The paper deals with the problem of output regulation for the class of multiinput multi-output square nonlinear systems satisfying a minimum-phase assumption and a “positivity” condition on the high-frequency gain matrix. By following a design paradigm proposed in [12] for single-input single-output nonlinear systems, it is shown how an internal model-based controller can be obtained, whose dim...

In the long-wave, weakly nonlinear limit a generic model for the interaction of two waves with nearly coincident linear phase speeds is a pair of coupled Korteweg-de Vries equations. Here we consider the simplest case when the coupling occurs only through linear non-dispersive terms, and for this case delineate the various families of solitary waves that can be expected. Generically, we demonst...

The runtime performance of modern SAT solvers on random k-CNF formulas is deeply connected with the ‘phase-transition’ phenomenon seen empirically in the satisfiability of random k-CNF formulas. Recent universal hashing-based approaches to sampling and counting crucially depend on the runtime performance of SAT solvers on formulas expressed as the conjunction of both k-CNF and XOR constraints (...

If there was a first-order phase transition in the early universe, there should be an associated stochastic background of gravitational waves. In this paper, we point out that the characteristic frequency of the spectrum due to phase transitions which took place in the temperature range 100 GeV–107 GeV is precisely in the window that will be probed by the second generation of space-based interf...

We analyze the eigenvalues and eigenvectors of the staggered Dirac operator in quenched lattice QCD in the vicinity of the deconfinement phase transition using the Lüscher-Weisz gauge action. The spectral and localization properties of the low-lying eigenmodes show characteristic differences between the Z3 sectors above the critical temperature Tc. These findings can be interpreted in terms of ...

To gain high power in a desirable higher frequency, combining a number of identical elements have been a good practical solution. In recent years significant effort has been carried out to combine independent oscillators coupled together. When these oscillators are coupled together the complexity of the whole system increases due to the fact that interaction between the elements occur in severa...

Because of the implications for plasmas in the laboratory and in space, attention has been drawn to inhomogeneous energy-density driven (IEDD) waves that are sustained by velocity-shear-induced inhomogeneity in crossfield plasma flow. These waves have a frequency ωr in the lab frame within an order of magnitude of the ion gyrofrequency ωci , propagate nearly perpendicular to the magnetic field ...

The lifetime of the antisymmetric stretch mode of interstitial oxygen in crystalline Si is measured directly by time-resolved, transient bleaching spectroscopy to be T1 = 229 ± 16 ps at 10 K. The temperature dependence of the lifetime shows that the stretch mode decays into eight vibrational modes of 142 ± 20 cm. The low-temperature width of the FTIR (IR) absorption line due to the stretch mode...

Electronic states in disordered conductors on the verge of localization are predicted to exhibit critical spatial characteristics indicative of the proximity to a metal-insulator phase transition. We used scanning tunneling microscopy to visualize electronic states in Ga(1-x)Mn(x)As samples close to this transition. Our measurements show that doping-induced disorder produces strong spatial vari...

Since the introduction of ultra-fast laser techniques for the generation and detection of broadband terahertz pulses, terahertz time-domain spectroscopy has become a versatile tool for vibrational spectroscopy of molecular systems in the far-infrared. Due to their highly collective and delocalized character vibrational modes in this part of the spectrum are highly sensitive to molecular structu...