Hector E. Nistazakis

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In this paper, we derive mathematical expressions for the evaluation of the average (ergodic) capacity of free-space optical (FSO) communication systems. Atmospheric turbulence conditions are modeled using the I-K distribution. Our newly derived expressions provide an efficient tool to assess the spectral efficiency of FSO communication systems. Numerically(More)
Turbulence fading is one of the main impairments affecting the operation of free-space optical (FSO) communication systems. The authors study the performance of FSO communication systems, also known as wireless optical communication systems, over log-normal and gamma–gamma atmospheric turbulenceinduced fading channels. These fading models describe the(More)
The free space optical communication systems are attracting great research and commercial interest due to their capability of transferring data over short distances, with high rate and security, low cost demands and without licensing fees. However, their performance depends strongly on the atmospheric conditions in the link’s area. In this work, we(More)
The dynamics of dark matter-wave solitons in elongated atomic condensates are discussed at finite temperatures. Simulations with the stochastic Gross-Pitaevskii equation reveal a noticeable, experimentally observable spread in individual soliton trajectories, attributed to inherent fluctuations in both phase and density of the underlying medium. Averaging(More)
This paper elaborates on the end-to-end capacity of dual-hop free-space optical (FSO) communication systems employing amplify-and-forward (AF) relaying, assuming channel state information is only known at the receiving terminals. The relay is assumed to either possess perfect channel state information or have a fixed gain. The performance of the considered(More)
We study the asymptotic behavior of complex discrete evolution equations of GinzburgLandau type. Depending on the nonlinearity and the data of the problem, we find different dynamical behavior ranging from global existence of solutions and global attractors, to blow up in finite time. We provide estimates for the blow up time, depending not only on the(More)
H. E. Nistazakis, D. J. Frantzeskakis, P. G. Kevrekidis, B. A. Malomed, R. Carretero-González, and A. R. Bishop Department of Physics, University of Athens, Panepistimiopolis, Zografos, Athens 15784, Greece Department of Mathematics and Statistics, University of Massachusetts, Amherst, Massachusetts 01003-4515, USA Department of Interdisciplinary Studies,(More)
Optical wireless communication (OWC) systems are rapidly gaining popularity as effective means of transferring data at high rates over short distances. OWC facilitates rapidly deployable, lightweight, high-capacity communication without licensing fees and tariffs. Nevertheless, the performance of this new technology depends strongly on the atmospheric(More)
H. E. Nistazakis, D. J. Frantzeskakis, P. G. Kevrekidis, B. A. Malomed, and R. Carretero-González Department of Physics, University of Athens, Panepistimiopolis, Zografos, Athens 15784, Greece Department of Mathematics and Statistics, University of Massachusetts, Amherst, Massachusetts 01003-4515, USA Department of Physical Electronics, Faculty of(More)
In a model of a dynamical lattice with the on-site second-harmonic-generating nonlinearity and harmonic intersite couplings (that may be equal or different for the fundamental and second harmonics), various solitary-wave solutions are considered in one and two dimensions (1D and 2D). Fundamental (single-hump) solitons are identified in either dimension and(More)