Ultra-intense femtosecond super-heavy ion beams driven by a multi-PW laser

The paper reports the results of numerical studies on the laser-driven acceleration of super-heavy ions by a multi-PW laser pulse of ultra-relativistic intensity attainable with the Extreme Light Infrastructure lasers currently being built in Europe. Using a multi-dimensional (2D3V) particle-in-cell code, it is shown that multi-GeV super-heavy (thorium) ion beams with an intensity of $～{10}^{21}\text{–}{10}^{22}\text{W}/{\text{cm}}^2$, fluence $～{10}^{17}\text{–}{10}^{18}{\text{cm}}^{?2}$ and time duration $～20\text{–}100\text{fs}$ can be produced from a sub-μm thorium target irradiated by a 150-J, 20-fs laser pulse with an intensity of ${10}^{23}\text{W}/{\text{cm}}^2$. Such ion beams are impossible to obtain presently with the use of conventional RF-driven accelerators, so they can open the door to new areas of research in both nuclear and high energy-density physics.     

Fuzzy quantum logics and infinite-valued Łukasiewicz logic

A new, physically more plausible definition of a fuzzy quantum logic is proposed. It is shown that this definition coincides with the previously studied definition of a fuzzy quantum logic; therefore it defines objects which are traditional quantum logics with ordering sets of states. The new definition is expressed exclusively in terms of fuzzy set operations which are generated by connectives of multiple-valued logic studied by ukasiewicz at the beginning of the 20th century. Therefore, the logic of quantum mechanics is recognized as a version of infinite-valued ukasiewicz logic.     

High-spin states in 44Ca

High-spin states of the ⁴⁴Ca nucleus populated in the 68 MeV ¹⁸O + ³⁰Si reaction have been studied in a γ-γ-recoil coincidence experiment. The level scheme of ⁴⁴Ca has been extended up to 12.2 MeV. In particular, the negative-parity band has been identified with the highest I = 13^- level at 10.6 MeV. This state is interpreted as the band-terminating state for the ( d _3/2 ^-1 f _7/2 ⁵) configuration. Received: 7 November 2001 / Accepted: 3 December 2001     

Rotations in isospace: a doorway to the understanding of neutron-proton superfluidity in N = Z nuclei

The T = 2 excitations in even-even N = Z nuclei are calculated within the isospin cranked mean-field approach. The response of pairing correlations to rotation in isospace is investigated. Whereas the isovector pairing rather modestly modifies the single-particle moment of inertia in isospace, the isoscalar pairing strongly reduces its value. This reduction of the isomoments of inertia with respect to its rigid body value is a strong indicator of collective isoscalar pairing correlations. These results are further generalized yielding beautiful analogies between the role of isovector pairing for the case of spatial rotations and the role of isoscalar pairing for the case of isorotations.     

Microscopic structure of fundamental excitations in N = Z nuclei

An extended mean-field model is presented that describes states of different isospin in odd-odd and even-even nuclei. Excitation energies of the T = 1 states in even-even as well as T = 0 and T = 1 states in odd-odd N = Z nuclei are calculated. It is shown that the structure of these states can be determined in a consistent manner when both isoscalar and isovector pairing collectivity as well as isospin projection (treated here within the isocranking approximation) are taken into account. In particular, in odd-odd N = Z nuclei, the interplay between quasiparticle excitations (relevant for the case of T = 0 states) and isorotations (relevant for the case of T = 1 states) explains the near degeneracy of these states.     

Fractional sequential mechanics — models with symmetric fractional derivative

The symmetric fractional derivative is introduced and its properties are studied. The Euler-Lagrange equations for models depending on sequential derivatives of type are derived using minimal action principle. The Hamiltonian for such systems is introduced following methods of classical generalized mechanics and the Hamilton’s equations are obtained. It is explicitly shown that models of fractional sequential mechanics are non-conservative. The limiting procedure recovers classical generalized mechanics of systems depending on higher order derivatives. The method is applied to fractional deformation of harmonic oscillator and to the case of classical frictional force proportional to velocity. Presented at the 10th International Colloquium on Quantum Groups: “Quantum Groups and Integrable Systems”, Prague, 21–23 June 2001.     

Ultrasonic system for accurate distance measurement in the air

This paper presents a system that accurately measures the distance travelled by ultrasound waves through the air. The simple design of the system and its obtained accuracy provide a tool for non-contact distance measurements required in the laser’s optical system that investigates the surface of the eyeball.     

All nonclassical correlations can be activated into distillable entanglement

We devise a protocol in which general nonclassical multipartite correlations produce a physically relevant effect, leading to the creation of bipartite entanglement. In particular, we show that the relative entropy of quantumness, which measures all nonclassical correlations among subsystems of a quantum system, is equivalent to and can be operationally interpreted as the minimum distillable entanglement generated between the system and local ancillae in our protocol. We emphasize the key role of state mixedness in maximizing nonclassicality: Mixed entangled states can be arbitrarily more nonclassical than separable and pure entangled states.     

Model-potential oscillator strengths for 4fn6s2–4fn6s6p transitions in Sm(I), Eu(I), Dy(I), Er(I) and Yb(I)

The 4fⁿ6s²?4fⁿ6s6p transitions are studied for neutral samarium, europium, dysprosium, erbium, and ytterbium. Four different couplings between the valence electrons and the 4fⁿ shell are considered, three are based on the LS and one on the J_IJ_II scheme. The radial integrals are computed with the model-potential method, which includes both exchange and core polarization. The results are compared with those obtained by employing the Coulomb approximation and the ab initio Hartree + Exchange (HX) approach, as well as with available experimental data. The core-polarization influence on oscillator strengths for these transitions is also investigated.