Classical Level Research Articles

Classification of classical spin liquids: Detailed formalism and suite of examples

The hallmark of highly frustrated systems is the presence of many states close in energy to the ground state. Fluctuations between these states can preclude the emergence of any form of order and lead to the appearance of spin liquids. Even on the classical level, spin liquids are not all alike: they may have algebraic or exponential correlation decay, and various forms of long wavelength description, including vector or tensor gauge theories. Here, we introduce a classification scheme, allowing us to fit the diversity of classical spin liquids (CSLs) into a general framework as well as predict and construct new kinds. CSLs with either algebraic or exponential correlation-decay can be classified via the properties of the bottom flat band(s) in their soft-spin Hamiltonians. The classification of the former is based on the algebraic structures of gapless points in the spectra, which relate directly to the emergent generalized Gauss's laws that control the low-temperature physics. The second category of CSLs, meanwhile, are classified by the fragile topology of the gapped bottom band(s). Utilizing the classification scheme we construct new models realizing exotic CSLs, including one with anisotropic generalized Gauss's laws and charges with subdimensional mobility, one with a network of pinch-line singularities in its correlation functions and a series of fragile topological CSLs connected by zero-temperature transitions. Published by the American Physical Society 2024

Quantum cosmology in teleparallel gravity with a boundary term

We quantize a homogeneous and isotropic universe for two models of modified teleparallel gravity: one wherein an arbitrary function of the boundary term, namely B, is present in the action, and in the other model, a scalar field that is non-minimally coupled to both the torsion and boundary term. In this regard, we study exact solutions of both the classical and quantum frameworks by utilizing the corresponding Wheeler–DeWitt (WDW) equations of the models. To correspond to the comprehensive classical and quantum levels, in the second model, we propose an appropriate initial condition for the wave packets and observe that they closely adhere to the classical trajectories and reach their peak. We quantify this correspondence using the de Broglie–Bohm interpretation of quantum mechanics. According to this proposal, the classical and Bohmian trajectories coincide when the quantum potential vanishes along the Bohmian paths. Furthermore, we apply the de-parameterization technique to our model in the realm of the problem of time in quantum cosmological models based on the WDW equation, utilizing the global internal time denoted as χ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\chi $$\\end{document}, which represents a scalar field.

Inflationary Krylov complexity

In this work, we have systematically investigated the Krylov complexity of curvature perturbation for the modified dispersion relation in inflation, using the algorithm in closed system and open system. Since many quantum gravitational frameworks could lead to this kind of modified dispersion relation, our analysis could be applied to the string cosmology, loop gravity, e.t.c. Following the Lanczos algorithm, we find the very early universe is an infinite, many-body, and maximal chaotic system. Our numerics shows that the Lanczos coefficient and Lyapunov index of the standard dispersion relation are mainly determined by the scale factor. As for the modified case, it is nearly determined by the momentum. In a method of the closed system, we discover that the Krylov complexity will show irregular oscillation before the horizon exits. The modified case will present faster growth after the horizon exists. Since the whole universe is an open system, the approach of an open system is more realistic and reliable. Then, we construct the exact wave function which is very robust only requiring the Lanczos coefficient proportional to n (main quantum number). Based on it, we find the Krylov complexity and Krylov entropy could nicely recover in the case of a closed system under the weak dissipative approximation, in which our analysis shows that the evolution of Krylov complexity will not be the same with the original situation. We also find the inflationary period is a strong dissipative system. Meanwhile, our numerics clearly shows the Krylov complexity will grow during the whole inflationary period. But for the small scales, there will be a peak after the horizon exits. Our analysis reveals that the dramatic change in background (inflation) will significantly impact the evolution of Krylov complexity. Since the curvature perturbation will transit from the quantum level to the classical level. We could expect that the decoherence will highly impact the Krylov complexity during inflation.

