Although the mechanical response of DNA to physiological torsion and tension is well characterized, the detailed structures are not yet known. By using molecular dynamics simulations on linear DNA with 300 base-pairs, we provide, for the first time, the conformational phase diagram at atomic resolution. Our simulations also reveal the dynamics and diffusion of supercoils. We observe a new state in negative supercoiling, where denaturation bubbles form in adenine/thymine-rich regions independently of the underlying DNA topology. We thus propose sequence-dependent bubbles could position plectonemes in longer DNA.

We determine the conditions under which the presence of long-range interactions reduce the energy losses due to defect generation during nonadiabatic evolution, crucial for enhancing the power to efficiency ratio of quantum thermal devices. In order to do so, we investigate the response of long-range systems to diverse external drivings, emphasizing their robustness against dynamic excitation in comparison to generic local systems. This phenomenon is demonstrated through the study of the quantum work statistics, revealing insights into energy transfer efficiency and dynamical quantum criticality. Our results demonstrate the benefits of including a long-range interacting medium for quantum thermodynamics application, highlighting the potential to optimize finite-time quantum thermal cycles. Thanks to the effective dimension approach our findings can be drawn in full generality and, then, specified to different experimentally relevant scenarios.

We treat privacy in a network of quantum sensors where accessible information is limited to specific functions of the network parameters, and all other information remains private. We develop an analysis of privacy in terms of a manipulation of the quantum Fisher information matrix, and find the optimal state achieving maximum privacy in the estimation of linear combination of the unknown parameters in a network of quantum sensors. We also discuss the effect of uncorrelated noise on the privacy of the network. Moreover, we illustrate our results with an example where the goal is to estimate the average value of the unknown parameters in the network. In this example, we also introduce the notion of quasiprivacy ($\epsilon$ privacy), quantifying how close the state is to being private.

In a quantum communication network, links represent entanglement between qubits located at different nodes. Even if two nodes are not directly linked by shared entanglement, they can still communicate via routing protocols. However, in contrast to classical communication, each quantum communication event removes all participating links along the routed path, disrupting the quantum communication network. Here, we propose a simple model, where randomly selected pairs of nodes communicate through the shortest paths. Each time such a path is used, all participating links are eliminated, leading to a correlated percolation process that we call “path percolation.” We study path percolation both numerically and analytically and present the phase diagram of the steady states as a function of the rate at which new links are being added to the network. As a key result, the steady state is found to be independent of the initial network topologies when new links are added randomly between disconnected components. We close by discussing extensions of path percolation and link replenishment, along with their potential applications.

We devise and demonstrate a method to search for nongravitational couplings of ultralight dark matter to standard model particles using space-time separated atomic clocks and cavity-stabilized lasers. By making use of space-time separated sensors, which probe different values of an oscillating dark matter field, we can search for couplings that cancel in typical local experiments. This provides sensitivity to both the temporal and spatial fluctuations of the field. We demonstrate this method using existing data from a frequency comparison of lasers stabilized to two optical cavities connected via a 2220 km fiber link [Schioppo et al., Nat. Commun. 13, 212 (2022)], and from the atomic clocks on board the global positioning system satellites. Our analysis results in constraints on the coupling of scalar dark matter to electrons, $d_{m_e}$, for masses between ${10}^{-19}$ and $2\times {10}^{-15}\mathrm{eV}/c^2$. These are the first constraints on $d_{m_e}$ alone in this mass range.

Certain precessing black-hole mergers produce gravitational waves with net circular polarization, understood as an imbalance between right- and left-handed amplitudes. According to the cosmological principle, such emission must average to zero across all binary mergers in our Universe to preserve mirror-reflection symmetry at very large scales. We present a new independent gravitational-wave test of this hypothesis. Using a novel observable based on the Chern-Pontryagin pseudoscalar, we measure the emission of net circular polarization across 47 black-hole mergers recently analyzed by [T. Islam et al., arXiv:2309.14473.] with a state-of-the art model for precessing black-hole mergers in general relativity. The average value obtained is consistent with zero. Remarkably, however, we find that at least 82% of the analyzed sources must have produced net circular polarization. Of these, GW200129 shows strong evidence for mirror asymmetry, with a Bayes factor of 12.6 or, equivalently, 93.1% probability. We obtain consistent (although stronger) results of 97.5% and 94.3%, respectively, using public results on this event from [M. Hannam et al., Nature (London) 610, 652 (2022).] and performing our own parameter inference. This finding further implies evidence of astrophysical sources that can spontaneously emit circularly polarized photons by quantum effects. Forthcoming black-hole merger detections will enable stronger constraints on large-scale mirror asymmetry and the cosmological principle.

