Three-level System Research Articles

Noise classification in three-level quantum networks by Machine Learning

Abstract We investigate a machine learning based classification of noise acting on a small quantum network with the aim of detecting spatial or multilevel correlations, and the interplay with Markovianity. We control a three-level system by inducing coherent population transfer exploiting different pulse amplitude combinations as inputs to train a feedforward neural network. We show that supervised learning can classify different types of classical dephasing noise affecting the system. Three non-Markovian (quasi-static correlated, anti-correlated and uncorrelated) and Markovian noises are classified with more than $99\%$ accuracy. On the contrary, correlations of Markovian noise cannot be discriminated with our method. Our approach is robust to statistical measurement errors and retains its effectiveness for physical measurements where only a limited number of samples is available making it very experimental-friendly. Our result paves the way for classifying spatial correlations of noise in quantum architectures.

Exploring Photon-Number-Encoded High-dimensional Entanglement from a Sequentially Excited Quantum Three-Level System

Exploring Photon-Number-Encoded High-dimensional Entanglement from a Sequentially Excited Quantum Three-Level System

Fast and robust production of quantum superposition states by the fractional shortcut to adiabaticity

The fractional shortcut to adiabaticity (f-STA) for the production of quantum superposition states is proposed firstly via a three-level system with a Λ-type linkage pattern and a four-level system with a tripod structure. The fast and robust production of the coherent superposition states is studied by comparing the populations for the f-STA and the fractional stimulated Raman adiabatic passage (f-STIRAP). The states with equal proportions can be produced by fixing the controllable parameters of the driving pulses at the final moment of the whole process. The effects of the pulse intensity and the time delay of the pulses on the production process are discussed by monitoring the populations on all of the quantum states. In particular, the spontaneous emission arising from the intermediate state is investigated by the quantum master equation. The result reveals that the f-STA exhibits superior advantages over the f-STIRAP in producing the superposition states.

Double Resonance of Electromagnetically Induced Transparency of Rydberg Atom in Counter-Propagating Configuration

The double resonance phenomenon of EIT is studied through the ladder three-level Rydberg system. A probe laser with the wavelength λp=852.35 nm is used to coupling the ground state 6S1/2 to the middle state 6P3/2, and a coupling laser with the wavelength λc=509.08 nm is implemented to couple the state 6P3/2 to the Rydberg state 62D5/2. A special optical scheme is designed, in which the co-propagating and counter-propagating configurations are both used. As a result, the double resonance of electromagnetically induced transparency (EIT) with the Rydberg atom is observed. By comparing the distance between the double peaks, it is found that the double resonance phenomenon comes from the Doppler effect, and the distance between the two resonance peaks in the absorption spectrum is related to the detuning of the resonant lasers.

Superposition of standing waves induced ultra high-resolution atom localization

Abstract In this study, we have theoretically demonstrated ultra-high resolution two-dimensional atom localization within a three-level $\lambda$-type atomic medium via superposition of asymmetric and symmetric standing wave fields. Our analysis provides understanding into the precise spatial localization of atomic positions at the atomic level, utilizing advanced theoretical approaches and principles of quantum mechanics. The dynamical behavior of a three-level atomic system is thoroughly analyzed using the density matrix formalism within the realm of quantum mechanics. A theoretical approach is constructed to describe the interaction between the system and external fields, specifically a control field and a probe field. The absorption spectrum of the probe field is thoroughly examined to clarify the spatial
localization of the atom within the proposed configuration. We have theoretically investigated that symmetric and asymmetric superposition phenomena significantly influence the localized peaks within a two-dimensional spatial domain. Specifically, the emergence of one and two sharp localized peaks has been observed within a region of one wavelength domain. We observed notable influences of the intensity of the control field, probe field detuning, and decay rates on atom localization. Ultimately, we have achieved an unprecedented level of ultra-high resolution and precision in localizing an atom within an area smaller than λ/35×λ/35. These findings hold promise for potential applications in domains such as Bose-Einstein condensation, nanolithography, laser cooling, trapping of neutral atoms, and the measurement of center-of-mass wave-functions.

