In optical diffraction, the phase difference between sources in a grating or multislit mask is determined by the angle to the imaging screen, yielding the familiar multilobed diffraction image. Here, we realize a similar phenomenon in a superconductor-semiconductor hybrid circuit configured to allow Andreev scattering from multiple parallel scatterers. Phase differences between scatterers are set by tapping off of a remote superconducting meander. We investigate arrays with two, three, four, and ten Andreev scatterers, examining local and nonlocal diffraction patterns, finding good agreement with a theory of multiple Andreev scattering, not to be confused with multiple Andreev reflection. Adding current-carrying taps to the meander allows individual phase control.

Tailoring charge transport in solids on demand is the overarching goal of condensed-matter research as it is crucial for electronic applications. Yet, often the proper tuning knob is missing and extrinsic factors such as impurities and disorder impede coherent conduction. Here, we control the very buildup of an electronic band from impurity states within the pseudogap of ternary ${\mathrm{Fe}}_{2\text{−}\mathrm{x}}{\mathrm{V}}_{1+x}\mathrm{Al}$ Heusler compounds via reducing the Fe content. Our density-functional theory calculations combined with specific heat and electrical resistivity experiments reveal that, initially, these states are Anderson-localized at low V concentrations $0<x<0.1$. As $x$ increases, we monitor the formation of mobility edges upon the archetypal Mott-Anderson transition and map the increasing bandwidth of conducting states by thermoelectric measurements. Ultimately, delocalization of charge carriers in fully disordered ${\mathrm{V}}_3\mathrm{Al}$ results in a resistivity exactly at the Mott-Ioffe-Regel limit that is perfectly temperature-independent up to 700 K—more constant than constantan.

The experimental demonstration of electric skyrmion bubbles and the recent prediction of their Brownian motion have brought topological ferroelectrics close to their magnetic counterparts. Electric bubbles (e-bubbles) could potentially be leveraged in applications for which magnetic skyrmions have been proposed (e.g., neuromorphic computing). Yet, we still lack a strategy to create currents of e-bubbles. Here, using predictive atomistic simulations, we illustrate two approaches to induce e-bubble currents by application of suitable electric fields, static or dynamic. We focus on regimes where e-bubbles display spontaneous diffusion, which allows us to generate a current by simply biasing their Brownian motion. Our calculations indicate that e-bubble velocities over $25\mathrm{m}/\mathrm{s}$ can be achieved at room temperature, suggesting that these electric quasiparticles could rival the speeds of magnetic skyrmions upon further optimization.

Non-Hermitian systems have recently shown new possibilities to manipulate wave scattering by exploiting loss, yet coherent perfect absorption at an exceptional point (CPA EP) remains elusive in acoustics. Here, we demonstrate it based on a two-channel waveguide with compact lossy resonators. We realize imbalanced losses crucial for CPA EP by using active components to independently modulate the non-Hermiticity. The CPA EP experimentally manifests as full absorption at a unique real frequency and shows high sensitivity to the incident phase variations. Our findings open an avenue to explore novel non-Hermitian physics for classical waves and develop innovative acoustic singularity-based devices.

Topological invariants have been utilized profoundly to classify the geometric features of electronic, photonic, and phononic structures. However, no invariant has ever been conceptualized to classify the functional properties of diverse thermal structures. Here, we formulate a heat diffusion invariant to reveal the explicit correlation between thermal functionality and diffusivity. The value goes beyond establishing a unified framework for various thermal metamaterials. The heat diffusion invariant offers a forward paradigm for precisely achieving freeform transient thermal metamaterials with isotropic thermal conductivity. We verify the competitiveness and robustness experimentally via a freeform transient thermal cloak. The heat diffusion invariant also paves the way for other functions, such as transient thermal illusion, and applies to thermal convection and radiation. These findings could open up an unprecedented invariant-based gateway to thermal management, metamaterial design, and nonequilibrium energy and mass transport.

Generative machine learning models are capable of learning the phase behavior in condensed matter systems such as the Ising model. We utilize a score-based modeling procedure called thermodynamic maps to describe the isotropic-nematic phase transition in a melt of Gay-Berne ellipsoids. When trained on samples from a single temperature on either side of the phase transition, this generative machine learning approach infers effectively the nematic order parameter at intermediate temperatures. These results demonstrate score-based models’ ability to learn the physics of a nontrivial liquid crystal phase transition.

