Using the worldline quantum field theory formalism, we compute conservative contributions to the scattering angle and impulse for classical black hole scattering at fifth post-Minkowskian and second self-force order. This four-loop calculation involves nonplanar Feynman integrals and requires advanced integration-by-parts reduction, novel differential-equation strategies, and efficient boundary-integral algorithms to solve a system of hundreds of master integrals in four integral families on high-performance computing systems. The resulting function space includes multiple polylogarithms as well as iterated integrals with a $K3$ period, which generate a spurious velocity divergence at $v/c=\sqrt{8}/3$, $\gamma =3$. This divergence is present in the potential region and must be canceled by contributions from the radiative memory region, while its dimensional-regularization pole should cancel against the radiative tail region. As the standard use of Feynman propagators fails to ensure this cancellation, we instead propose a “($\gamma -3$)” conservative prescription that realizes both cancellations, leading to a physically sensible answer. All available low-velocity checks of our result against the post-Newtonian literature are satisfied.

We apply harmonic analysis to study the $T\overline{T}$-deformed torus partition function. We first express the CFT partition functions in terms of Maass waveforms, including the Eisenstein series and cusp forms. These basis functions turn out to deform in a very simple way under the $T\overline{T}$ deformation. The spectral decomposition provides a numerically stable and efficient method to compute the partition function at finite values of the deformation parameter $\lambda$, allowing us to clearly resolve the analytic structure of the partition function as a function of $\lambda$. The resulting deformed partition function exhibits a Hagedorn singularity. Building on the harmonic analysis approach, we propose a natural analytic continuation beyond the Hagedorn singularity, which enables us to compute the full partition function for any value of $\lambda$.

A measurement of the flavor-untagged decay-time-integrated $CP$ asymmetry in the flavor-specific decay $B_s^0\to D_s^{-}{\pi }^{+}$, $⟨A_{\text{untagged}}^s⟩$, is performed using proton-proton collision data collected by the LHCb experiment between 2016 and 2018 at a center-of-mass energy of 13 TeV, corresponding to a total integrated luminosity of $5.4{\mathrm{fb}}^{-1}$. The $CP$ asymmetry is measured in two $D_s^{-}$ meson decay modes, $D_s^{-}\to K^{-}{K}^{+}{\pi }^{-}$ and $D_s^{-}\to {\pi }^{-}{\pi }^{+}{\pi }^{-}$. The combined result, $⟨A_{\text{untagged}}^s⟩=(-1.4\pm 5.9(\mathrm{stat})\pm 1.1(\mathrm{syst}))\times {10}^{-3}$, is consistent with the Standard Model expectation and provides a direct constraint on new physics in tree-level $b$-hadron decays.

We present the first calculation of hadron production in deep-inelastic scattering (DIS) at finite transverse momentum to next-to-next-to-leading order (NNLO) in perturbative QCD. To overcome the long-standing challenge of infrared divergences in semi-inclusive processes with identified final state hadrons at finite transverse momentum, we implement the recently developed $q_T$-subtraction framework based on the recoil-free jet definition. By utilizing the winner-take-all recombination scheme, we achieve a consistent factorization for hadron-jet associated production, enabling the inclusion of $\mathcal{O}({\alpha }_s^3)$ corrections. Our NNLO results generally demonstrate an improved convergence of the perturbative expansion and a reduction in scale uncertainties compared to previous next-to-leading order ones, especially for comparisons to multiplicity data from the ZEUS Collaboration. This Letter provides a high precision theoretical foundation for the upcoming electron-ion collider era and establishes a new benchmark for the exploration of the nucleon’s three-dimensional structure.

Nonthermal attractors govern the emergent self-similar dynamics of far-from-equilibrium quantum systems, from ultrarelativistic nuclear collisions to cold-atom experiments. Within the framework of adiabatic hydrodynamization, the approach to a nonthermal attractor is described by the decay of excited states of an effective Hamiltonian. Using an exactly solvable kinetic theory—the longitudinally expanding, overoccupied gluon plasma dominated by small-angle elastic scattering—we establish a direct correspondence between the eigenmodes of adiabatic hydrodynamization and the quasinormal mode spectrum of the nonthermal attractor. This equivalence suggests a general framework for identifying universal dynamical structures in nonequilibrium systems. As a byproduct, we derive analytic prescaling solutions for strongly longitudinally expanding systems.

