-haul optical fiber networks.

Thermal escape is governed by the Arrhenius law, where the mean escape time scales exponentially with the barrier height. We show that the non-Markovianity induced by time-delayed feedback in the confining force removes this exponential scaling. Beyond a threshold set by the curvature of the minimum, the delay destabilizes the well, and the thermal noise seeds an instability that is subsequently amplified deterministically to the boundary leading to slingshot escape trajectories. The escape time becomes logarithmic in the barrier, its fluctuations follow a Gumbel law, and an optimal delay enables escape faster than free diffusion. Our results propose time delay as a tunable and experimentally feasible control parameter for accelerating activated processes.

In nonmagnetic centrosymmetric materials, $\mathcal{PT}$ symmetry enforces vanishing total phonon angular momentum (phonon AM) at every wave vector, making them appear unsuitable as hosts of axial phonons. Here, using first-principles calculations for BaAgAs and representative van der Waal's layered materials, we show that centrosymmetric slabs can still host large hidden layer-resolved phonon AM with both chiral and cycloidal modes. This hidden phonon AM texture produces layer resolved phonon thermal Edelstein-like responses and a real-space phonon AM dipole response, both tunable by strain. Our results establish centrosymmetric layered materials as an exciting platform for hidden axial phonon and multipolar phonon thermal response.

We show that Anderson localization fundamentally reshapes dissipative superconducting electrodynamics, replacing the linear Mattis–Bardeen pair-breaking onset with a parametrically weaker quadratic Mott edge while leaving the quasiparticle spectrum unchanged. We derive this behavior for a weakly disordered single-channel wire with a spatially uniform $s$-wave pair potential using a Nambu-space extension of the Berezinskii diagram technique that resums elastic impurity scattering to all orders. Conservation of the Bogoliubov branch collapses the Nambu diagram hierarchy onto an exactly solvable localization problem. The localization length remains equal to its normal-state value, whereas the localization time diverges at the gap edge. The new absorption edge results from the product of the superconducting pair-creation coherence factor and the Mott-suppressed current matrix elements between localized orbitals, which generates the characteristic double logarithm. Localization also reduces the Hebel–Slichter coherence peak. The resulting theory provides an all-orders benchmark for microwave and spin-relaxation experiments on localized superconducting nanowires.

In this contribution, Part I, we present a coupled thermo-hydro-mechanical formulation for modeling and analyzing water-to-ice phase change in a deformable fully-saturated porous medium. It is implemented in the multi-physics computational platform OpenGeoSys-6. We compute a series of carefully designed benchmark problems which critically examine the corresponding formulation components and the overall implementation. Several ingredients that have a qualitative and quantitative impact on the numerical results are identified, particularly dissected and commented on. Simulations also account for soil deformation induced by freezing (as a result of 9% volumetric expansion caused by water-to-ice phase transition). The forthcoming Part II will complete the code verification and validation campaign by considering a real full-scale three-dimensional case study of shallow subsurface ice storage. More specifically, we simulate the ice growth process in a fully saturated soil specimen surrounding a group of borehole heat exchangers (BHEs) that contain subzero temperature coolant fluid. A snapshot of the numerical results of this task is already depicted here in Part I as a teaser.

Superconductors with high critical temperatures that emerges beyond the phonon-mediated regime are usually considered unconventional in nature, yet unlike conventional superconductors, no broadly applicable predictive theory currently guides their discovery. Here, we use interpretable machine learning to uncover a common materials-space signature of high-$T_{\mathrm{c}}$ unconventional superconductors and develop a data-driven strategy for materials discovery. We construct a unified feature representation for each material by integrating compositional statistics, structural information, and latent representations from trained property-prediction models, followed by structure-aware filtering of an experimentally established superconducting dataset. Without using transition-temperature information, unsupervised analysis shows that cuprate and iron-based superconductors occupy a common region of materials space, characterized primarily by large electronegativity deviation and intermediate mean valence-electron number. A supervised $T_{\text{c}}$ model independently identifies the same descriptors as dominant features, providing complementary evidence for their relevance. Using this empirical materials-space prior together with the $T_{\text{c}}$ model, we prioritize candidate materials, recover recently discovered nickelate superconductors, and identify chemically distinct candidates for future investigation.