Autler-Townes splitting and linear dichroism in colloidal CdSe nanoplatelets driven by near-infrared pulses.

Coherent interaction between light fields and matter has led to many exotic physical phenomena, one of which is the Autler-Townes splitting originating from the optical Stark effect of a three-level system. It has been well documented for atoms, molecules, and low-dimensional, epitaxial-grown semiconductors but rarely for solution-processed samples. Here, we report on Autler-Townes splitting observed in CdSe nanoplatelets. The strong intersubband transition of these nanoplatelets situated in the near-infrared allows us to coherently drive it with femtosecond near-infrared pulses, and meanwhile, their strong interband transition in the visible records the resultant spectral changes. The splitting is most prominent with cross-polarized, linear pump-probe pulses, consistent with the orthogonal polarizations of interband and intersubband transition dipoles. When the nanoplatelets are driven from tilted incident angles, we observe anomalous spectral lineshapes arising from a competition between interband and intersubband drivings, which are nevertheless quantitatively captured by our dressed-state model simulation.

Accelerating quantum information transfer in a three-level system via a specified intermediate Hamiltonian

Abstract We propose a general approach to speed up quantum adiabatic processes for fast quantum information transfer in a three-level system. In the approach, by using an intermediate Hamiltonian which is assumed to be formed by the original Hamiltonian H 0 ( t ) and its counterdiabatic driving Hamiltonian H cd ( t ) with a simple linear relationship, we design exact dynamics following the eigenstates of the intermediate Hamiltonian to speed up the desired population processes. We apply the present approach to a three-level system to show that by suitably choosing the parameters, not only the population processes could be sped up, but also the existence of the undesired off-diagonal terms, the populations of the intermediate states, and even the shapes of the pulses would be controllable in the speeding up scheme.

Supernormal Temperature Sensing Performance Realized through the Blue Emitting Level of Er3+ along with Detection Ability in Deep Tissues.

Fluorescence intensity ratio (FIR)-type optical thermometers based on thermally coupled energy levels (TCLs) of rare earth ions are suitable candidates for noncontact temperature detection in living organisms, microelectronics apparatus, and so forth. Therefore, the improvement of the thermometric sensitivity of TCL-based thermometers has become a research hotspot in recent years. Herein, ultrahigh sensitivity and outstanding resolution for temperature sensing have been realized in YNbO4: Yb3+/Er3+. Unusually, the thermally coupled three-level system of Er3+: 4F7/2/2H11/2/4S3/2 is first employed for optical thermometry based on FIR technology. A supernormal thermometric sensitivity of 2.67% K-1 is obtained from the thermally coupled 4F7/2 and 4S3/2 states due to the large energy gap between them, significantly surpassing that of most temperature sensors in the same category. Furthermore, the existence of the intermediate level 2H11/2 can effectively prevent the decoupling effect between 4F7/2 and 4S3/2. Additionally, the temperature sensing behavior realized by the Stark sublevels of the Er3+: 4I13/2 → 4I15/2 transition, with a penetration depth of 8 mm, shows the potential of temperature measurement in deep biological tissues, benefiting from its excitation and emission wavelengths located in the biological window. All of the data reveal that YNbO4: Yb3+/Er3+ is an ultrasensitive optical thermometer and exhibits the capacity of temperature detection in deep tissues.

Исследование многоуровневых моделей управления вагонопотоками в адрес припортовых станций с применением теории дифференциальных уравнений

