This week the top physics headlines included such discoveries as a new architecture for a quantum computer, a solution of a 20-year debate regarding glassy surfaces and another step in the search for dark matter. As always, let’s do a short summary of the top news of this week. If you would like to receive the top news of physics straight to your email, plus free physics videos and books, register for our email newsletter.
The idea of a quantum computer — a machine that would use quantum physics in calculations — has fascinated scientists for a very long time. Such a computer, in theory, would be much faster and powerful than even the most powerful conventional supercomputers. However, creating such a machine is not an easy task.
The computational heart of a quantum computer is composed of multiple quantum bits, or qubits, that can each store 0 and 1 at the same time. These qubits become “entangled” or correlated in ways that are impossible in conventional machines. However, for a large number of qubits, it becomes significantly harder to maintain entanglement. Or in simple words, as quantum systems are made bigger, they generally lose their “quantum-ness”.
Recently, however, physicists led by ion-trapper Christopher Monroe at the JQI have proposed a modular quantum computer architecture that promises scalability to much larger numbers of qubits. The components of this architecture have individually been tested and are available, making it a promising approach. To find out more, use the link above.
A step closer to the solution to the mystery of dark matter
The Leiden astrophysicist Alexey Boyarsky and his fellow researchers may have identified a trace of dark matter that could signify a new particle: the sterile neutrino. Interestingly, a research group in Harvard reported a very similar signal just a few days earlier.
The finding that both groups reported was an indirect signal from dark matter in the spectra of galaxies and clusters of galaxies. In particular, they observed a tiny spike that was hidden in the X-ray spectra of the Perseus galaxy cluster, at a frequency that cannot be explained by any known atomic transition. A possible interpretation of this could be a decay of a new kind of neutrino, called ‘sterile’ because it has no interaction with other known neutrinos.
In a series of experiments, University of Waterloo researchers and colleagues started with very thin slices of polystyrene stacked to create tiny staircase-like steps about 100-nanometers high — less than 0.001 per cent the thickness of a human hair. They then measured these steps as they became shorter, wider and less defined over time. The paper investigated how the top layer of glassy polymers is always moving despite the layers underneath being frozen or solid-like.
These findings offer a convincing solution to the 20-year-old debate on how and why glass can flow depending on temperature. Understanding the mobility of glassy surfaces has implications for the design and manufacture of thin-film coatings and also sets practical limits on how small we can make nanoscale devices and circuitry.