Significant research advances have led to a consensus that the Fermi-Hubbard model and its extended variants are archetypical frameworks for elucidating the intertwined relationship between stripe orders and superconductivity in hole-doped high-$T_c$ materials. Notably, the Hubbard quantum simulator has recently achieved several remarkable breakthroughs, e.g., being cooled down to the cryogenic regime and enabling the observation of stable fluctuating stripes. However, the microscopic mechanism underlying the $d$-wave pairing of electrons in the presence of stripes at low temperatures remains poorly understood due to the intricate interplay between strongly correlated effects and non-negligible thermal fluctuations. Here, we conduct a close investigation of a partially filled stripe in the representative $t\text{−}J$ and $t\text{−}{t}^{\prime }\text{−}U$ models with both numerical and analytical methods. Analogous to quantum gas microscopy, the perfect sampling technique allows us to obtain the high-confidence-level statistics of the Fock basis states appearing in the ground-state wave function. In a novel physical paradigm, these data demonstrate that two spinons with opposite chiralities tend to pair spontaneously into a singlet state, thereby naturally giving rise to the $d$-wave pairing pattern. Then, using the updated effective theory of quantum colored string, we have reconstructed the wave function and have determined the nature of spinon pairing and its connection to the $d$-wave sign structure of pair-pair correlation. Furthermore, spinon singlet pairs enable the establishment of a long-range pair-pair correlation between the two stripes. Our Letter offers new insights into the microscopic physics of stripes and paves the way for further exploration of multistripe-mediated pairing mechanisms in the Fermi-Hubbard model.

Gaussian boson sampling (GBS) is one of the leading approaches for demonstrating quantum computational advantage, but its application to practical real-world problems remains a central challenge. Here, we propose a GBS-based image recognition scheme inspired by extreme learning machine to enhance the performance of perceptron and implement it using our latest GBS device, jiǔzhāng 4.0. By avoiding in situ programmability of the photonic circuit, the scheme substantially reduces experimental overhead while retaining a large, fixed random feature map. Our approach utilizes an 8176-mode temporal-spatial hybrid encoding photonic processor, achieving approximately 2200 average photon clicks in the quantum computational advantage regime. We apply this scheme to classify images from the MNIST and Fashion-MNIST datasets, achieving a testing accuracy of 95.86% on MNIST and 85.95% on Fashion-MNIST, respectively. These results surpass both classical linear-kernel support vector machines and the three previous physical extreme-learning-machine experiments. In addition, we systematically explore the influence of three key hyperparameters and the efficiency of GBS in our experiments. Our results not only demonstrate the potential of GBS in real-world machine learning applications but will also inspire further advancements in powerful machine learning schemes utilizing GBS technology.

The toric code, when deformed in a way that preserves the self-duality ${\mathbb{Z}}_2$ symmetry exchanging the electric and magnetic excitations, admits a transition to a topologically trivial state that spontaneously breaks the ${\mathbb{Z}}_2$ symmetry. Numerically, this transition was found to be continuous, which makes it particularly enigmatic given the longstanding absence of a continuum field-theoretic description. In this Letter we propose such a continuum field theory for the transition dubbed the $SO(4{)}_{2,-2}$ Chern-Simons-Higgs (CSH) theory. We show that our field theory provides a natural “mean-field” understanding of the phase diagram. Moreover, it can be generalized to an entire series of theories, namely the $SO(4{)}_{k,-k}$ CSH theories, labeled by an integer $k$. For each $k>2$, the theory describes an analogous transition involving different non-Abelian topological orders, such as the double Fibonacci order ($k=3$) and the $S_3$ quantum double ($k=4$). For $k=1$, we conjecture that the corresponding CSH transition is in fact infrared dual to the $3d$ Ising transition, in close analogy with the particle-vortex duality of a complex scalar.

