We propose generating atom-atom three-body interactions in quantum gases by placing a quasi-two-dimensional Bose-Einstein condensate in front of two reflecting mirrors and illuminating it with dichromatic laser beams. These pumping fields traverse the condensate twice, thereby inducing a feedback effect on the atoms. We demonstrate that this optical feedback gives rise to an effective three-body interaction with unique long-range and nonreciprocal properties. Because of its long-range nature, this three-body interaction can give rise to various stable stationary droplet cluster states, as well as a distinct ring state that emerges through a purely self-organizing process. Furthermore, we show that the nonreciprocal nature of this interaction can lead to remarkable self-acceleration of the condensate. Additionally, our scheme offers a highly controllable setting, where pairwise two-body interactions can be tuned to vanish. This flexibility provides a promising route for exploring exotic physics associated with multibody interactions.

Percolative superconductivity frequently arises in two-dimensional van der Waals materials due to reduced dimensionality, enhanced quantum fluctuations, and complex electron-phonon interactions, providing a unique platform where normal electrons coexist with Cooper pairs. We report the observation of substantial third-order nonlinear transport in a trilayer $1T^{\prime }\text{−}{\text{MoTe}}_2$ superconductor within its percolative transition regime. The third-harmonic longitudinal voltage ($V_{\parallel }^{3\omega }$) exhibits a clear cubic dependence on excitation current below a threshold, with both its magnitude and nonlinear coefficient strongly correlated with the superconducting state. This nonlinear response is semiquantitatively captured by the superconducting fluctuation within the time-dependent Ginzburg-Landau theory, where nonlinear transport arises due to fluctuating Cooper pairs. Our results demonstrate that third-order nonlinear transport serves as a sensitive probe of superconducting transitions in percolative systems and establish a foundation for exploring higher-order transport phenomena in strongly correlated systems.

Topological insulators with bulk-boundary correspondence have been widely explored in condensed-matter, photonic, and phononic systems. Two-dimensional second-order topological insulators are typically characterized by zero-dimensional boundary states localized at sharp corners. While these corner bound states have been widely explored across multiple platforms as robust signatures of second-order topology, their strong confinement to sharp corners severely limits practical applications. Here, we experimentally demonstrate control over topological boundary states in a honeycomb-lattice acoustic second-order topological insulator. Specifically, we reveal that the boundary Dirac mass exhibits a sensitive and diverse dependence on the edge types, enabled by sublattice degrees of freedom. By engineering the edges, we achieve not only arbitrary spatial relocation of topological boundary states from their conventional corner positions, but also precise, continuous tuning of their wave-function profiles from bound to extended as desired. Our Letter establishes a universal approach for manipulating topological boundary states, offering possibilities for designing advanced acoustic devices.

Multipolar order, such as octupolar order, is a key concept in condensed matter physics, particularly in light of elusive hidden orders. However, its experimental identification remains challenging due to the absence of direct coupling to conventional external stimuli. In this Letter, we propose that dual-circular Raman scattering serves as a probe of multipolar anisotropies. By combining symmetry analysis with microscopic calculations, we identify that both time-reversal-even ($\theta$ -even) and time-reversal-odd ($\theta$ -odd) axial multipolar phases exhibit the sizable Raman optical activity as a direct consequence of multipolar symmetry breaking. The quantitative significance of the proposed response is demonstrated by the first-principles study of pyrite, a prototypical axial octupolar material. Furthermore, we reveal that a multipolar phonon, a three-dimensional and alternating displacement resembling the chiral phonon, plays a vital role in the proposed optical phenomena. Our findings open a pathway for identifying multipolar orders in various materials through dual-circular Raman spectroscopy as a sensitive and versatile probe.

