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We have observed ultrashort electromagnetic pulse radiation from YBa2Cu3O7-δ thin-film dipole antennas. The supercurrent transient is created by the excitation of the supercarriers into quasiparticles with a femtosecond laser pulse, and freely propagated electromagnetic pulses are measured and characterized. A pulse with 0.5 ps full width at half-maximum was obtained, containing frequency components up to 2.0 THz. A femtosecond time-resolved characterization of the spectra revealed that they strongly depend on the excitation conditions, and the quasiparticle recombination time becomes longer with increase in the excitation intensity. It is also observed that the radiation power increases in proportion to the square of both the bias current and the laser power in the region of weak excitation, which is consistent with the classical theory based on a two-fluid model. In the region of strong excitation, deviation from the classical theory was observed.

Ultrashort electromagnetic waves (600 fs width) from superconducting YBCO thin films have been observed by irradiating current-biased samples with femtosecond optical laser pulses (80 fs width). The Fourier component of the pulse extends up to ∼2 THz. The characteristics of the radiation are studied and the radiation mechanism is ascribed to the ultrafast supercurrent modulation by the laser pulses, which induce the nonequilibrium superconductivity.

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Making it easier to design interactions between agents and humans is essential for realizing multi-agent simulations of social phenomena such as group dynamics. To realize large-scale social simulations, we have developed the scenario description languages Q and IPC (Interaction Pattern Card); they enable experts in the application domain (often not computing professionals) to easily create complex scenarios. We have also established a four-step process for creating scenarios: 1) defining a vocabulary, 2) describing scenarios, 3) extracting interaction patterns, and 4) integrating real and virtual experiments. In order to validate the scenario description languages and the four-step process, we ran a series of evacuation simulations based on the proposed languages and process. We successfully double-check the result of the previous controlled experiment done in a real environment.