Purpose: To consider the issue of sustainability of multi-level control systems for car flows to port railway stations in the conditions of intellectualization of transportation management processes. To assess the influence of three-level and two-level control systems for the operational work of port roads on the quality of planning the supply of trains to port stations under various modes of operational operation of railways. Determine the conditions for the stability of the car flow control system by constructing and studying the corresponding hard and soft mathematical models described by autonomous systems of ordinary linear differential equations. Methods: In this study, the methods of the theory of stability of solutions of differential equations, as well as the theory of control and dynamical systems are used. A phase space is used in a visual representation, a qualitative and quantitative analysis of the behavior of phase trajectories in it is performed, corresponding to undisturbed and perturbed solutions of systems of differential equations describing the constructed models of control systems. Results: A comparison of the characteristics of multistage car traffic control systems is given. A study of the stability of multilevel models of car traffic management in the context of the intellectualization of management functions is proposed. In the environment of the analytical computing system, the conditions of asymptotic stability in time of a two-level wagon traffic control system are found and studied. Practical importance: The results obtained by computational experiment make it possible to assess the stability of the functioning of port-side transport and technological systems in the context of changes in the organization of production and the intellectualization of transportation management processes. Computer mathematics systems make it possible to implement the heuristic component of research and obtain theoretically sound and visual solutions to problems of optimizing cargo and wagon traffic control modes.

Microplastic transport and ecological risk in coastal intruded aquifers based on a coupled seawater intrusion and microplastic risk assessment model

Seawater-groundwater interactions can enhance the migration process of microplastics to coastal aquifers, posing increased associated environmental risks. Here, we aim to analyze the relationship between seawater intrusion (SWI) and groundwater microplastic pollution in Laizhou Bay (LZB), which is a typical area of sea-land interactions. The results showed that modern seawater intrusion was the main process controlling the migration of microplastics. The detected microplastics in the study area showed a migration pattern from nearshore marine areas to groundwater aquifers along the SWI direction. In addition, the microplastics also reached the brine formed by palaeo-saltwater intrusion through hydraulic exchange between aquifers. By comparing the spatial distributions of different microplastic parameters, we found that nearshore fisheries, commercial, tourism, textile, and agricultural activities were the main sources of microplastics in groundwater in the study area. A risk assessment model of microplastics associated with SWI was further optimized in this study using a three-level classification system by assigning appropriate weights to different potential influencing factors. The results showed moderate comprehensive ecological risks associated with microplastics from seawater intrusion in the study area, with high microplastic enrichment risks. This study provides a scientific basis for future research on seawater-groundwater interactions and microplastic pollution in coastal regions.

Electromagnetically induced grating via amplitude and phase modulations in a three-level V-type atomic medium

Abstract A probe laser beam can be completely absorbed in an atomic resonance frequency region, however, if a coupling laser beam is further applied to the atom, the atomic medium can exhibit electromagnetically induced transparency (EIT), i.e, the probe beam can be completely transmitted through the atomic medium. Thus, if the coupling beam is a standing wave field with nodes and antinodes, it will cause in space a periodic modulation of the transmitted spectrum of the probe field. This means that the probe field propagates through the atomic medium just as it passes through a diffraction grating which is called electromagnetically induced grating (EIG). Based on amplitude or phase modulation of transmission function, the absorption grating or the phase grating can be formed, respectively. In this work, based on controllable absorption and dispersion properties of a three-level V-type atomic system, we study the control of the absorption grating and the phase grating with respect to the intensity and the frequency of the laser fields. The absorption diffraction pattern at the two-photon resonance is obtained, while the phase diffraction pattern appears when there is a frequency shift of either the coupling frequency or the probe frequency compared to the corresponding atomic resonance frequency. By adjusting the coupling or/and probe laser frequency, the absorption grating can be converted into the phase grating and the high-order diffraction efficiency can also be improved.

THE ORIGIN OF ACADEMIC WRITING STYLE IN KAZAKH LINGUISTICS

It is well known, that academic writing becomes an independent branchof Kazakh linguistics and covers not onlyscientific texts’ writing, as well as all types of written work performed in secondaryschools, special and higher educational institutionsthat areincluded in the academic writing discourse’sscope. In this article we determine the foundations for the development and formation of this field based on the domestic scientists’ worksby conducting the empirical research. The aim of the article isa review of works in the field of stylistics to determine the factors that influenced to the emergence of academic writing in the educational space of our countryand to identify its branching out as a separate scientific style.Theoretical significance of the article contributes to the formation of the foundations and theory of academic writing development in the country, as well as the history of the formation, research of academic writing in Kazakh science. Furthermore, in order to highlight the prerequisitesfor the formation of academic discourselanguage, issues of language terminology arediscussedin presented article.The article is of great practical importance, because the results obtained in the article can be used in a three-level education system (bachelor, master and doctoral) in universities, in teaching students entering into written communication in a new integrated environment.

