We consider the far-from-equilibrium quantum transport dynamics in a 1D Josephson junction chain of multimode Bose-Einstein condensates. We develop a theoretical model to examine the experiment of Labouvie et al. [Phys. Rev. Lett. 115, 050601 (2015)], wherein the phenomenon of negative differential conductivity (NDC) was reported in the refilling dynamics of an initially depleted site within the chain. We demonstrate that a unitary $c$-field description can quantitatively reproduce the experimental results over the full range of tunnel couplings, and requires no fitted parameters. With a view toward atomtronic implementations, we further demonstrate that the filling is strongly dependent on spatial phase variations stemming from quantum fluctuations. Our findings suggest that the interpretation of the device in terms of NDC is invalid outside of the weak coupling regime. Within this restricted regime, the device exhibits a hybrid behavior of NDC and the ac Josephson effect. A simplified circuit model of the device will require an approach tailored to atomtronics that incorporates quantum fluctuations.

It is found that, in the studies of heavy ion transport with gyrokinetic simulations, the ion parallel drift frequency can reverse sign in velocity space when the amplitude variation of the electrostatic potential fluctuation is strong along the magnetic field line. As a result, the particle transport related to the parallel dynamics is strongly enhanced. It is noted that, while parallel gradient of the fluctuation amplitude can be instigated by a large magnetic shear or safety factor in a tokamak, the generic mechanism is independent of its cause, which suggests broader applications to kinetic plasma problems. Some relevant topics are briefly addressed in the end.

The Rashba parameter ${\alpha }_R$ is usually assumed to scale linearly with the amplitude of polar displacements by construction of the spin-orbit interaction. On the basis of first-principles simulations, ferroelectric phases of ${\mathrm{SrTiO}}_3$ reached under epitaxial compressive strain are characterized by (i) large Rashba effects at the bottom of the conduction band near the paraelectric-ferroelectric boundary and (ii) an unexpected suppression of the phenomena when the amplitude of polar displacements increases. This peculiar behavior is ascribed to the inverse dependence of the Rashba parameter with the crystal field ${\mathrm{\Delta }}_{\mathrm{CF}}$ induced by the polar displacements that alleviates the degeneracy of Ti $t_{2g}$ states and annihilates the Rashba effects. Although ${\alpha }_R$ has intrinsically a linear dependance on polar displacements, the latter becomes antagonist to Rashba phenomena at large polar mode amplitude. Thus, the Rashba coefficient may be bound to an upper value.

We theoretically propose that the van der Waals layered ternary transition metal chalcogenide ${\mathrm{V}}_{2}M{X}_4$ ($M=\mathrm{W}$, Mo; $X=\mathrm{S}$, Se) is a new family of quantum anomalous Hall insulators with sizable bulk gap and Chern number $\mathcal{C}=-1$. The large topological gap originates from the deep band inversion between spin-up bands contributed by $d_{xz}$, $d_{yz}$ orbitals of V and spin-down band from $d_{z^2}$ orbital of $M$ at the Fermi level. Remarkably, the Curie temperature of monolayer ${\mathrm{V}}_{2}M{X}_4$ is predicted to be much higher than that of monolayer ${\mathrm{MnBi}}_2{\mathrm{Te}}_4$. Furthermore, the thickness dependence of the Chern number for few multilayers shows interesting oscillating behavior. The general physics from the $d$ orbitals here applies to a large class of ternary transition metal chalcogenide such as ${\mathrm{Ti}}_2{WX}_4$ with the space group $P\text{−}42m$. These interesting predictions, if realized experimentally, could greatly promote the research and application of topological quantum physics.

We develop a theory for heat transport via electromagnetic waves inside media, and use it to derive a spatially nonlocal thermal conductivity tensor, in terms of the electromagnetic Green’s function and potential, for any given system. While typically negligible for optically dense bulk media, the electromagnetic component of conductivity can be significant for optically dilute media, and shows regimes of Fourier transport as well as unhindered transport. Moreover, the electromagnetic contribution is relevant even for dense media, when in the presence of interfaces, as exemplified for the in-plane conductivity of a nanosheet, which shows a variety of phenomena, including absence of a Fourier regime.

