物理最新文献

Ground-level ozone is a major air pollutant whose concentrations are influenced by meteorological conditions and other air pollutants. Understanding the causal relationships among ozone, meteorological variables, and other air pollutants is important for two reasons: (1) accurate prediction and forecasting and (2) effective air quality management. This study employs a combination of Granger causality testing, cross-correlation analysis, multiple linear regression, deep NARMAX modelling, and structural equation modelling to investigate the causal and time-lagged effects of meteorological and anthropogenic factors on ozone formation and depletion. A five-year dataset of hourly measurements of ozone, other air pollutants, and meteorological parameters is analysed for Craiova, Romania, to identify the dominant drivers of ozone variability. The results provide a basis for developing improved predictive models and offer insights into the delayed effects of air pollutants and weather conditions on urban ground-level ozone concentrations, supporting informed strategies for air quality management.

In this article, we investigate the bound orbits of the timelike particles and the gravitational waveforms emitted from these orbits around a renormalization group improved Kerr black hole in the framework of the asymptotic safety approach. The running Newton coupling in the metric is characterized by two free quantum parameters ((omega ,,gamma )) arising from the non-perturbative renormalization group theory and the appropriate cutoff identification, respectively. As expected, the radii of the horizon, the marginally bound orbits and the innermost stable orbit are all decrease as the quantum parameters increase. Under the extreme mass-ratio inspirals approximation the deviation of gravitational waveforms radiated by the periodic orbits from those in the classical Kerr background increases with the two quantum parameters. However, this effect is much smaller in the retrograde case compared to the prograde case. Especially, by comparing the characteristic strain of those gravitational wave with the sensitivity curve of several potential detectors, we find that their characteristic frequencies can fall within the sensitivity ranges of several planned gravitational wave observatories, suggesting that such signals may be detectable with sufficient instrumental sensitivity.

Microfluidics technology, as an emerging method for cell/microparticle manipulation, offers advantages such as low cost, simplicity, and high efficiency. In previous research, we developed multi-channel swirl microfluidic chips that enabled various manipulation functions, including particle capture, transfer, assembly, sorting, and enrichment. To achieve more precise control of microparticle, this paper investigates the relationship between microparticle’s physical properties and manipulation performance based on a two-microchannel swirl microfluidic chip. First, we conduct physical mechanisms analysis to reveal the force applied to microparticle in a swirl. We analyze the correlation between microparticle parameters and manipulation performance, specifically the capture time and post-capture angular velocity. Additionally, we establish a predictive model between these variables. The results show that the model can achieve bidirectional predictions between microparticle property and manipulation performance, with a mean squared error of less than 0.01. This study introduces data-driven to enrich the traditional approaches of microfluidic chips for particle manipulation and analysis. The results provide guidance for advanced microfluidic chips.

Graphical Abstract

This paper investigates the relationship between microparticle’s physical properties and manipulation performance based on a two-microchannel swirl microfluidic chip. We analyzed the correlation between particle parameters and their manipulation performance, specifically the capture time and post-capture rotational angular velocity. This study introduces data-driven and machine learning, enriching the traditional approaches of microfluidic chips for particle manipulation and analysis. The results provide guidance for manipulating particles in microfluidic chips and offer valuable insights for future applications in biosensors, biomedicine, and chemistry research.

We produce the gravitational waveforms for the extreme mass ratio inspiral systems (EMRIs) of binary stars moving around central supermassive black hole (SBH), or called B-EMRIs. We calculate the external orbits of the binary stars via the commonly used Hamilton–Jacobi (HJ) approach, and calculate the internal orbits of the binary stars via Lagrangican approach. To improve accuracy we adopt the quadrupole-octupole expression of gravitational wave (GW) and study the contribution of radiation reaction. Compared to the waveforms of EMRIs, there are higher frequency oscillations superposed on the waveforms of B-EMRIs. We perform frequency spectrum analysis of the GW waveforms, and find that higher frequency signals give their prominency in the waveforms of B-EMRIs. To obtain high precise result for future observation of GWs from space-based detector, we take into account gravito-electromagnetic (GEM) force, and compare the waveforms of B-EMRIs with GEM effects against those of B-EMRIs without GEM effects and against those of EMRIs. The result of mismatch shows that the waveforms of B-EMRIs are credibly distinguishable by the space-based GW detectors when GEM force is considered.

In this paper, we investigate the dynamical evolution of the innermost stable circular orbit and light ring of a charged black hole under the influence of scalarization dynamics. This is achieved through a series of nonlinear simulations within the framework of the Einstein–Maxwell-dilaton theory. By combining these nonlinear simulations with a (3+1) approach to geodesics in the dynamical spacetime, we derive the conditions for determining the ISCO and light ring in such a dynamical spacetime. Our results demonstrate how the ISCO and light ring evolve as a ‘hairless’ charged black hole transitions to a scalarized state. Moreover, we find that black hole scalarization leads to an increase in the areal radii of both the ISCO and light ring. These findings provide new insights into black hole scalarization, particularly concerning the dynamical evolution of the ISCO and light ring in a dynamically evolving spacetime.

Owing to their unique nonlinear dynamical characteristics, discrete memristive chaotic systems have received extensive attention in recent years. In this study, a two-dimensional discrete memristive chaotic system with non-equidistant initial value offset boosting characteristics (2D-NDMS) is constructed, and its dynamical distribution and spectral entropy complexity are systematically analyzed. The study finds that in the process of increasing the offset of initial values, the system exhibits alternating offsets between two non-equidistant regions, accompanied by local abnormal offset behavior during region switching. Further analysis of the system's evolution from transient chaos to steady state reveals the existence of dual-channel transient chaotic paths, which eventually converge to the same non-connected stable attractor. In terms of engineering applications, this study implements the chaotic attractor of the system on the STM32 hardware platform and applies it to the design of a pseudorandom number generator, with the generated sequences passing the NIST tests. Furthermore, the system is applied to image encryption, and the security of the encryption system is evaluated from multiple perspectives.