Proteins and many other colloids carry ionizable surface groups that are both spatially inhomogeneous (patchy) and pH-responsive (charge-regulating). In the description of the electrostatic interactions between such particles, these two aspects are often treated separately, especially from a theoretical perspective. We present a unified, closed-form theory that unites charge regulation and patchiness within the linearized Poisson–Boltzmann approximation. For spherical particles with anisotropic distributions of titratable sites, we derive both the leading-order mean-field interaction energy as well as the Kirkwood–Shumaker fluctuation interaction. The theory exposes a qualitatively new effect between two electroneutral anisotropic particles: proximity-induced charge regulation generates a net monopole, and splits orientational branches that are degenerate in any linear fixed-charge model. The accompanying correction to the interaction energy has no fixed sign—it softens like-charge repulsion but can deepen or create attraction away from the isoelectric point. We benchmark three ingredients of the theory against published results; no existing simulation probes their combination, which would capture the central prediction of the theory. Lastly, we apply the theory to two proteins—lysozyme and $\alpha$-chymotrypsinogen A—and show that it not only reproduces the measured second virial coefficients reasonably well but also predicts how charge regulation expands the range of pH and screening strength where the protein–protein interaction is attractive.

We investigate the effect of thermal oxidation on BaTiO$_3$ single crystals. Our results reveal that, even at moderate temperatures of up to 1000 {\deg}C, complex segregation mechanisms occur involving the movement of Ba-rich compounds to the upper surface, where they form inhomogeneously distributed BaO nanocrystals. As a result, deeper regions of the surface layer become depleted in Ba and become TiO$_2$-rich. A sandwich-like structure evolves in the surface layer, exhibiting a measurable electromotive force and self-polarization. This, in turn, screens the polarization and diminishes the global ferroelectric response. The conductivity is also strongly influenced by the irreversible segregation effects in the surface region. An as-received crystal can be transformed into a metallic state, while oxidation induces semiconducting properties and prevents a return to the metallic state upon subsequent reduction. Nanoscale analysis demonstrates that the conductivity is channeled to filaments forming along dislocations, whose local chemical composition changes upon reduction and oxidation even at moderate temperatures due to preferential Ba and O pipe diffusion thus determining the electric behavior of the whole sample.

Accurate design and optimization of photonic multilayer structures like distributed Bragg reflectors (DBRs) require precise knowledge of material optical constants, particularly the temperature dependence of the refractive index. While these parameters are well established for widely used semiconductors, for emerging materials such as antimonides they are often limited to room-temperature data, especially for new spectral ranges of interest. Antimonide compounds, in particular GaSb-based alloys, are promising for quantum photonics applications. In this work, we investigated DBRs lattice-matched to GaSb and designed for operation in the third telecommunication window. Reflectivity spectra were measured in the temperature range from 11.5 K to 300 K, and then fitted using the transfer matrix method (TMM), combined with a dedicated recursive numerical fitting algorithm. Initial parameters included layer thicknesses determined by scanning electron microscopy (SEM) and literature values of refractive indices at room temperature. This approach enabled extraction of the temperature-dependent refractive indices of two AlGaAsSb alloys suitable for forming DBR mirrors for 1.5 um wavelengths. The obtained results provide essential input for reliable DBR design, ensuring proper stopband positioning and high reflectivity under cryogenic operating conditions required for efficient quantum emitter performance.

We extend the functional determinant approach (FDA), previously restricted to static impurities, to the case of finite-mass impurities by using the mass-gap description of Fermi polarons [Phys. Rev. Lett. 135, 193401 (2025)]. The quadratic structure of the mass-gap model enables the exact evaluation of many-body spectra and Ramsey dynamics for mobile impurities. We show that this mass-gap FDA smoothly interpolates between the Fermi-edge singularity for infinitely heavy impurities and the emergence of quasiparticle weight for finite impurity mass. Our results demonstrate that the mass-gap FDA provides a transparent and computationally efficient framework to describe the quantum dynamics of mobile impurities.