We investigate critical transport and the dynamical exponent through the spreading of an initially localized particle in quadratic Hamiltonians with short-range hopping in lattice dimension $d_l$. We consider critical dynamics that emerges when the Thouless time, i.e., the saturation time of the mean-squared displacement, approaches the typical Heisenberg time. We establish a relation, $z=d_l/d_s$, linking the critical dynamical exponent $z$ to $d_l$ and to the spectral fractal dimension $d_s$. This result has notable implications: it says that superdiffusive transport in $d_l\ge 2$ and diffusive transport in $d_l\ge 3$ cannot be critical in the sense defined above. Our findings clarify previous results on disordered and quasiperiodic models and, through Fibonacci potential models in two and three dimensions, provide nontrivial examples of critical dynamics in systems with $d_l\ne 1$ and $d_s\ne 1$.

An efficient implementation of the Toffoli gate is of conceptual importance for running various quantum algorithms, including Grover’s search and Shor’s integer factorization. However, direct implementation of the Toffoli gate either entails a prohibitive increase in the number of two-qubit gates or requires ancilla qubits, whereas both of these resources are limited in the current generation of noisy intermediate-scale quantum devices. Here, we experimentally demonstrate a scalable $N$-qubit Toffoli gate improvement using ${}^{171}{\mathrm{Yb}}^{+}$ trapped-ion-based optical-metastable-ground encoded qutrits for the cases of up to $N=10$. With the use of the Mølmer-Sørensen gate as a basic entangling operation, we compare the standard qubit decomposition with the qutrit approach, where upper levels are used as ancillae. The presented decomposition requires only global control of the ancilla levels, which simplifies experimental implementation of the proposed approach. Using the example of a three-qubit Grover’s search, we also demonstrate an increase in the algorithm’s accuracy by monitoring the leakage from the qubit subspace during a qutrit-based Toffoli gate implementation.

We investigate state designs for continuous-variable quantum systems using the aid of latticelike quantum states. These are code states of Gottesman-Kitaev-Preskill (GKP) codes. We show that the set of all GKP states forms a rigged continuous-variable state 2-design for an $n$-mode system. We use these lattice state designs to construct a continuous variable shadow tomography protocol, derive sample complexity bounds for both global and local GKP shadows under reasonable physical assumptions, and provide the physical gadgets needed to implement this protocol.

Compact stars above a critical stellar mass develop large scalar fields in some scalar-tensor theories. This scenario called spontaneous scalarization has been an intense topic of study since it passes weak-field gravity tests naturally while providing clear observables in the strong-field regime. The underlying mechanism for the onset of scalarization is often depicted as a second-order phase transition. Here, we show that a first-order phase transition is in fact the most common mechanism. This means metastability and transitions between locally stable compact object configurations are much more likely than previously believed, opening vast new avenues for observational prospects.

In nuclei with an odd nucleon number the nonvanishing spin number density is the source of a pseudomagnetic field, which favors the splitting of the nucleon Cooper pairs. Such a pseudomagnetic field is generated always in the dynamics of any nucleus, but its effects on Cooper pairs are significantly enhanced in the dynamic evolution of nuclei with an odd number of nucleons. We present for the first time a microscopic study of the induced fission of the odd neutron compound nuclei ${}^{239}\mathrm{U}$, ${}^{241,243}\mathrm{Pu}$, and the odd proton, odd neutron compound nucleus ${}^{238}\mathrm{Np}$, performed within the time-dependent density functional theory extended to superfluid fermion systems, without any simplifying assumptions, with controlled numerical approximations, and for a very large number of initial conditions. Because of the presence of the unpaired odd nucleon(s), the time-reversal symmetry of the fission compound nucleus is spontaneously broken, an aspect routinely neglected in the most advanced microscopic approaches of the past. The emerging fission fragment properties are quite similar to the properties of fission fragments of neighboring even-even nuclei. The time from saddle-to-scission is often significantly longer in odd-odd or odd-mass nuclei than for even-even nuclei, since systems with unpaired nucleons are easier to excite and the potential energy surfaces of these nuclei have more structure, often resembling a very complicated obstacle course, rather than a more direct evolution of the nuclear shape from the top of the outer fission barrier to the scission configuration. The Pauli blocking approximation, often invoked in the literature, expected to inhibit the fission of nuclei with unpaired nucleons, is surprisingly strongly violated during the fission dynamics.

