Modern precision experiments often probe unknown classical fields with bosonic sensors in quantum-noise-limited regimes where vacuum fluctuations limit conventional readout. We introduce quantum signal learning, a sensing framework that extends metrology to a broader property-learning setting, and propose a quantum-enhanced protocol that simultaneously estimates many properties of a classical signal with shot noise suppressed below the vacuum level. Our scheme requires only two-mode squeezing, passive optics, and static homodyne measurements, and enables post hoc classical estimation of many properties from the same experimental dataset. We prove that our protocol enables a quantum speedup for common classical sensing tasks, including measuring electromagnetic correlations, real-time feedback control of interferometric cavities, and Fourier-domain matched filtering. To establish these separations, we introduce an optimal-transport conditioning method and show both worst-case exponential separations from all entanglement-free strategies and practical speedups over homodyne and heterodyne baselines. We further show that when squeezing is treated as a resource, a protocol with squeezed light can sense a structured classical background exponentially faster than any coherent classical probe.

The past decade has witnessed significant progress in topological materials investigation. Symmetry-indicator theory and topological quantum chemistry provide an efficient scheme to diagnose topological phases from only partial information of wave functions without full knowledge of topological invariants, which has resulted in a recent comprehensive materials search. However, not all topological phases can be captured by this framework, and topological invariants are needed for a more refined diagnosis of topological phases. In this study, we present a systematic framework to construct topological invariants for a large part of symmetry classes, which should be contrasted with the existing invariants discovered through one-by-one approaches. Our method is based on the recently developed Atiyah-Hirzebruch spectral sequence in momentum space. As a demonstration, we construct topological invariants for time-reversal-symmetric spinful superconductors with conventional pairing symmetries of all space groups, for which symmetry indicators are silent. We also validate that the obtained quantities work as topological invariants by computing them for randomly generated symmetric Hamiltonians. Remarkably, the constructed topological invariants completely characterize $K$ groups in 159 space groups. Our topological invariants for normal conducting phases are defined under some gauge conditions. To facilitate efficient numerical simulations, we discuss how to derive gauge-independent topological invariants from the gauge-fixed topological invariants through some examples. Combined with first-principles calculations, our results will help us discover topological materials that could be used in next-generation devices and pave the way for a more comprehensive topological materials database.

We search for gravitational-wave background signals produced by various early Universe processes in the Advanced LIGO O4a dataset, combined with the data from the earlier O1, O2, and O3 (LIGO-Virgo) runs. The absence of detectable signals enables powerful constraints on fundamental physics. We derive gravitational-wave background energy density upper limits from the O1–O4a data to constrain parameters associated with various possible processes in the early Universe: first-order phase transitions, cosmic strings, domain walls, stiff equation of state, axion inflation, second-order scalar perturbations, primordial black hole binaries, and parity violation. In our analyses, the presence of an astrophysical background produced by compact (black hole and neutron star) binary coalescences throughout the Universe is also considered. We address the implications for various cosmological and high-energy physics models based on the obtained parameter constraints. We conclude that LIGO-Virgo data already yield significant constraints on numerous early Universe scenarios.