Deriving Three-Outcome Permutationally Invariant Bell Inequalities.

We present strategies to derive Bell inequalities valid for systems composed of many three-level parties. This scenario is formalized by a Bell experiment with N observers, each of which performs one out of two possible three-outcome measurements on their share of the system. As the complexity of the set of classical correlations prohibits its full characterization in this multipartite scenario, we consider its projection to a lower-dimensional subspace spanned by permutationally invariant one- and two-body observables. This simplification allows us to formulate two complementary methods for detecting nonlocality in multipartite three-level systems, both having a complexity independent of N. Our work can have interesting applications in the detection of Bell correlations in paradigmatic spin-1 models, as well as in experiments with solid-state systems or atomic ensembles.

Risk Categories for Discharge Planning Using AM-PAC "6-Clicks" Basic Mobility Scores in Non-Surgical Hospitalized Adults.

Early discharge planning is important for safe, cost-effective, and timely hospital discharges.Patients with deconditioning are at risk for prolonged lengths of stay related to discharge needs. Functional mobility outcome measures are associated with discharge disposition. The purpose of this study is to examine the clinical usefulness of risk categories based on the Activity Measure for Post-Acute Care (AM-PAC) "6-clicks" Basic Mobility (6cBM) scores on predicting discharge destination. A retrospective cohort study of 3739 adults admitted to general medical units at an urban, academic hospital between January 1, 2018 and February 29, 2020 who received at least twophysical therapy visits and had an AM-PAC 6cBM recorded within 48 hours of admission and before discharge. The outcome variable was discharge destination dichotomized to post-acute care facilities (PACF); inpatient rehabilitation, skilled nursing facility, or subacute rehabilitation) or home (with or without home care services). The predictor variables were 6cBM near admission and discharge. Logistic regression was used to estimate the odds of being discharged to PACF compared to home, based on the Three-level risk categorization system: (a) low (6cBM score > 20), (b) moderate (6cBM score 15-19), or (c) high (6cBM score < 14) risk. Analysis indicated important differences between the three risk categories in both time periods. Based on 6cBM at admission, patients in the high-risk category were nine times more likely to be discharged to PACF than those in the low-risk category. At discharge, those in the high-risk category were 29 times more likely to go to PACF than those in the low-risk category. Other characteristics differentiating patients who went to PACF were sex (males), age (older) and longer hospitalization. Predicting risk for discharge to a PACF using risk categories based on AM-PAC 6cBM can be useful for early discharge planning.

An Investigation of Parturient Ocular Appearance in Sows.

Protocols that enable prompt identification of sows in need of assistance during farrowing are important for optimal production outcomes. Change in the colour and appearance of the sclera of the eye can indicate increased stress. This warrants investigation into its use for the identification of sows in need of assistance at the time of parturition. To this end, a three-level ocular scoring system for the pig was devised and subsequently used in a preliminary investigation into the relationship between farrowing kinetics and visual changes in the sclera at farrowing. Data were collected and analysed from twenty randomly selected Large White × Landrace crossbred sows during farrowing. It was determined that sows with a severe ocular score were more likely to experience a prolonged farrowing duration (p = 0.013) and incur increased parturient straining of either total straining time (p = 0.011) or straining per piglet (p = 0.025). There was a significant association between ocular score and litter size (p = 0.043). Ocular score was not associated with sow parity (p = 0.728) and inter-piglet interval (p = 0.075). The proposed three-level scoring system successfully identified sows experiencing an abnormal parturition as defined by a prolonged farrowing duration and increased straining time. Findings from this study suggest the potential application of this simple ocular scoring tool for identifying sows experiencing an abnormal farrowing via in-person application or integration into remote monitoring systems in the future.