Any experimental evidence of nucleons paired in spin-triplet states will confirm the existence of an exotic phase of nuclear systems. This type of nuclear superfluidity has been hypothesized in heavy nuclei, where the antagonizing spin-orbit effects are damped, and there it oftentimes coexists with traditional spin-singlet pairing, leading to the possibility of mixed-spin pairing. Realistic nuclear deformation, not considered in such studies, could make-or-break these proposals, since its effect on triplet pairing, and the competition (and coexistence) of the two superfluid phases, was expected to be crucial. We report on a thorough study on the effect of deformation on triplet, singlet, and mixed-spin pairing in the relevant region of the nuclear chart. We find that, at low isospin asymmetries, spin-triplet pairing is enhanced by deformation, while below the proton-drip line, the novel superfluid phase survives alongside the usual spin-singlet pairing. These results suggest that spin-triplet superfluidity exists in realistic nuclei and can be probed in the lab.

Measurements of the difference between the squared charge radii of the helion (${}^3\mathrm{He}$ nucleus) and the $\alpha$ particle (${}^4\mathrm{He}$ nucleus) have been characterized by longstanding tensions recently spotlighted in the $3.6\sigma$ discrepancy of the extractions from ordinary atoms versus those from muonic atoms [Karsten Schuhmann et al., arXiv:2305.11679]. Here, we present a novel analysis of uncertainties in nuclear structure corrections that must be supplied by theory to enable the extraction of the difference in radii from spectroscopic experiments. We use modern Bayesian inference techniques to quantify uncertainties stemming from the truncation of the chiral effective field theory expansion of the nuclear force for both muonic and ordinary atoms. With the new nuclear structure input, the helium isotope-shift puzzle cannot be explained, rather, it is reinforced to a $4\sigma$ discrepancy.

We report the experimental observation of double intermolecular Coulombic decay (dICD) and reveal its potential for radiation biology in some prototypical molecular dimers consisting of benzene, pyridine, and water. In dICD, the inner-shell vacancy is filled by an electron from an outer shell and the energy released is transferred to doubly ionize the neighboring molecule with the emission of two low-energy electrons. The system further relaxes by a three-body Coulomb explosion process, e.g., ${\mathrm{CH}}_3^{+}+{\mathrm{C}}_5{\mathrm{H}}_3^{+}+{\mathrm{C}}_6{\mathrm{H}}_6^{+}$ for benzene dimer. Through multicoincidence momentum imaging, we find that dICD is an efficient relaxation pathway for the Auger-accessible inner-shell ionization states in molecular complexes. Moreover, this ultrafast decay mechanism causes a direct breaking of the aromatic rings, which is observed to be a general phenomenon occurring in biological systems and thus can play an important role in radiation biology.

The quantum rotor is one of the simplest model systems in quantum mechanics, but only in recent years has theoretical work revealed general fundamental scaling laws for its decoherence. For example, a superposition of orientations decoheres at a rate proportional to the sine squared of the angle between them. Here, we observe scaling laws for rotational decoherence dynamics for the first time, using a $4\mathrm{\mu }\mathrm{m}$ diameter planar rotor composed of two Paul-trapped ions. We prepare the rotational motion of the ion crystal into superpositions of angular momentum with well-defined differences ranging from $1-3\hslash$, and measure the rate of decoherence. We also tune the system-environment interaction strength by introducing resonant electric field noise. The observed scaling relationships for decoherence are in excellent agreement with recent theoretical work, and are directly relevant to the growing development of rotor-based quantum applications.

Experiments have shown that surfactant introduced to a liquid-filled maze can find the solution path. We reveal how the maze-solving dynamics arise from interactions between the added surfactant and endogenous surfactant present at the liquid surface. We simulate the dynamics using a nonlinear model solved with a discrete mimetic scheme on a graph. Endogenous surfactant transforms local spreading into a nonlocal problem with an omniscient view of the maze geometry, key to the maze-solving dynamics. Our results offer insight into surfactant-driven transport in complex networks such as lung airways.