We consider a population of globally coupled oscillators in which phase shifts in the coupling are random. We show that in the maximally disordered case, where the pairwise shifts are independent identically distributed random variables, the dynamics of a large population reduces to one without randomness in the shifts but with an effective coupling function, which is a convolution of the original coupling function with the distribution of the phase shifts. This result is valid for noisy oscillators and/or in the presence of a distribution of natural frequencies. We argue also, using the property of global asymptotic stability, that this reduction is valid in a partially disordered case, where random phase shifts are attributed to the forced units only. However, the reduction to an effective coupling in the partially disordered noise-free situation may fail if the coupling function is complex enough to ensure the multistability of locked states.

We find a closed-form expression for the Poisson’s coefficient of curved-crease variants of the “Miura ori” origami tessellation. This is done by explicitly constructing a continuous one-parameter family of isometric piecewise-smooth surfaces that describes the action of folding out of a reference state. The response of the tessellations in bending is investigated as well: using a numerical convergence scheme, the effective normal curvatures under infinitesimal bending are found to occur in a ratio equal and opposite to the Poisson’s coefficient. These results are the first of their kind and, by their simplicity, should provide a fruitful benchmark for the design and modeling of curved-crease origami and compliant shell mechanisms. The developed methods are used to design a curved-crease 3D morphing solid with a tunable self-locked state.

Using $(10087\pm 44)\times {10}^{6}J/\psi$ events collected with the BESIII detector, numerous ${\mathrm{\Xi }}^{-}$ and $\mathrm{\Lambda }$ decay asymmetry parameters are simultaneously determined from the process $J/\psi \to {\mathrm{\Xi }}^{-}{\overline{\mathrm{\Xi }}}^{+}\to \mathrm{\Lambda }(p{\pi }^{-}){\pi }^{-}\overline{\mathrm{\Lambda }}(\overline{n}{\pi }^0){\pi }^{+}$ and its charge-conjugate channel. The precisions of ${\alpha }_{\mathrm{\Lambda }0}$ for $\mathrm{\Lambda }\to n{\pi }^0$ and ${\overline{\alpha }}_{\mathrm{\Lambda }0}$ for $\overline{\mathrm{\Lambda }}\to \overline{n}{\pi }^0$ compared to world averages are improved by factors of 4 and 1.7, respectively. The ratio of decay asymmetry parameters of $\mathrm{\Lambda }\to n{\pi }^0$ to that of $\mathrm{\Lambda }\to p{\pi }^{-}$, $⟨{\alpha }_{\mathrm{\Lambda }0}⟩/⟨{\alpha }_{\mathrm{\Lambda }-}⟩$, is determined to be $0.873\pm 0.012_{-0.010}^{+0.011}$, where the first and the second uncertainties are statistical and systematic, respectively. The ratio is smaller than unity more than $5\sigma$, which signifies the existence of the $\mathrm{\Delta }I=3/2$ transition in $\mathrm{\Lambda }$ for the first time. Besides, we test for $CP$ symmetry in ${\mathrm{\Xi }}^{-}\to \mathrm{\Lambda }{\pi }^{-}$ and in $\mathrm{\Lambda }\to n{\pi }^0$ with the best precision to date.

How predictable are turbulent flows? Here, we use theoretical estimates and shell model simulations to argue that Eulerian spontaneous stochasticity, a manifestation of the nonuniqueness of the solutions to the Euler equation that is conjectured to occur in Navier-Stokes turbulence at high Reynolds numbers, leads to universal statistics at finite times, not just at infinite time as for standard chaos. These universal statistics are predictable, even though individual flow realizations are not. Any small-scale noise vanishing slowly enough with increasing Reynolds number can trigger spontaneous stochasticity, and here we show that thermal noise alone, in the absence of any larger disturbances, would suffice. If confirmed for Navier-Stokes turbulence, our findings would imply that intrinsic stochasticity of turbulent fluid motions at all scales can be triggered even by unavoidable molecular noise, with implications for modeling in engineering, climate, astrophysics, and cosmology.