Bright entangled photon sources with on-demand quantum state control are essential for advancing quantum science and technologies. However, simultaneously achieving high brightness and state tunability remains challenging, as this necessitates a dual-phase control mechanism that facilitates both longitudinal phase matching and transverse polarization modulation. Here, we report a twin-twisted two-dimensional (2D) van der Waals (vdW) crystal architecture that enables spontaneous parametric down-conversion (SPDC) with both high generation efficiency and continuously tunable quantum states. The designed crystal comprises two sections of twisted 2D GaSe vdW flakes with opposite chiral handedness, in which interflake twist angle induces phase matching in SPDC, and intersection twisting provides an additional degree of freedom on tunability. We demonstrate that the twin-twisted GaSe crystals achieve a record-high photon-pair generation rate exceeding 13 200 Hz and a Bell state fidelity above 99% within 2D material family, and enable unprecedented tunability of quantum states from the maximally polarization entangled states to the fully separable states. This study opens a practical avenue toward twist-engineered quantum states, and paves the way for developing compact quantum photonic systems with tailored properties.

Matter-induced neutrino flavor mixing (the Mikheyev-Smirnov-Wolfenstein, or MSW, effect) is a central prediction of the neutrino mixing framework, but it has not been conclusively observed. Direct observation of the energy-dependent MSW transition in the solar electron-neutrino survival probability would solve this, but backgrounds have been prohibitive. We show that our new technique for suppressing muon-induced spallation backgrounds will allow JUNO to measure the MSW transition at $>4\sigma$ significance in 10 years. This would strongly support upcoming multibillion-dollar next-generation experiments and their goals in cementing the neutrino mixing framework.

We study the breakup dynamics of a two-dimensional strip of active chiral fluid using continuum hydrodynamics. Using slender body theory, we show that the breakup is driven by the interplay between chiral and surface tension forces, and that the minimum strip thickness decays to zero as a power law in finite time. The power law exponent and corresponding scaling function describing the shape of the strip near the break point are computed analytically, and shown to be in excellent agreement with numerical simulations of the underlying hydrodynamics. Qualitative agreement between experiment and simulation is also found.

We investigate $(k_1,k_2)$ extendibility of fermionic Gaussian states, a property central to quantum correlations and approximations of separability. We show that these states are $(k_1,k_2)$-extendible if and only if they admit a fermionic Gaussian extension, yielding a complete covariance-matrix characterization and a simple semidefinite program (SDP) whose size scales linearly with the number of modes. This provides necessary conditions for arbitrary fermionic states and is sufficient within the Gaussian setting. Our main result is a finite de Finetti–type theorem: we derive trace-norm bounds between $(k_1,k_2)$-extendible fermionic Gaussian states and separable states, improving previous exponential scaling to linear in the number of modes, with complementary relative entropy and squashed entanglement bounds. For two modes, upper and lower bounds match at order $1/\sqrt{k_1{k}_2}$. Extendibility also provides operational support for one of the different notions of separability in fermionic systems. Finally, for fermionic Gaussian channels, we provide a simple semidefinite program criterion for antidegradability and show that entanglement-breaking channels coincide with replacement channels, implying no nontrivial entanglement-breaking fermionic Gaussian channels exist.

We elucidate the boundary between classical and quantum computation by constructing qubit Clifford circuits with nonstabilizer inputs that can be efficiently simulated classically. We do so by casting the quantum circuits realizable by defect braiding in the surface code in terms of a Kirkwood-Dirac (KD) quasiprobability distribution, a generalization of a joint probability distribution. If this distribution remains a proper (positive) probability distribution throughout a circuit, then a classical algorithm can simulate the circuit efficiently. By leveraging recent results on the geometry of KD-positive states, we construct bound-magic states. Classical computers can efficiently simulate these bound-magic states’ evolutions under the circuits, although other magic states enable universal quantum computation when inputted. Furthermore, we show that KD nonpositivity is a resource monotone in this model. Thus, we establish KD nonpositivity as a necessary resource for quantum-computational advantages.