The interplay of superconductivity, band topology, and spontaneous time-reversal-symmetry breaking (TRSB) is expected to enable topological superconducting boundary states. Intriguingly, the iron-chalcogenide superconductor ${\mathrm{FeTe}}_{0.55}{\mathrm{Se}}_{0.45}$ exhibits spontaneous magnetization in the superconducting state, motivating its use as a single-material platform in which three ingredients coexist. Here, we report evidence for a nontrivial, boundary-mediated superconducting transport response in exfoliated Fe(Te,Se) devices, exhibiting long-range nonlocality and strongly suppressed thermal broadening. Polar Kerr measurements establish that TRSB emerges below $T_{\text{Kerr}}<T_c$ and coexists with superconductivity across multiple Fe(Te,Se) compositions studied here, providing an independent symmetry-breaking scale that can be directly compared with transport. To reliably access boundary transport, we engineer crystallographically sharp, continuous edges and implement side-surface-dominant contacts, as validated by contact-size analysis and cross-sectional imaging. Under these conditions, topological ${\mathrm{FeTe}}_{0.55}{\mathrm{Se}}_{0.45}$ exhibits an anomalous conductance plateau that is absent in topologically trivial ${\mathrm{FeTe}}_{0.40}{\mathrm{Se}}_{0.60}$ and ${\mathrm{Fe}}_{1.02}{\mathrm{Te}}_{0.55}{\mathrm{Se}}_{0.45}$ under comparable measurements. This plateau requires both the source and drain to be attached to uninterrupted sharp edges, persists over micrometer-scale separations far exceeding the bulk coherence length, has markedly reduced thermal decoherence, and collapses when the drain is moved to the top surface. Its temperature evolution is governed by TRSB: The plateau shows minimal thermal broadening below $T_{\text{Kerr}}^{*}$ and disappears near $T_{\text{Kerr}}$ rather than $T_c$. Collectively, the doping selectivity, TRSB correlation, edge-geometry requirement, and long-range nonlocal nature establish experimentally grounded criteria for identifying boundary-mediated superconducting transport in ${\mathrm{FeTe}}_{0.55}{\mathrm{Se}}_{0.45}$ and motivate further phase-sensitive and theoretical work to determine its microscopic origin.

We study quantum and classical many-body Hamiltonian systems that combine integrable contact interactions with generic long-range two-body potentials. Starting from an ansatz for the state at time $t$, which we call the correlated fluid-cell ensemble, we show that the dynamics of local observables at macroscopic times and length scales can be cast into a generalized Bogoliubov-Born-Green-Kirkwood-Yvon (BBGKY) hierarchy formulated in terms of the quasiparticle densities of the underlying integrable model and their correlations. We derive this hierarchy and validate these predictions against microscopic molecular-dynamics simulations, finding perfect agreement. At late times, the one-particle distribution relaxes via a Boltzmann-type scattering integral encoding the interplay between integrable contact processes and long-range collisions, whereas higher-point correlations remain strongly nonthermal on thermalization timescales, indicative of a form of incomplete or generalized thermalization. Focusing on long-range dipolar quantum gases, where the relevant matrix elements can be obtained explicitly, we show that our collision integral reduces exactly to the Fermi golden rule result and provide a complete theoretical account of the experimental observations of Tang et al. [Phys. Rev. X 8, 021030 (2018)]. More broadly, our framework extends the BBGKY program to regimes with strong local interactions and applies to a wide class of experimentally relevant systems, from one-dimensional dipolar cold-atom gases to Lennard-Jones molecular fluids.

Quantum systems coupled to (non-) Markovian environments attract increasing attention due to their peculiar physical properties. Exciting prospects such as unconventional nonequilibrium phases beyond the Mermin-Wagner limit or dissipative state preparation demand a systematic analysis of quantum many-body phases out of equilibrium. Akin to the equilibrium case, this requires the computation of the low-lying eigenstates of Lindbladians, a problem challenging conventional approaches for simulating quantum many-body systems. Here, we undertake a first step to overcome this limitation and introduce a tensor-network-based framework to systematically compute not only steady states, but also low-lying excited states for large, driven quantum many-body systems. Our framework is based on recent advances utilizing complex-time Krylov spaces, and we leverage these ideas to create a toolbox tailored to solve the challenging non-Hermitian eigenvalue problem ubiquitous in open quantum systems. With an example of the interacting Bose-Hubbard model driven by dissipation-assisted hopping, we demonstrate the high efficiency and accuracy. From a reliable finite-size-scaling analysis of the spectral gap, we find strong evidence for nonlinear hydrodynamic behavior consistent with Kardar-Parisi-Zhang-type superdiffusive relaxation and establish the existence of exponentially accelerated, anomalous relaxation. This method unlocks the capability of spectral analysis of generic open quantum many-body systems suitable also for non-Markovian environments.

