Questions In Physics Research Articles

Intermolecular correlations of liquid and glassy CS2 studied by synchrotron radiation x-ray diffraction.

How is the orientation of molecular liquids ordered on cooling? What are the basic structures of molecular glasses, e.g., close to the crystalline structure or some special structures such as icosahedral cluster? These are long-standing questions in liquid and glass physics. We have constructed a novel cryostat to prepare simple molecular glasses by vapor deposition and performed in situ synchrotron radiation x-ray diffraction experiments. The glassy state of a simple molecule CS2, which cannot be vitrified by normal liquid quenching, was successfully prepared with this instrument, and its diffraction data were collected in a wide Q-range of 0.16-25.7 Å-1 with a high-energy diffractometer at BL04B2, SPring-8. The diffraction data of liquid CS2 were also recorded in a wide temperature range of 160-300K. These diffraction data were analyzed with molecular dynamics simulations and reverse Monte Carlo modelings to investigate orientational correlation. From the obtained 3D structure models, the orientational correlation between neighboring CS2 molecules was investigated quantitatively as a function of temperature. At room temperature, the parallel and T-shaped arrangements are preferred for the nearest neighbor correlation. On cooling, these arrangements are developed gradually, and its rate became prominent below the melting temperature (162K). In the glassy state, the slipped-parallel arrangement is dominant as well as the T-shaped arrangement. Both arrangements appear in the CS2 crystal, indicating that the structure of glassy CS2 is close to that of crystalline CS2.

A muon–ion collider at BNL: The future QCD frontier and path to a new energy frontier of [formula omitted] colliders

We propose the development and construction of a novel muon–ion collider (MuIC) at Brookhaven National Laboratory (BNL) in the USA as an upgrade to succeed the electron–ion collider (EIC) that is scheduled to commence in the early 2030s, by a joint effort of the nuclear and particle physics communities. The BNL facility could accommodate a muon storage beam with an energy up to about 1 TeV with existing magnet technology. When collided with a 275 GeV hadron beam, the MuIC center-of-mass energy of about 1 TeV will extend the kinematic coverage of deep inelastic scattering physics at the EIC (with polarized beams) by more than an order of magnitude in Q2 and x, opening a new QCD frontier to address many fundamental scientific questions in nuclear and particle physics. This coverage is comparable to that of the proposed Large Hadron–Electron Collider (LHeC) at CERN, but with complementary lepton and hadron kinematics, ion species, and beam polarization. Additionally, the development of a MuIC at BNL will focus the worldwide R&D efforts on muon collider technology and serve as a demonstrator toward a future muon–antimuon collider at O(10) TeV energy, which is an attractive option to reach the next high energy frontier in particle physics at an affordable cost and a smaller footprint than a future circular hadron collider. We discuss here the possible design parameters of the MuIC, kinematic coverage, science cases, and detector design considerations including resolution estimates on DIS kinematic variables. A possible road map toward the future MuIC and muon–antimuon colliders is also presented.

Investigating unprompted and prompted diagrams generated by physics majors during problem solving

Diagrams are ubiquitous in physics, especially in physics education and physics problem solving. Physics problem solvers may generate diagrams to orient to a scenario, to organize information, to directly obtain an answer, or as a tool of communication. In this study, we asked 19 undergraduate and graduate physics majors to answer 18 multiple-choice (MC) physics questions and then complete six diagramming tasks of situations similar to six of the MC problems: the MC problems contained no prompting regarding diagrams, while the diagramming tasks explicitly asked participants to carefully generate diagrams. This prompting placed participants in one of two epistemic frames, problem solving or communicating, which allowed us to explore which elements and features the students include (or not) in diagrams generated when students are working within these two frames. By comparing students’ spontaneously generated diagrams to their prompted diagrams, we found differences in size, accuracy, and amount of detail in unprompted problem-solving diagrams and prompted communicating diagrams. We also looked at correlations between the presence and features of unprompted diagrams with participants’ answer choice. Looking at the different cohorts (e.g., lower-division undergraduate and graduate students), we found that the differences in diagramming between cohorts were generally smaller than the differences within a cohort. We also explore implications for teaching and research.4 MoreReceived 16 June 2021Accepted 20 December 2021DOI:https://doi.org/10.1103/PhysRevPhysEducRes.18.010104Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasResearch methodologyScientific reasoning & problem solvingPhysics Education Research

Planck Speed: the Missing Speed of Physics? Absolute Still Without Breaking Lorentz Symmetry!