This research offers a thorough analysis of the non-classical features associated with cavity radiation produced by a combination of superposed non-degenerate three-level lasers and non-degenerate subharmonic light beams. The Q-functions of the individual light beams are utilized to derive the Q-function for the superposed cavity radiation. From this derived Q-function, we analyze the expectation values of operators. Using the relevant expectation values (correlations) of these operators, we calculate the quantum discord for the superposed cavity light beams being studied. The results indicate that quantum discord increases with the linear gain coefficient and atomic coherence, while it decreases with the parameter (gamma ) and population inversion, (xi ). Although the trends of forward and backward quantum discord are generally similar, it is distinctly observed that the forward quantum discord is consistently less than the backward quantum discord. The variation in quantum discord observed in the forward and reverse processes is primarily linked to the differences in the mean photon numbers of mode-a and mode-b within the non-degenerate three-level laser system. Additionally, a juxtaposition of quantum discord with entanglement, evaluated through the Logarithmic Negativity criterion, reveals that the quantum discord associated with the superposed cavity radiation remains above the Logarithmic Negativity level. Nonetheless, for certain values of (gamma ) exceeding 0.3, quantum discord may fall below the Logarithmic Negativity threshold. This observation underscores the notion that quantum discord is a significant aspect of entanglement. Through the application of quantum discord and the Logarithmic Negativity criterion, it is established that the superposed non-degenerate cavity radiation manifests quantum properties and entanglement.

We investigate the evolution and formation of double-layered vacuum bubbles during cosmological phase transitions with multiple vacua. We employ lattice simulations to show that flyover transitions can produce double-layered vacuum bubbles by overcoming successive potential barriers, thereby suggesting a novel bubble vacuum configuration in cosmological phase transitions. The evolution of these bubbles, including wall acceleration, collisions, and the formation of trapped regions, is explored through numerical simulations. Our results show that the dynamics of double-layered bubbles differ significantly from standard single-wall bubbles, with implications for cosmological observables such as gravitational wave production and baryogenesis.

Studying heavy-quark hadrons is crucial due to the nonperturbative nature of low-energy QCD, with Heavy-Quark Symmetry (HQS) serving as a key framework for understanding their spin and flavor symmetries. However, a key issue is that the theoretically expected (B^{(*)}bar{K}) molecular states have not yet been observed, although they are considered the bottom-quark counterparts of the observed (bar{D}^{(*)}bar{K}) molecular states (corresponding to (D_{s0}(2317/2460)^{-})), which challenges the universality of HQS. The main goal of this work is to search for the theoretically predicted (Bbar{K}) and (B^{*}bar{K}) molecular states, namely (B_{s0}^{*}(5725)) and (B_{s1}^{*}(5778)), via the reactions (K^{-}p rightarrow varLambda _{b}^{0} B_{s0}^{*}) and (K^{-}p rightarrow varLambda _{b}^{0} B_{s1}^{*}). Within an effective Lagrangian framework, we compute the relevant cross sections, considering t-channel (B^{(*)}) exchanges and (K^{-}p) initial-state interactions (ISI). The results show that the production cross sections of (B_{s0}^{*}(5725)) and (B_{s1}^{*}(5778)) can reach the order of 0.01 nb, and we suggest that experiments searching for (B_{s0}^{*}(5725)) are best performed at (P_{K^{-}} = 12.18~textrm{GeV}), while higher energies are most favorable for producing (B_{s1}^{*}(5778)). The ISI play a crucial role, as they not only significantly enhance the production cross sections of (B_{s0}^{*}(5725)) and (B_{s1}^{*}(5778)) (by roughly one order of magnitude) but also markedly affect the angular distributions of the produced particles. We also calculated the production cross sections of the conventional quark–antiquark states (B_{s0}^*(5700)) and (B_{s1}^*(5720)), which are found to be nearly the same as those of (B_{s0}^{*}(5725)) and (B_{s1}^{*}(5778)). Although their internal structures remain ambiguous, these results can inform future experimental searches at CERN and J-PARC.

The integrability or non-integrability of a spacetime usually refers to whether the motion of massive or massless particles in the spacetime is integrable or not. The standard black hole spacetimes such as the Schwarzschild and Kerr metrics are always integrable for both timelike and null geodesics. They belong to a first type of spacetime. However, the Melvin type spacetimes as a second type of spacetime are non-integrable, regardless of whether they are for massive or massless particle motion. In this paper, we discover the possibility of a third type of spacetime with non-integrable dynamics of timelike geodesics and integrable dynamics of null geodesics. In fact, conformal transformations may transform type one solutions into type three. This is due to the conformal factors preventing the separation of variables from the Hamilton–Jacobi equation and leading to the absence of a fourth constant of motion for the massive particle dynamics. Nevertheless, the massless particle motion still remains integrable in these metrics for any conformal factors because the conformal factors have no effect on the null geodesics whatsoever. The conformal Kerr metric is an example of the third type of spacetime. In addition to the conformal transformation method, other paths may yield the third type of spacetime. The Kerr–Bertotti–Robinson black hole metric and the accelerating Schwarzschild spacetime are two examples of non-conformal solutions that are also of type three.