Magnesium oxide (MgO) is a prototypical strongly bonded ionic solid and an expected major constituent of rocky planet mantles and gas giant cores, yet its high-pressure phase diagram and shock response remain incompletely understood. Here we combine laser-driven decaying-shock and steady-shock compression with nanosecond x-ray diffraction, velocimetry, and optical pyrometry to investigate phase transitions in single-crystal MgO compressed to 600 GPa and 13 000 K. We observe a pronounced crystallographic orientation dependence in the $\mathrm{B}1\to \mathrm{B}2$ transformation pathway and subsequent melting behavior. For compression along [111], the shock-temperature evolution exhibits distinct plateaus consistent with equilibrium $\mathrm{B}1\to \mathrm{B}2\to \mathrm{liquid}$ transitions. In contrast, compression along [110] produces a single temperature discontinuity and diffraction signatures indicative of B2 nucleation from a transient disordered layer at the shock front. The combined thermodynamic and structural data indicate that near-instantaneous disordering can mediate stress relaxation under rapid uniaxial compression. Above $572\pm 24\mathrm{GPa}$, all orientations converge to complete melting at $13200\pm 600\mathrm{K}$, constraining the B2-liquid boundary at multimegabar pressures and identifying MgO as the highest-temperature solid measured at planetary interior conditions. These results demonstrate that crystallographic orientation governs phase-transition pathways in strongly compressed ionic solids and provide a benchmark for modeling matter under extreme planetary interior conditions.

Quantum signal processing (QSP) transforms a unitary parametrized by a classical variable $\theta$ into one governed by a polynomial function $f(\theta )$. Though quantum mechanics is linear, such highly nonlinear transformations arise naturally from the curvature of the qubit Bloch sphere. This capability underpins many quantum algorithms and enables robust control by decreasing sensitivity to errors in a control parameter, or quantum sensing by increasing sensitivity to variations one seeks to measure. Here, we extend QSP from classical, commuting control parameters to noncommuting quantum operators. We call this new multivariate class non-Abelian QSP. Rather than treating the noncommutativity of quantum control variables as a complication, non-Abelian QSP exploits their richer commutator algebra as a resource for efficient control. A natural setting is hybrid oscillator-qubit systems realized in superconducting and trapped-ion processors, where the control variables can be the noncommuting position and momentum of a quantum harmonic oscillator. We introduce the Gaussian-controlled rotation (GCR), a canonical instance of non-Abelian QSP that cancels the Gaussian quantum-fluctuation error of an oscillator-controlled qubit rotation, matching the robustness of classical composite pulses with a much shorter circuit and an order-of-magnitude lower error. GCR enables fully analytical circuits for preparing squeezed, cat, GKP, and Fock states with performance comparable to state-of-the-art numerically optimized protocols. Building on this primitive, we develop an analytical framework for universal control of GKP bosonic codes, in which logical readout doubles as piecewise gate teleportation, yielding the first high-fidelity, error-mitigated single- and two-qubit logical gates for finite-energy GKP that surpass prior schemes even in the noiseless regime. The same framework supplies midcircuit error detection and extends in closed form to arbitrary lattices, qudits, and multimode codes relevant to the superconducting-circuit experiments now demonstrating beyond-break-even GKP memory. We further apply these ideas to close a key gap in oscillator-assisted quantum phase estimation. Together, these results show that the non-Abelian structure of quantum control operators can provide a practical resource for robust and efficient quantum control, establishing non-Abelian QSP as both a new theoretical framework and an experimentally accessible control paradigm.

