Atom as a “dressed” nucleus

We show that the electrostatic potential of an atomic nucleus “seen” by a fast charged projectile at short distances is quantum mechanically smeared due to nucleus motion around the atomic center of inertia. For example, the size of the “positive charge cloud” in the Hydrogen ground state is much larger than the proper proton size. For target atoms in excited initial states, the effect is even larger. The elastic scattering at large angles is generally weaker than the Rutherford scattering since the effective potential at short distances is softer than the Colombian one due to a natural “cutoff”. In addition, the large-angle scattering leads to target atom excitations due to pushing the nucleus (⇒ inelastic processes). The Rutherford cross section is in fact inclusive rather than elastic. These results are analogous to those from QED. Non-relativistic atomic calculations are presented. The difference and the value of these calculations arise from nonperturbatively (exact) nucleus “dressing” that immediately leads to correct physical results and to significant technical simplifications. In these respects a nucleus bound in an atom is a simple but rather realistic model of a “dressed” charge in the QFT. This idea is briefly demonstrated on a real electron model (electronium) which is free from infinities.      

Magnetic charge as a “hidden” gauge symmetry

A theory containing both electric and magnetic charges is formulated using two vectors potentials,A andC . This has the aesthetic advantage of treating electric and magnetic charges both as gauge symmetries, but it has the experimental disadvantage of introducing a second massless gauge boson (the magnetic photon) which is not observed. This problem is dealt with by using the Higgs mechanism to give a mass to one of the gauge bosons while the other remains massless. This effectively hides the magnetic charge, and the symmetry associated with it, when one is at an energy scale far enough removed from the scale of the symmetry breaking.This paper is dedicated to my grandparents Herbert and Anneliese Schmidt.     

“Bulk-SQUID effect” in a complex system as a consequence of its nonergodicity

The dynamics of the phases in a discrete superconductor model has been studied both theoretically and in computer simulation for the case of the passage of a direct current higher than the total critical current of junctions. It has been shown that a bulk-SQUID phenomenon appears in the system in this case and the system is nonergodic. This means that the dynamics of the system certainly depends on the initial conditions and dynamical attractors are limit cycles each having an attracting domain in the configuration space of initial conditions. A mathematical technique for recovering ergodicity in the system under investigation has been proposed. It has also been demonstrated that the bulk-SQUID phenomenon is not observed when the ergodicity is recovered in the system. It has been shown that the results are quite general and describe the behavior of a class of dynamical systems.

     

“Bulk-SQUID effect” in a complex system as a consequence of its nonergodicity

The dynamics of the phases in a discrete superconductor model has been studied both theoretically and in computer simulation for the case of the passage of a direct current higher than the total critical current of junctions. It has been shown that a bulk-SQUID phenomenon appears in the system in this case and the system is nonergodic. This means that the dynamics of the system certainly depends on the initial conditions and dynamical attractors are limit cycles each having an attracting domain in the configuration space of initial conditions. A mathematical technique for recovering ergodicity in the system under investigation has been proposed. It has also been demonstrated that the bulk-SQUID phenomenon is not observed when the ergodicity is recovered in the system. It has been shown that the results are quite general and describe the behavior of a class of dynamical systems.     

Existence of “free will” as a problem of physics

The proof of Bell's inequality is based on the assumption that distant observers can freely and independently choose their experiments. As Bell's inequality isexperimentally violated, it appears that distant physical systems may behave as a single, nonlocal, indivisible entity. This apparent contradiction is resolved. It is shown that the free will assumption is, under usual circumstances, an excellent approximation.I have set before you life and death, blessing and cursing: therefore choose life....

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X-Ray “knife” as a submicrometer tool for studying focusing lens quality

A mobile x-ray “knife” developed by the authors is described. The device is intended for determining the profile of the spatial intensity distribution in the ionizing radiation beam. Its automated motion system combines two actuator types. Significant displacements are performed using a goniometric module with a piezoelectric actuator. The angular step of this module is 1 arc second, which corresponds to a linear displacement of 0.97 μm. As a “fine” drive, a rotating module with a piezoelectric column is used. Its linear step can be varied from 0.01 to 1 μm at a total number of steps of 1000. The x-ray knife was experimentally tested at the Kurchatov Center of Synchrotron Radiation for diagnostics of the parameters of a short-focus x-ray lens at a photon energy of 18 keV. In the vertical direction, the width of the profile for the intensity distribution in the beam formed by the lens was 2.4 μm.     

