@article{43194, abstract = {{For incident light polarized perpendicular to the tube axis the multi-band semiconductor Bloch equations (MB-SBEs) that involve various screened interband Coulomb interactions (ICIs) are derived. The calculated E 12 peak is very close to the longitudinal excitonic peak E 22. Compared with the previous theoretical peak positions, the blue-shift of the peak in our results is about 0.5 eV. Then, subsequent detailed analyses show that the screening effect on the diagonal ICIs (D-ICIs) plays a key role in this big blue-shift. The valley-degenerate transverse pair excitations holding the same selection rule further enhance the screening effect on D-ICIs. Specially at q = 0 the dielectric function acting on the D-ICIs enhances two times. In our calculation the strong screening effect contributes 90% of the big blue-shift, while the non-diagonal ICIs (ND-ICIs) contribute to 10% of the blue-shift.}}, author = {{Meier, Torsten and Liu, Hong}}, journal = {{The European Physical Journal B}}, title = {{{Influence of strong screening effect on the perpendicular polarized linear excitonic absorption spectra of semiconducting carbon nanotubes}}}, doi = {{10.1140/epjb/e2016-70476-8}}, volume = {{89}}, year = {{2016}}, } @article{13917, abstract = {{We present the synthesis of indium oxide (In2O3) inverse opal films with photonic stop bands in the visible range by a structure replication method. Artificial opal films made of poly(methyl methacrylate) (PMMA) spheres are utilized as template. The opal films are deposited via sedimentation facilitated by ultrasonication, and then impregnated by indium nitrate solution, which is thermally converted to In2O3 after drying. The quality of the resulting inverse opal film depends on many parameters; in this study the water content of the indium nitrate/PMMA composite after drying is investigated. Comparison of the reflectance spectra recorded by vis-spectroscopy with simulated data shows a good agreement between the peak position and calculated stop band positions for the inverse opals. This synthesis is less complex and highly efficient compared to most other techniques and is suitable for use in many applications.}}, author = {{Amrehn, Sabrina and Berghoff, Daniel and Nikitin, Andreas and Reichelt, Matthias and Wu, Xia and Meier, Torsten and Wagner, Thorsten}}, issn = {{1569-4410}}, journal = {{Photonics and Nanostructures - Fundamentals and Applications}}, pages = {{55--63}}, title = {{{Indium oxide inverse opal films synthesized by structure replication method}}}, doi = {{10.1016/j.photonics.2016.02.005}}, volume = {{19}}, year = {{2016}}, } @article{13915, abstract = {{The dynamics of a pair of harmonic oscillators represented by three-dimensional fields coupled with a repulsive cubic nonlinearity is investigated through direct simulations of the respective field equations and with the help of the finite-mode Galerkin approximation (GA), which represents the two interacting fields by a superposition of 3+3 harmonic-oscillator p-wave eigenfunctions with orbital and magnetic quantum numbers l=1 and m=1, 0, −1. The system can be implemented in binary Bose-Einstein condensates, demonstrating the potential of the atomic condensates to emulate various complex modes predicted by classical field theories. First, the GA very accurately predicts a broadly degenerate set of the system's ground states in the p-wave manifold, in the form of complexes built of a dipole coaxial with another dipole or vortex, as well as complexes built of mutually orthogonal dipoles. Next, pairs of noncoaxial vortices and/or dipoles, including pairs of mutually perpendicular vortices, develop remarkably stable dynamical regimes, which feature periodic exchange of the angular momentum and periodic switching between dipoles and vortices. For a moderately strong nonlinearity, simulations of the coupled-field equations agree very well with results produced by the GA, demonstrating that the dynamics is accurately spanned by the set of six modes limited to l=1.}}, author = {{Driben, R. and Konotop, V. V. and Malomed, B. A. and Meier, Torsten}}, issn = {{2470-0045}}, journal = {{Physical Review E}}, number = {{1}}, title = {{{Dynamics of dipoles and vortices in nonlinearly coupled three-dimensional field oscillators}}}, doi = {{10.1103/physreve.94.012207}}, volume = {{94}}, year = {{2016}}, } @inproceedings{13918, author = {{Podzimski, Reinold and Duc, Huynh Thanh and Priyadarshi, Shekhar and Schmidt, Christian and Bieler, Mark and Meier, Torsten}}, booktitle = {{Ultrafast Phenomena and Nanophotonics XX}}, editor = {{Betz, Markus and Elezzabi, Abdulhakem Y.