Contemporary Physics Research Articles

Scaling Green-Kubo Relation and Application to Three Aging Systems

The classical Green-Kubo formula, capturing the essential physics of particle diffusion, is one of the most fundamental important results in statistical physics, but has recently been found to be invalid for systems that never reach equilibrium. A generalization of the formula to such ``aging'' systems is provided here, laying down a new fundamental piece of contemporary statistical physics.

Measurement of parity violation in electron–quark scattering

Symmetry permeates nature and is fundamental to all laws of physics. One example is parity (mirror) symmetry, which implies that flipping left and right does not change the laws of physics. Laws for electromagnetism, gravity and the subatomic strong force respect parity symmetry, but the subatomic weak force does not. Historically, parity violation in electron scattering has been important in establishing (and now testing) the standard model of particle physics. One particular set of quantities accessible through measurements of parity-violating electron scattering are the effective weak couplings C2q, sensitive to the quarks' chirality preference when participating in the weak force, which have been measured directly only once in the past 40 years. Here we report a measurement of the parity-violating asymmetry in electron-quark scattering, which yields a determination of 2C2u - C2d (where u and d denote up and down quarks, respectively) with a precision increased by a factor of five relative to the earlier result. These results provide evidence with greater than 95 per cent confidence that the C2q couplings are non-zero, as predicted by the electroweak theory. They lead to constraints on new parity-violating interactions beyond the standard model, particularly those due to quark chirality. Whereas contemporary particle physics research is focused on high-energy colliders such as the Large Hadron Collider, our results provide specific chirality information on electroweak theory that is difficult to obtain at high energies. Our measurement is relatively free of ambiguity in its interpretation, and opens the door to even more precise measurements in the future.

Broken Symmetry and Yang–Mills Theory

From its inception in statistical physics to its role in the construction and in the development of the asymmetric Yang–Mills phase in quantum field theory, the notion of spontaneous broken symmetry permeates contemporary physics. This is reviewed with particular emphasis on the conceptual issues.

Exploring the Use of Metaphor in Communication of Contemporary Physics

The paper deals with the role of analogical and metaphorical thinking in the public communication of contemporary physics. We focus on the cognitive aspects: how to disseminate complicated formal physical concepts to a non-professional public maintaining the ‘correct’ disciplinary meaning (communication of ‘good physics’). To face the issue from the perspective of cognitive linguistics, we analyze the characterization of the generative aspect of ‘new’ meanings in the analogical and metaphorical use in order to evaluate the construction of ‘actual’ physical meaning. We investigate the research problem by analyzing a set of ‘relevant’ analogies and metaphors taken from popular science literature within the framework of conceptual metaphor. A case study is presented: Schrödinger's analogy for ‘elementary particle’.The results of the analysis suggest that the conceptual metaphor perspective might be a potential tool both to assess the quality of analogical forms used in dissemination of physics and to design new and ‘better’ analogies and metaphors. Besides, in a recursive process this analysis could help to focus on those meaningful cognitive aspects that characterize, and refine, a ‘complete’ and ‘correct’ physical conceptWe think that fruitful results of inquiry might come from a deeper interdisciplinary approach between linguistics and physics.

All was done with measure, number and weight: a story of numbers and geometry linked with contemporary physics

All was done with measure, number and weight: a story of numbers and geometry linked with contemporary physics

How Psychoanalysis is Like a Roach Motel: Better Termination Through Better Metaphors

In this article I explore how experiences I had with a former analyst are shaping my views about termination and posttreatment contact with patients. Borrowing metaphors from contemporary physics that corroborate and extend some current views of termination, I suggest ways to think about the future of an analysis. I contrast models of termination in the psychoanalytic canon and, using the lens of relational psychoanalysis, I suggest ways to think about how one might work flexibly with patients at termination, keeping in mind the relational future of the analytic dyad.

