This week in science is a review of the most interesting scientific news of the past week.
The first detection of gravitational waves by both LIGO and Virgo detectors
Early last year, the National Science Foundation (NSF) announced the first-ever detection of gravitational waves, an achievement made possible by using the two Laser Interferometer Gravitational-Wave Observatory (LIGO) detectors located in Livingston, Louisiana, and Hanford, Washington. This week, another detection was announced, this time in partnership with the Virgo detector, located near Pisa, Italy, and funded by the Centre Nationnal de la Recherche Scientifique (CNRS) and the National Institute for Nuclear Physics (INFN).
The collision, designated GW170814, was observed on August 14 and consisted of gravitational wave signals from a pair of black holes colliding. The black holes, located about 1.8 billion light-years away, had masses about 31 times and about 25 times that of the Sun, but formed a spinning black hole with about 53 times the mass of the Sun. Therefore, about three solar masses were converted into gravitational-wave energy, which propagated throughout the space.
Also, because this measurement was made in three different locations, it was possible to narrow down the area in the sky from which the gravitational wave was coming to only 60 square degrees. For a matter of comparison, this area is more than 10 times smaller than what could be accomplished by using data available from the two LIGO interferometers alone. As stated by David H. Reitze, executive director of the LIGO Laboratory:
Virgo brings a powerful new capability to detect and better locate gravitational-wave sources, one that will undoubtedly lead to exciting and unanticipated results in the future.
Finally, the precision in location allowed by the partnership between LIGO and Virgo can be used to enable other partner facilities to perform follow-up observations, which could generate even more data about such events. This time, though, no additional data was detected coming from the region of the GW170814 event, as expected for the collision of two black holes.
A new type of supercomputer proposed and successfully tested
The supercomputers we have nowadays can only deal with a small subset of huge mathematical problems each time. Since many of the real world problems require several dimensions to be modeled or their structures don't allow a quick search for a minimized - or optimal - solution, scientists around the world face huge issues when trying to solve such problems.
In fact, not even a quantum computer could improve this task, since, for a brute-force search for the global minimum, the theorized speed-up would be only quadratic. That is why a team of scientists from Cambridge, Southampton, and Cardiff Universities in the UK and the Skolkovo Institute of Science and Technology in Russia has proposed a few years ago a new type of supercomputer that uses quantum particles known as polaritons, which are half light and half matter.
The team's first successful results from experimental data were recently published in the journal Nature Materials. In the experiment, the polaritons were used as a type of 'beacon', capable of showing the way to the simplest solution. Because polaritons can achieve sufficient densities to form a Bose-Einstein condensate, they can form a single quantum object and be detected through photoluminescence measurements.
The polaritons were created by shining a laser at stacked layers of gallium, arsenic, indium, and aluminum atoms. After that, they were put in a potential landscape that corresponds to the mathematical function to be minimised. There, the polaritons would then condense at the lowest point of the potential, where they could be detected after forming a Bose-Einstein condensate.
As stated by Professor Pavlos Lagoudakis, Head of the Hybrid Photonics Lab at the University of Southampton and the Skolkovo Institute of Science and Technology, the team is yet beginning to explore the potential of polariton graphs for solving complex problems. They are currently scaling up the device with the ultimate goal of building a microchip capable of operating at ambient conditions.
To round off our weekly science wrap up, the UAE has announced it is going to build the largest Mars base here on Earth. The Mars Scientific City aims to be a fully functioning simulation of what it will be like on an actual Mars base and scientists will be able to spend a year there completely isolated from the outside world. The project will cost £100 million and will be built in the Emirati Desert.