We present a comprehensive analysis of non-equilibrium fluctuation-dissipation relations connect- ing experimentally accessible chiral-current auto- and cross-correlations to the tunneling-current noise and conductance in Laughlin edge states coupled through a quantum point contact (QPC). We examine their validity for two chiral Laughlin edges held at different temperatures and voltages and show that the relations remain exact for arbitrary tunneling strength, voltage bias, and edge- state temperatures. We further generalize them to spatially extended QPCs and to tunneling am- plitudes with an explicit voltage dependence, and discuss the conditions and limitations associated with these generalizations. Our results establish that the local tunneling-current noise generated at the QPC can be reliably reconstructed from experimentally accessible auto- and cross-correlations measured downstream, providing a robust route to characterize non-equilibrium transport in chiral edge states.

Atomic reconstruction at twisted two-dimensional interfaces governs many of their emergent optical, electronic, and mechanical properties, including sliding ferroelectricity. Despite recent progress in understanding lattice reconstruction in suspended twisted bilayers, structural changes at van der Waals heterointerfaces between multilayer crystals remain largely unexplored. Here we use multi-slice electron ptychography to non-invasively recover the three-dimensional atomic structure at marginally twisted rhombohedral interfaces between thick transition-metal dichalcogenide crystals. With a position precision of ~3 pm and a depth resolution ~1 nm, we resolve the twist-induced lattice reconstruction field per layer, and the resulting dislocation network at the buried interface. Despite the bulk nature, we observe markedly strong in-plane interfacial reconstruction due to suppression of the out-of-plane bending by outer layers, exceeding predictions from our three-dimensional modelling. Furthermore, we extract the strain tensor evolution during the decay of the reconstruction into the bulk, providing a structural foundation for understanding multi-layer moiré systems.

Atomic coordinates specify a structure, but they do not reveal how chemical connectivity across several length scales relates to atomic motion and configurational energy ordering. We formulate chemically directed persistent homology at four resolutions—complete networks, individual sites, spatial fields, and substitutional arrangements—while retaining the chemical identity and length scale of each connectivity feature. In ab initio molecular dynamics (AIMD) trajectories of $\delta$- and $\gamma$-CsPbI$_3$ at five temperatures spanning 500–700 K, the corner-sharing $\gamma$ network has a lower Pb–I restoring stiffness and permits larger iodide excursions, yet iodide positional correlations decay 2.27 times more slowly and Pb-network topology retains memory 1.63 times longer than in the edge-sharing $\delta$ phase. Local softness and loss of network memory are therefore distinct. At individual sites, rare $\gamma$-phase Pb environments with a $\delta$-like Cs-cage connectivity precede 0.17 $\mathring{\mathrm{A}}$ greater Pb displacement over the subsequent 0.5 ps. The same Pb-network coordinate resolves disruption of corner-sharing connectivity across a 2560-atom $\delta|\gamma$ boundary. In substituted CsPbI$_3$, compact dopant arrangements undergo greater cooperative host relaxation and lie lower in density-functional-theory (DFT) energy than dispersed arrangements of the same composition. SchNet and Allegro model families with comparable energy errors encode opposite ordering along this coordinate, and 61 of 247 supplied models with errors below 1 meV atom$^{-1}$ on separate test structures reverse the DFT relation. Because relative configurational energies set Boltzmann populations, chemical network topology links structure to physical response and tests whether learned energy models preserve DFT configurational ordering even when their average errors are small.

