Physical review letters最新文献

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.

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 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 (ε privacy), quantifying how close the state is to being private.

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 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., CH_{3}^{+}+C_{5}H_{3}^{+}+C_{6}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.

Like the letters in the alphabet forming words, reusing components of a heterogeneous mixture is an efficient strategy for assembling a large number of target structures. Examples range from synthetic DNA origami to proteins self-assembling into complexes. The standard self-assembly paradigm views target structures as free-energy minima of a mixture. While this is an appealing picture, at high speed structures may be kinetically trapped in local minima, reducing self-assembly accuracy. How then can high speed, high accuracy, and combinatorial usage of components coexist? We propose to reconcile these three concepts not by avoiding kinetic traps, but by exploiting them to encode target structures. This can be achieved by sculpting the kinetic pathways of the mixture, instead of its free-energy landscape. We formalize these ideas in a minimal toy model, for which we analytically estimate the encoding capacity and kinetic characteristics, in agreement with simulations. Our results may be generalized to other soft-matter systems capable of computation, such as liquid mixtures or elastic networks, and pave the way for high-dimensional information processing far from equilibrium.

We present a first experimental study of dark current in a quanta image sensor (QIS) based on complementary metal-oxide-semiconductor (CMOS) technology. With the extremely low noise levels of this sensor it is possible to observe spatial and temporal dark current quantization. Analysis of dark carrier emission timing confirms that carrier generation behaves as a Poisson process. The mean of this Poisson distribution is the only parameter needed to characterize a sensor, thus greatly reducing the required measurement and computational resources typically employed in device noise analysis. The impact of this new characterization method will be useful to a range of industrial and scientific applications requiring high accuracy in photoelectron counting, such as in particle detection or quantum sensing. The ability to observe single carrier emission in a QIS leads to a deeper understanding of the mechanism of dark current generation in state-of-the-art semiconductors, thereby promoting improvements in the development of device design and process technology.

We devise a Floquet theory of longitudinal and dispersive readout in circuit quantum electrodynamics (cQED). By studying qubits coupled to cavity photons and driven at the resonance frequency of the cavity ω_{r}, we establish a universal connection between the qubit ac Stark shift and the longitudinal and dispersive coupling to photons. We find that the longitudinal coupling g_{∥} is controlled by the slope of the ac Stark shift as function of the driving strength A_{q}, while the dispersive shift χ depends on its curvature. The two quantities become proportional to each other in the weak drive limit (A_{q}→0). Our approach unifies the adiabatic limit (ω_{r}→0)-where g_{∥} is generated by the static spectrum curvature (or quantum capacitance)-with the diabatic limit, where ω_{r} is large and the static spectrum plays no role. We derive analytical results supported by exact numerical simulations. We apply them to superconducting and spin-hybrid cQED systems, showcasing the flexibility of faster-than-dispersive longitudinal readout.