Noncommutative spaces for parafermions

We introduce ringed spaces, referred to as para-manifolds, whose non-commutative nilpotent coordinates naturally describe parafermions at the classical level in a similar way as Grassmann variables describe usual fermions. Given a supermanifold X, we construct a family of para-manifolds X(p) for positive integers p, such that X(1) recovers the supermanifold itself. A differential analysis on para-manifolds is developed, which can be readily applied to model physical problems. Two classes of para-manifolds, respectively corresponding to X being affine superspaces and projective superspaces, are treated in detail as examples. Green's theory of parafermions is reformulated in terms of para-manifolds.

Classical versus quantum features of the Berthelot cosmological model

In this paper, we compare and contrast the classical versus quantum dynamics of a cosmological model based on the literature (Modified) Berthelot equation of state for the description of the dark sector of the universe. At the classical background level we identify a Minkowski-like and a de Sitter-like equilibrium epochs, with the latter occurring only beyond a certain threshold for a parameter in the equation of state; at the classical perturbed level we find that this same parameter realizes a duality in the adiabatic speed of sound between the two equilibrium epochs. The quantum evolution of this model is studied in the context of quantum geometrodynamics by solving analytically the Wheeler–DeWitt equation in the Born–Oppenheimer approximation for the scalar field potentials about the two equilibrium epochs. We identify the phenomenon of quantum decoherence to arise at the same threshold which constitutes the bifurcation between the two equilibrium epochs at the classical level. We comment on the quantum modified power spectrum focusing on some consequences dealing with the formation of astrophysical structures within the Press–Schechter framework. Our paper is intended to scrutinize which classical features of a certain cosmological model are preserved at its quantum level, and under which assumptions.

On the nature of two-photon transitions for a collection of molecules in a Fabry-Perot cavity.

We investigate the effect of a cavity on nonlinear two-photon transitions of a molecular system and we analyze how such an effect depends on the cavity quality factor, the field enhancement, and the possibility of dephasing. We find that the molecular response to strong light fields in a cavity with a variable quality factor can be understood as arising from a balance between (i) the ability of the cavity to enhance the field of an external probe and promote multiphoton transitions more easily and (ii) the fact that the strict selection rules on multiphoton transitions in a cavity support only one resonant frequency within the excitation range. Although our simulations use a classical level description of the radiation field (i.e., we solve Maxwell-Bloch or Maxwell-Liouville equations within the Ehrenfest approximation for the field-molecule interaction), based on experience with this level of approximation in the past studies of plasmonic and polaritonic systems, we believe that our results are valid over a wide range of external probing.

Penerapan Pembelajaran Daring pada Kompetensi Dasar Pembuatan Bolero/Rompi Siswa Kelas XI Tata Busana 1 di SMK Negeri 8 Surabaya

The advancement of information and communication technology today can influence the development of education, one of which is through online learning. Online learning can be utilized by teachers and students anytime and anywhere. This research aims to describe: 1) the feasibility of implementing online learning using Google Classroom, Google Meet, and WhatsApp Group on the Basic Competencies of Making Bolero/Vest for 11th-grade students in Fashion Design 1 class at State Vocational High School 8 Surabaya, and 2) students' learning outcomes through the implementation of online learning. This research is descriptive in nature and was conducted at State Vocational High School 8 Surabaya in the Fashion Design 1 class, focusing on the subject of custom-made fashion garment production, specifically the competence of making bolero/vest, during September - October of the 2020/2021 academic year. The number of respondents was 35 students. Data collection methods included observation and assessment of bolero/vest products. The research instruments used were observation sheets and product assessment rubrics. Data analysis was conducted descriptively by calculating the average observation results and categorizing values between complete and incomplete. The research results indicate: 1) the feasibility of learning conducted over 4 meetings shows that the WhatsApp Group application was used during the opening of the lesson, Google Classroom was used in the opening and core learning activities, and Google Meet was used in the core and closing parts. The observation results of the feasibility of learning with the application of Google Classroom, Google Meet, and WhatsApp Group on the basic competencies of making bolero/vest for 11th-grade students in Fashion Design 1 class at State Vocational High School 8 Surabaya are categorized as very good, with an average score of 84, and 2) the learning outcomes of students, where 28 students were declared complete and 7 students were declared incomplete. The classical learning completeness level reached 80%, exceeding the school's KKM (Minimum Mastery Criteria) standard of >76%.