The axion insulator exhibits a topological magnetoelectric effect characterized by an axion angle $\theta =\pi$, while the time-reversal-doubled axion insulator ($T$-DAXI) can be viewed as two copies of an axion insulator related by time-reversal symmetry. In this work, we show that a nonsymmorphic topological crystalline insulator with glide (or screw) symmetry can host the nonsymmorphic $T$-DAXI phase, diagnosed by the nontrivial hourglass (screw) invariant ${\delta }_h=1$ (${\delta }_s=1$). In this phase, the partial axion angles (${\theta }^{\pm }=\pi$) are quantized by the glide and/or screw symmetry, and the gapped surfaces realize half-quantized quantum spin Hall states. Furthermore, we show that nonsymmorphic $T$-DAXIs also exhibit the spin-magnetoelectric effect. Namely, an external magnetic field can induce a topological nonlocal spin polarization in real space. When the magnetic field is time periodic, this leads to an alternating spin current detectable in experiment. Using ab initio calculations, we demonstrate that mixed bismuth monohalides ${\mathrm{Bi}}_4{\mathrm{Br}}_x{\mathrm{I}}_{4-x}$ realize the nonsymmorphic $T$-DAXI. Our findings not only reveal the symmetry-enforced $T$-DAXIs in nonsymmorphic topological crystalline insulators, but also demonstrate the spin-magnetoelectric effect as a detectable topological spin response in nonsymmorphic $T$-DAXIs.

We develop a self-contained theoretical framework that classifies the topological phases and critical phenomena of classical pyrochlore magnets with arbitrary spin $S$, subject to competing exchange and single-ion anisotropies. We work first in the monopole-free (ice-rule) limit. In the small-$w$ regime, where the single-ion term favors low spin amplitudes, dualities reveal a dichotomy: Integer spins exhibit a continuous 3D $XY$ deconfinement transition, whereas half-integer spins remain in a U(1) Coulomb liquid without any transition. In the large-$w$ regime, where the local spin amplitudes are maximized ($|S^z|=S$), the macroscopic flux is quantized to multiples of $2S$. By mapping the defect structure to topological loop gases, we prove that the compatibility between the physical ice rule and the modular ${\mathbb{Z}}_{2S}$ flux conservation holds at the vertex level if and only if $S\le 3/2$. For $S=3/2$, this maps the system to the three-state Potts model, whose symmetry-allowed cubic invariant drives a first-order transition. For $S\ge 2$, no mapping to a discrete clock model exists. Using a decomposition of the partition function, we show that the only processes sensitive to the discrete ${\mathbb{Z}}_{2S}$ structure carry exponentially small statistical weight and correspond to irrelevant operators at the 3D $XY$ fixed point, so the deconfinement transition is of the 3D $XY$ type. Finally, incorporating thermal monopoles, we show that they act as a symmetry-breaking effective magnetic field that severs defect strings. Consequently, the continuous transitions are rounded into crossovers, whereas the first-order $S=3/2$ transition is predicted to survive at finite temperatures, terminating at a critical end point. Classical Monte Carlo simulations for $S$ up to $7/2$ corroborate the predicted crossover behavior at the accessible temperatures; these temperatures lie above the estimated critical end point, so the predicted survival of the $S=3/2$ first-order transition remains to be tested directly.

Hematite ($\alpha \text{−}\mathrm{F}{\mathrm{e}}_2{\mathrm{O}}_3$) is a prototypical room-temperature antiferromagnet whose time-reversal-odd magnetic structure has recently attracted renewed attention. While such magnetic symmetry can be characterized in terms of higher-order multipoles beyond the magnetic dipole, their manifestation in measurable physical phenomena has remained largely elusive. In this work, we investigate x-ray absorption near the Fe $K$-edge of hematite under an applied electric field, which explicitly breaks space-inversion symmetry. We observe an electric-field-induced x-ray nonreciprocal linear dichroism that reflects the time-reversal-odd nature of the magnetic order. A symmetry-resolved multipole analysis attributes this response to the electric-field-induced magnetic quadrupole and the magnetic toroidal octupole induced by the applied electric field. Furthermore, numerical simulations based on ab initio density functional theory reproduce the observed spectra, including their dependence on the antiferromagnetic domain and x-ray polarization. These results indicate that electric-field-modulated x-ray absorption measurements, combined with simulations, provide a framework for identifying the higher-order multipoles contributing to measurable physical responses in time-reversal-odd antiferromagnets, thereby facilitating the investigation of hidden symmetry properties in magnetic materials.