In Situ Subwavelength Microscopy of Ultracold Atoms Using Dressed Excited States

In this work, we implement a new method for imaging ultracold atoms with subwavelength resolution capabilities and determine its regime of validity. It uses the laser-driven interaction between excited states to engineer hyperfine ground-state population transfer in a three-level system on scales much smaller than the optical resolution. Subwavelength imaging of a quantum gas is atypical in the sense that the measurement itself perturbs the dynamics of the system. To avoid induced dynamics affecting the measurement, one usually “rapidly” measures the wave function in a so-called strong imaging regime. We experimentally illustrate this regime using a thermal gas ensemble, and demonstrate subwavelength resolution in quantitative agreement with a fully analytical model. Additionally, we show that, counterintuitively, the opposite weak imaging regime can also be exploited to reach subwavelength resolution. As a proof of concept, we demonstrate that this regime is a robust solution to select and spatially resolve a 30-nm-wide wave function, which was created and singled out from a tightly confined one-dimensional optical lattice. Using a general dissipation-included formalism, we derive validity criteria for both regimes. The formalism is applicable to other subwavelength methods. Published by the American Physical Society 2024

Bifunctional acoustic lossy coupler for broadband power splitting and absorption

In this work, we propose a bifunctional acoustic lossy coupler for broadband power splitting and absorption. Following the three-level system in quantum physics, the three-waveguide (WG) acoustic system is proposed to obtain efficient energy transfer behaviors. Given the agreement in form between Schr o¨ dinger equation and coupled mode equation, the time-dependent external fields are mapped into space-varying coupling actions between adjacent WGs. The propagation paths of the incident waves can be predicted by Schr o¨ dinger-like equation, which are verified by numerical simulations and experimental measurements. Owing to the different responses to lossy medium in WG B for WG A incidence and WG C incidence, the acoustic coupler can be considered as a broadband power splitter and muffler by selecting different input ports. Meanwhile, according to the reversibility of acoustic path, a switchable acoustic logic gate with functions of “OR” and “XOR” is constructed as well by taking advantage of the lossless adiabatic coupler, and the function can be controlled conveniently by reversing the phase of input waves from WG A or C. Our work provides a new scheme for the design of bifunctional acoustic coupler, which may have a profound impact on the development of non-resonance acoustic high-performance devices.

A Multi-Center Study on the Implementation and Challenges of Nursing Three-Level Ward Rounds in Tertiary Hospitals in Shanxi Province.