Universal Definition of the Nonconformal Trace Anomaly.

We show that there exists a generalized, universal notion of the trace anomaly for theories which are not conformally invariant at the classical level. The definition is suitable for any regularization scheme and clearly states to what extent the classical equations of motion should be used, thus resolving existing controversies surrounding previous proposals. Additionally, we exhibit the link between our definition of the anomaly and the functional Jacobian arising from a Weyl transformation.

Label-based meta-analysis of functional brain dysconnectivity across mood and psychotic disorders

BackgroundResting-state functional magnetic resonance imaging (rsfMRI) studies have revealed patterns of functional brain dysconnectivity in psychiatric disorders such as major depression disorder (MDD), bipolar disorder (BD) and schizophrenia (SZ). Although these disorders have been mostly studied in isolation, there is mounting evidence of shared neurobiological alterations across them. MethodsTo uncover the nature of the relatedness between these psychiatric disorders, we conducted an innovative meta-analysis of dysconnectivity findings reported separately in MDD, BD and SZ. Rather than relying on a classical voxel level coordinate-based approach, our procedure extracted relevant neuroanatomical labels from text data and examined findings at the whole brain network level. Data were drawn from 428 rsfMRI studies investigating MDD (158 studies, 7429 patients/7414 controls), BD (81 studies, 3330 patients/4096 patients) and/or SZ (223 studies, 11,168 patients/11,754 controls). Permutation testing revealed commonalities and differences in hypoconnectivity and hyperconnectivity patterns across disorders. ResultsHypoconnectivity and hyperconnectivity patterns of higher-order cognitive (default-mode, fronto-parietal, cingulo-opercular) networks were similarly observed across the three disorders. By contrast, dysconnectivity of lower-order (somatomotor, visual, auditory) networks in some cases differed between disorders, notably dissociating SZ from BD and MDD. ConclusionsFindings suggest that functional brain dysconnectivity of higher-order cognitive networks is largely transdiagnostic in nature while that of lower-order networks may best discriminate between mood and psychotic disorders, thus emphasizing the relevance of motor and sensory networks to psychiatric neuroscience.

Quantum system ascribed to the Oppenheimer–Snyder model of massive stars

We quantize the Oppenheimer–Snyder model of black holes using the integral quantization method. We treat spatial and temporal coordinates on the same footing at both the classical and quantum levels. Our quantization resolves or smears the singularities of the classical curvature invariants. Quantum trajectories with bounces can replace singular classical trajectories. The considered quantum black hole may have finite bouncing time. As a by-product, we obtain the resolution of the gravitational singularity of the Schwarzschild black hole at the quantum level.

Eternal inflation and collapse theories

The eternal inflation problem continues to be considered one of standard's cosmology most serious shortcomings. This arises when one considers the effects of “quantum fluctuations” on the zero mode of inflaton field during a Hubble time in the inflationary epoch.In the slow-roll regime it is quite clear that such quantum fluctuations could dwarf the classical rolling down of the inflaton, and with overwhelming probability this prevents inflation from ever ending. When one recognizes that quantum fluctuations can not be taken as synonymous of stochastic fluctuations, but rather intrinsic levels of indefiniteness in the quantities in question, one concludes that the eternal inflation problem simply does not exist. However, the same argument would serve to invalidate the account for the generation of the primordial seeds of cosmic structure as has been amply discussed elsewhere [1,2,3]. In order to do address that issue, one must explain the breaking of homogeneity and isotropy of the situation prevailing during the early inflationary epoch (at both the quantum and classical levels of the description). For that one needs to rely on some additional element, beyond those present in the traditional treatments. The so called spontaneous collapse theories offer a viable candidate for that element, namely the stochastic and spontaneous state reduction characteristic of those proposals possesses the basic features to break those symmetries. In fact, a version of the CSL theory adapted to the cosmological context has been shown to offer a satisfactory account for the origin the seeds of cosmic structure with an adequate power spectrum [2], and will serve as the basis of our analysis. However, once such stochastic collapse is introduced into the theoretical framework the eternal inflation problem has the potential reappear.In this manuscript we explore those issues in detail and discuss an avenue that seems to allow for a satisfactory account for the generation of the primordial inhomogeneities and anisotropies while freeing the theory from the eternal inflation problem.