We propose a ferromagnetic vortex stabilized by the interfacial Dzyaloshinskii–Moriya interaction (iDMI) and investigate its properties through theoretical analysis and micromagnetic simulations. Our results demonstrate that this vortex can remain stable even in nanoscale ferromagnetic disks with radii below $5\,\text{nm}$—far smaller than those of conventional nanodot vortices having about $1\,\mu\text{m}$ radius. We analytically solve the nonlinear equation of motion describing the anharmonic vortex oscillation, and identify the critical frequency that determines the stability of the driven oscillation of the vortex. This nanoscale vortex exhibits conventional properties of microscale vortices, including gyrotropic oscillation and resonance frequency shift under an out-of-plane magnetic field. It also exhibits unconventional behaviors, such as a strongly anharmonic potential, nonlinear oscillations, and a Duffing-oscillator-like response under the external AC bias.

Dark excitons play a central role in the nonequilibrium dynamics of two-dimensional semiconductors, but remain difficult to characterize. Transient-absorption experiments, with probes tuned in exciton-exciton transitions energy range (exc-tr-abs), can detect excitations from any populated dark excitons, including symmetry-forbidden, spin-forbidden, and finite-momentum ones. In this work, we develop a $GW$+BSE scheme for computing exc-tr-abs spectra from arbitrary populated exciton distributions. These dark excitons are included equally by evaluating exciton-exciton dipoles in a locally smooth gauge, including intra- and inter-band contributions. For monolayer MoS$_2$, the exc-tr-abs signal arises from the $\Gamma$, $K$, $M$, and $Q$ valleys, differing substantially from the $\Gamma$-only interpretation. Exciton-exciton dipoles show similar intensities across these valleys, while their weights are dictated by initial excitonic populations. State- and spin-resolved analyses assign the peaks to $1s \rightarrow 2p$ and $1s \rightarrow 3p$ transitions from both spin-flip and spin-conserving A and B excitons across valleys and momenta.

In Metamorphosis of Plants (1790), Goethe traced diverse plant organs to transformations of a common leaf-like structure – a principle modern mechanics attributes to two material ingredients: non-uniform in-plane strain from differential growth or shrinkage, and spatially patterned stiffness. Here we translate this principle into a synthetic fabrication framework called Polymer Membrane Tensegrity (PMT). A flat elastomeric film swollen with a second monomer is selectively UV-cured through a liquid-crystal display (LCD) photomask in a single-side digital photopatterning step, producing rigid rods embedded in a soft, shrinkable membrane. After the unreacted monomer is extracted with a solvent and the film is dried, the membrane shrinks far more than the rods, generating a ~50% in-plane strain differential and a ~2,000-fold modulus contrast – conditions under which the contracting membrane is held in tension by mutually unconnected rods, a tensegrity-inspired arrangement within a single film. An origami-based inverse design algorithm computes the rod layout that morphs the film into a prescribed 3D surface. We demonstrate PMT on a dome, a hyperbolic surface, and a gyroid unit cell – positively and negatively curved targets – reproducing all three with mean deviations of 1.0-2.1% of the target size; perimeter curve optimization halves the mean deviation of the gyroid. Because patterning occurs on one side only, PMT eliminates the front-to-back alignment demanded by bilayer methods, offering a scalable route from flat polymer films to freeform 3D surfaces.

Understanding the dehydration mechanism of hydrated salts remains fundamentally important in solid state chemistry, as their behavior affect fields ranging from heat storage to heritage conservation and pharmaceutical crystallization. Combining Raman confocal microscopy, dynamic weight loss measurements, SEM, and micro CT, we show that dehydration kinetics of sodium sulfate decahydrate (mirabilite) unfold through two regimes: an initial nucleation controlled phase, where atomic rearrangement drives two dimensional lateral growth following an exponential law, and a subsequent phase boundary controlled regime, where growth advances into the crystal depth, limited by water vacancy formation at the hydrated dehydrated interface. The resulting thenardite product shows around 35 percent shrinkage and forms a porous, layered dual porosity nanocrystalline structure, with relative humidity directly governing crystal size. Extending this analysis to other sulfate hydrates reveals that crystallographic symmetry changes between hydrate and anhydrous phases dictate surface morphology, linking microstructure to mechanism. This multiscale framework uncovers dynamics hidden from bulk measurements and suggests structural indicators could predict dehydration pathways in other hydrated salt families, and opening route toward designing thermal energy storage materials without exhaustive experimental screening.