Xfel: Mighty view into microworld

European x-ray free electron laser, i.e. company and institute European XFEL GmbH (EuXFEL), represents the center point of contemporary particle physics, as well as precise, sophisticated and advanced engineering. Scientific and engineering teams work together on discovering secrets of the matter, deeper than compound, cell or molecule level. Using the technique easily described as immensely precise electronic microscope, or even better, as a never before seen digital camera, the very atomic structure is investigated, in search for answers looked by physics, biology, medicine, and recently even genetics, in last decades or even centuries. Goals of EuXFEL are altruistic, humane and turned towards knowledge, and as such, they are the perfect starting point for all those who want to know more about secrets of the micro world surrounding us, but also to take part in projects that reach engineering heights, as precise as those achieved by space technology. Place of Serbia in this project is yet to be found and defined, and it will depend solely on wishes and good will of domestic scientific and political communities, as well as on the awareness on the impact of far-reaching, long-term scientific and technological enterprises.

Super neutron-rich nuclei: Results of prospects of investigations

The production of exotic nuclei in the vicinity of the neutron drip line and the investigation of their properties are one of the most important lines of research in contemporary nuclear physics. The present article is devoted to discussing various allied issues. Methods for producing such nuclei at accelerators are described, and unusual properties of new, artificially synthesized, light nuclei are considered. New information concerning the use of beams of radioactive nuclei in various investigations, including studies in astrophysics, is presented.

O modelo atômico de Bohr e as abordagens para seu ensino na escola média

Teaching the modern and contemporary Physics subjects in high school is indispensable and it was already justified by several researchers. Among the subjects which must be taught, there is, for instance, Bohr’s Atomic Model. However, as it was noticed in literature review, many didactic materials do not deal with this model adequately, since that they do not take into account Bohr ideas, which involved Planck studies on black-body radiation, Einstein's theory on photoelectric effect, Rutherford experiences and his atomic model, and empiric results upon the spectrums of chemical elements emission. From that, it is extremely important teaching through approaches which potentialize the learning of the model proposed by Niels Bohr. On the other hand, teachers from high schools cannot have clearness about which approaches can be applied for teaching the mentioned model. Thus, it is presented some possibilities for teaching Bohr Atomics Model, with examples and justifications for the use of each one. Special treatment was attributed to the teaching of Science History and Philosophy, from the reading of scientific diffusion and original scientific texts, from analogies, from comic strips, and from computer simulations.

Axisymmetric Coulomb Interaction and Research of Its Stability by System Galactica

Indeterministic consideration of micro-world based on quantum mechanics has resulted in its probabilistic understanding. At the same time the study of the micro-world based on Coulomb interactions in some cases gives deterministic view of it. However, at this way it is necessary to solve complex problems of many particles interaction. The program Galactica have to be developed for the numerical solution with high accuracy gravitational problems of many-bodies. The paper considers a modification of the program algorithm for solution of Coulomb interaction. For integrating differential equations of motion, the initial conditions have to be given, which are determined by the geometry of the interacting particles. Since in contemporary physics the atoms geometry is not specified, as an example, their axisymmetric models are studied. They consist of positively charged nucleus and are symmetrically arranged on the plane of the electrons. The necessary tasks were solved to determine positions and velocities of particles at the initial time. Based on their results, the program in environment MathCad for creation of a file of inital conditions is developed. Using the modified program Galactica, the motion of particles in an axisymmetric structure with eight peripheral electrons is researched. It has appeared that they are unstable. For comparison, a similar problem was studied with the gravitational interaction. It also proved to be unstable. So more detailed studies of the problem of stability of axisymmetric structures were made. They showed that the stability of the structure increases with the decrease of the interaction parameters. Such stable structure with eight peripheral bodies is considered for gravitational interaction. The paper also considers an example of a helium atom at axisymmetric interaction with two peripheral electrons. This structure is also unstable. At the same time two-particle interaction on the example of the hydrogen atom, considered using the Galactica, is stable and the results of numerical solutions coincide with the exact analytical solution. The studies showed that the program Galactica can be used to research the Coulomb interactions. The paper shows that axially symmetric structure of the atom can be used to create his other geometries. The developed methods and programs may be used in these studies. In the future, they will increase the degree of determinateness of micro-world. This paper, as well as the book, will be useful to physicists, students, senior pupils and everything who are interested in the scientific worldview. The programs are the free access (http://www.ikz.ru/~smulski/GalactcW/) and can be used for student projects.