A Project to Collect and Study the Language of a Group of Contemporary Tihama Al-Hijaz Tribes

A project aimed at collecting and studying the language of a group of contemporary Tihama tribes in the Hijaz, namely: Fahm tribe, Hudhayl tribe, and Banu Kinana (Al-Jahadla). These tribes inhabit the southern region of Makkah al-Mukarramah in the western part of the Kingdom of Saudi Arabia and reside in close proximity, despite the scattered nature of their homes, as indicated by demographic and geographical studies. Renowned for their eloquence, these tribes' language holds significant importance in contemporary linguistic research. The project is structured around two main aspects, each branching into secondary auxiliary facets: firstly, gathering linguistic material used by the mentioned tribes in various daily life situations and communication contexts, and secondly, conducting a linguistic study on the phonetic, morphological, grammatical, and semantic levels based on the collected field data. The research addresses a fundamental problem: monitoring linguistic phenomena in the study sample to answer key questions such as the roots of these phenomena in the classical level of Arabic, their developmental trajectory, and the pathways they traversed to attain their present-day usage. The study yielded crucial results, notably the abundance of morphological phenomena within the tribes, with some maintaining their traditional form while others have evolved. These variations appear in patterned forms in the contemporary dialects of the study environment. The research also revealed the presence of phenomena influenced by multiple linguistic sources. Emphasizing the significance of linguistic geography in achieving planned results, the study recommends further scientifically valuable research in the realm of applied linguistics. Additionally, it suggests that specialized research centers and language academies focus on dialects within the realms of first eloquence.

Giant retroperitoneal liposarcoma with spread to the upper third of the left thigh

Background. Large tumors, such as giant liposarcoma, are a challenge for modern medicine because of difficulty of treatment and possible impact on functions of the adjacent tissues and organs. The review of this clinical case may help develop new strategies and approaches to treatment of similar pathologies. Purpose. Review of the clinical case has a goal to educate medical specialists and students by helping to expand their understanding of rare oncologic diseases and to prove high effectiveness of surgery in locally advanced types of retroperitoneal liposarcomas using the clinical case as an example. Materials and methods. Female patient C., 56 years old, sought for medical help in the clinical unit of State Organization «Grigoriev Institute for Medical Radiology and Oncology of the National Academy of Medical Sciences of Ukraine» in June 2021. The following diagnosis was established: retroperitoneal liposarcoma with spread to the left thigh, St. II–ІІІ сТ3N0M0. An en-bloc surgery (removal of the retroperitoneal tumor with mobilization of the left ureter, intraabdominal removal of the thigh part of the tumor of the left thigh from beneath the inguinal ligament) was performed after the standard preoperative preparation. The surgery went without complications. The wound healed primarily. The follow-up period of the patient was 16 months. Clinical laboratory examination did not show any local recurrences and distant metastases. Results. For retroperitoneal sarcoma, the goal of surgery is to achieve the complete resection of the tumor (R0). Partial removal (R2) tumor should be strongly avoided, as this has been demonstrated to have higher recurrence risk and a detrimental effect on oncologic outcomes. The tumor involvement of organs and structures does necessitate concomitant resection. Resection of one or more adjacent organs is carried out in 58–87% of all cases of primary RPS. Most commonly, ipsilateral nephrectomy and partial colectomy are also performed. In cases of hypothetical necessity of removing all adjacent organs, an extended or compartmental approach to resection is recommended. The main idea is to resect not only evidently affected organs but also surfaces to obtain circumferential «soft tissue margins». This approach is controversial but data from some sarcoma care centers in Italy and France indicate its effectiveness. Conclusions. Treating RPS in specialized centers of oncosurgery with surgical planning based on CT and MRI data is of vital importance, especially using assessment by related surgical specialists. In large RPS, achieving a classic R0 resection level is a challenge, even in a compartmental approach, therefore division of resections into R2 and R0/R1 is reasonable. The choice of approach determines success of the surgery due to the narrowness of the surgical field.

