Last year may not have been the greatest (or the happiest) in history, but as far as physics goes it did not let us down. We saw a continuance of the excellent discussions, propositions, theories, experiments and discoveries that marked the previous few years, as well as a surge in discussions about gender equality in physics and making young students better aware of careers in physics.
In our first editorial of 2016, we take a look back at the most notable events in the world of physics in 2016. From astrophysics to high-energy physics to condensed matter physics, there was something interesting in every field this past year.
LIGO discovers gravitational waves
We published an explainer about LIGO almost as soon as the news was announced because this was a big discovery in physics. It was perhaps the biggest since the discovery of the Higgs boson. In 1915, Einstein’s theory of general relativity led to several predictions, among which gravitational waves were some of the more exotic ones. (Wormholes, we hope, are on the way.) Thanks to the success of LIGO, a more precise Advanced LIGO is now in the works.
While gravitational waves did not prove Einstein’s theory, they were an important confirmation of his predictions. With a black hole merger giving off energy as gravitational waves, the two Laser-Interferometer Gravitational-waves Observatories in America, consisting of 4 km tunnels placed 3,000 km apart, simultaneously detected spatial expansions/contractions due to these waves in an historic confirmation of Einstein’s theory that came 101 years after his first paper on general relativity.
CERN and the tetraquark
Quarks are one of the most fundamental particles we know today. And we knew that pairs and triplets of quarks existed. But earlier this year CERN results showed the presence of quadruplets of quarks that exist together, albeit for only a tiny fraction of time, before decaying into other (deemed less exotic) particles.
The LHCb collaboration noticed quite a few such tetraquarks made up of charm, anti-charm, strange and anti-strange quarks when studying the decay of B-mesons. Although first proposed in 2003, the first solid evidence came in 2014, with some doubts being cast on further candidates in February 2016 before three promising candidates were finally named in June of last year.
Topology stars in the 2016 Nobel
Another year, another Nobel for condensed matter physics. David Thouless, Duncan Haldane and Michael Kosterlitz won the physics Nobel in 2016 for their work on topological phase transitions.
We published an interesting explainer on their work, complete with an introduction to topology and details of its role in physics. The KT transition, their explanation of the quantum hall effect and how their use of topology paved the way for similar analysis of various other phenomena across physics.
Relative, time symmetric crystals
A new type of crystal symmetry was defined in 2016 wherein the symmetry is not defined based on atomic or molecular positions in space but rather based on the relationship between their periodic motions. Interestingly enough, this concept arose form the symmetry one may quickly recognised among satellites (which, needless to say, are in periodic motion).
Physicists working on a proposed gravitational wave observatory thought of having four satellites in non-coplanar orbit around the Sun, which led to the proposal of this new type of crystal structure. The amount of such relative positional symmetry among periodically moving bodies is given by their choreography.
Dead/alive cats are back, now in twos
The rather funnily named two-mode Schrödinger’s cat state speaks of the famous dead/alive cat-in-the-box thought experiment but this time in terms of two cats dead or alive and also possibly in two boxes at once. Nobody asked for this. In all seriousness, though, this is the idea of having photons in superposition and in two entangled states, represented by the cats, dead/alive states and the boxes respectively.
The reason this idea is on our list is because it marks a milestone in quantum computing as physicists find ways of defining increasingly complex quantum states that can one day make everyday quantum computing a reality. The experiment involved using two harmonic oscillators, generating microwave fields that would be confined in two cavities and then comparing the states of the photons in these cavities. Sciencea concise description provided when the study came out in May last year.
More in physics — and in Physics Capsule
There were many more discussions this year that proved to be extremely interesting and sparked several debates. New potentially habitable planets were found, some questioned dark matter while others tried to explain it, the idea of a sterile neutrino was cast aside, negative refraction of electrons was discovered in graphene etc. And there were some news we never wanted to hear: Vera Rubin, one of the first physicists to help confirm the existence of dark matter, died in December. And yet, thorough the year, in the spirit of physics, some indulged in fun bubble blowing.
Here at Physics Capsule, we went through some big changes ourselves: we moved hosting to Los Angeles, ramped up security, speed and reliability and refined some of our backstage work. We also refined our design with bolder images and a generally more wholesome and polished user experience. For a second year, we retained Adobe Text as our main typeface, accompanied by Filson Pro and, for headings, we moved to a classic choice that embodies our website, aims and beliefs: Cheltenham.
We hope to have a lot more for you this year, in writing and otherwise, and we are thrilled and thankful to have you with us on this wonderful journey. Here’s looking forward to a great year ahead.