We propose a refined definition of mixed-state phase equivalence based on locally reversible channel circuits. We show that such circuits preserve topological degeneracy and the locality of all operators including both strong and weak symmetries. Under a locally reversible channel, weak unitary symmetries are locally dressed into channel symmetries, a generalization of symmetry for open quantum systems. For Abelian higher-form symmetries, we show the refined definition preserves anomalies and spontaneous breaking of such symmetries within a phase. As a primary example, a two-dimensional classical loop ensemble is trivial under the previously adopted definition of mixed-state phases. However, it has nontrivial topological degeneracy arising from a mutual anomaly between strong and weak 1-form symmetries, and our results show that it is not connected to a trivial state via locally reversible channel circuits.

We show that no Einstein-Podolsky-Rosen (EPR)–like bipartite entanglement can be distilled from a tripartite Haar random state $|\mathrm{\Psi }{⟩}_{ABC}$ by local unitaries or local operations when each subsystem $A$, $B$, or $C$ has fewer than half of the total qubits. Specifically, we derive an upper bound on the probability of sampling a state with EPR-like entanglement at a given EPR fidelity tolerance, showing a doubly exponential suppression in the number of qubits. Our proof relies on a simple volume argument supplemented by an $\epsilon$-net argument and concentration of measure. Viewing $|\mathrm{\Psi }{⟩}_{ABC}$ as a bipartite quantum error-correcting code $C\to AB$, this implies that neither output subsystem $A$ nor $B$ supports any nontrivial logical operator. We also establish general constraints on the structure of tripartite entanglement in Haar random states, showing that W- or Greenberger-Horne-Zeilinger–like entanglement cannot be distilled and that nontrivial global symmetries are absent. Finally, we discuss a physical interpretation in the AdS/CFT correspondence, indicating that a connected entanglement wedge does not necessarily imply bipartite entanglement, contrary to a previous belief.

Kerr-cat qubits have been experimentally shown to exhibit a large noise bias, with one decay channel suppressed by several orders of magnitude. In superconducting implementations, increasing the microwave drive on the nonlinear oscillator that hosts the Kerr-cat qubit should, in principle, further enhance this bias. Instead, experiments reveal that above a critical drive amplitude the tunneling time, which is the less dominant decay channel, ceases to increase and even decreases. Here, we show that this breakdown arises from the multimode nature of the circuit implementation. Specifically, additional modes, including the buffer mode used to deliver the stabilizing drive and higher modes of the Josephson junction array, can induce multiphoton resonances that sharply degrade Kerr-cat coherence. We uncover this mechanism by retaining the full circuit nonlinearities and treating the strong drive exactly within a Floquet-Markov framework that accounts for quasidegeneracies of the Kerr-cat spectrum. Our results not only provide an explanation for the sudden reduction of the tunneling time, but also demonstrate that the Kerr-cat qubit can be very robust in the presence of a carefully engineered electromagnetic environment. Beyond the Kerr-cat qubit, the tools developed here open the door to study a broad range of drive-induced phenomena in dissipative superconducting circuits, in both resonant and off-resonant driving regimes. Examples include inelastic scattering in circuits with arbitrary anharmonicity and drive strength as well as subharmonically driven devices such as parametric amplifiers and couplers and other protected qubits whose coherence is governed by quasidegeneracies.