A novel aeroengine real-time model for active stability control: Compressor instabilities integration

Developing a high-confidence entire aeroengine model that accurately incorporating unstable modes is imperative for advancing active stability control. This paper proposes a real-time model for the active stability control of aeroengines, which integrates the compressor's instability into the classical component level model (CLM). Firstly, the principles of CLM and modeling methods for inlet distortion, compressor instability dynamics, and air injector are introduced. Then, the collaborative relationship between the compressor and the other engine's components are studied to construct a real-time model with coupled instability mechanisms, involving the extension of compressor characteristics and the parameters matching between various instability models and the CLM. Finally, simulation cases under multiple unstable modes are set up to verify the effectiveness of the model, and standard instability detection algorithms are employed to confirm the confidence of the unstable signals generated by the model. The results show that the proposed model effectively captures the dynamic characteristics of stall and surge, as well as the steady-state and dynamic simulation capabilities during full operating range. Besides, it can also simulate the impact of the inlet distortion and the air injection on compressor stability. The pulsating characteristics of pressure signals and the variations of performance parameters of the model during stall and surge are highly consistent with the real test data. Moreover, the model achieves a single-step run time of no more than 7.16 ms on the embedded platform, fulfilling real-time requirements. Consequently, the model can serve as a foundation for verifying three critical aspects of active stability control: instability detection, practical actuator, and feedback control algorithms.

Restoring strong cosmic censorship in Reissner–Nordström–de Sitter black holes via non-minimal electromagnetic-scalar couplings

We investigate whether the Strong Cosmic Censorship (SCC) Conjecture can be reinstated at the classical level in Reissner–Nordström–de Sitter (RNdS) black holes by introducing non-minimal couplings between the electromagnetic and scalar fields in Einstein–Maxwell-scalar (EMS) theory. By conducting numerical calculations, we find that the SCC can be restored within a specific range of the coupling constant. Notably, for a given value of the cosmological constant, there exists a critical coupling constant above which the EMS theory satisfies the SCC. These findings suggest that the non-minimal couplings between the electromagnetic and scalar fields may play a crucial role in the restoration of the SCC in RNdS spacetime. Additionally, under negative coupling constants, the low-lying modes of nearly extremal black holes exhibit β>1,\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\beta > 1,$$\\end{document} enabling C2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$C^2$$\\end{document} extensions beyond the Cauchy horizon and intensifying the violation of the SCC.

Flipbook Sebagai Media untuk Meningkatkan Keterampilan Menulis Kembali Teks Non-fiksi pada Peserta Didik Kelas 5 Sekolah Dasar

Writing is the most complex language skill, because writing skills involve proficiency in language selection, pouring logical and structured ideas. Writing skills in grade 5A students of SD Negeri Jomblangan are still relatively low. The purpose of this study is to improve the skills of rewriting nonfiction texts using flipbook media. This research uses Classroom Action Research, which consists of two cycles and consists of four main steps, namely planning, implementation, observation and reflection. Data collection techniques in this research include interviews, observation, tests, and documentation. Data analysis used quantitative and qualitative descriptive. The research results showed that, as seen in each research cycle, the skills of class 5 A students in rewriting nonfiction texts were improved by using flipbook media. The average score of students in cycle I rewriting nonfiction texts was 68.03 with a classical completeness level of 53.57%. In cycle II there was an increase in value, namely 79.82 with a classical completion level of 82.14%. For activities in cycle I, students obtained a score of 67.19% and in cycle II it increased to 90.63%. The conclusion of this research is that students in class 5 A of Jomblangan State Elementary School can effectively improve their skills in rewriting nonfiction texts using flipbook media.

