Generation of inequivalent generalized Bell bases

The notion of equivalence of maximally entangled bases of bipartite d-dimensional Hilbert spaces is introduced. An explicit method of inequivalent bases construction is presented

Properties of localized protons in neutron star matter for realistic nuclear models

We study the localization of protons in the core of neutron stars for ten realistic nuclear models that share a common behaviour of nuclear symmetry energy which saturates and eventually decreases at high densities. This results in the low proton fraction of beta-stable neutron star matter. Protons form a small admixture in the neutron star core, which is localized at sufficiently high densities. For every model we calculate the density $n_{loc}$ above which the localization effect is present. Our results indicate that localization occurs at densities above $0.5-1.0 fm^{-3}$. The phase with localized protons occupies a spherical shell or a core region inside neutron stars which contains significant fraction of all nucleons. Proton localization is of great importance for astrophysical properties of neutron stars as it strongly affects transport coefficients of neutron star matter and can produce spontaneous magnetization in neutron stars.Comment: 6 pages, 3 figures, Presented at the XXIX Mazurian Lakes Conference on Physics, Piaski, Poland, August 30 - Septenber 6, 200

Structure of Proton Component of Neutron Star Matter for Realistic Nuclear Models

We study properties of the proton component of neutron star matter for a number of realistic nuclear models. Protons which form a few percent admixture tend to be localized in potential wells corresponding to neutron matter inhomogeneities created by the protons in the neutron medium. We calculate the energy of the Wigner-Seitz cell enclosing a single localized proton. The neutron background is treated in the Thomas-Fermi approximation and the localized proton is described by the Gaussian wave function. The neutron density profile is obtained by solving the appropriate variational equation. This approach gives lower energies of localized protons than obtained previously with less sophisticated methods.Comment: LaTeX with the APPolB style (included), 10 pages, 16 figures, to appear in Acta Physica Polonica

Quasiperiodic dynamics of coherent diffusion: a quantum walk approach

We study the dynamics of a generalization of quantum coin walk on the line which is a natural model for a diffusion modified by quantum or interference effects. In particular, our results provide surprisingly simple explanations to phenomena observed by Bouwmeester et al. (Phys. Rev. A, 61, 13410 (1999)) in their optical Galton board experiment, and a description of a stroboscopic quantum walks given by Buershaper and Burnett (quant-ph/0406039) through numerical simulations. We also provide heuristic explanations for the behavior of our model which show, in particular, that its dynamics can be viewed as a discrete version of Bloch oscillations

Measurement of the overlap between quantum states with the use of coherently addressed teleportation

We will show how to measure the overlap between photon polarization states with the use of linear optics and postselection only. Our scheme is based on quantum teleportation and succeeds with the probability of 1/8

Electronic states and localization in nanoscopic chains and rings from first principles: EDABI method

We summarize briefly the main results obtained within the proposed EDABI method combining Exact Diagonalization of (parametrized) many-particle Hamiltonian with Ab Initio self-adjustment of the single-particle wave function in the correlated state of interacting electrons. The properties of nanoscopic chains and rings are discussed as a function of their interatomic distance R and compared with those obtained by Bethe ansatz for infinite Hubbard chain. The concepts of renormalized orbitals, distribution function in momentum space, and of Hubbard splitting as applied to nanoscopic systems are emphasized.Comment: 22 pages, 12 figures. Submitted to Proceedings of the NATO Advanced Research Workshop: Molecular Nanowires and other Quantum Objects, Kluwer Publ., Dordrecht, 200

Puzzling magneto-optical properties of ZnMnO films

Optical and magneto-optical properties of ZnMnO films grown at low temperature by Atomic Layer Deposition are discussed. A strong polarization of excitonic photoluminescence is reported, surprisingly observed without splitting or spectral shift of excitonic transitions. Present results suggest possibility of Mn recharging in ZnO lattice. Strong absorption, with onset at about 2.1 eV, is related to Mn 2+ to 3+ photo-ionization. We propose that the observed strong circular polarization of excitonic emission is of a similar character as the one observed by us for ZnSe:Cr.Comment: 19 pages, 4 figures, 38 reference

Computational quest for Kaos-land

Using bi-parametric sweeping based on symbolic representation we reveal self-similar fractal structures induced by hetero- and homoclinic bifurcations of saddle singularities in the parameter space of two systems with deterministic chaos. We start with the system which displays several homoclinic bifurcations of higher codimension: resonant saddle, orbit-flip and inclination switch that all give rise to the onset of the Lorenz-type attractor in $Z_2$-systems with the homoclinic butterfly. The second system is the classic Lorenz model of 1963, originated in fluid mechanics

Above-Bandgap Magneto-optical Kerr Effect in Ferromagnetic GaMnAs

We have performed a systematic magneto-optical Kerr spectroscopy study of GaMnAs with varying Mn densities as a function of temperature, magnetic field, and photon energy. Unlike previous studies, the magnetization easy axis was perpendicular to the sample surface, allowing us to take remanent polar Kerr spectra in the absence of an external magnetic field. The remanent Kerr angle strongly depended on the photon energy, exhibiting a large positive peak at $\sim1.7$ eV. This peak increased in intensity and blue-shifted with Mn doping and further blue-shifted with annealing. Using a 30-band ${\bf k\cdot p}$ model with antiferromagnetic $s,p$-$d$ exchange interaction, we calculated the dielectric tensor of GaMnAs in the interband transition region, assuming that our samples are in the metallic regime and the impurity band has merged with the valence band. We successfully reproduced the observed spectra without \emph{ad hoc} introduction of the optical transitions originated from impurity states in the band gap. These results lead us to conclude that above-bandgap magneto-optical Kerr rotation in ferromagnetic GaMnAs is predominantly determined by interband transitions between the conduction and valence bands.Comment: 12 pages, 15 figure

Absence of unidirectionally propagating surface plasmon-polaritons in nonreciprocal plasmonics

In the presence of an external magnetic field, the surface plasmon polariton that exists at the metal-dielectric interface is believed to support a unidirectional frequency range near the surface plasmon frequency, where the surface plasmon polariton propagates along one but not the opposite direction. Recent works have pointed to some of the paradoxical consequences of such a unidirectional range, including in particular the violation of the time-bandwidth product constraint that should otherwise apply in general in static systems. Here we show that such a unidirectional frequency range is nonphysical, using both a general thermodynamic argument, and a detailed calculation based on a nonlocal hydrodynamic Drude model for the metal permittivity. Our calculation reveals that the surface plasmon-polariton remains bidirectional for all frequencies. This work overturns a long-held belief in nonreciprocal photonics, and highlights the importance of quantum plasmonic concepts for the understanding of nonreciprocal plasmonic effects