含羞草传媒

Professor Aephraim Steinberg (left) and his former graduate student Krister Shalm are delighted to that their quantum mechanics experiment has been named the year's top experiment by Physics World magazine. (Arts and Science photo)

U of Toronto experiment named top breakthrough of 2011 by Physics World

Professor Aephraim Steinberg, colleagues at Centre for Quantum Information and Quantum Control lauded

Professor Aephraim Steinberg and colleagues at the Centre for Quantum Information and Quantum Control at the 含羞草传媒 had the top physics breakthrough of the year according to Physics World magazine.

Steinberg led an international team in applying a modern measurement technique to the historical two-slit interferometer experiment in which a beam of light shone through two slits results in an interference pattern on a screen behind.  That famous experiment and the 1927 debates between Niels Bohr and Albert Einstein, seemed to establish that you could not watch a particle go through one of two slits without destroying the interference effect: you had to choose which phenomenon to look for.  Thus the quantum mechanics quandary: how can we know reality if we cannot measure it without distorting it?

With their new experiment, Steinberg鈥檚 group did what the physics textbooks said was impossible.  They succeeded in experimentally reconstructing full trajectories which provide a description of how light particles move through the two slits and form an interference pattern.  Their description of the experiment was published in Science and resulted in coverage by the world鈥檚 science media, including a feature in .

鈥淏y applying a modern measurement technique to the historic experiment, we were able to observe the average particle trajectories undergoing wave-like interference, which is the first observation of its kind.  This result should contribute to the ongoing debate over the various interpretations of quantum theory,鈥 said Steinberg. 鈥淚t shows that long-neglected questions about the different types of measurement possible in quantum mechanics can finally be addressed in the lab, and weak measurements such as the sort we used in this work may prove crucial in studying all sorts of new phenomena.鈥

With regards to the being named top breakthrough of the year, Steinberg said, 鈥淲hen I was  a graduate student, I told a mentor of mine that I was perplexed and fascinated by quantum mechanics and wished to spend my career studying it.  He nodded and replied, 鈥楾hat鈥檚 all right in a young physicist 鈥 hopefully you鈥檒l grow out of it.鈥  So what pleases me most about this honour is how much times have changed. Physics World is recognizing the study of the foundations of quantum mechanics as a respectable, even important endeavour. 

" I hope that lifting taboos about what questions one can still ask will lead to continued discoveries about the implications of quantum mechanics and perhaps in the long term even new applications, as has been the case in the realm of quantum information processing.鈥
 

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