Canadian Physics Wins 3 of Top 10 Breakthroughs of the Year

Published by the UK's prestigious Institue of Physics, Physics World announced its annual Top 10 Breakthroughs of the Year today.  Canadian physicists captured a spot in 3 of the results, including first place. Seventh place goes to the Tokai-to-Kamiokande (T2K) neutrino experiment in Japan for which Canada is one of the lagrest international partners and TRIUMF is an active leader in the accelerator, detector, computing, and physics analysis.

Quoting from the website, the top 10 breakthroughs were as follows:

1. Shifting the morals of quantum measurement. Work from Aephraim Steinberg and colleagues at the University of Toronto stood out because it challenges the widely held notion that quantum mechanics forbids us any knowledge of the paths taken by individual photons as they travel through two closely spaced slits to create an interference pattern. This interference is exactly what one would expect if we think of light as an electromagnetic wave. But quantum mechanics also allows us to think of the light as photons – although with the weird consequence that if we determine which slit individual photons travel through, then the interference pattern vanishes. By using weak measurements Steinberg and his team have been able to gain some information about the paths taken by the photons without destroying the pattern. In the experiment, the double slit is replaced by a beamsplitter and a pair of optical fibres. A single photon strikes the beamsplitter and travels along either the right or the left fibre. After emerging from the closely spaced ends of the parallel fibres, it creates an interference pattern on a detector screen. The weak measurement is performed by passing the emerging photons through a piece of calcite, which imparts a tiny rotation in the polarization of the photon. The amount of rotation depends on the direction of travel of the photon – in other words, its momentum. The photons are then "post-selected" according to where they strike the screen, which allows the researchers to determine the average direction of travel of photons that arrive there. The experiment reveals, for example, that a photon detected on the right-hand side of the diffraction pattern is more likely to have emerged from the optical fibre on the right than from the optical fibre on the left. While this knowledge is not forbidden by quantum mechanics, Steinberg says that physicists have been taught that "asking where a photon is before it is detected is somehow immoral".
2. Measuring the wavefunction. Second place goes to another group that has asked a "forbidden question". Led by Jeff Lundeen at the National Research Council of Canada in Ottawa – a former colleague of Steinberg – a team has used weak measurement to map out the wavefunction of an ensemble of identical photons without actually destroying any of them. Quantum tomography, in contrast, maps out the wavefunction at the expense of destroying the state. As well as boosting our understanding of the fundamentals of quantum mechanics, the technique could prove useful in cases where tomography cannot be used.
3. Cloaking in space and time. Researchers at Cornell University and Imperial College London described a technique for cloaking an event in space and time and then built a device using two split time lenses to accomplish that eat. 
4. Measuring the universe using black holes.  Researchers at the University of Copenhagen and the University of Queensland found a way to use supermassive black holes in glaaxy cores known as Active Galactic Nuclei as standard candles for measuring the size and expansion of the universe.
5. Turning darkness into light.  Physicists at the Chalmers University of Technology in Sweden with collaborators in the US, Japan, and Australia have been the first to observe the dynamical Casimir effect which validates the ideas of vacuum polarization.
6. Taking the temperature of the early universe.  Just after the Big Bang, the universe was a complicated soup of free quarks and gluons that eventually condensed to form the protons and neutrons we see today. Sixth place in our top 10 goes to a team of physicists in the US, India and China that has made the best calculation yet of this condensation temperature: two trillion degrees Kelvin.
7. Catching the flavour of a neutrino oscillation. Seventh place is awarded to the international team of physicists working on the Tokai-to-Kamioka (T2K) experiment in Japan. The researchers fired a beam of muon neutrinos 300 km underground to a detector, where they found that six neutrinos had changed, or "oscillated", into electron neutrinos. While the measurement is not good enough to claim the discovery of the muon-to-electron neutrino oscillation, it is the best evidence yet that one "flavour" of neutrino can oscillate into another.  TRIUMF has been a key partner in the T2K project, particularly with the host laboratories KEK and J-PARC.  Not only did an element of the experiment's advantageous design come from TRIUMF, but also researchers at TRIUMF helped build the accelerator and target areas as well as the near detectors. 
8. Living laser brought to life. In a fascinating bit of biophysics, Harvard Medical School researchers share eighth place for being the first to make a laser from a living biological cell.
9. Complete quantum computer made on a single chip. Researchers at the University of California, Santa Barbara for being the first to implement a quantum version of the "Von Neumann" architecture found in PCs.
10. Seeing pure relics from the Big Bang. Researchers at the University of California, Santa Cruz and Saint Michael's College in Vermont take 10th spot for being the first to catch sight of clouds of gas that are pure relics of the Big Bang.

Congratulations to all these dedicated researchers and the teams that support them.  Keep up the good work!

-- by T.I. Meyer, Head of Stategic Planning & Communications