From a Taylor dispersion perspective, we determine the fourth cumulant and the tails of the displacement distribution, considering general diffusivity tensors and potentials, such as those from walls or external forces like gravity. Our theoretical framework successfully accounts for the fourth cumulants measured in experimental and numerical analyses of colloid motion parallel to a wall. Interestingly, in deviation from Brownian motion models that lack Gaussianity, the displacement distribution's tails showcase a Gaussian shape, diverging from the exponential form. Our findings in their entirety represent additional tests and limitations for the inference of force maps and the characteristics of local transport near surfaces.
Transistors are fundamental to electronic circuits, enabling operations such as isolating or amplifying voltage signals. Considering the point-based, lumped-element nature of conventional transistors, the conceptualization of a distributed, transistor-type optical response within a substantial material warrants further investigation. We argue that low-symmetry two-dimensional metallic systems hold the key to effectively implementing a distributed-transistor response. The semiclassical Boltzmann equation is applied here to describe the optical conductivity of a two-dimensional material experiencing a static electric field. In a manner akin to the nonlinear Hall effect, the linear electro-optic (EO) response exhibits a dependence on the Berry curvature dipole, potentially creating nonreciprocal optical interactions. Intriguingly, our investigation reveals a new non-Hermitian linear electro-optic effect, resulting in both optical amplification and a distributed transistor behavior. Based on strained bilayer graphene, we analyze a possible embodiment. Our investigation into the optical gain of light traversing the biased system demonstrates a dependence on light polarization, frequently reaching substantial magnitudes, particularly in multilayer arrangements.
Quantum information and simulation rely critically on coherent tripartite interactions between disparate degrees of freedom, but these interactions are generally difficult to achieve and have been investigated to a relatively small extent. In a hybrid system featuring a solitary nitrogen-vacancy (NV) centre and a micromagnet, we anticipate a three-part coupling mechanism. Through modulation of the relative movement between the NV center and the micromagnet, we aim to establish direct and robust tripartite interactions involving single NV spins, magnons, and phonons. By introducing a parametric drive, specifically a two-phonon drive, to control the mechanical motion—for instance, the center-of-mass motion of an NV spin in diamond (electrically trapped) or a levitated micromagnet (magnetically trapped)—we can attain a tunable and potent spin-magnon-phonon coupling at the single quantum level, potentially enhancing the tripartite coupling strength by up to two orders of magnitude. Quantum spin-magnonics-mechanics, with realistic experimental parameters, allows for, for instance, tripartite entanglement amongst solid-state spins, magnons, and mechanical motions. With readily available techniques in ion traps or magnetic traps, this protocol is easily implementable and could facilitate general applications in quantum simulations and information processing, capitalizing on the direct and strong coupling of tripartite systems.
Latent symmetries, which are concealed symmetries, become apparent through the reduction of a discrete system to a lower-dimensional effective model. Continuous wave setups are made possible by exploiting latent symmetries in acoustic networks, as detailed here. Selected waveguide junctions, for all low-frequency eigenmodes, are systematically designed to possess a pointwise amplitude parity, induced by their latent symmetry. To connect latently symmetric networks with multiple latently symmetric junction pairs, we devise a modular approach. Asymmetrical configurations are designed by associating these networks with a mirror-symmetric subsystem, displaying eigenmodes with domain-specific parity. Our work, crucial to bridging the gap between discrete and continuous models, fundamentally advances the exploitation of hidden geometrical symmetries in realistic wave setups.
The electron's magnetic moment, now precisely determined as -/ B=g/2=100115965218059(13) [013 ppt], boasts an accuracy 22 times greater than the previous value, which held sway for 14 years. A key property of an elementary particle, determined with the utmost precision, offers a stringent test of the Standard Model's most precise prediction, demonstrating an accuracy of one part in ten to the twelfth. Should the discrepancies observed in the fine-structure constant measurements be removed, a ten-fold boost in the test's quality would arise. This is because the Standard Model prediction hinges on this value. The new measurement, taken in concert with the Standard Model, indicates that ^-1 equals 137035999166(15) [011 ppb], a ten-fold reduction in uncertainty compared to the present discrepancy between the various measured values.