}}, publisher = {{SPIE}}, title = {{{Photocurrents in semiconductors and semiconductor quantum wells analyzed by k.p-based Bloch equations}}}, doi = {{10.1117/12.2208572}}, volume = {{9746}}, year = {{2016}}, } @article{4246, abstract = {{Spins in semiconductor quantum dots have been considered as prospective quantum bit excitations. Their coupling to the crystal environment manifests itself in a limitation of the spin coherence times to the microsecond range, both for electron and hole spins. This rather short-lived coherence compared to atomic states asks for manipulations on timescales as short as possible. Due to the huge dipole moment for transitions between the valence and conduction band, pulsed laser systems offer the possibility to perform manipulations within picoseconds or even faster. Here, we report on results that show the potential of optical spin manipulations with currently available pulsed laser systems. Using picosecond laser pulses, we demonstrate optically induced spin rotations of electron and hole spins. We further realize the optical decoupling of the hole spins from the nuclear surrounding at the nanosecond timescales and demonstrate an all-optical spin tomography for interacting electron spin sub-ensembles.}}, author = {{Varwig, S. and Evers, E. and Greilich, A. and Yakovlev, D. R. and Reuter, Dirk and Wieck, A. D. and Meier, Torsten and Zrenner, Artur and Bayer, M.}}, issn = {{0946-2171}}, journal = {{Applied Physics B}}, keywords = {{Spin Polarization, Pump Pulse, Trion, Spin Component, Coherence Time}}, number = {{1}}, publisher = {{Springer Nature}}, title = {{{Advanced optical manipulation of carrier spins in (In,Ga)As quantum dots}}}, doi = {{10.1007/s00340-015-6274-y}}, volume = {{122}}, year = {{2016}}, } @article{13910, author = {{Ma, Xuekai and Driben, Rodislav and Malomed, Boris A. and Meier, Torsten and Schumacher, Stefan}}, issn = {{2045-2322}}, journal = {{Scientific Reports}}, title = {{{Two-dimensional symbiotic solitons and vortices in binary condensates with attractive cross-species interaction}}}, doi = {{10.1038/srep34847}}, volume = {{6}}, year = {{2016}}, } @article{43196, abstract = {{A method is presented to transfer a system of two-level atoms from a spin coherent state to a maximally spin squeezed Dicke state, relevant for quantum metrology and quantum information processing. The initial state is the ground state of an initial linear Hamiltonian that is gradually turned into a final quadratic Hamiltonian whose ground state is the selected Dicke state. We use compensating operators to suppress diabatic transitions to unwanted states that would occur if the change were not slow. We discuss the possibilities of constructing the compensating operators by sequential application of quadratic Hamiltonians available in experiments.}}, author = {{Meier, Torsten and Opatrný, T. and Saberi, H. and Brion, E. and Mølmer, K.}}, journal = {{Physical Review A}}, number = {{2}}, title = {{{Counterdiabatic driving in spin squeezing and Dicke-state preparation}}}, doi = {{10.1103/PhysRevA.93.023815}}, volume = {{93}}, year = {{2016}}, } @article{43195, abstract = {{We propose an entanglement classification for symmetric quantum states based on their diagonal matrix-product-state (MPS) representation. The proposed classification, which preserves the stochastic local operation assisted with classical communication (SLOCC) criterion, relates entanglement families to the interaction length of Hamiltonians. In this manner, we establish a connection between entanglement classification and condensed matter models from a quantum information perspective. Moreover, we introduce a scalable nesting property for the proposed entanglement classification, in which the families for N parties carry over to the N + 1 case. Finally, using techniques from algebraic geometry, we prove that the minimal nontrivial interaction length n for any symmetric state is bounded by .}}, author = {{Sanz, M. and Egusquiza, I.L. and Candia, R. Di and Saberi, H. and Lamata, L. and Solano, E.