 
 
 Today, the speed of light is one of the cornerstones of modern physics. It is the maximum speed limit for transferring information, and plays a very central role in relativity theory. It also seems to be the same as the assumed and measured speed of gravity (gravitons and/or gravitational waves). We are not questioning the speed of light, as we indeed think it is the maximum speed limit and that it is identical to the speed ofgravity, but we also think photons lead us to a second speed limit, which we will term the Planck speed. Photon-photon collisions are part of modern physics, but what is not discussed is the speed of two photons during the very moment of a photon-photon collision. How can photons move during a collision? Or, assumea photon is reflected by a mirror; to do so it must collide with the building blocks of the mirror, yet how can it be moving during the very collision point? Also, modern physics assumes mass can be created in a photon-photon collision. We suggest this mass is the Planck mass particle and that it only lasts one Planck time, so when two photons collide, we will claim they must stand still for the direct observer. That is, we suggest thatthe speed of the Planck mass particle is always zero, but that this zero-velocity can only last for one Planck time. That it only lasts one Planck time means it will not break with the relativity principle or Lorenz symmetry, or at least what we can call weak Lorentz symmetry. We will show that the missing Plank mass particle is the very collision point between two photons, and that this is fully in line with predictions in other researchers’ findings in relation to the possible photon mass. This new view seems to solve the missing mass-gap, and seems able to unify gravity with quantum mechanics. This again seems to unify photons with mass, because one of the long-outstanding questions in physics is whether photons have mass or not. In addition, we showhow to find, in a very simple way directly from gravitational observations, lp/tp= cg = c, which is the upper speed limit (the speed of light and gravity) independent of any knowledge of G or ~ or c.
 
 

Singlet fermion dark matter and Dirac neutrinos from Peccei-Quinn symmetry

The Peccei-Quinn (PQ) mechanism not only acts as an explanation for the absence of strong CP violation but also can play a main role in the solution to other open questions in particle physics and cosmology. Here we consider a model that identifies the PQ symmetry as a common thread in the solution to the strong CP problem, the generation of radiative Dirac neutrino masses and the origin of a multicomponent dark sector. Specifically, scotogenic neutrino masses arise at one loop level with the lightest fermionic mediator field acting as the second dark matter (DM) candidate thanks to the residual $Z_2$ symmetry resulting from the PQ symmetry breaking. We perform a phenomenological analysis addressing the constraints coming from the direct searches of DM, neutrino oscillation data and charged lepton flavor violating (LFV) processes. We find that the model can be partially probed in future facilities searching for WIMPs and axions, and accommodates rates for rare leptonic decays that are within the expected sensitivity of upcoming LFV experiments.

Impact of a science and technology strategy on the learning of physics

The use of smartphones and some applications for educational purposes are valuable tools in the laboratory since they are motivating for students and the teacher can take advantage of this advantage for the teaching of physics. The experience is based on the anthropological theory of didactics and the teaching approach in science, technology, engineering, and mathematics. It is proposed to investigate a trigger question in physics. To respond, an application is used that uses the smartphone’s sensors to record the simulation data. The experience is described, and results of its implementation are presented. Methodologically, a qualitative descriptive approach was used in a group of tenth grade students taking the physics course. Finally, it is concluded that the students felt motivated since they felt they participated in the construction of their own learning, supported using technologies that facilitate the integration of knowledge in physics.