Hysterons provide a minimal description of memory in driven matter: bistable elements with distinct switching thresholds whose collective dynamics generate hysteresis, avalanches, and history-dependent switching. Experimental realizations have so far been dominated by solid-state mechanical systems, where bistability is usually encoded structurally through buckling, snap-through, or geometric incompatibility. Here we realize hysteron physics through a hydrodynamic route. A single elastic fiber anchored in a microfluidic channel becomes bistable through nonlinear elastohydrodynamic feedback: Viscous loading deforms the fiber, deformation reshapes hydraulic resistance, and flow redistribution modifies the loading. This feedback produces a fluidic hysteron whose onset is organized by a cusp catastrophe in geometric control parameters. A parallel bypass channel acts as a geometric load line that reshapes, and can even eliminate, bistability while simultaneously mediating long-ranged hydraulic interactions between fibers. In arrays, varying a single geometric parameter drives a transition from a noninteracting Preisach regime with return-point memory to an interacting regime with configuration-dependent thresholds, mixed-direction switching paths, and projected trajectories that cross the independent-Preisach envelope. These results establish a passive hydrodynamic route to hysteron networks, in which memory emerges from flow-structure feedback and global hydraulic constraints.

We construct an effective field theory (EFT) that captures the universal behavior of out-of-time-order correlators (OTOCs) at late times in generic quantum many-body systems with conservation laws. The EFT hinges on a generalization of the strong-to-weak spontaneous symmetry-breaking pattern adapted to out-of-time-order observables and reduces to conventional fluctuating hydrodynamics when time-ordered observables are probed. We use the EFT to explain different power-law behavior observed in OTOCs at late times and show that many OTOCs are entirely fixed by conventional transport data at leading order. Nevertheless, we show that a specific combination of OTOCs is sensitive to novel transport parameters not visible in regular time-ordered correlators. We test our predictions in Hamiltonian and Floquet spin chains in one spatial dimension.

Optical cavities are a foundational technology for controlling light-matter interactions. While interfacing a single cavity to either an atom or ensemble has become a standard tool, the advent of single-atom control in large atomic arrays has spurred interest in a new frontier of “many-cavity QED,” featuring many independent resonators capable of separately addressing individual quantum emitters. In this fast-evolving landscape, the cavity array microscope was recently introduced—employing free space intracavity optics to engineer a two-dimensional array of tightly spaced cavity ${\mathrm{TEM}}_{00}$ modes with wavelength-scale waists, ideally suited for interfacing with atom arrays. Here, we realize the next generation of this architecture, achieving hundreds of degenerate cavity modes with improved, uniform finesse, and explore the technical features of the system which will enable further scalability. In particular, we study imperfections, including optical aberrations, field of view constraints, array nondegeneracies, and losses from optical elements. We identify the sensitivity to these various factors and exposit the control knobs and techniques necessary to align and operate the system in a stable manner. Ultimately, we lay out a pathway toward operation with tens of thousands of independent cavities while maintaining compatibility with existing atom arrays, paving the way to myriad applications including highly parallelized remote entanglement generation, fast and nondestructive midcircuit readout, and the implementation of hybrid atom-photon Hamiltonians.

