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Macchi A.,National Research Council Italy | Macchi A.,University of Pisa | Borghesi M.,Queens University of Belfast | Borghesi M.,ASCR Institute of Physics Prague | Passoni M.,Polytechnic of Milan
Reviews of Modern Physics | Year: 2013

Ion acceleration driven by superintense laser pulses is attracting an impressive and steadily increasing effort. Motivations can be found in the applicative potential and in the perspective to investigate novel regimes as available laser intensities will be increasing. Experiments have demonstrated, over a wide range of laser and target parameters, the generation of multi-MeV proton and ion beams with unique properties such as ultrashort duration, high brilliance, and low emittance. An overview is given of the state of the art of ion acceleration by laser pulses as well as an outlook on its future development and perspectives. The main features observed in the experiments, the observed scaling with laser and plasma parameters, and the main models used both to interpret experimental data and to suggest new research directions are described. © 2013 American Physical Society. Source

Hlinka J.,ASCR Institute of Physics Prague
Physical Review Letters | Year: 2014

The Letter draws the attention to the spatiotemporal symmetry of various vectorlike physical quantities. The symmetry is specified by their invariance under the action of symmetry operations of the nonrelativistic space-time rotation group O(3)×{1,1′}=O′(3), where 1′ is a time-reversal operation, the symbol×stands for the group direct product, and O(3) is a group of proper and improper rotations. It is argued that along with the canonical polar vector, there are another seven symmetrically distinct classes of stationary physical quantities, which can be - and often are - denoted as standard three-component vectors, even though they do not transform as a static polar vector under all operations of O′(3). The octet of symmetrically distinct "directional quantities" can be exemplified by two kinds of polar vectors (electric dipole moment P and magnetic toroidal moment T), two kinds of axial vectors (magnetization M and electric toroidal moment G), two kinds of chiral "bidirectors" C and F (associated with the so-called true and false chirality, respectively) and still another two bidirectors N and L, achiral ones, transforming as the nematic liquid crystal order parameter and as the antiferromagnetic order parameter of the hematite crystal α-Fe2O3, respectively. © 2014 American Physical Society. Source

Paidar V.,ASCR Institute of Physics Prague
Progress in Materials Science | Year: 2011

The changes of sample shape are caused by plastic deformation or by martensitic phase transformations. In both cases the mechanisms of atomic rearrangements are based on collective displacements of atomic aggregates. The internal structure of dislocations, carriers of plastic deformation, can be examined using the energies of generalized stacking faults displayed by so called γ-surfaces calculated for bcc metals by Vasek Vitek already more than 40 years ago. This approach can be extended to the shuffling of atomic planes that plays a crucial role in martensitic phase transformations. Similarities and differences between displacive processes of lattice shearing and atomic plane alternate shuffling are discussed. © 2011 Elsevier Ltd. All rights reserved. Source

Erler T.,ASCR Institute of Physics Prague
Journal of High Energy Physics | Year: 2011

We present a class of analytic solutions of cubic superstring field theory in the universal sector on a non-BPS D-brane. Computation of the action and gauge invariant overlap reveal that the solutions carry half the tension of a non-BPS D-brane. However, the solutions do not satisfy the reality condition. In fact, they display an intriguing topological structure: We find evidence that conjugation of the solutions is equivalent to a gauge transformation that cannot be continuously deformed to the identity. © SISSA 2011. Source

Tasevsky M.,ASCR Institute of Physics Prague
International Journal of Modern Physics A | Year: 2014

We review activities in the field of theoretical, phenomenological and experimental studies related to the production of the Higgs boson in central exclusive processes at LHC in models beyond Standard Model. Prospects in the context of the Higgs boson discovery at LHC in 2012 and of proposals to build forward proton detectors at ATLAS and CMS side are summarized. © World Scientific Publishing Company. Source

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