Exciton-phonon interactions play a central role in defining the optical response of hexagonal boron nitride (hBN), yet their quantitative determination has remained incomplete. Here, we reveal the Fröhlich-type exciton-phonon coupling in boron-10-enriched hBN using low-temperature cathodoluminescence. We resolve the indirect exciton $5.95\pm 0.02\mathrm{eV}$ together with its longitudinal optical phonon replica detuned by $184\pm 56\mathrm{meV}$, enabling the extraction of a Fröhlich-coupling constant $\alpha =0.159$, and a larger exciton binding energy of 161 meV, larger than previously reported values for natural abundance hBN, which is attributed to isotope enrichment. The inferred polaron radius exceeds the lattice constant, indicating large-polaron behavior. We deduced an exciton scattering time $\sim 97\mathrm{fs}$ (homogeneous linewidth $\sim 6.76\mathrm{meV}$), a polaron binding energy of magnitude $\sim 48\mathrm{meV}$, and an effective mass of $1.045m_0$. These results provide a direct quantitative characterization of exciton-phonon coupling in isotopically engineered hBN and establish a foundation for tailoring its phonon-polaritonic and quantum-optical properties.

Understanding diffusion in disordered systems composed of obstacle particles is crucial for elucidating transport phenomena ranging from biological tissues to engineered porous materials. Existing studies predominantly employ the random sequential adsorption method and characterize media solely by density $\rho$. We show that this is fundamentally incomplete: These structures exhibit a tunable hyperuniformity exponent $\beta$ that spans from periodic lattices to Poisson processes, yielding qualitatively different diffusion even at identical $\rho$. We derive a $\beta$-dependent analytical expression for the diffusion coefficient $1-D/D_0\sim {\rho }^{2-\beta /2}$ in the low-$\rho$ limit and predict a $\beta$-dependent percolation threshold ${\rho }_c(\beta )$ in the high-$\rho$ regime. Brownian dynamics simulations across the full $(\beta ,\rho )$ plane complete the picture, yielding both the diffusion coefficients and the phase diagram of normal, hopping, and trapped states.

There exist pairs of orthogonal Latin squares of any order $n$ except if $n=2$ or $n=6$ [Bose et al., Further results on the construction of mutually orthogonal latin squares and the falsity of Euler’s conjecture, Can. J. Math. 12, 189 (1960)]. In particular, the problem of Euler’s thirty-six officers does not have a solution. However, it has a “quantum solution”: there exist so-called entangled quantum Latin squares of order 6 [Rather et al., Thirty-six entangled officers of Euler: Quantum solution to a classically impossible problem, Phys. Rev. Lett. 128, 080507 (2022)]. We prove that mutually orthogonal quantum Latin squares of order 6 do not exist if entanglement is not allowed.

Feedback control in open quantum dynamics is crucial for the advancement of various coherent platforms. However, currently only a handful of feedback master equations exist in the literature, which are restricted to specific types of feedback. In this letter we first introduce a unifying framework, based on a single general equation, that describes all possible feedback schemes in sequentially (and continuously) measured systems, and from which all previous results follow. Next, we specialize it to the case of quantum jumps and introduce a new type of feedback based on the channel of the last detected jump, as well as the time elapsed since it occurred. Our description is experimentally grounded, and naturally allows for the introduction of realistic effects, such as time-delays in the feedback loop. We illustrate our results with two time-dependent feedback protocols conditioned on quantum-jump detections: one achieving population inversion of a two-level system against a thermal bath, and another enabling real-time reversal of quantum transitions, both admitting steady-state solutions.

We prove an analog of the “bottleneck theorem,” well-known for classical Markov chains, for Markovian quantum channels. In particular, we show that if two regions (subspaces) of Hilbert space are separated by a region that has very low weight in the channel’s steady state, then states initialized on one side of this barrier will take a long time to relax, putting a lower bound on the mixing time in terms of an appropriately defined “quantum bottleneck ratio.” Importantly, this bottleneck ratio involves not only the probabilities of the relevant subspaces, but also the size of off-diagonal matrix elements between them. For low temperature quantum many-body systems, we use the bottleneck theorem to bound the performance of any quasilocal Gibbs sampler. This leads to a new perspective on thermally stable quantum phases in terms of a decomposition of the Gibbs state into multiple components separated by bottlenecks. As a concrete application, we show rigorously that weakly perturbed commuting projector models with extensive energy barriers (which include certain classical and quantum expander codes) have exponentially large mixing times.

