An arbitrary optical waveform can be measured using the technique called the ‘petahertz optical oscilloscope’ in which an electron trajectory in the process of high harmonic generation is used as a fast temporal gate. In the petahertz optical oscilloscope, a signal laser pulse that needs to be measured is superposed on a fundamental laser pulse that generates high harmonic radiation. The additi...

The phase diagram of a system of electrons hopping on a square lattice and interacting through long-range Coulomb forces is studied as a function of density and interaction strength. The presence of a lattice strongly enhances the stability of the Wigner crystal phase as compared to the case of the two-dimensional electron gas.

Increasing evidence suggests that brain signal variability is an important measure of brain function reflecting information processing capacity and functional integrity. In this study, we examined how maturation from childhood to adulthood affects the magnitude and spatial extent of state-to-state transitions in brain signal variability, and how this relates to cognitive performance. We looked ...

By applying the renormalization group method to two-coupled chains in the Tomonaga model, the role of interchain hopping has been studied in the entire energy region. The energy for a crossover from the perturbational regime to the relevant regime becomes smaller than that of the interchain hopping due to one-dimensional fluctuations of the mutual interaction. From the calculation of response f...

We present in situ high-pressure synchrotron X-ray diffraction (XRD) and Raman spectroscopy study, and electrical transport measurement of single crystal WSe2 in diamond anvil cells with pressures up to 54.0-62.8 GPa. The XRD and Raman results show that the phase undergoes a pressure-induced iso-structural transition via layer sliding, beginning at 28.5 GPa and not being completed up to around ...

Small para-H2 clusters (pH2)N with N=2,...,8 have been identified by Raman spectroscopy in cryogenic free jets of the pure gas, near the Q(0) Raman line of the H2 monomer. The high resolution in space, time, and number size makes it possible to follow their growth kinetics with distance from the orifice. At lower source temperatures liquid clusters appear early in the expansion and then undergo...

We propose a novel reconfigurable time domain spectral phase encoding (SPE) scheme for coherent optical code-division-multiple-access application. In the proposed scheme, the ultra-short optical pulse is stretched by dispersive device and the SPE is done in time domain using high speed phase modulator. The time domain SPE scheme is robust to wavelength drift of the light source and is very flex...

Conventional speech enhancement methods typically utilize the noisy phase spectrum for signal reconstruction. This letter presents a novel method to estimate the clean speech phase spectrum, given the noisy speech observation in single-channel speech enhancement. The proposed method relies on the phase decomposition of the instantaneous noisy phase spectrum followed by temporal smoothing in ord...

The short-time Fourier transform (STFT) of a speech signal has two components: the magnitude spectrum and the phase spectrum. In this paper, the relative importance of short-time magnitude and phase spectra for speech perception is investigated. Human perception experiments are conducted to measure intelligibility of speech stimuli synthesized either from magnitude spectra or phase spectra. It ...