}}, journal = {{Scientific Reports}}, title = {{{Entanglement classification with matrix product states}}}, doi = {{10.1038/srep30188}}, volume = {{6}}, year = {{2016}}, } @article{22942, abstract = {{A microscopic approach that is based on the multisubband semiconductor Bloch equations formulated in the basis of a 14-band k⋅p model is employed to compute the temporal dynamics of photocurrents in GaAs quantum wells following excitation with femtosecond laser pulses. This approach provides a transparent description of the interband, intersubband, and intraband excitations, fully includes all resonant as well as off-resonant excitations, and treats the light-matter interaction nonperturbatively. For linearly polarized excitations, the photocurrents contain contributions from shift and rectification currents. We numerically compute and analyze these currents generated by excitation with femtosecond laser pulses for [110]- and [111]-oriented GaAs quantum wells. It is shown that the often employed perturbative χ(2) approach breaks down for peak fields larger than about 10 kV/cm, and that nonperturbative effects lead to a reduction of the peak values of the shift and rectification currents and to temporal oscillations that originate from Rabi flopping. In particular, we find a complex oscillatory photon energy dependence of the magnitudes of the shift and rectification currents. Our simulations demonstrate that this dependence is the result of mixing between the heavy- and light-hole valence bands. This is a surprising finding since the band mixing has an even larger influence on the strength of the photocurrents than the absorption coefficient. For [110]-oriented GaAs quantum wells, the calculated photon energy dependence is compared to experimental results, and good agreement is obtained. This validates our theoretical approach.}}, author = {{Duc, Huynh Thanh and Podzimski, Reinold and Priyadarshi, Shekhar and Bieler, Mark and Meier, Torsten}}, issn = {{2469-9950}}, journal = {{Physical Review B}}, number = {{8}}, publisher = {{American Physical Society}}, title = {{{Ultrafast shift and rectification photocurrents in GaAs quantum wells: Excitation intensity dependence and the importance of band mixing}}}, doi = {{10.1103/physrevb.94.085305}}, volume = {{94}}, year = {{2016}}, } @article{13916, abstract = {{Nonlinearity is the driving force for numerous important effects in nature typically showing transitions between different regimes, regular, chaotic or catastrophic behavior. Localized nonlinear modes have been the focus of intense research in areas such as fluid and gas dynamics, photonics, atomic and solid state physics etc. Due to the richness of the behavior of nonlinear systems and due to the severe numerical demands of accurate three-dimensional (3D) numerical simulations presently only little knowledge is available on the dynamics of complex nonlinear modes in 3D. Here, we investigate the dynamics of 3D non-coaxial matter wave vortices that are trapped in a parabolic potential and interact via a repulsive nonlinearity. Our numerical simulations demonstrate the existence of an unexpected and fascinating nonlinear regime that starts immediately when the nonlinearity is switched-on and is characterized by a smooth dynamics representing torque-free precession with nutations. The reported motion is proven to be robust regarding various effects such as the number of particles, dissipation and trap deformations and thus should be observable in suitably designed experiments. Since our theoretical approach, i.e., coupled nonlinear Schrödinger equations, is quite generic, we expect that the obtained novel dynamical behavior should also exist in other nonlinear systems.}}, author = {{Driben, R. and Konotop, V. V. and Meier, Torsten}}, issn = {{2045-2322}}, journal = {{Scientific Reports}}, title = {{{Precession and nutation dynamics of nonlinearly coupled non-coaxial three-dimensional matter wave vortices}}}, doi = {{10.1038/srep22758}}, volume = {{6}}, year = {{2016}}, } @article{13920, abstract = {{We investigate the transient optical response in high-quality Cd0.88Zn0.12Te crystals in the regime of slow light propagation on the lower exciton-polariton branch. Femtosecond photoexcitation leads to very substantial transmission changes in a ∼10-meV broad spectral range within the transparency window of the unexcited semiconductor. These nonlinear optical signatures decay on picosecond time scales governed by carrier thermalization and recombination. The temporal and spectral dependence indicate the dynamical optical response as arising from excitation-induced dephasing and perturbed free induction decay. Model simulations for the optical response taking into account the actual exciton-polariton dispersion and excitation-induced dephasing of a nonlinearly driven two-level system support this interpretation.}}, author = {{Lohrenz, J. and Melzer, S. and Ruppert, C. and Akimov, I. A. and Mariette, H. and Reichelt, Matthias and Trautmann, Alexander and Meier, Torsten and Betz, M.}}, issn = {{2469-9950}}, journal = {{Physical Review B}}, number = {{7}}, title = {{{Ultrafast dynamical response of the lower exciton-polariton branch in CdZnTe}}}, doi = {{10.1103/physrevb.93.075201}}, volume = {{93}}, year = {{2016}}, } @article{13923, author = {{Oreshnikov, I. and Driben, R. and Yulin, A. V.