Calcium mineralisation underpins processes ranging from biomineralisation to scalable carbon storage, yet the earliest stages of nucleation remain unresolved. Here we investigate calcium-containing solutions under nanoscopic confinement while remaining undersaturated with respect to bulk calcium carbonate precipitation. Using sensitive surface force measurements, we identify a long-range non-DLVO repulsive interaction specific to calcium solutions, which we attribute to hydrated ion networks at mineral interfaces. These interfacial networks exhibit viscoelastic behaviour distinct from the bulk solution, persist across a broad pH range, and can be disrupted by competing ions with strong surface affinity. Our findings provide experimental evidence that stable hydrated ion networks can emerge at mineral interfaces under undersaturated conditions, supporting the possibility that interfaces and confinement stabilise intermediate ion assemblies prior to nucleation. These results bridge classical and nonclassical descriptions of mineral nucleation and highlight the central role of interfaces and confinement in directing crystallisation pathways.

We demonstrate coherent coupling of ferromagnetic resonance in two individual permalloy stripes via a superconducting coplanar waveguide resonator. The two stripes are placed on top of the resonator with an angle of 50$^{\circ}$ between their respective long axes. This alignment enables us to separately tune their ferromagnetic resonance frequency by exploiting their shape anisotropy by simply rotating the external bias magnetic field in the sample plane. Both individual ferromagnets exhibit strong coupling with the microwave resonator. This method avoids the use of local individual bias coils and facilitates the integration of similar experiments into planar device infrastructures.

We develop a microscopic scattering theory of the phase-dependent equilibrium mechanical response of a ballistic superconductor-graphene-superconductor Josephson junction. The calculation is based on an energy-dependent Dirac scattering matrix embedded in a normalized Matsubara determinant, so the reported force correction contains the complete Bogoliubov-de Gennes spectrum of the stated ideal model. At charge neutrality the full determinant approaches a closed-form evanescent-mode result proportional to $\Delta W/L^2$, reaching $2\ln 2\,\Delta W/(\pi L^2)$ at phase difference $\pi$ in the zero-temperature short-junction limit. Gate doping produces propagating channels and Fabry-Pérot structure, causing large oscillations and sign reversals of the phase-dependent force correction $\delta F=F(\phi)-F(0)$. We distinguish the interband-to-intraband Andreev crossover, controlled by $|\mu|/\Delta$, from the evanescent-to-propagating crossover, controlled by $|\mu|L/(\hbar v_F)$. Exact real-energy subgap poles obtained from the same energy-dependent scattering matrix are used to diagnose specular/interband and retro/intraband character; these labels are not treated as separately measurable thermodynamic forces in the mixed regime. We also quantify the difference between the complete determinant result and the frozen-scattering short-junction approximation without identifying that difference with a pure continuum force. The resulting gate- and phase-dependent mechanical signal provides a Dirac-material extension of earlier superconductivity-induced mechanical-force proposals.

Conventionally, the differential form of the Clausius inequality is adopted for infinitesimal irreversible processes. We show that the correct first-order form for infinitesimal quasi-static irreversible processes is the equality d'Q=TdS rather than d'Q < TdS. This provides a purely thermodynamic proof that internal entropy production is second-order or higher and confirms that entropy remains a well-defined state quantity even when quasi-static irreversible processes are included, without resorting to the Boltzmann relation.