We apply a voltage pulse to electrically excite the incompressible region of a two-dimensional electron liquid in the $\nu =2/3$ fractional quantum Hall state and investigate the collective excitations in both the bulk and edge via photoluminescence spectral energy shifts. Introducing an offset in the voltage pulse significantly enhances the excitation signal. Real-space and time-resolved measurements reveal the dynamics of the bulk excitations, with an estimated group velocity of approximately $3\times {10}^4\mathrm{m}/\mathrm{s}$. These bulk excitations align well with the magnetoplasmon model. Because bulk and edge magnetoplasmons are composed of two polarization degrees of freedom of the gauge field, our results highlight a connection that could serve as a resource for their entanglement—similar to the polarization of a photon—and offer a novel approach to exploring solid-state analogs of quantum gravity.

We describe a mechanism by which both a ferroelectric polarization and a magnetization can be created in nonpolar, nonmagnetic materials. Using a combination of phenomenological modeling and first-principles calculations, we demonstrate that ferroelectric polarization, magnetization, or both simultaneously can be transiently induced by an ultrashort laser pulse upon linearly, circularly, or elliptically polarized excitation of phonon modes in $\gamma \text{−}{\text{LiBO}}_2$. The direction and magnitude of the multiferroic polarization can be controlled by the chirality of the laser pulse and the phonon modes, offering a pathway for controlling multiferroicity and magnetoelectricity on ultrafast timescales.

The quantum metric and Berry curvature capture essential properties of nontrivial Bloch states and underpin many fascinating phenomena. However, it becomes increasingly evident that a more comprehensive understanding of quantum state geometry is necessary to explain properties involving Bloch states of multiple bands, such as optical transitions. To this end, we employ quantum state projectors to develop an explicitly gauge-invariant formalism and demonstrate its power with applications to nonlinear optics and the theory of electronic polarization. We provide a simple expression for the shift current that resolves its precise relation to the moments of electronic polarization, clarifies the treatment of band degeneracies, and reveals its decomposition into the sum of the skewness of the occupied states and intrinsically multistate geometry. The projector approach is applied to calculate nonlinear optical properties of transition metal dichalcogenides (TMDs) layers, using previously calculated minimal tight-binding models, and demonstrated analytically on a three-band generalization of the Rice-Mele chain to elucidate the different contributions. We close with comments on further applications of the projector operator approach to multistate geometry.

The oblique collisions and dynamical interference patterns of two-dimensional dispersive shock waves are studied numerically and analytically via the temporal dynamics induced by wedge-shaped initial conditions for the Kadomtsev-Petviashvili II equation. Various asymptotic wave patterns are identified, classified, and characterized in terms of the incidence angle and the amplitude of the initial step, which can give rise to either subcritical or supercritical configurations, including the generalization to dispersive shock waves of the Mach reflection and expansion of viscous shocks and line solitons. An eightfold amplification of the amplitude of an obliquely incident flow upon a wall at the critical angle is demonstrated. Applications of the results include bore interactions in geophysical fluid dynamics.

The propagation of physicochemical heterogeneity from particles to electrodes under galvanostatic cycling conditions largely determines battery performance but is often computationally unreachable. We formulate a Real 2D (R2D) full-battery model via an electrode-adaptive mathematical framework that addresses the electrochemically correlated nonlinear current-potential responses of the electrodes. This allows us to quantify the impact of multiphysics coupling on cycling performance in emerging solid-state batteries. R2D advances the modeling efficiency and can be generally applied to heterogeneous battery systems, providing a new pathway for accurate full battery simulations.

Characterizing large-scale quantum systems is central to fundamental physics and essential for applications of quantum technologies. While a full characterization requires exponentially increasing resources, focusing on application-relevant information can often lead to significantly simplified analysis. Overlapping tomography is such a scheme, allowing one to obtain all the information contained in specific subsystems of multiparticle quantum systems in an efficient manner, but the ultimate limits of this approach remain elusive. We present protocols for overlapping tomography that are optimal with respect to the number of measurement settings. First, by providing algorithmic approaches based on graph theory we find the minimal number of Pauli settings, relating overlapping tomography to the problem of covering arrays in combinatorics. This significantly reduces the number of measurement settings, showing for instance that two-body overlapping tomography of nearest neighbors in qubit systems with planar topologies can always be performed with nine Pauli settings. Second, we prove that using general projective measurements, all $k$-body marginals can be reconstructed with only $3^k$ settings, independently of the system size. Finally, we demonstrate the practical applicability of our methods in a six-photon experiment. Our results will find applications in learning noise and interaction patterns in quantum computers as well as characterizing fermionic systems in quantum chemistry.