Decay of an electronic vortex of a collisionless shock wave as a possible mechanism of a “Coulomb explosion”

A new mechanism of a “Coulomb explosion,” where ions are accelerated by the electric field separating charges at the magnetic Debye radius r _B∼B/4πen _e, is proposed on the basis of a nonquasineutral model of electronic vortices in a magnetic field. It is shown by means of numerical calculations that in the process of acceleration of the ions a collisionless shock wave, whose front has an effective width of the order of δ∼r _B, determined by the breakdown of quasineutrality, is formed in a time of the order of ω _pi ⁻¹ , where ω_pi is the ion plasma frequency. The origin of such explosive dynamics is the formation of “holes” in the electron density at characteristic times of the order of ω _pe ⁻¹ (ω_pe is the electronic plasma frequency) as a result of the generation of electronic vorticity by the Weibel instability of an electromagnetic wave. Calculations for a laser pulse with intensity J∼6×10¹⁸ W/cm² show that the ions expand in the radial direction with velocities up to 3.5×10⁸ cm/s. Pis’ma Zh. éksp. Teor. Fiz. 70, No. 10, 669–674 (25 November 1999)     

Products of distributions and collision of a δ-wave with a δ′-wave in a turbulent model

We study the possibility of collision of a δ-wave with a stationary δ′-wave in a model ruled by equation f (t)u _t+[u²?β(x?γ(t))u]_x = 0, where f, β and γ are given real functions and u = u(x, t) is the state variable. We adopt a solution concept which is a consistent extension of the classical solution concept. This concept is defined in the setting of a distributional product, which is not constructed by approximation processes. By a convenient choice of f, β and γ, we are able to distinguish three distinct dynamics for that collision, to which correspond phenomena of solitonic behaviour, scattering, and merging. Also, as a particular case, taking f = 2 and β = 0 we prove that the referred collision is impossible to arise in the setting of the inviscid Burgers equation. To show how this framework can be applied to other physical models, we included several results already obtained.     

Polarized biphotons as “optical quarks”

The transformation properties and the measurable parameters of a quasimonochromatic optical field consisting of two photons with the same directions of propagation and average frequency are analyzed. Like quarks, such a field possesses SU(3) symmetry. Pis’ma Zh. éksp. Teor. Fiz. 69, No. 11, 795–799 (10 June 1999)     

Ideal gas/liquid transition as a generalization of the problem of “partitio numerorum”

It is shown that the Boltzmann-Maxwell distribution is not applicable to the generalized notion of ideal gas and corresponds to this ideal gas at low density only. The behavior of an ideal gas and its transition to liquid is studied as a result of a kind of generalization of the problem of ??partitio numerorum??. The reflection of particles of the ideal gas from the walls of the vessel walls is taken into account (as a kind of ??trap?? for the Bose gas). Two constants are additionally introduced, namely, the constant ?? inversely proportional to the mass and the heat g of the phase transition as T ?? 0 (the constant of the Clausius-Clapeyron relation), and also the experimental value of the critical compressibility factor for the given gas and the experimental value of the pressure at the triple point, from which one can find the value of the constant ??.     

ℂP 2 as a gravitational Instanton

We compare some of the properties of P ² with those of the SU(2) Yang-Mills Instanton and conclude that P ² may be regarded as a gravitational pseudoparticle surrounded by an event horizon.     

Graphene-based Mach–Zehnder nanophotonics interferometer working as a splitter/switch and as a multiplexer/demultiplexer

We developed and are presenting a graphene-based nanophotonic Mach–Zehnder Interferometer (MZI), which can operate as a signal follower, switch and splitter and as a multiplexer/demultiplexer. Due to the excellent electrical/optical parameters inherent to the graphene, we showed that the device we are presenting can works in several different ways, which can not be supported by MZI based on conventional materials. It is worth mentioning that the operations of the device we have developed take into account the electrical/optical parameters of the graphene, which provide greater versatility and efficiency compared to the MZIs manufactured with conventional materials. In addition, these parameters can be controlled via, for example, gate voltage, so that many operations can be performed in parallel, which is also not possible through the use of conventional materials. Due to its manometric dimensions, this MZI can be integrated within photonic integrated circuits, so that we can use this device in dense wavelength division multiplexing optical communications.     

Specifics of the stochastic ionization of a Rydberg collision complex with Förster resonance

The physics of the formation of dynamic nonlinear resonances in an isolated Rydberg collisional complex is described. The development of the stochastic instability of Rydberg electron trajectories due to charge exchange in the complex is considered. The realization of the resonance in external statistic magnetic and electric fields is predicted to be accompanied by a significant narrowing of areas of stochastic motion with a concurrent decrease in the rates of the ionization of real quasimolecular systems proceeding through the migration over the Rydberg crowding of quantum states.     