Pellets of frozen material traveling into a magnetically confined fusion plasma are accelerated by the so-called pellet rocket effect. The nonuniform plasma heats the pellet ablation cloud asymmetrically, producing pressure-driven, rocketlike propulsion of the pellet. We present a semianalytical model of this process by perturbing a spherically symmetric ablation model. Predicted pellet accelerations match experimental estimates in current tokamaks ($\sim {10}^5\mathrm{m}/{\mathrm{s}}^2$). Projections for ITER high-confinement scenarios ($\sim {10}^6\mathrm{m}/{\mathrm{s}}^2$) indicate significantly shorter pellet penetration than expected without this effect, which could limit the effectiveness of disruption mitigation.

We investigate the role of molecular flexibility on the electrical transport properties of model electrolytes containing ions and an underlying disordered network structure with changing connectedness. Rather than focusing on the effect of ion content in a stoichiometric network former ${\mathrm{AY}}_2$ (e.g., ${\mathrm{SiS}}_2$), we explore the possibility of increasing the $\mathrm{Y}:\mathrm{A}$ ratio (flexibility index $m$) in order to reduce connectivity and to promote the occurrence of flexible modes and topological degrees of freedom in the network structure. At fixed ion content and below a certain threshold modifier composition $x_c$, topological constraint counting indicates that a mean-field stress-to-flexible transition is expected for a flexibility index $m_c$, and an ion hopping model predicts a substantial increase of conductivity once $m>m_c$. Molecular dynamics simulations on a typical amorphous electrolyte, $x{\mathrm{Na}}_2\mathrm{S}-(1-x){\mathrm{SiS}}_m$, independently and quantitatively confirm the prediction as anomalous changes with $m$ are obtained, and these manifest by waterlike diffusivity anomalies, and a substantial increase of ionic conductivity upon moderate change of $m$. The analysis disentangles contributions from mobility and the free carrier rate in the electrical transport, and finally suggests that molecular flexibility can serve as an efficient way for conductivity enhancement in all solid-state batteries using amorphous electrolytes.

Evaluations of the orbital Hall effect (OHE) have retained only interband matrix elements of the position operator. Here, we evaluate the OHE including all matrix elements of the position operator, including the technically challenging intraband elements. We recover previous results and find quantum corrections due to the noncommutativity of the position and velocity operators and interband matrix elements of the orbital angular momentum. The quantum corrections dominate the OHE responses of the topological antiferromagnet CuMnAs and of massive Dirac fermions.

We develop a theory of adiabatic orbital pumping, highlighting qualitative differences from spin pumping. An oscillating magnetic field pumps not only orbital angular momentum current, but also orbital angular position current. The latter, which has no spin counterpart, underscores the incompleteness of existing orbital torque theories. Importantly, both types of orbital currents can be detected as transverse electric voltages, which contain considerable second-harmonic components unlike in spin pumping. Moreover, orbital currents can be pumped by lattice dynamics that carry phonon angular momentum, implying that orbital currents can, in turn, induce phonon angular momentum. Our Letter open up new possibilities for generating orbital currents and provides a broader understanding of the interplay between spin, orbital, and phonon dynamics.

We demonstrate in situ control of the elastic wave polarization in a surface acoustic wave (SAW). It allows us to create highly reconfigurable SAW microfluidics that can be switched on demand between the acoustohydrodynamic (AHD) regime and electrohydrodynamic (EHD) regime for manipulating particles and cells. The control of wave polarization comes from our experimental and theoretical identification of an unexpected shear-horizontal (SH) wave mode in a conventional Rayleigh (R) wave design, which is stereotyped to excite only vertically polarized Rayleigh SAWs. The SH wave mode is predominantly horizontally polarized and can be selectively excited to propagate in the same direction as the Rayleigh SAW. Such a selective wave generation between the SH mode and R mode allows for reconfiguration between AHD and EHD regimes that leads to unprecedented colloidal patterns and assembly dynamics. Such a reconfiguration of the particle manipulation mechanism can be explained by the controllable competition or synergism between the coexisting acoustic and electric fields. Remarkably, in the EHD regime, a virtual zero-boundary electric quadrupole is created, and a novel colloidal diamond-shaped assembly is observed in this piezoelectric-quadrupole trap, which was rarely reported in acoustic or electric microfluidics. The presented in situ control of polarization revolutionizes our understanding of SAW and acoustofluidics, expands its potential by assuming the advantages of AHD and EHD on demand, and inspires new strategies in micro- and nanoscale manufacturing and manipulation, with applications beyond fundamental scientific interest.