Galactic and extragalactic sources of very high energy gamma rays

Very high energy $$\gamma $$ -rays are one of the most important messengers of the relativistic non-thermal Universe. The major motivation of very high energy $$\gamma $$ -ray astronomy is to find sources of high energy cosmic rays. Several astrophysical sources are known to accelerate cosmic rays to very high energies under extreme conditions. Very high energy $$\gamma $$ -rays are produced at these astrophysical sites or in their vicinity through interactions of cosmic rays in the surrounding medium close to the sources. Gamma rays, being neutral, travel in a straight line and thus give us valuable information about the cosmic ray sources and their surroundings. Additionally, very high energy $$\gamma $$ -ray astronomy can probe many fundamental physics questions. Ground-based $$\gamma $$ -ray astronomy began its journey in 1989 when Whipple telescope detected TeV $$\gamma $$ -rays from the Crab, a pulsar wind nebula in our galaxy. In the last 2 decades, technological improvements have facilitated the development of the latest generation of very high energy detectors and telescopes which have delivered exciting new results. Until now, over two hundred very high energy $$\gamma $$ -ray sources, both galactic and extra-galactic, have been detected. These observations have provided a deeper insight into a large number of important questions in high energy astrophysics and astroparticle physics. This review article is an attempt to enumerate the most important results in the exciting and rapidly developing field of very high energy $$\gamma $$ -ray astronomy.

Determining the Neutrino Mass Eigenstates and the Effective Majorana Mass

This paper aims at solving several open questions in current neutrino physics: the neutrino mass hierarchy, the Dirac CP violating phase, the absolute mass of neutrinos, the nature of neutrinos (Dirac or Majorana), the Majorana matrix and the absolute value of the effective Majorana neutrino mass. In the research presented in this paper, we have shown that the precise definition of the mass splittings between neutrino mass eigenstates, done in the latest analysis of experimental data, can be of crucial importance for defining the nature of neutrino mass hierarchy. The Standard Model has three generations of fundamental matter particles. Three generations of the charged lepton mass show a hierarchical structure: mτ > mμ > me. Owing to that, there is a belief and it is considered that neutrinos may follow such hierarchical structure. In our calculations, we have also included the latest data obtained, based on the processing of measurement results, which showed that even with such data, obtained results favor the normal neutrino mass hierarchy. As for the individual neutrino mass calculated in this paper, in today’s neutrino physics it is only known that neutrino mass scale is bounded only from above, and both the Dirac and the Majorana character of neutrinos are compatible with all observations. Among some of the questions resolved in this paper, which are related to the properties of neutrinos, a positive answer was also given to the question of whether light neutrinos are self-conjugate particles or not.

Probing the neutrino mass scale with the KATRIN experiment

The absolute mass scale of the neutrino is one of the most fundamental open questions in contemporary particle physics, with implications from particle theory to cosmology. Through precision measurements of beta-decay kinematics, the KATRIN experiment probes the neutrino mass with unprecedented sensitivity.

Comments on Physics and Basic Physics questions in 2022 Common Test for University Admissions

Comments on Physics and Basic Physics questions in 2022 Common Test for University Admissions

Answer to January 2022 Figuring Physics Question

Answer to January 2022 Figuring Physics Question

Investigation of the background in coherent J/ψ production at the EIC

Understanding various fundamental properties of nucleons and nuclei are among the most important scientific goals at the upcoming Electron-Ion Collider (EIC). With the unprecedented opportunity provided by the next-generation machine, the EIC might provide definitive answers to many standing puzzles and open questions in modern nuclear physics. Here we investigate one of the golden measurements proposed at the EIC, which is to obtain the spatial gluon density distribution within a lead ($Pb$) nucleus. The proposed experimental process is the exclusive $J/\psi$ vector-meson production off the $Pb$ nucleus - $e+Pb\rightarrow e'+J/\psi+Pb'$. The Fourier transformation of the momentum transfer $|t|$ distribution of the coherent diffraction is the transverse gluon spatial distribution. In order to measure it, the experiment has to overcome an overwhelmingly large background arising from the incoherent diffractive production, where the nucleus $Pb'$ mostly breaks up into fragments of particles in the far-forward direction close to the hadron-going beam rapidity. In this paper, we systematically study the rejection of incoherent $J/\psi$ production by vetoing products from these nuclear breakups - protons, neutrons, and photons, which is based on the BeAGLE event generator and the most up-to-date EIC Far-forward Interaction Region design. The achieved vetoing efficiency, the ratio between the number of vetoed events and total incoherent events, ranges from about 80% - 99% depending on $|t|$, which can resolve at least the first minimum of the coherent diffractive distribution based on the Sar$\it{t}$re model. Experimental and accelerator machine challenges as well as potential improvements are discussed.