}}, issn = {{0146-9592}}, journal = {{Optics Letters}}, number = {{23}}, title = {{{Interaction of high-order solitons with external dispersive waves}}}, doi = {{10.1364/ol.40.005554}}, volume = {{40}}, year = {{2015}}, } @article{13924, author = {{Oreshnikov, I. and Driben, R. and Yulin, A. V.}}, issn = {{0146-9592}}, journal = {{Optics Letters}}, number = {{21}}, title = {{{Weak and strong interactions between dark solitons and dispersive waves}}}, doi = {{10.1364/ol.40.004871}}, volume = {{40}}, year = {{2015}}, } @article{13925, author = {{Driben, R. and Yulin, A. V. and Efimov, A.}}, issn = {{1094-4087}}, journal = {{Optics Express}}, number = {{15}}, title = {{{Resonant radiation from oscillating higher order solitons}}}, doi = {{10.1364/oe.23.019112}}, volume = {{23}}, year = {{2015}}, } @article{13929, author = {{Oreshnikov, I. and Driben, R. and Yulin, A. V.}}, issn = {{0146-9592}}, journal = {{Optics Letters}}, number = {{23}}, title = {{{Interaction of high-order solitons with external dispersive waves}}}, doi = {{10.1364/ol.40.005554}}, volume = {{40}}, year = {{2015}}, } @article{13930, author = {{Oreshnikov, I. and Driben, R. and Yulin, A. V.}}, issn = {{0146-9592}}, journal = {{Optics Letters}}, number = {{21}}, title = {{{Weak and strong interactions between dark solitons and dispersive waves}}}, doi = {{10.1364/ol.40.004871}}, volume = {{40}}, year = {{2015}}, } @article{13931, author = {{Driben, R. and Yulin, A. V. and Efimov, A.}}, issn = {{1094-4087}}, journal = {{Optics Express}}, number = {{15}}, title = {{{Resonant radiation from oscillating higher order solitons}}}, doi = {{10.1364/oe.23.019112}}, volume = {{23}}, year = {{2015}}, } @article{43250, abstract = {{We present radiation mechanism exhibited by a higher order soliton. In a course of its evolution the higher-order soliton emits polychromatic radiation resulting in formation of multipeak frequency comb-like spectral band. The shape and spectral position of this band can be effectively controlled by the relative strength of the third order dispersion. An analytical description is corroborated by numerical simulations. It is shown that for longer pulses the described effect persists also under the action of higher order perturbations such as Raman and self-steepening.}}, author = {{Driben, R. and Yulin, A. V. and Efimov, A.}}, journal = {{Optics Express}}, number = {{15}}, pages = {{19112--19117}}, title = {{{Resonant radiation from oscillating higher order solitons}}}, doi = {{10.1364/OE.23.019112}}, volume = {{23}}, year = {{2015}}, } @article{43249, abstract = {{The effect of mutual interactions between dark solitons and dispersive waves is investigated numerically and analytically. The condition of the resonant scattering of dispersive waves on dark solitons is derived and compared against the results of the numerical simulations. It is shown that the interaction with intense dispersive waves affects the dynamics of the solitons by accelerating, decelerating, or destroying them. It is also demonstrated that two dark solitons can form a cavity for dispersive waves bouncing between the two dark solitons. The differences of the resonant scattering of the dispersive waves on dark and bright solitons are discussed. In particular, we demonstrate that two dark solitons and a dispersive wave bouncing in between them create a solitonic cavity with convex “mirrors,” unlike the concave “mirror” in the case of bright solitons.}}, author = {{Oreshnikov, I. and Yulin, A. V. and Driben, R.}}, journal = {{Optics Letters}}, number = {{21}}, pages = {{4871--4874}}, title = {{{Weak and strong interactions between dark solitons and dispersive waves}}}, doi = {{10.1364/OL.40.004871}}, volume = {{40}}, year = {{2015}}, } @inproceedings{43892, abstract = {{The discovery of Airy waves, in the context of solutions to the linear Schrödinger equation [1], inspired extensive research for self-accelerating waves in optical settings [2-6]. Fascinating self-accelerating, self-healing light beams propagating along the bending trajectories can manifest themself in the spatial and the temporal domains and are promising for a large variety of potential applications.}}, author = {{Meier, Torsten and Driben, R. and Konotop, V.V.}}, booktitle = {{European Conference on Lasers and Electro-Optics - European Quantum Electronics Conference}}, isbn = {{978-1-4673-7475-0}}, location = {{Munich, Germany}}, publisher = {{IEEE}}, title = {{{Vectorial self-accelerating beams}}}, year = {{2015}}, }