Bankrupting physics: how today's top scientists are gambling away their credibility

The recently celebrated discovery of the Higgs boson has captivated the public's imagination with the promise that it can explain the origins of everything in the universe. It's no wonder that the media refers to it grandly as the God particle. Yet behind closed doors, physicists are admitting that there is much more to this story, and even years of gunning the Large Hadron Collider and herculean number crunching may still not lead to a deep understanding of the laws of nature. In this fascinating and eye-opening account, theoretical physicist Alexander Unzicker and science writer Sheilla Jones offer a polemic. They question whether the large-scale, multinational enterprises actually lead us to the promised land of understanding the universe. The two scientists take us on a tour of contemporary physics and show how a series of highly publicized theories met a dead end. Unzicker and Jones systematically unpack the recent hot theories such as parallel universes, string theory, and inflationary cosmology, and provide an accessible explanation of each. They argue that physics has abandoned its evidence-based roots and shifted to untestable mathematical theories, and they issue a clarion call for the science to return to its experimental foundation.

As crenças de autoeficácia de professores de Física: um instrumento para aferição das crenças de autoeficácia ligadas a Física Moderna e Contemporânea

Teaching practices are governed by many factors, both internal and external to individuals that conduct their activities in the classroom. The self-efficacy beliefs, proposed by Bandura (1986), are an interesting psychological construct that help understanding of human behavior. Thus, this study aims to present a measuring instrument of self-efficacy beliefs of Physics teachers about their work on the Modern and Contemporary Physics (MCP). This instrument is a questionnaire consisting of 21 items, built on a Likert scale, which was applied to a set of 78 Physics teachers to measure their levels of self-efficacy beliefs in teaching and personal self-efficacy beliefs. Through the validation process presented by Silveira (1993) we obtained evidence that the instrument is appropriate for assessing self-efficacy beliefs in teaching and personal self-efficacy beliefs of Physics teachers concerning the MCP.

ANALYSIS OF THE SYMMETRY ENERGY IN A MICROSCOPIC APPROACH

A major goal of contemporary nuclear physics is to improve our knowledge of the nuclear matter equation of state (EoS). In particular, the EoS of isospin-asymmetric matter (that is, with unequal concentrations of protons and neutrons), is not well understood, mostly due to our limited knowledge of the symmetry energy. The latter reduces the binding energy in a nucleus with unequal number of protons and neutrons, and is crucial for understanding nuclear stability. We will review experimental, phenomenological and theoretical facts about the symmetry energy, with particular emphasis on analyzing how the various components of the nuclear force, in a microscopic model, contribute to this important quantity.

Reflections on the four facets of symmetry: how physics exemplifies rational thinking

In contemporary theoretical physics, the powerful notion of symmetry stands for a web of intricate meanings among which I identify four clusters associated with the notion of transformation, comprehension, invariance and projection. While their interrelations are examined closely, these four facets of symmetry are scrutinised one after the other in great detail. This decomposition allows us to examine closely the multiple different roles symmetry plays in many places in physics. Furthermore, some connections with others disciplines like neurobiology, epistemology, cognitive sciences and, not least, philosophy are proposed in an attempt to show that symmetry can be an organising principle also in these fields.

Toward an Efficient Prediction of Solar Flares: Which Parameters, and How?