To study the high-pressure phase diagram of molecular hydrogen, we use path integral molecular dynamics simulations and a machine-learned interatomic potential, parameterized with quantum Monte Carlo forces and energies. In addition to the HCP and C2/c-24 phases, two novel stable phases, each possessing molecular centers within the Fmmm-4 structure, are observed; these phases exhibit a temperature-dependent molecular orientation transition. The high-temperature isotropic Fmmm-4 phase's reentrant melting line surpasses previous estimations, reaching a maximum at 1450 K under 150 GPa pressure, and it crosses the liquid-liquid transition line around 1200 K and 200 GPa.
The enigmatic pseudogap behavior in high-Tc superconductivity, characterized by the partial suppression of electronic density states, is a source of great contention, with some supporting preformed Cooper pairs as the cause and others highlighting the potential for competing interactions nearby. Quasiparticle scattering spectroscopy of the quantum critical superconductor CeCoIn5 reveals a pseudogap, characterized by an energy gap 'g', manifested as a dip in the differential conductance (dI/dV) below the characteristic temperature 'Tg'. When encountering external pressure, T<sub>g</sub> and g increment gradually, reflecting the increasing trend of quantum entangled hybridization between the Ce 4f moment and conducting electrons. Differently, the superconducting energy gap and its transition temperature display a maximum value, producing a dome-shaped graph under pressure. see more The distinct pressure dependencies of the two quantum states suggest a diminished role for the pseudogap in the formation of SC Cooper pairs, controlled instead by Kondo hybridization, and demonstrating a novel form of pseudogap in CeCoIn5.
Future magnonic devices, operating at THz frequencies, find antiferromagnetic materials with their intrinsic ultrafast spin dynamics to be ideal candidates. Current research prioritizes the examination of optical approaches to generate coherent magnons efficiently in antiferromagnetic insulators. Spin-orbit coupling in magnetic lattices possessing orbital angular momentum generates spin dynamics through the resonant excitation of low-energy electric dipoles, like phonons and orbital resonances, which interact with the spins. Still, in magnetic systems lacking orbital angular momentum, microscopic pathways for the resonant and low-energy optical excitation of coherent spin dynamics are not readily apparent. An experimental examination of the relative efficacy of electronic and vibrational excitations for achieving optical control of zero orbital angular momentum magnets is detailed, concentrating on the antiferromagnet manganese phosphorous trisulfide (MnPS3) made up of orbital singlet Mn²⁺ ions. Our study focuses on the correlation of spins with two excitation types within the band gap. One involves an orbital excitation of a bound electron, transitioning from the singlet ground state of Mn^2+ to a triplet orbital, leading to coherent spin precession. The other is a vibrational excitation of the crystal field, creating thermal spin disorder. Our investigation identifies orbital transitions within magnetic insulators, composed of centers with null orbital angular momentum, as crucial targets for magnetic control.
Short-range Ising spin glasses, in equilibrium at infinite system size, are considered; we prove that, for a specific bond configuration and a chosen Gibbs state from an appropriate metastable ensemble, each translationally and locally invariant function (such as self-overlaps) of a single pure state contained within the Gibbs state's decomposition displays the same value across all the pure states within that Gibbs state. see more We detail a number of substantial applications for spin glasses.
A measurement of the c+ lifetime, determined absolutely, is reported using c+pK− decays within events reconstructed from Belle II data collected at the SuperKEKB asymmetric electron-positron collider. see more A total integrated luminosity of 2072 inverse femtobarns was observed in the data sample, which was gathered at center-of-mass energies close to the (4S) resonance. The precise measurement, (c^+)=20320089077fs, encompassing both statistical and systematic uncertainties, stands as the most accurate to date, aligning with prior measurements.
Crucial to the success of both classical and quantum technologies is the process of extracting useful signals. Conventional noise filtering methods rely on variations in signal and noise patterns across frequency and time domains, but their reach is limited, especially in quantum sensing methodologies. We advocate a signal-nature-dependent method, not a signal-pattern-driven one, to isolate a quantum signal from its classical noise. This method leverages the system's inherent quantum characteristics.