Entanglement has been identified as a key resource for enhancing charging performance in quantum batteries. We show that the kicked-Ising model at the self-dual point provides an explicit charging mechanism, where maximal entanglement growth yields maximal energy injection. Identifying the Floquet dynamics as a Clifford quantum cellular automata and considering exact diagonalization in momentum space, we analytically characterize the charging process, featuring a stable performance while achieving maximal charging. We further propose a fixed time window protocol that accelerates charging toward the continuously driven transverse-field limit. Spin-correlator analysis reveals that scrambling and light-cone spreading govern charging performance. The protocols remain compatible with diverse platforms, underscoring their scalability and practical feasibility.

Until very recently, it was generally believed that the (approximate) 2-design property is strictly stronger than anticoncentration of random quantum circuits, mainly because it was shown that the latter anticoncentrate in logarithmic depth, while the former generally need linear depth circuits. This belief was disproven by recent results that show that so-called relative-error approximate unitary designs can, in fact, be generated in logarithmic depth, implying anticoncentration. Their result does not, however, apply to ordinary local random circuits, a gap that we close in this Letter, at least for 2-designs. More precisely, we show that anticoncentration of local random quantum circuits already implies that they form relative-error approximate state 2-designs, making them equivalent properties for these ensembles. Our result holds more generally for any random circuit that is invariant under local (single-qubit) unitaries, independent of the architecture.

Orbital angular momentum (OAM) entanglement gives access to multiple qubit and high dimensional Hilbert spaces but is unfortunately susceptible to disturbance, decaying in real-world noisy channels. Here, we show that an underlying topology arising from OAM entanglement remains robust to such channels, which we demonstrate using atmospheric turbulence—exemplary of stochastic or chaotic media. Using a quantum channel with various turbulence strengths, we find that the OAM topological observable is preserved even though the OAM itself is shown to be highly sensitive to the turbulence. We show this is true for mixed states too, with the OAM topology intact even as the purity of the state decreases due to decoherence. Our Letter offers a new perspective on harnessing OAM entanglement in noisy channels, and may easily be extended to other spatial bases, degrees of freedom, and complex channels.

The dynamics of quantum correlations are central to understanding many physical properties of quantum systems. Here we experimentally study the correlation dynamics via two-particle quantum walks in superconducting Bose-Hubbard qutrit arrays, with tunable on-site interaction $U$ realized by Floquet engineering. Quantum walks show the characteristic change from bosonic bunching to fermionic antibunching with increasing $U$. The two-site entanglement and quantum correlation dynamics, as measured by negativity and quantum discord, are investigated. We find that, depending on the initial state, the propagation of entanglement can be strongly suppressed with increasing $U$, while that of quantum discord exhibits considerably larger amplitude, or both appear insensitive to $U$. Furthermore, the forms of entanglement are found to persist throughout particle walks for $U=0$, and it is generally not the case when $U$ increases. Our Letter highlights the role of interaction in shaping quantum dynamics and extends the realm of simulating correlated quantum systems with superconducting circuits.

We realize a nanoscale accelerometer with a levitated nanoparticle near the ground state, exploiting its dynamical behavior triggered by the abrupt quench of its trapping potential. We find that rapid quenching provides a readout time at which the sensitivity is enhanced by 2 orders of magnitude with a favorable combination of a large acceleration-induced displacement and a reduced position uncertainty, enabling us to detect a weak acceleration obscured by the zero-point fluctuation in the initial potential. With rapid quenching, the observed sensitivity is in good agreement with a numerical simulation based on the quantum Langevin equation. Our results provide a step toward inertial sensing with levitated nanoparticles through time-optimal quench dynamics in the quantum regime.

Nickel, one of the most tightly bound nuclei alongside iron, is the most abundant heavy element beyond iron in cosmic rays. With DAMPE’s excellent charge resolution and broad energy range, a high-precision energy spectrum provides valuable insights into the acceleration sources of heavy nuclei and their propagation through the interstellar medium. In this analysis, we report the direct measurement of cosmic-ray nickel spectrum from 10 GeV/n to 2 TeV/n with nine years of flight data. The nickel spectrum is consistent with a single power law with spectral index $-2.60\pm 0.03$ from 40 GeV/n to 1 TeV/n. This Letter provides an accurate measurement of differential flux of nickel with kinetic energy extending to TeV/n for the first time.

