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We present new oscillation criteria for the second order nonlinear neutral delay differential equation a (t) (y (t) + p (t) y (t − τ)) + q (t) |y (σ (t))| α−1 y (σ (t)) = 0, where t ≥ t 0 , τ, and α are positive constants and the functions p, q, a, σ ∈ C ([t 0 , ∞) , R). Our results generalize and improve some known results for oscillation of second order… (More)

- Andreas Ruffing, Thomas Deck, Martin Schlichenmaier
- 1992

The propagation differential for bosonic strings on a complex torus with three symmetric punctures is investigated. We study deformation aspects between two point and three point differentials as well as the behaviour of the corresponding Krichever-Novikov algebras. The structure constants are calculated and from this we derive a central extension of the… (More)

We give a conceptual introduction to the q-umbral calculus of the author, a motivation for the q-complex numbers and a historical background to the development of formal computations, umbral calculus and calculus. The connection to trigonometry , prosthaphaeresis, logarithms and Cardan's formula followed by the notational inventions by Viéte and Descartes… (More)

Throughout the paper we discuss results related to the class of entire functions ϕ N (z) ≡ ϕ N (z; λ, q) for N ∈ N, defined by ϕN (0) = 1 and ϕ N (z) = λN z N −1 ϕN (qz) for all z ∈ C, where λ = 0 and while the basic parameter q ∈ (0, 1) assigns a fixed delay. In that sense the functions ϕ N may be regarded as q-delayed analogs of the standard exponentials… (More)

- S Mathias, M Wiesenmayer, F Deicke, A Ruffing, L Miaja-Avila, M M Murnane +3 others
- 2008

The angle resolved photoelectron spectroscopy (ARPES) has emerged as a leading technique in identifying static key properties of complex systems such as the electronic band structure of adsorbed molecules, ultrathin quantum-well films or high temperature superconductors. We efficiently combined ARPES by using a two-dimensional analyzer for parallel energy… (More)

A generalization of the ladder operator formalism for the harmonic oscillator in one-dimensional Schrödinger theory to time scales T shall be considered. Stemming from a fundamental decomposition of the Hamiltonian H into ladder operators A and A † , this can be achieved at least on unitary lattices — characterized by a constant growth of graininess. In… (More)

- S Mathias, S Eich, J Urbancic, S Michael, A V Carr, S Emmerich +16 others
- Nature communications
- 2016

Capturing the dynamic electronic band structure of a correlated material presents a powerful capability for uncovering the complex couplings between the electronic and structural degrees of freedom. When combined with ultrafast laser excitation, new phases of matter can result, since far-from-equilibrium excited states are instantaneously populated. Here,… (More)

- Jerico B. Bacani, Gunther Peichl, Andreas Ruffing
- 2014

- Valery Romanovski, Marko Robnik, Yonghui Xia, Ilknur Kusbeyzi Aybar, Orhan Ozgur Aybar, Xingwu Chen +13 others
- 2013

- Dimitris Andresas, Benjamin Batistić, Janez Bonča, Maša Dukarić, Kristina Gornik, Marko Gosak +22 others
- 2012