The "Key Points of the Core System of Medical Quality and Safety" (hereinafter referred to as the "Key Points") was promulgated by the National Health Commission of China in 2018, requiring that nursing ward rounds should be carried out with reference to the three-level ward round system; In 2020 and 2022 editions of the "Evaluation Standards for Tertiary Hospitals", which were implemented in China, required that nursing ward rounds should be carried out with reference to the "Key Points". Additionally, the Action Plan for Comprehensively Improving Medical Quality (2023-2025) also mentions the need to improve the quality of three-level ward rounds. However, there are no detailed guidelines regarding implementing "Nursing Three-level Ward Rounds". This study aimed to investigate the current situation of nursing three-level ward rounds in tertiary hospitals after the promulgation of the "Key Points of the Core System of Medical Quality and Safety" to provide insights and guidelines regarding relevant standards, so as to better implement of the requirements of "nursing ward rounds" in the "Evaluation Standards for Tertiary Hospitals" and "improving the quality of three-level ward rounds" in the "Action Plan". A multi-center study was conducted in February 2024, including all tertiary public hospitals in the Shanxi Province, China. A questionnaire survey using the self-designed "Questionnaire on the Implementation of Nursing Three-level Ward Rounds" was carried out. The questionnaire included the basic information of the hospital and the implementation of the three-level (namely I, II, and III) rounds (including "five aspects": ward round personnel, object, content, frequency, and record), which is expressed by quantity and composition ratio. Next is the text analysis method. First, the "five aspects" of the hospital that filled in the questionnaire survey with "nursing three-level ward rounds have been carried out" were assessed. Second, the five aspects of each hospital were assessed for consistency with the "Nursing Three-level Ward Rounds System" (hereinafter referred to as the "System") of their respective hospitals.Third, the consistency of the "System" of the hospital with the "Key Points" was assessed. The results of the analysis of the former are expressed in terms of quantity and composition ratio; the results of the latter two were analyzed using Fisher's exact test method to compare any differences. Notably, 14 of the 67 tertiary public hospitals (20.9%) carried out nursing three-level ward rounds. There were 4-10 situations in the five aspects of I, II, and III ward rounds filled in by the hospitals. The five aspects of the I, II, III ward rounds in 14 hospitals were significantly comparable with the "System", which, in turn, was comparable with the "Key Points" (P < 0.05). Not all tertiary public hospitals in the Shanxi Province have not all carried out nursing three-level ward rounds. Furthermore, the five aspects of the hospitals that carried out nursing three-level ward rounds were not entirely consistent in terms of ward round personnel, object, content, frequency, and record. The filling in of the nursing three-level ward rounds carried out by the hospitals is inconsistent with the respective "System"; the "System" of the hospital is not in line with the "Key Points". Nursing administrators should be aware of the newly issued norms and requirements in their workplace, and revise the relevant systems in accordance with the norms and requirements in a timely manner. Additionally, the revision of the system should cover the core requirements of the norms and be practicable. The system should be supervised to ensure that 100% of the implementation is in accordance with the system.

Tax potential of municipalities as the basis of regional budgets

In the Russian Federation (hereinafter referred to as RF, Russia), which is a federal state with a three-level budget system, it is assumed that there is tax potential at all levels: federal, regional, and local. With the help of taxes, the financial basis of local governments is formed and the socio-economic development of municipalities is ensured. In developed countries, municipal budgets are formed mainly from the taxes assigned to them. In Russia, they continue to remain the most problematic link in the country’s budget system. The purpose of the article is to study the influence of the taxes assigned to local budgets on the formation of the tax potential of the municipalities. Objectives are the following: analysis and assessment of revenues of the Russian local budgets in dynamics, justification of directions for increasing the tax potential. The methodological basis of the research is founded on a systematic approach, within which the following methods have been used: analysis and synthesis, generalisation, grouping, tabular method, etc. The research has found that over the past years, with the introduction of the Tax Code of the RF, problems of insufficient tax and non-tax revenues remain for most municipalities, low level of the tax potential and predominance of interbudgetary transfers in their budgets are current. Due to the increasing centralisation of the tax revenues, the degree of dependence of the municipalities on the federal centre is high. Without actually enhancing the tax potential of the municipalities, the development of the regional economy is impossible. The re -search results can be used in practice when developing economic policy for municipal development.

Data quality control system and long-term performance monitor of LHAASO-KM2A

The KM2A is the largest sub-array of the Large High Altitude Air Shower Observatory (LHAASO). It consists of 5216 electromagnetic particle detectors (EDs) and 1188 muon detectors (MDs). The data recorded by the EDs and MDs are used to reconstruct primary information of cosmic-ray and gamma-ray showers. To ensure the reliability of the LHAASO-KM2A data, a three-level quality control system has been established. It is used to monitor the status of detector units, stability of reconstructed parameters and the performance of the array based on observations of the Crab Nebula and Moon shadow. This paper will introduce the control system and its application on the LHAASO-KM2A data collected from August 2021 to July 2023. During this period, the pointing and angular resolution of the array were stable. From the observations of the Moon shadow and Crab Nebula, the results achieved using the two methods are consistent with each other. For example, according to the observation of the Crab Nebula with KM2A at energies from 25 TeV to 100 TeV, the time averaged pointing errors are estimated to be −0.003°±0.005° and 0.001°±0.006° in the R.A. and Dec directions, respectively.