Solar flare prediction has become a forefront topic in contemporary solar physics, with numerous published methods relying on numerous predictive parameters, that can even be divided into parameter classes. Attempting further insight, we focus on two popular classes of flare-predictive parameters, namely multiscale (i.e., fractal and multifractal) and proxy (i.e., morphological) parameters, and we complement our analysis with a study of the predictive capability of fundamental physical parameters (i.e., magnetic free energy and relative magnetic helicity). Rather than applying the studied parameters to a comprehensive statistical sample of flaring and non-flaring active regions, that was the subject of our previous studies, the novelty of this work is their application to an exceptionally long and high-cadence time series of the intensely eruptive National Oceanic and Atmospheric Administration (NOAA) active region (AR) 11158, observed by the Helioseismic and Magnetic Imager on board the Solar Dynamics Observatory. Aiming for a detailed study of the temporal evolution of each parameter, we seek distinctive patterns that could be associated with the four largest flares in the AR in the course of its five-day observing interval. We find that proxy parameters only tend to show preflare impulses that are practical enough to warrant subsequent investigation with sufficient statistics. Combining these findings with previous results, we conclude that: (i) carefully constructed, physically intuitive proxy parameters may be our best asset toward an efficient future flare-forecasting; and (ii) the time series of promising parameters may be as important as their instantaneous values. Value-based prediction is the only approach followed so far. Our results call for novel signal and/or image processing techniques to efficiently utilize combined amplitude and temporal-profile information to optimize the inferred solar-flare probabilities.

Has a Frog Human a Soul? – Huxley, Tertullian, Physicalism and the Soul, Some Historical Antecedents

AbstractMuch theology presupposes a metaphysical spirit or soul, the existence of which has been questioned in contemporary neurobiological research. Green, Murphy and others argue for alternatives to metaphysical description. If the neuroscience is correct and the soul, if it exists, is not metaphysical then many theological descriptions will need serious revision or possibly even abandonment. One such theological description, directly affected and long considered to be an essential part of Christianity, is God's personal self-communication to humans. This has traditionally been understood to occur through the metaphysical human soul or spirit. The question explored in this article is whether the existence of a metaphysical soul is an all or nothing matter for Christian theology.A rational and strong challenge to the existence of metaphysical soul is demonstrably not new. Nonetheless, from the beginnings of modernity it has been generally assumed, utilising Augustinian anthropology, that the soul was a metaphysical element of human anatomy. Huxley's work on sensation, including ‘Has the Frog a Soul’, determines the anatomical location of the soul by its supposed function. Huxley questions early modernity's assumptions regarding the nature of sensation and the presumed role of the metaphysical soul within the sensorium. Huxley deduces limits and conditions on the existence of the soul and arrives at a description which has similarities to Tertullian's corporeal description of the soul. Huxley, however, does not engage with Tertullian, whose relatively orthodox description of the soul answers a number of issues that Huxley raises. Tertullian's careful revision of the Aristotelian category of corporeality is not exactly the same as Huxley's nineteenth-century materialism or contemporary physicalism. Tertullian's description of the soul is remarkably similar to Augustine's, differing mainly on the issue of corporeality and metaphysicality. Tertullian's description ironically draws on and shares the same functions as Greek philosophy and medicine. This description of the soul seems to be based more on these sources than scripture, unusually for Tertullian. Some form of reappropriation of Tertullian's non-metaphysical soul may be useful in the contemporary debate, noting the limitations of his understandings of biology and physics. It seems possible to take note, in some form, of changed and better contemporary worldviews, in order to better describe theological anthropology and in particular that element related to the soul.

IS A GRAVITON DETECTABLE?

IS A GRAVITON DETECTABLE?

