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Yayın Blow-up and global existence for a general class of nonlocal nonlinear coupled wave equations(Academic Press Inc Elsevier Science, 2011-02-01) Duruk, Nilay; Erbay, Hüsnü Ata; Erkip, AlbertWe study the initial-value problem for a general class of nonlinear nonlocal coupled wave equations. The problem involves convolution operators with kernel functions whose Fourier transforms are nonnegative. Some well-known examples of nonlinear wave equations, such as coupled Boussinesq-type equations arising in elasticity and in quasi-continuum approximation of dense lattices, follow from the present model for suitable choices of the kernel functions. We establish local existence and sufficient conditions for finite-time blow-up and as well as global existence of solutions of the problem.Yayın Time-dependent lateral diffusion in WO3 thin films(Elsevier B.V., 2023-10) Karakurt, İsmail; Başar, Günay; Leiderer, Paul; Parlatan, Şeyma; Arapoğlu, NihanWe have studied the anomalous lateral diffusion process in thin tungsten trioxide films by optical means. The diffusion process seems to start at imperfections within the film a few seconds after the H+ ion intercalation begins, and progresses parallel to the surface of the film. We measured the mean square displacement of the diffusion front and used its time-dependence to calculate the instantaneous diffusion coefficient. The anomalous exponents are found to be 2.24 and 2.92 for 400 nm and 270 nm thick films, respectively. We explain the observed large diffusion coefficients and depth dependence of the expansion of the film by interfacial job-sharing diffusion of electrons and protons. Raman measurements were also carried out on virgin films, and on films after the lateral diffusion. Although the observed spectrum after the lateral diffusion is, in general, consistent with the literature for H+ intercalated films, we observe an additional strong band at 855 cm?1. This lateral diffusion process is observed to be irreversible; therefore, it has to be avoided in electrochromic switching devices based on WO3.Yayın Quantum Zeno repeaters(Nature Research, 2022-09-12) Bayrakçı, Veysel; Özaydın, FatihQuantum repeaters pave the way for long-distance quantum communications and quantum Internet, and the idea of quantum repeaters is based on entanglement swapping which requires the implementation of controlled quantum gates. Frequently measuring a quantum system affects its dynamics which is known as the quantum Zeno effect (QZE). Beyond slowing down its evolution, QZE can be used to control the dynamics of a quantum system by introducing a carefully designed set of operations between measurements. Here, we propose an entanglement swapping protocol based on QZE, which achieves almost unit fidelity. Implementation of our protocol requires only simple frequent threshold measurements and single particle rotations. We extend the proposed entanglement swapping protocol to a series of repeater stations for constructing quantum Zeno repeaters which also achieve almost unit fidelity regardless of the number of repeaters. Requiring no controlled gates, our proposal reduces the quantum circuit complexity of quantum repeaters. Our work has potential to contribute to long distance quantum communications and quantum computing via quantum Zeno effect.
