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A great year for Physics

The world of Physics may be one of the most complex and abstract sciences to understand. Yet, it is the field of Physics that helps us to understand the world – in all its dimensions – in which we live.

Wits physicists are at the leading edge of experiments at the LHC, which was restarted in 2015 after a two-year shut-down. These experiments have reported a number of tantalising peculiarities in the data.

“With the discovery of the Higgs boson a new window of opportunity has opened to discover new particles and interactions in nature. These may help us understand many unresolved mysteries, such as where most of the matter in the Universe comes from, among others,” says Professor Bruce Mellado from the Wits School of Physics. “Experiments in the LHC also provide an insight of what happened right after the Big Bang via the study of collisions of heavy ions at high energies.”

Processing the vast amounts of data generated by the LHC pushes the boundaries of technology. In collaboration with the HEP group, Trax, a South African company, has produced the most complex electronics board ever manufactured in the country. This is a prototype of an electronics board for the upgrade of the ATLAS detector at the LHC and will be fully manufactured in South Africa.

Wits’ newly-launched Light Laboratory, under the leadership of Distinguished Professor Andrew Forbes, saw two papers on ground- breaking research on the behaviour and manipulation of light being published shortly after the launch of the lab.

Working with his former colleagues from the CSIR, Forbes found a way to change the angular orbital momentum (OAM) or “twist” of a laser beam at the source.

“Our novelty was to realise that by using custom-geometric phase optics to map polarisation to OAM, the laser could be designed to tell the difference between the clockwise and anticlockwise light,” said Forbes.

The world of Physics is entering a highly exciting period this year. Experiments that the world’s top physicists – including those of Wits – have been working on for decades have been coming to fruition, and are paying off with fascinating findings.

Earlier this year, researchers at the Laser Interferometer Gravitational-Wave Observatory (LIGO), in the US, have found evidence of Gravitational Waves, a phenomenon that Albert Einstein had described almost exactly 100 years ago.

LIGO’s gravitational wave detectors used laser interferometry to measure the minute ripples in space-time caused by passing gravitational waves from cataclysmic cosmic sources such as the mergers of pairs of neutron stars or black holes, or by supernovae.

In September 2015, the LIGO team detected a disturbance on the 4km arms of the LIGO detector. The disturbance came from two black holes that spent aeons circling each other, hurtling closer and closer, before they eventually collided, releasing great shudders of gravitational energy. Those waves — whose power output briefly exceeded that of all the visible stars in the universe combined — travelled for 1.3 billion years before they washed over the Earth.

The ripples that were detected changed the length of the arms of the LIGO detector by just one-ten-thousandth the diameter of a proton, but this was enough for the team to confirm the existence of Gravitational Waves.

“It was a major discovery, and it opens up a whole new field of Astrophysical research,” says Professor Andreas Faltenbacher of the Wits School of Physics, who, along with his colleagues Professors Kevin Goldstein and Andrew Forbes presented a public lecture on the research.

Working on a completely different part of the World at the European Organisation for Nuclear Research (CERN), the Wits High Energy Physics group (HEP) is terribly excited at the prospects of new discoveries at the Large Hadron Collider (LHC).

Article from Wits Leader, edition 2, 2016

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