A proposal of the existence of an Anomalous phase ($\mathcal{A}$ phase) [Das et al., Phys. Rev. Lett. 131, 056202 (2023)] at the experimental range of moderate Landau-level-mixing strength has recently been made for the $5/2$ state. We here report that the gapped $\mathcal{A}$ phase is generic to the sequence of spin-polarized fractional quantum Hall states with filling fractions $\nu =n/(nm-1)$ and $\nu =1-n/(nm-1)$, $(n\ge 1,m\ge 3)$, that exhausts almost all the observed states and also predicts some states in the second Landau level for GaAs systems. Our proposed trial wave functions for all these states have remarkably high overlaps with the corresponding exact ground states and can support non-Abelian quasiparticle excitations with charge $e/[2(nm-1)]$. By analyzing edge modes, we predict experimentally verifiable thermal Hall conductance $2.5({\pi }^2{k}_B^{2}T/3h)$ for all the states in these sequences.

Computing thermal transport from first-principles in ${\mathrm{UO}}_2$ is complicated due to the challenges associated with Mott physics. Here, we use irreducible derivative approaches to compute the cubic and quartic phonon interactions in ${\mathrm{UO}}_2$ from first principles, and we perform enhanced thermal transport computations by evaluating the phonon Green’s function via self-consistent diagrammatic perturbation theory. Our predicted phonon lifetimes at $T=600\mathrm{K}$ agree well with our inelastic neutron scattering measurements across the entire Brillouin zone, and our thermal conductivity predictions agree well with previous measurements. Both the changes due to thermal expansion and self-consistent contributions are nontrivial at high temperatures, though the effects tend to cancel, and interband transitions yield a substantial contribution.

Despite significant theoretical efforts devoted to studying the interaction between quantized light modes and matter, the so-called ultrastrong coupling regime still presents significant challenges for theoretical treatments and prevents the use of many common approximations. Here we demonstrate an approach that can describe the dynamics of hybrid quantum systems in any regime of interaction for an arbitrary electromagnetic (EM) environment. We extend a previous method developed for few-mode quantization of arbitrary systems to the case of ultrastrong light-matter coupling, and show that even such systems can be treated using a Lindblad master equation where decay operators act only on the photonic modes by ensuring that the effective spectral density of the EM environment is sufficiently suppressed at negative frequencies. We demonstrate the validity of our framework and show that it outperforms current state-of-the-art master equations for a simple model system, and then study a realistic nanoplasmonic setup where existing approaches cannot be applied.

Biased locomotion is a common feature of microorganisms, but little is known about its impact on self-organization. Inspired by recent experiments showing a transition to large-scale flows, we study theoretically the dynamics of magnetotactic bacteria confined to a drop. We reveal two symmetry-breaking mechanisms (one local chiral and one global achiral) leading to self-organization into global vortices and a net torque exerted on the drop. The collective behavior is ultimately controlled by the swimmers’ microscopic chirality and, strikingly, the system can exhibit oscillations and memorylike features.

Deep generative models are key-enabling technology to computer vision, text generation, and large language models. Denoising diffusion probabilistic models (DDPMs) have recently gained much attention due to their ability to generate diverse and high-quality samples in many computer vision tasks, as well as to incorporate flexible model architectures and a relatively simple training scheme. Quantum generative models, empowered by entanglement and superposition, have brought new insight to learning classical and quantum data. Inspired by the classical counterpart, we propose the quantum denoising diffusion probabilistic model (QuDDPM) to enable efficiently trainable generative learning of quantum data. QuDDPM adopts sufficient layers of circuits to guarantee expressivity, while it introduces multiple intermediate training tasks as interpolation between the target distribution and noise to avoid barren plateau and guarantee efficient training. We provide bounds on the learning error and demonstrate QuDDPM’s capability in learning correlated quantum noise model, quantum many-body phases, and topological structure of quantum data. The results provide a paradigm for versatile and efficient quantum generative learning.