Developing novel and efficient materials that are beyond silicon for photovoltaic (PV) applications is required to meet the upcoming energy needs of our societies. To identify novel candidate materials that can act as PVs, we use first principles calculations to perform a systematic screening of the pnictide chemical space (i.e., nitrides and phosphides). Specifically, we explore three different ternary and quaternary pnictide classes, namely, ABCX$_2$, BB'B"X$_2$, and A$_4$BX$_2$ (A = Li, Na, or K; B, B', B" = Ca, Sr, Mg, or Zn; C = Al, Ga, or In; X = N or P), leading to a set of 104 possible pnictide compositions. Based on our evaluations of ground state structures, 0 K thermodynamic stabilities, electronic structures, carrier effective masses, dynamic stabilities, and intrinsic point defect formation energies, we arrive at three promising candidates, namely, NaCaInN$_2$, NaSrInN$_2$, and K$_4$ZnP$_2$. Notably, all the identified candidates are thermodynamically (meta)stable, exhibit direct (or nearest direct) band gaps that are optimal for PV applications, and are resistant to forming several types of point defects. We hope that our first principles driven workflow and the identified candidates will advance the development of novel PV materials and reinvigorate interest in the exploration of pnictides.

The classical Bloch equation forms the foundation of magnetic resonance theory but may be insufficient to capture the complex effective dynamics observed in heterogeneous materials such as biological tissue. Here an effective-medium strategy is proposed to describe magnetic resonance dynamics from observations at macro-scale (order 1 mm$^3$). In this framework, the classical Larmor torque is retained while the relaxation term is replaced by a general nonlinear field (i.e. the effective medium term). This field is required to preserve key physical properties, including rotational symmetry, global stability of thermal equilibrium, and dissipativity. These requirements lead to a complete characterization of admissible relaxation fields and provide a constructive framework for generating nonlinear relaxation models. The resulting theory recovers classical Bloch dynamics as a special case and provides a principled foundation for effective-medium descriptions of magnetic resonance phenomena.

Charge order is conventionally viewed as a static modulation of the electronic density, despite growing experimental capabilities to probe and manipulate its nonequilibrium evolution. In contrast to spin-ordered systems, a microscopic framework for charge-order dynamics and its control under external driving remains largely underdeveloped. Here, starting from an extended Hubbard model, we derive an effective pseudospin model in which the charge-ordered state maps onto staggered pseudospin order. The resulting charge-order dynamics is governed by Landau–Lifshitz–Gilbert-like equations for the pseudospins, closely analogous to those of a bipartite antiferromagnet. We show that an external electric field directly controls the staggered pseudospin order and, above a threshold field, drives coherent reversal of the charge-order polarity by destabilizing collective pseudospin excitations. Our results establish the charge pseudospin as a microscopic dynamical degree of freedom for coherent switching and control of charge order, providing a charge-sector analogue of the well-established framework for spin-order dynamics in spintronics.

The transport of anisotropic tracers in active fluids exhibits rich dynamical behavior arising from the interplay between particle shape, activity, and steric interactions. We employ Brownian dynamics simulations to investigate the motion of an elliptical tracer immersed in a suspension of active dumbbells. We find that both translational and rotational transport, characterized by the mean-square speed and diffusivity, are enhanced by more than an order of magnitude with increasing area fraction, $\phi$, of active dumbbells. Notably, tracer motion is enhanced along the major axis relative to the minor axis, with $\mathrm{v}_{\parallel}>\mathrm{v}_{\perp}$ and $D_{\parallel}>D_{\perp}$. Remarkably, both translational and rotational transport exhibit an optimum at an intermediate packing fraction of active dumbbells, with the corresponding transport coefficients decreasing at higher densities. We show that this non-monotonic transport arises from the anisotropic accumulation and aggregation of active dumbbells around the tracer, which control the non-equilibrium force and torque fluctuations. Thus, establish a direct connection between the collective organization of active dumbbells at the tracer surface and its emergent translational and rotational transport.