Key to solving many societally relevant problems in materials science, quantum chemistry, and nuclear physics is understanding their fundamental microscopic quantum behavior. All of these problems can be phrased as fermionic (e.g., electrons, quarks) and bosonic particles (e.g., lattice vibrations, photons) interacting with each other. However, solving these systems of strongly interacting fermions and bosons is out of reach for classical computers and also non-error-corrected qubit-only quantum computers. In this paper, we introduce a hybrid qubit and bosonic-oscillator quantum-simulation framework, which is so efficient that it could simulate some of these strongly correlated problems even without error correction. Specifically, we leverage the available universal bosonic gate set with $\mathcal{O}(1)$ operations per gate as a function of the bosonic cutoff. This enables our framework to provide exact decompositions of higher-order fermion-boson interactions, including notoriously challenging terms such as $(2+1)\mathrm{D}$ gauge theories. We show how to compile dynamics, ancilla-free partial error detection, nonlocal observable measurements, and ground-state energy estimation using both qubit-boson variational quantum eigensolvers and quantum signal processing. We introduce a “post-qubit quantum advantage” experiment which is out of reach for both near-term qubit-only quantum computers and classical computers. We justify this proposal by estimating bosonic gate fidelities through high–boson-occupation Lindblad simulation and by comparing to qubit-only algorithms. For the latter, we develop a new qubit-based algorithm for simulating a beam splitter with a boson number cutoff $N_{\max }$, which scales as $\tilde{\mathcal{O}}(N_{\max }^{1+o(1)})$, asymptotically outperforming previously known qubit methods. However, to reach the same circuit fidelity as qubit-boson hardware with 99.9% per-gate fidelity, a qubit quantum computer using the best-known method would still need fidelities of at least 99.9999%, likely requiring substantial error correction. Our framework can be used in superconducting hardware, which we focus on, as well as trapped-ion and neutral-atom hardware. This work establishes digital hybrid qubit-boson quantum simulation as a promising and advantageous method for solving the many challenging, strongly correlated, fermion-boson models of relevance to science and technology.

Moiré superlattices in van der Waals heterostructures, arising from lattice mismatch or twist angle, provide a powerful platform for engineering correlated electronic and excitonic states. Moiré excitons form when electrons and holes are individually modulated by the moiré potential yet remain bound by Coulomb interaction, resulting in exciton wave functions with a highly nontrivial and rich real-space structure. However, achieving in situ and dynamic control over the interplay between excitonic Coulomb interaction and the moiré potential remains a central challenge. Here, we demonstrate that hydrostatic pressure provides a continuous and effective means of enhancing the moiré potential and tuning moiré excitons in ${\mathrm{WSe}}_2/{\mathrm{WS}}_2$ moiré heterobilayers. As pressure increases, intralayer moiré excitons exhibit systematic redshifts as the moiré potential deepens. Crucially, above $\sim 3\mathrm{GPa}$ the system enters a strong-moiré regime, where a new higher-energy intralayer moiré exciton emerges that is not accessible otherwise. Combining dual-gate optical spectroscopy with Bethe-Salpeter equation calculations, we reveal that this emerging moiré exciton state arises from strong pressure-induced hybridization between two distinct exciton series: Wannier-Rydberg and charge-transfer excitons. Enhanced exciton-electron and exciton-exciton interactions observed in doping-dependent photoluminescence further evidence the strengthened moiré potential under pressure. Our work establishes a pioneering paradigm of moiré excitonic wave function engineering, enabling the on-demand creation of tailored excitonic species in moiré superlattices.

Superconductivity in three dimensions is almost universally governed by Ginzburg-Landau mean-field theory, with critical fluctuations typically confined to within a few percent of the transition temperature ($T_{\mathrm{c}}$). We report that the heavy-fermion superconductor ${\mathrm{UTe}}_2$ exhibits superconducting fluctuations that extend over a temperature range as wide as $T_{\mathrm{c}}$ itself—the largest observed for any three-dimensional superconductor. Through ultrasound measurements of the elastic moduli and sound attenuation, we find that ${\mathrm{UTe}}_2$ transitions from a mean-field-like state at ambient pressure to a fluctuation-dominated state at higher pressures. This regime is marked by elastic softening and an increase in sound attenuation that onsets well above $T_{\mathrm{c}}$, with the attenuation remaining anomalously high deep in the superconducting state. Our analysis suggests that these features stem from an extremely low superfluid phase stiffness. This results in a kinetic inductance as high as that of granular aluminum, but achieved in the clean limit. We propose a model where this exotic state is driven by dominant interband pairing mediated by ferromagnetic fluctuations, leading to “local” Cooper pairs with a coherence length of only a few lattice constants.