Improving Skill Indonesian language in 4th grade Elementary School Students of the Macro Role Playing Approach

Through the use of role-playing, this study seeks to improve 4th-grade pupils' command of the Indonesian language. Students from SDN 1 Waringin in the fourth grade make up the research subjects. The role-playing technique is expected to enhance students' command of the Indonesian language, according to the study's action hypothesis. The study, which was conducted as a classroom action research project, spans three cycles. The outcomes show that the role-playing method can successfully increase students' command of Indonesian vocabulary, as indicated by their (1) better and fluent pronunciation of vocabulary, and (2) improved comprehension and application of vocabulary, progressing with each cycle. The following findings may be taken from the conducted research and discussion regarding the application of the macro role-playing learning approach to increase Indonesian vocabulary among 4th grade students at SDN 1 Waringin: The implementation of the macro role-playing learning method can enhance learning outcomes in the subject of Indonesian language, specifically in the material of student interviews for 4th-grade students in Waringin. The research findings indicate that in Cycle I, the average class score was 74.5, although it had not yet reached the defined classical mastery level of 80%, achieving a classical mastery percentage of 75%. Meanwhile, in Cycle II, there was an increase in the average class score to 86.75, with a classical mastery rate of 92%.Bagian Atas Formulir

The Effectiveness of Web-Based Comic Media to Train Students' Creative Thinking Skills in Learning Immune System Materials

The purpose of this study is to determine the effectiveness of web-based immune system comic media that has been previously developed through a development research process. This research is a pre-experimental study with typesone group pretest-posttest design. The sample of this research was students of class XI MIPA 1, XI MIPA 5, and XI MIPA 6 in one of the high schools in Purworejo. The sampling technique that was adopted in this research was cluster random sampling, involving 107 students as the total sample. In this study the learning process of the immune system material held by using web-based immune system comic media. The research data is in the form of students' creative thinking skills, types of activities in comics and their benefits for practicing creative thinking skills, and data on the implementation of teaching and learning processes. The data collection method was carried out by giving students formative tests (comic gap questions and description questions), observation sheets, and student response questionnaires. Descriptive qualitative method was used to analyze to obtained data. The research results show that creative thinking skills (could be known from the N-gain score). Student those who achieved moderate and high N-gain categories were 83% and 14% respectively (3% of students achieved low N-gain categories). The classical completeness level is 87.8%. This shows > 75% of students have achieved KKM (with good category). Based on the results of observing the learning process using comics, the information showed that the learning process that was carried out was useful to train creative thinking skills on students and the teaching and learning process can be carried out according to the RPP. The conclusion of this research is that web-based immune system comic media is effective for training students' creative thinking skills.

Realization of Dirac quantization in loop quantum gravity

The system of gravity coupled to the non-rotational dust field is studied at both classical and quantum levels. The scalar constraint of the system can be written in the form of a true physical Hamiltonian with respect to the dust time. In the framework of loop quantum gravity, the scalar constraint is promoted to two versions of well-defined operators in a suitable Hilbert space of the coupled system, such that the physical Hamiltonian can become some symmetric operators. By the deparametrized form, a general expression of the solutions to either of the quantum scalar constraints is obtained, and the observables on the space of solutions can be constructed. Thus, the Dirac quantization procedure can be fully carried out in loop quantum gravity by this system.

The impact of household structure on disease-induced herd immunity

The disease-induced herd immunity level h_D is the fraction of the population that must be infected by an epidemic to ensure that a new epidemic among the remaining susceptible population is not supercritical. For a homogeneously mixing population h_D equals the classical herd immunity level h_C, which is the fraction of the population that must be vaccinated in advance of an epidemic so that the epidemic is not supercritical. For most forms of heterogeneous mixing h_D<h_C, sometimes dramatically so. For an SEIR (susceptible rightarrow exposed rightarrow infective rightarrow recovered) model of an epidemic among a population that is partitioned into households, in which individuals mix uniformly within households and, in addition, uniformly at a much lower rate in the population at large, we show that h_D>h_C unless variability in the household size distribution is sufficiently large. Thus, introducing household structure into a model typically has the opposite effect on disease-induced herd immunity than most other forms of population heterogeneity. We reach this conclusion by considering an approximation {tilde{h}}_D of h_D, supported by numerical studies using real-world household size distributions. For n=2, 3, we prove that {tilde{h}}_D>h_C when all households have size n, and conjecture that this inequality holds for any common household size n. We prove results comparing {tilde{h}}_D and h_C for epidemics which are highly infectious within households, and also for epidemics which are weakly infectious within households.