A first-order phase transition could occur in the late Universe when vacuum energy begins dominating the energy density ($z\lesssim 0.3$) and convert some latent heat into other forms such as invisible radiation. This generic possibility also has concrete motivation in particle physics models, which invoke a multitude of vacua to address theoretical puzzles. The naïve constraint on such an event comes from measurements of the Hubble expansion rate, but this can only probe transitions involving $\mathcal{O}(10)\%$ of the dark energy. In this Letter, we show that significantly tighter constraints appear when accounting for phase transition fluctuations affecting CMB photon propagation anisotropically. For instance, if a completed phase transition has $\beta /H_{\star }\lesssim 25$, current CMB data limit the associated vacuum energy released to less than 1% of the dark energy. A transition to negative vacuum energy (quasi-anti–de Sitter) is allowed only for $\beta /H_{\star }\gtrsim 300$. For $\beta /H_{\star }\lesssim 500$, the Universe will not crunch for at least 14 Gyr.

We perform fully relativistic general-relativistic magnetohydrodynamics simulations of magnetized, self-gravitating black hole disk (BHD) systems in which the black hole spin is misaligned with the disk angular momentum. Massive disks (disk to black hole mass ratios of 16%–28%) around rapidly rotating black holes ($\chi \lesssim 0.97$) develop a nonaxisymmetric instability for tilt angles from 0° to 180°. Magnetic stresses damp, but do not completely suppress, the nonaxisymmetric instability, and corresponding gravitational wave emission, in aligned systems, while they enhance it in antialigned BHDs: magnetorotational instability (MRI) driven turbulence enhances angular momentum transport and accelerates nonlinear instability evolution in misaligned configurations. All models launch magnetically driven jets consistent with the Blandford-Znajek mechanism, with collimation depending on spin orientation. The gravitational waves reflect strong nonaxisymmetric structure from a persistent $m=1$ mode. The coupling between fast MRI and the slower nonaxisymmetric instability growth governs the outcome, with tilt controlling how MRI modifies the global mode. These simulations provide the first self-consistent general-relativistic magnetohydrodynamics treatment of tilted, self-gravitating BHD systems and support their role as multimessenger sources.

We analyze the expectation value of the energy-momentum tensor and its fluctuations in quantum field theory on curved spacetimes. A generally accepeted condition for the conceptual consistency of semiclassical gravity is that the fluctuations of the energy momentum tensor remain small compared to its expectation value. We study the renormalization of both the energy-momentum tensor $⟨T_{ab}(x){⟩}_{\mathrm{ren}}$ and the fluctuation tensor $⟨T_{ab}(x)T_{cd}(x){⟩}_{\mathrm{ren}}$ for suitably well behaved states, using the operator product expansion for a free scalar field on a fixed curved background. We show that states (usually referred to as “squeezed vacua”)—arising naturally in black hole evaporation and in inflationary cosmology—fail to satisfy the natural semiclassicality criterion.

The two-dimensional $\mathrm{O}(\mathrm{N})$ nonlinear sigma model (NLSM) is asymptotically free for $N>2$: it exhibits neither a nontrivial fixed point nor spontaneous symmetry breaking. Here, we show that a nontrivial fixed point generically does exist in the complex coupling plane and is described by a complex conformal field theory (CCFT). This CCFT fixed point is generic in the sense that it has a single relevant singlet operator, and is thus expected to arise in any non-Hermitian model with $\mathrm{O}(\mathrm{N})$ symmetry upon tuning a single complex parameter. We confirm this prediction numerically by locating the CCFT at $N=3$ in two non-Hermitian spin-1 antiferromagnetic Heisenberg chains, and in a non-Hermitian spin-$1/2$ ladder, finding good agreement between the complex central charge and scaling dimensions and those obtained by analytic continuation of real fixed points from $N\le 2$. The low-energy spectra also reveal a noninvertible symmetry inherited from the $\mathrm{O}(\mathrm{N})$ loop model, realized as an emergent symmetry at the NLSM fixed point and exactly in the spin-1/2 ladder. We further construct a realistic Lindbladian for a spin-1 chain whose no-click dynamics are governed by the non-Hermitian Hamiltonian realizing the CCFT. Since the CCFT vacuum is the eigenstate with the smallest decay rate, the system naturally relaxes under dissipative dynamics toward a conformal field theory state, thus providing a route to preparing long-range entangled states through engineered dissipation.