Plantinga on Providence and Physics

In Where the Conžict Really Lies, Alvin Plantinga argues that there is nothing more than a supercial conžict between contemporary science and traditional eistic belief. He goes on to argue that there is a deep conžict between contemporary science and atheistic naturalism. I will concern myself here with only one part of Plantinga’s argument for the rst thesis, i.e. that there is only supercial conžict between science and Christian eism. I will focus, in particular, on the argument from Chapters 3 and 4 to the ešect that there is no conžict at all — not even supercial conžict — between contemporary physics and the claim that God can, and does, on occasion interact in “special” ways with God’s creation. In the spirit of constructive criticism, I will raise four issues about Plantinga’s discussion of providence and physics. Each of these issues can be resolved, I would suggest, via a more thoroughgoing application of Plantinga’s “Reformed” epistemological outlook. First, Plantinga indicates that if God acts in history, then the laws of physics are not deterministic. But from the point of view of Reformed epistemology, the character of the laws of physics should be irrelevant to one’s warrant in believing that God has acted. Second, Plantinga argues that divine intervention is consistent with the laws of Newtonian mechanics, since these laws carry provisos. However, the provisos leave room only for intervention by other physical systems. ird, Plantinga proposes that God could cause events by exploiting “collapse” of the quantum wavefunction. However, this proposal only adds the sound of scientic respectability to theology; it doesn’t actually use the science in any substantive way to correct or enrich theology. Finally, Plantinga’s discussion presupposes that science aims to establish laws of nature, and that divinely caused events contravene the laws of nature (for closed systems). But “Reformed” considerations suggest eliminating any dichotomy between “law” and “miracle.”

Evaporation residue excitation function and spin distribution for31P + 170Er

Background: Synthesis of a doubly magic spherical nucleus beyond ${}_{82}^{208}$Pb${}_{126}$ is a key question in contemporary nuclear physics. Such nuclei can exist solely because of shell stabilization. As the formation cross section of super heavy elements is prohibitively low, attempts have been made to understand stabilizing effects of closed proton ($Z$) and neutron ($N$) shells in the vicinity of ${}_{82}^{208}$Pb${}_{126}$.Purpose: The present work attempts to elucidate the stabilizing effect of shell closure, in general, and the same of $Z=82$, in particular.Methods: The evaporation residue (ER) excitation function and ER-gated $\ensuremath{\gamma}$-multiplicity distribution have been measured for the reaction ${}^{31}$P + ${}^{170}$Er at a laboratory energy range of 134--172 MeV. The measurements have been carried out using the HYbrid Recoil mass Analyzer (HYRA) in gas-filled mode and a $4\ensuremath{\pi}$ spin spectrometer consisting of 29 NaI(Tl) detectors. Results of the present reaction have been compared with those of the reaction ${}^{30}$Si + ${}^{170}$Er. Statistical model calculation has been performed for both the systems.Results: The two reactions, induced by ${}^{30}$Si and ${}^{31}$P projectiles, resulted in compound nuclei (CN) ${}^{200}$Pb ($Z=82$) and ${}^{201}$Bi ($Z=83$), respectively. To reproduce experimental ER cross sections, the liquid drop fission barrier (${B}_{\mathrm{f}}$) had to be scaled in the statistical model calculation. The scaling factor (${K}_{\mathrm{f}}$) varies from $0.75$ to $1.05$ and $0.90$ to $1.05$ for ${}^{30}$Si and ${}^{31}$P induced reactions, respectively. No significant differences have been found between $\ensuremath{\gamma}$-multiplicity distribution and the distribution moments of the two systems.Conclusions: No clear signature has been observed in favor of extra stability of the ERs with closed proton shell ($Z=82$) as ${K}_{\mathrm{f}}$ values of the two systems match within errors. More exclusive measurements and comparison between more systems forming CN/ER around $Z=82$ are desirable.

Probing nuclei by deeply penetrating and peripherally interacting Hadron: Bridging low and high-energy processes

The search for signals of new phenomenon is an important trend in the contemporary strong interaction physics. The nuclear J/ψ suppressions are considered as like candidates for the signals of unusual events, e.g. quark-gluon plasma. They were explained in the framework of Glauber approximation. On the contrary, we show that new experimental data on the total cross section of K+-nucleus interaction at intermediate energies cannot be described by the novel well-elaborated Glauber model. This may indicate a unique event in ground state nuclei (in-medium effect).