Analysis of Physical Education Study Final Test Questions during the Pandemic Period in Class VIII of SMP Negeri 3 Bengkulu Tengah

This study aims to find out how the UAS questions in physical education lessons are made by sports teachers at SMP Negeri 3 Bengkulu Tengah. This research is a qualitative research. The subjects in this study were sports teachers who made UAS questions in class VII. The instruments in this research are content validity test instruments and construct validity tests. The results of the study show that the questions made by the sports teacher at SMP Negeri 3 in Central Bengkulu have not been said to be good. Because the teacher is not consistent in making questions for example in the content validity test. It is said on the grid of questions that are contained in the indicators totaling 10 but in fact only 5 items are contained in the indicators, and it is also said on the grid of questions that are contained in indicators from No. 1-10 while in fact on questions of No. 26 – 30 . on the items that are not contained in the lattice indicators totaling 25 items. Analysis of the questions on the construct validity test on the rules of writing a good question at No. 14 which contains each question must use language that is in accordance with the rules of the Indonesian language. In the problems analyzed, the researchers found that the writing on foreign language words was not italicized.

Spiral high-speed scanning tunneling microscopy: Tracking atomic diffusion on the millisecond timescale

Scanning tunneling microscopy (STM) is one of the most prominent techniques to resolve atomic structures of flat surfaces and thin films. With the scope to answer fundamental questions in physics and chemistry, it was used to elucidate numerous sample systems at the atomic scale. However, dynamic sample systems are difficult to resolve with STM due to the long acquisition times of typically more than 100 s per image. Slow electronic feedback loops, slow data acquisition, and the conventional raster scan limit the scan speed. Raster scans introduce mechanical noise to the image and acquire data discontinuously. Due to the backward and upward scan or the flyback movement of the tip, image acquisition times are doubled or even quadrupled. By applying the quasi-constant height mode and by using a combination of high-speed electronics for data acquisition and innovative spiral scan patterns, we could increase the frame rate in STM significantly. In the present study, we illustrate the implementation of spiral scan geometries and focus on the scanner input signal and the image visualization. Constant linear and constant angular velocity spirals were tested on the Ru(0001) surface to resolve chemisorbed atomic oxygen. The spatial resolution of the spiral scans is comparable to slow raster scans, while the imaging time was reduced from ∼100 s to ∼8 ms. Within 8 ms, oxygen diffusion processes were atomically resolved.

Laser Frequency Combs with Fast Gain Recovery: Physics and Applications

AbstractThe dynamics of semiconductor lasers with fast gain is generally considered to suppress amplitude modulation, resulting in a frequency‐modulated output. Since their first demonstration of frequency comb operation, quantum cascade lasers—ideal representatives of this class of lasers with fast gain dynamics—were indeed shown to emit frequency‐modulated combs. The understanding of these frequency comb regimes has progressively evolved, being refined from simpler arguments to more advanced theories, considering the role of Kerr nonlinearity and linewidth enhancement factor. By now, the traditional frequency‐modulated combs are rather well understood in quantum cascade lasers, but new types of frequency combs have emerged, reopening interesting physics questions in these lasers. Recent advancements on two open frontiers will be discussed: harmonic frequency combs, characterized by mode skipping of many free spectral ranges, and spatiotemporal structures with solitonic features, recently reported in unidirectional ring cavities. These new types of frequency combs open technological and fundamental perspectives, sprouting new interest in quantum cascade lasers.

