田中秀治研究室 ~Student Page~

IFCS 2016 held in New Orleans

    The story began few billion years ago, two black holes orbiting around each other started converging till they finally merged together, creating a unique black hole. The difference in energy between the prior and post-merger states created a ripple in the space-time frame that propagated in space as a gravitational wave (GW). In the meantime, following the theoretical prediction of GWs, scientists all over the world were enticed to design systems that could detect them. One of the detecting facilities was almost completely built by 1997: the laser interferometer gravitational wave observatory (LIGO). It has an L-shaped interferometer, with 4 km arms connecting the beam splitter to the mirrors maintained in constant vacuum. While for years, no acquired measurements led to the detection of GWs, improvements were introduced to the system in order to improve its sensitivity, that now is in the order of 1/10 000th the proton diameter.
    On the second half of last year, only three days prior to the switch of the LIGO from the engineering mode to the research mode, a chirp signal of 0.2 seconds has been detected. Further analysis proved that this signal was in fact created by the previously mentioned GW. However, from now on, detecting GWs won’t the social phenomenon it was the first time anymore. For indeed, the next detected GW on December 26 went almost invisible. While the detection of the first GW proved the existence of GWs, this isn’t the only reason it was grand at least not for the people involved in the LIGO team. It is impressive for being the fruit of years of small improvements in various fields (mechanics, optics, electronics, …) done by a number of people at a time when a finish line wasn’t visible yet.
    Previously this year, I had the chance to join the International Frequency Control Symposium in New Orleans, visiting the LIGO facilities nearby and assist to the talks of some of the people involved in the LIGO project. The scope of the conference was quite large, for it dealt with theoretical aspects as well as practical ones and from the nanoscale to the light-years scale. This year happened to be also the 50th anniversary of the Allan variance, so special sessions regarding the subjects were held. The host city was a very stimulating one from a cultural point of view, with its historical heritage as well as the heavy presence of museums, galleries and artistic venues.
    However, while the city of New Orleans is quite interesting and the different given lectures during the symposium were thought provoking, the most inspiring part was seeing how long can collaborative work spiced up with tenacity and perseverance go.

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