High-resolution iterative ptychography typically relies on a well-aligned, high-convergence-angle electron probe. Here we explore whether it can instead be performed at small convergence angles, relaxing the need for probe correctors and enabling experiments at low accelerating voltages or with a de-excited objective lens, as in Lorentz mode. Through experiments and simulations, we show that once the convergence angle is small enough that no diffracted disks overlap, the resulting reconstruction is ambiguous, posing a significant challenge for robust interpretation of results. This challenge arises because of the lack of interference between Bragg disks in the recorded diffraction pattern intensity, leading to no phase information for each reflection. Reconstructions with these data lead to degenerate objects in which rigid translations of the lattice and reversals of contrast of the object produce the same error between experimental data and the ptychography forward model. Increasing the real-space overlap between probe positions does not lift this degeneracy. An amorphous substrate can supply the missing phase relationships by giving the Bragg beams support in the gaps between disks. This phasing is fragile, however, and survives only where the forward model matches the experiment. At fixed dose, either constraining the object to be a pure phase object or introducing thermal motion into the forward model is enough on its own to make the solution non-unique, highlighting why our experimental reconstructions below the overlap threshold are ambiguous despite ample dose and real-space redundancy. Most troublingly, the lattice spacing and orientation are always recovered correctly, so a non-unique reconstruction looks convincing and can be diagnosed only by repeating the reconstruction from different starting points.

In this article, we apply the idea of emergent symmetries to construct holographic representations of a broad class of topological quantum critical points (tQCPs) that appear in fermionic classes in the Bott clock. We show explicitly that around the Bott clock, an emergent symmetry $U_{EM}$ exists at a tQCP between different symmetry protected gapped phases with protecting symmetry $G_p$ in $d$ spatial dimensions. This emergent symmetry can be used to construct a $(d+1)$ spatial dimensional lattice model with a properly upgraded symmetry such as $U_{EM}\times G_p$ or $U_{EM} \rtimes G_p$, etc. By doubling the degrees of freedom of the adjacent topological class in $d$-dimensions, we successfully show that the $(d+1)$-dimensional lattice models constructed in this way have the desired enlarged symmetry groups that precisely belong to the adjacent topological classes, counterclockwise around the Bott clock. Furthermore, $d$-dimensional boundaries of these $(d+1)$ dimensional lattice models of gapped topological classes are shown to exhibit identical infrared dynamics as the corresponding tQCPs in the $d$-dimensional adjacent topological phases in the Bott clock, with lower symmetries.

Circulating currents in triangular triple quantum dots reverse repeatedly with bias even at zero magnetic flux and for a real Hamiltonian, a phenomenon whose origin has remained unclear. We show that dissipative tunneling prepares an orbital pseudospin, while virtual charge fluctuations generate a noncollinear Lamb field that rotates it toward the chiral direction. Bias changes their relative orientation and thereby reverses the current. This reservoir-induced orbital Hanle effect converts a nonchiral orbital polarization into scalar spin chirality, which an exact ground-multiplet identity links to the circulating current. Hierarchical-equations-of-motion calculations show that the low-bias reversal survives beyond the second-order weak-coupling description, while the quadratic growth of chirality after a sudden voltage switch identifies precession. More broadly, time-reversal-odd responses can emerge in open quantum systems from the interplay between dissipative state preparation and coherent precession.

We investigate the ground state properties of a superconducting ring embedded with a quantum dot (QD) by using a variational wave-function approach. A theoretical formulation for the treatment of the finite-U Anderson impurity coupled with a superconducting ring are presented. We demonstrate singlet-doublet transitions of the ground state for this system with the QD in the mixed valence regime. It is shown that the supercurrent in the superconductor ring shows oscillations with the external enclosed magnetic flux and exhibits abrupt jumps at the singlet-doublet phase transition points.

Interfaces of crystalline materials are strongly affected by the anisotropy of interface energy. A key quantity in this context is the interface stiffness tensor, which characterizes the response of the interface energy to changes in interface orientation and plays a role in determining the driving force for interface migration. The latter is expressible via contraction of the stiffness tensor and interface curvature tensor. Practical computations involving tensors necessarily rely on their individual components. In this work, an explicit component-wise expression is derived for the contraction of the stiffness and curvature tensors, valid in arbitrary coordinate systems. Within this formulation, to get the driving force, the curvature tensor is contracted with the pullback of a stiffness-related tensor - originally defined in three-dimensional Euclidean space - onto the interface manifold. This covariant treatment establishes a physically consistent foundation for three-dimensional computational models involving interface stiffness.