This thesis presents measurements of collective modes and ultrafast carrier relaxation dynamics in charge-density-wave (CDW) conductors and colossal magneto-resistance (CMR) manganites by means of femtosecond time-resolved optical spectroscopy. In these experiments, a femtosecond laser pump pulse excited a broad frequency spectrum of low-energy collective modes and electron-hole pairs via inter...

The dynamic structure factor of glassy and liquid glycerol has been measured by inelastic X-ray scattering in the exchanged momentum (Q) region Q=2÷23 nm and in the temperature range 80÷570 K. Beside the propagating longitudinal excitations modes, at low temperature the spectra show a second non Q-dispersing peak at ~ΩT≈8.5 meV. We assign this peak to the transverse dynamics that, in topologica...

The quantum theory of U(1) connections admits a diffeomorphism invariant representation in which the electric flux through any surface is quantized. This representation is the analog of the representation of quantum SU(2) theory used in loop quantum gravity. We investigate the relation between this representation, in which the basic excitations are ‘polymer-like’, and the Fock representation, i...

Like adiabatic time-dependent density-functional theory (TD-DFT), the Bethe–Salpeter equation (BSE) formalism of many-body perturbation theory, in its static approximation, is “blind” to double (and higher) excitations, which are ubiquitous, for example, conjugated molecules like polyenes. Here, we apply spin-flip ansatz (which considers lowest triplet state as reference configuration instead s...

A renormalizable coupling between the Higgs and a scalar unparticle operator OU of non-integer dimension dU < 2 triggers, after electroweak symmetry breaking, an infrared divergent vacuum expectation value for OU . Such IR divergence should be tamed before any phenomenological implications of the Higgs-unparticle interplay can be drawn. In this paper we present a novel mechanism to cure that IR...

By using observations from pump-probe stroboscopic confocal microscopy and spectroscopy, we demonstrate the dynamics of trions fractional quantum Hall edge on order ∼1 ps. The propagation state excited by a voltage pulse is detected as temporal change in reflectance downstream probed optical pulses synchronized with pulse. resolution such measurements fast duration time probe (∼1 ps). This ultr...