Impacts of mistreatment on the psychological and physical health of older adults living in sheltered homes

ObjectivesTo assess the impact of the mistreatment on psychological and physical health among older adults living in sheltered homes. MethodsThis cross-sectional study included 446 older adults living in 43 sheltered homes. The psychological effects questions screened for suicidal ideation, depression, anxiety, and sleep problems. The physical health effects questions assessed perceived physical health status and healthcare resource utilization. ResultsAll subtypes of mistreatment of older adults were associated with increased prevalence rates of anxiety symptoms, depressive symptoms, and sleep problems. Perceived poor physical health is common among older mistreated adults; it was self-reported by 74% who experienced physical mistreatment and 49% who experienced other types of mistreatment. Increased healthcare utilization was higher among older adults who experienced mistreatment. DiscussionMistreatment of older adults living in sheltered homes is associated with negative impacts on physical and psychological health, as well as increased healthcare utilization compared to those who are not mistreated.

Paradigm of Village Physical Activity During Pandemic

One of the measures to maintain body immunity in the midst of the Covid-19 pandemic is to exercise regularly. The Covid-19 virus was officially declared to have entered Indonesia by the central government since March 2020. The purpose of this research was to find out the differences in the paradigm of physical activity of the residents of Dusun XI, Pond Village, especially those aged 17 years and over, between before the Covid-19 pandemic. 19 and during the Covid-19 pandemic. The research used in the preparation of this scientific article uses quantitative methods which are presented in descriptive form. The paradigm of sports activities for the residents of Dusun XI, Pond Village, which was studied by researchers on a one-week scale, was the intensity of sunbathing, duration of sunbathing, intensity of exercise, duration of exercise, and type of exercise. The research instrument used to measure the physical activity paradigm of residents is the Short-Form version of the Physical Activity Question (PAQ), which is filled out by 50 residents via Google Form. The answers to the questions in the questionnaire which were filled out by the residents of Dusun XI, Pond Village, are the conclusions of this scientific article. The results showed that the paradigm of residents' physical activity that changed after the Covid-19 pandemic was the intensity of sunbathing, the intensity of exercise, and the type of exercise. The Covid-19 pandemic has caused the majority of the residents of Dusun XI of the Pool Village to increase their sunbathing intensity to every day, the majority of the residents of Dusun XI of the Pool Village have decreased their exercise intensity to once a week,

Al-Kindī’s Two-Volume Compendium of Aristotelian Philosophy: Al-Falsafa al-Ūlā and al-Falsafa al-Dākhila

Abstract This study argues that the first two titles listed in the bibliography of Abū Yūsuf Yaʿqūb b. Isḥāq al-Kindī (d. ca. 259/873) presented in the Fihrist of Ibn al-Nadīm (d. 380/990) – his well-known work al-Falsafa al-ūlā (First Philosophy), on metaphysics, and a lost work entitled al-Falsafa al-dākhila (Internal Philosophy) – form an intentional pair. Together, they presented an epitome of Aristotle’s collective works on philosophy, including an outline of metaphysics in al-Falsafa al-ūlā and a discussion of detailed questions of logic, physics, psychology, and metaphysics in al-Falsafa al-dākhila. Drawing primarily on al-Kindī’s work On the Quantity of Aristotle’s Books, the study suggests several emendations to the full title of al-Falsafa al-dākhila as recorded in the Fihrist of Ibn al-Nadīm.