We demonstrate a memory for light based on optomechanically induced transparency. We achieve a long storage time by leveraging the ultralow dissipation of a soft-clamped mechanical membrane resonator, which oscillates at MHz frequencies. At room temperature, we demonstrate a lifetime $T_1\approx 23\mathrm{ms}$ and a retrieval efficiency $\eta \approx 40\%$ for classical coherent pulses. We anticipate the storage of quantum light to be possible at moderate cryogenic conditions ($T\approx 10\mathrm{K}$). Such systems could find applications in emerging quantum networks, where they can serve as long-lived optical quantum memories by storing optical information in a phononic mode.

Quantum many-body interactions can induce quantum entanglement among particles, rendering them valuable resources for quantum-enhanced sensing. In this work, we establish a link between the bound on the growth of the quantum Fisher information and the Lieb-Robinson bound, which characterizes the operator growth in locally interacting quantum many-body systems. We show that for initial separable states, despite the use of local many-body interactions, the precision cannot surpass the shot noise limit at all times. This conclusion also holds for an initial state that is the nondegenerate ground state of a local and gapped Hamiltonian. These findings strongly hint that when one can only prepare separable initial states, nonlocal and long-range interactions are essential resources for surpassing the shot noise limit. This observation is confirmed through numerical analysis on the long-range Ising model. Our results bridge the field of many-body quantum sensing and operator growth in many-body quantum systems and open the possibility to investigate the interplay between quantum sensing and control, many-body physics and information scrambling.

We use multimessenger observations of the neutron star merger event GW170817 to derive new constraints on axionlike particles (ALPs) coupling to photons. ALPs are produced via Primakoff and photon coalescence processes in the merger, escape the remnant, and decay back into two photons, giving rise to a photon signal approximately along the line of sight to the merger. We analyze the spectral and temporal information of the ALP-induced photon signal and use the Fermi Large Area Telescope (Fermi-LAT) observations of GW170817 to derive our new ALP constraints. We also show the improved prospects with future MeV $\gamma$-ray missions, taking the spectral and temporal coverage of Fermi-LAT as an example.

The metastable hypermassive neutron star produced in the coalescence of two neutron stars can copiously produce axions that radiatively decay into $\mathcal{O}(100)\mathrm{MeV}$ photons. These photons can form a fireball with characteristic temperature smaller than 1 MeV. By relying on x-ray observations of GW170817/GRB 170817A with CALET CGBM, Konus-Wind, and Insight-HXMT/HE, we present new bounds on the axion-photon coupling for axion masses in the range 1–400 MeV. We exclude couplings down to $5\times {10}^{-11}{\mathrm{GeV}}^{-1}$, complementing and surpassing existing constraints. Our approach can be extended to any feebly interacting particle decaying into photons.

We investigate the effect of resonant spin conversion of the neutrinos induced by the geometrical phase in a twisting magnetic field. We find that the geometrical phase originating from the rotation of the transverse magnetic field along the neutrino trajectory can trigger a resonant spin conversion of Dirac neutrinos inside the supernova, even if there were no such transitions in the fixed-direction field case. We have shown that, even though resonant spin conversion is too weak to affect solar neutrinos, it could have a remarkable consequence on supernova neutronization bursts where very intense magnetic fields are quite likely. We demonstrate how the flavor composition at Earth can be used as a probe to establish the presence of non-negligible magnetic moments, potentially down to ${10}^{-15}{\mu }_B$ in upcoming neutrino experiments like the Deep Underground Neutrino Experiment and the Hyper-Kamiokande. Possible implications are analyzed.