First order wetting of rough substrates and quantum unbinding

Replica and functional renormalization group methods show that, with short range substrate forces or in strong fluctuation regimes, wetting of a self-affine rough wall in 2D turns first-order as soon as the wall roughness exponent exceeds the anisotropy index of bulk interface fluctuations. Different thresholds apply with long range forces in mean field regimes. For bond-disordered bulk, fixed point stability suggests similar results, which ultimately rely on basic properties of quantum bound states with asymptotically power-law repulsive potentials.Comment: 11 pages, 1 figur

Coherent control for the spherical symmetric box potential in short and intensive XUV laser fields

Coherent control calculations are presented for a spherically symmetric box potential for non-resonant two photon transition probabilities. With the help of a genetic algorithm (GA) the population of the excited states are maximized and minimized. The external driving field is a superposition of three intensive extreme ultraviolet (XUV) linearly polarized laser pulses with different frequencies in the femtosecond duration range. We solved the quantum mechanical problem within the dipole approximation. Our investigation clearly shows that the dynamics of the electron current has a strong correlation with the optimized and neutralizing pulse shape.Comment: 11 Pages 3 Figure

Schrodinger equation for the one particle density matrix of thermal systems: An alternative formulation of Bose-Einstein condensation

We formulate a linear Schrodinger equation with the temperature-dependent potential for the one-particle density matrix and obtain the condensation temperature of the Bose-Einstein condensate from a bound-state condition for the Schrodinger equation both with and without the confining trap. The results are in very good agreement with those of the full statistical physics treatment. This is an alternative to the Bose-Einstein condensation in the standard ideal Bose gas treatment.Comment: 4 pages, 2 figure

Ethics of Artificial Intelligence Demarcations

In this paper we present a set of key demarcations, particularly important when discussing ethical and societal issues of current AI research and applications. Properly distinguishing issues and concerns related to Artificial General Intelligence and weak AI, between symbolic and connectionist AI, AI methods, data and applications are prerequisites for an informed debate. Such demarcations would not only facilitate much-needed discussions on ethics on current AI technologies and research. In addition sufficiently establishing such demarcations would also enhance knowledge-sharing and support rigor in interdisciplinary research between technical and social sciences.Comment: Proceedings of the Norwegian AI Symposium 2019 (NAIS 2019), Trondheim, Norwa

Probing calculated O-2(+) potential-energy curves with an XUV-IR pump-probe experiment

Citation: Corlin, P., Fischer, A., Schonwald, M., Sperl, A., Mizuno, T., Thumm, U., . . . Moshammer, R. (2015). Probing calculated O-2(+) potential-energy curves with an XUV-IR pump-probe experiment. Physical Review A, 91(4), 8. doi:10.1103/PhysRevA.91.043415We study dissociative photoionization of molecular oxygen in a kinematically complete XUV-IR pump-probe experiment. Detecting charged fragments and photoelectrons in coincidence using a reaction microscope, we observe a pump-probe delay-dependent yield of very low energetic O+ ions which oscillates with a period of 40 fs. This feature is caused by a time-dependent vibrational wave packet in the potential of the binding O-2(+)(a(4)Pi(u))state, which is probed by resonant absorption of a single infrared photon to the weakly repulsive O-2(+)(f(4)Pi(g)) state. By quantitative comparison of the experimental kinetic-energy-release (KER) and quantum-beat (QB) spectra with the results of a coupled-channel simulation, we are able to discriminate between the calculated adiabatic O-2(+) potential-energy curves (PECs) of Marian et al. [Marian, Marian, Peyerimhoff, Hess, Buenker, and Seger, Mol. Phys. 46, 779 (1982)] and Magrakvelidze et al. [Magrakvelidze, Aikens, and Thumm, Phys. Rev. A 86, 023402 (2012)]. In general, we find a good agreement between experimental and simulated KER and QB spectra. However, we could not reproduce all features of the experimental data with these PECs. In contrast, adjusting a Morse potential to the experimental data, most features of the experimental spectra are well reproduced by our simulation. By comparing this Morse potential to theoretically predicted PECs, we demonstrate the sensitivity of our experimental method to small changes in the shape of the binding potential

Probing O+ 2 potential curves with an XUV-IR pump-probe experiment

Citation: Cörlin, P., Fischer, A., Schönwald, M., Sperl, A., Mizuno, T., Thumm, U., . . . Moshammer, R. (2015). Probing O+ 2 potential curves with an XUV-IR pump-probe experiment. 635(11). doi:10.1088/1742-6596/635/11/112060Upon ionization of ground state O2 molecules in a short XUV pulse, we observe a time-dependent vibrational wave packet in the potential of the binding O+ 2 (a4?u) state. Our pump-probe delay dependent kinetic-energy-release (KER) spectra are in qualitative agreement with the results of coupled-channel simulations that are based on calculated Born-Oppenheimer potential-energy curves (PECs). Using a Morse potential adjusted to the experimental data most features of the experimental spectra are reproduced quantitatively. © Published under licence by IOP Publishing Ltd

Limitations on the superposition principle: superselection rules in non-relativistic quantum mechanics

The superposition principle is a very basic ingredient of quantum theory. What may come as a surprise to many students, and even to many practitioners of the quantum craft, is tha superposition has limitations imposed by certain requirements of the theory. The discussion of such limitations arising from the so-called superselection rules is the main purpose of this paper. Some of their principal consequences are also discussed. The univalence, mass and particle number superselection rules of non-relativistic quantum mechanics are also derived using rather simple methods.Comment: 22 pages, no figure

Fractal Analysis of Protein Potential Energy Landscapes

The fractal properties of the total potential energy V as a function of time t are studied for a number of systems, including realistic models of proteins (PPT, BPTI and myoglobin). The fractal dimension of V(t), characterized by the exponent \gamma, is almost independent of temperature and increases with time, more slowly the larger the protein. Perhaps the most striking observation of this study is the apparent universality of the fractal dimension, which depends only weakly on the type of molecular system. We explain this behavior by assuming that fractality is caused by a self-generated dynamical noise, a consequence of intermode coupling due to anharmonicity. Global topological features of the potential energy landscape are found to have little effect on the observed fractal behavior.Comment: 17 pages, single spaced, including 12 figure