ANALYSIS OF AVAILABILITY OF HOTS IN PHYSICS EXAM QUESTIONS AT SENIOR HIGH SCHOOL IN LIMA PULUH KOTA DISTRICT

The 2013 curriculum requires students to have thinking skills, such as Higher Order Thinking Skills (HOTS). One strategy to train students' higher-order thinking skills is to apply HOTS questions in the learning evaluation. Through evaluation, the teacher can determine the level of students' skills in higher-order thinking. Preliminary observations show that the Physics exam questions use in SHS in Lima Puluh Kota District have not identified whether it already contains HOTS in it. Therefore, the study conducts an analysis of the availability of HOTS on physics questions at SHS in Lima Puluh Kota District. This research is descriptive research with a qualitative approach. The data population in this study are all SHS in Lima Puluh Kota District. The sample in this study is six SHS in Lima Puluh Kota District. Sampling for schools carries out using the Proportionate Stratified Random Sampling technique. The research data takes using the instrument of analysis of the questions presented and collecting data through documentation. Based on the analysis, it is found that the percentage of HOTS availability on the questions for each skill is as follows. Transfer one concept to another 19.98%, process and applying information 40.50%, find connections from different kinds of information 32.23%, use the information to solve problems 36.67%, critically examine ideas and information 8 .10%. Based on these data, it can be concluded that the percentage of the availability of HOTS in physics questions for senior high schools in Lima Puluh Kota District is 27,9%, with the category of less available

Response to Comment by Shlyonsky

Dr. Shlyonsky makes some important points in his comment on my paper but perhaps misunderstands the discussion of assessments because of cultural differences. In the United States, the use of standardized assessments, or concept inventories, is quite common in introductory physics courses to measure learning gains by students (and effectiveness of teaching by instructors) through the use of pretests and posttests (1). These concept inventories are research based and standardized to allow comparison between different modes of courses in the same university or universities across the country. Their usefulness is based on a consensus among physicists of what should be included in these inventories, a consensus that is challenged by this new curriculum to make the topics more relevant to life science students. Therefore, a new concept inventory must be developed for this new curriculum.More generally, I agree with the commenter's discussion of assessments within the course itself. Physics is the primary course in which life science students learn valuable analytical skills and stands in contrast to typical modes of teaching in biology, where memorization is emphasized. At Michigan State we have continued to use written problem-based exams that utilize analytical skills, but many of the problems used in our traditional courses are no longer useful because they cover topics not included in this curriculum. It is my hope that a new library of problems will be created by instructors teaching this course here and at other universities that focus on the new topics covered, such as diffusion and entropy.As Shlyonsky has demonstrated in his own work (2), showing students how physics is integrated into real-world life science problems is a great motivator, and I wholeheartedly agree with this approach, but this curriculum demonstrates that molecular and cellular biology (MCB) topics can be even more tightly integrated into the curriculum rather than as a qualitative follow-on to a “real” physics question. For example, Shlyonsky (2) has an example of how muscle fibers are modeled by springs, including a calculation of energy produced by shivering in cold weather. We also include a similar set of problems to calculate the force in one myofibril, but we further integrate a discussion of the myosin molecule itself and the basic mechanism of the power stroke that provides the force. The terminology is presented within the problem so students are not expected to bring much prior knowledge of MCB; nor do we test their vocabulary. This deep dive requires 1–2 h of class time and demonstrates to the students that physics is not just relevant, but underlies biological phenomena they consider important.In response to the author's surprise at the elimination of certain topics, I will give a longer rationale than was feasible in the paper. First, rotation is an integral component of adenosine triphosphate (ATP) synthase function, but the topic of rotation in a traditional curriculum focuses on conservation of angular momentum. Because the ATP synthase motor operates in water, angular momentum is completely damped by the solvent, and it is difficult to see the principles of rotation in play in this example. In fact, it is difficult to observe conservation of momentum of any type in an aqueous environment (i.e., dynamics at low Reynolds number) except at the level of molecular collisions, which we cover in the discussion of diffusion. Second, the topics of electromagnetic induction and advanced circuits (direct or alternating current) have their use in biophysical methods such as electroencephalography and patch clamp techniques, but they are not intrinsic physics concepts in MCB in the same way that the potential across a membrane is. Michigan State offers advanced courses that cover such methods in detail, and I believe that the grounding the students receive in the basic ideas of electric potential and Ohm's law serves them well in mastering the methods later.