The harnessing of quantum phenomena, such as superposition and entanglement, holds great promise for constructing future supercomputers using quantum technology. One huge advantage of these so-called quantum computers is that they are capable of performing a variety of tasks much quicker than their conventional counterparts.
They do, however, raise a significant challenge: how can one verify the results provided by a quantum computer?
It is only recently that theoretical developments have provided methods to test a quantum computer without having an additional quantum computer at hand. Now, the University of Vienna's Philip Walther and his international team of researchers have demonstrated a new protocol, where the quantum computational results can be verified without using additional quantum computer resources.
To do this, the scientists inserted 'traps' - short intermediate calculations to which the user knows the result in advance - into the tasks. If the quantum computer 'malfunctions' the trap delivers a result that differs from the expected one. The more traps the user builds into the tasks the better the user can be sure that the quantum computer indeed computes accurately.
The test was designed in such a way that the quantum computer cannot distinguish the trap from its normal tasks - an important requirement that guarantees no 'tweaking' of the test result by the quantum computer. The researchers have also tested whether the quantum computer really resorts to quantum resources, so that they can ensure that even a maliciously constructed quantum computer cannot fool them into accepting incorrect results.
For their first demonstration the researchers used an optical quantum computer, where photons carry the information. The protocol is generic, but optical quantum computers facilitate easier interactions, thanks to photon mobility.
Philip Walther is optimistic about the prospects raised by this experiment, which he believes shows promising control mechanisms for future quantum computers. Moreover, it might even lead to new tools for probing complex quantum resources.
Plastics found on Titan!
NASA's Cassini spacecraft has detected propylene, a chemical used to make food-storage containers, car bumpers and other consumer products, on Saturn's moon Titan. This is the first definitive detection of the plastic ingredient on any moon or planet, other than Earth. The small amount of propylene was identified in Titan's lower atmosphere by Cassini's Composite Infrared Spectrometer (CIRS).
The detection of the chemical fills in a mysterious gap in Titan observations that dates back to NASA's Voyager 1 spacecraft and the first-ever close flyby of this moon in 1980.
Voyager identified many of the gases in Titan's hazy brownish atmosphere as hydrocarbons, which form when sunlight breaks down methane, the second-most plentiful gas in that atmosphere.
These freed 'fragments' link to form chains with two, three or more carbon atoms - a family of chemicals that includes ethane, propane and propyne. Another member of this family - propylene - proved elusive to Voyager 1's instruments. It was finally found as a result of more detailed analysis of the CIRS data.
Scott Edgington, Cassini's deputy project scientist at NASA's Jet Propulsion Laboratory says he always gets excited when scientists discover a molecule that has never been observed before in an atmosphere. "This new piece of the puzzle will provide an additional test of how well we understand the chemical zoo that makes up Titan's atmosphere," he adds.
Let’s get the facts right
According to an article published recently on Renold's web site there is a growing trend for manufacturers of industrial chain to claim innovations as their own when in fact they have merely copied an already established technology.
In one example a chain manufacturer claims that it was the pioneer of lubrication-free chain technology in the late 1980s, when in fact other manufacturers had developed ranges thirty years earlier in the 1950s.
David Turner, the author of the article, and Renold's marketing communications manager for chain, states that whilst these false claims are nothing new they are certainly becoming more widespread. It's important, Turner argues, because engineers are being misled.
If a company claims to have invented a particular technology then it's understandable to believe that it might be better than everyone else’s version of it. So it's always worthwhile checking when manufacturers claim to have been the innovators of something.
You can read David's article here.