Resonance Conversion as a Catalyzer of Nuclear Reactions

It is shown that resonance internal conversion offers a feasible tool for mastering nuclear processes with laser or synchrotron radiation. The physics of the process is discussed in detail in a historical aspect. Possible experimental application is shown in the case of the M1 70.6-keV transition in nuclei of 169 Yb. The nuclear transition rate in hydrogen-like ions of this nuclide can be enhanced by up to four orders of magnitude.     

Seiberg–Witten theory as a Fermi gas

We explore a new connection between Seiberg–Witten theory and quantum statistical systems by relating the dual partition function of SU(2) Super Yang–Mills theory in a self-dual \(\Omega \) background to the spectral determinant of an ideal Fermi gas. We show that the spectrum of this gas is encoded in the zeroes of the Painlevé \(\mathrm{III}_3\) \(\tau \) function. In addition, we find that the Nekrasov partition function on this background can be expressed as an O(2) matrix model. Our construction arises as a four-dimensional limit of a recently proposed conjecture relating topological strings and spectral theory. In this limit, we provide a mathematical proof of the conjecture for the local \({\mathbb P}^1 \times {\mathbb P}^1\) geometry.     

Kerr–Newman Solution as a Dirac Particle

For m ² < a ² + q ², with m, a, and q respectively the source mass, angular momentum per unit mass, and electric charge, the Kerr–Newman (KN) solution of Einstein's equation reduces to a naked singularity of circular shape, enclosing a disk across which the metric components fail to be smooth. By considering the Hawking and Ellis extended interpretation of the KN spacetime, it is shown that, similarly to the electron-positron system, this solution presents four inequivalent classical states. Making use of Wheeler's idea of charge without charge, the topological structure of the extended KN spatial section is found to be highly non-trivial, leading thus to the existence of gravitational states with half-integral angular momentum. This property is corroborated by the fact that, under a rotation of the space coordinates, those inequivalent states transform into themselves only after a 4 rotation. As a consequence, it becomes possible to naturally represent them in a Lorentz spinor basis. The state vector representing the whole KN solution is then constructed, and its evolution is shown to be governed by the Dirac equation. The KN solution can thus be consistently interpreted as a model for the electron-positron system, in which the concepts of mass, charge and spin become connected with the spacetime geometry. Some phenomenological consequences of the model are explored.     

Bimodality as a signal of a liquid-gas phase transition in nuclei?

We use the heavy-ion phase-space exploration model to discuss the origin of the bimodality in charge asymmetry observed in nuclear reactions around the Fermi energy. We show that it may be related to the important angular momentum (spin) transferred into the quasiprojectile before secondary decay. As the spin overcomes the critical value, a sudden opening of decay channels is induced and leads to a bimodal distribution for the charge asymmetry. In the model, it is not assigned to a liquid-gas phase transition but to specific instabilities in nuclei with high spin. Therefore, we propose to use these reactions to study instabilities in rotating nuclear droplets.     

Graphene on SiC as a Q-switcher for a 2 μm laser

Double-layer graphene epitaxially grown on silicon carbide was used to Q-switch a Tm:YAG laser. Stable Q-switched laser pulses at the central wavelength of 2.01 μm were obtained. The maximum average output power, pulse repetition rate, and single pulse energy were 38 mW, 27.9 kHz, and 1.74 μJ, respectively. Our results illustrate that graphene can be used as a saturable absorber at the 2 μm region.     

Inaccurate mate recognition as a mating strategy of a ‘pioneer male’

Heterosubspecific mating experiments were carried out between two subspecies of cabbage butterflies, British Pieris rapae rapae and Japanese P. rapae crucivora, to examine how accurately males recognize the mates. The two subspecies are different in that the wings of female P. rapae rapae reflect little UV light, whereas those of female P. rapae crucivora are strongly UV-reflective. The wing colouration of P. rapae crucivora involving UV is believed to be critical in mate recognition. The results showed that males of both subspecies displayed mating behaviours, to and copulated with, females of both subspecies. Furthermore, P. rapae crucivora males exhibited mating behaviours and attempted to copulate with females of Pieris melete with low UV reflectance which are critically different from P. rapae crucivora females with high UV reflectance. Based on these findings, we propose the “pioneer male” hypothesis, which argues that such inaccurate mate recognition may sometimes be selectively beneficial for males and thus an adaptive mating strategy. The “pioneer male” was discussed in terms of its possible role in the evolution.