The spectral properties of the 1-D Hubbard model are obtained from quantum Monte Carlo simulations using the maximum entropy method. The one-particle excitations are characterized by dispersive cosine-like bands. Velocities for spin-and charge excitations are obtained that lead to a conformal charge c = 0:98 0:05 for the largest system simulated (N = 84). An exact sum-rule for the spin-excitati...

2014 The spectrum of amplitudons and phasons has been calculated for a 3-k triangular incommensurate structure (such as it is found in quartz-type crystals) using a phenomenological model. Two excitations have acoustic-like dispersion curves (gapless phasons) and four excitations are optic-like, one of the latter corresponding to fluctuations of the sum of the phases of the three modulation wav...

The design of excitation signals for Magnetic Resonance Imaging (MRI) is cast as an optimal control problem. Here, we demonstrate that signals other than pulse excitations, which are ubiquitous in MRI, can provide adequate excitation, thus challenging the optimality and ubiquity of pulsed signals. A class of on-resonance piecewise continuous amplitude modulated signals is introduced. It is show...

Pulse period of earthquake records has been known as a key parameter in seismology and earthquake engineering. This paper presents a detailed characterization of this parameter for a special class of earthquake records called pulse-like ground motions. This type of motions often resulting from directivity effects is characterized by a strong pulse in the velocity time history of motion, in norm...

The Kitaev model exhibits a canonical quantum spin liquid as ground state and hosts two fractional quasiparticles, itinerant Majorana fermion localized flux excitation. former can carry heat modulations in the liquid, but role of latter remains unknown for transport phenomena. Here, we focus on presence excited fluxes report that they yield strong interference propagation fermions, which feel g...

The main objective of this paper is to present a wavelet-based procedure to characterize principle features of a special class of motions called pulse-like ground motions. Initially, continues wavelet transform (CWT) which has been known as a powerful technique both in earthquake engineering and seismology field is applied easily in automated detecting of strong pulse of earthquakes. In this pr...