During the last years many dreams has been coming true. Lonely singers have became idols, quantum computers have began to compute – stop. Really is it true?
Until you’ll meet quantum computer nearby the seller in the supermarket, don’t imagine it. That’s sad, surely. But one technology has a problem, another comes to the speech.
Quantum computers are because of their nature somewhere on the border between science and genuine magic. Theoretically, they, simulating the quantum effect, should be able to calculate ultraquickly because they can stay simultaneously in several states. Despite the fact that it sounds like they are in parallel universes, in fact, currently even pocket calculators of your child are better than the quantum computer. Also where is the problem –
Coherence crucial limits the operation, which could be done by the q-computer, that results from the newest study by Dutch theoretical physicists from the Foundation for Fundamental Research on Matter and Leiden University. Coherence holds the computer unit qubit in two states simultaneously and it is well known that contact with the external environment will destroy this equilibrium quickly. Until now, however, it was assumed that the isolated qubit should survive longer.
But what for surprise appeared with the study – the coherence may completely disappear by itself! Without any external influences. Spontaneous violation of symmetry in quantum objects could explain it, study informs, the smaller the qubit is, the more quick it disappears. But don’t worry now – although the newest theory supposes it, finally we maybe find out how to overstep it.
The world of computer was, however, excited by different good news. In the June issue of Nano Letters a team of physicists Berkeley National Laboratory at the University of California and their counterparts from Pennsylvanian State University announce a new type of memory element. In comparison with the current bests the memory medium has got not only higher capacity; the duration of data storage is completely unrivaled – one billion years.
The best current hard drives record per 1 cm square is about 40 billion bits of information. Such recorded data are stored for a period of about 10 to 30 years. For storage media, in general, it is negotiated that the larger the storage density record, the faster and easier it will be destroyed. But the announced apparel introduces the information as a short nanotube with iron nanoparticle in the inside. Location of nanoparticles with an accuracy of a nanometer could be redirected by using electrical signals. The difference between the type of bits “0″ and “1″ thus represents the location of various nanoparticles. So the information in this new type of memory is represented with a specific combination of the Fe-nanoparticles position in thick clusters nanotubes. That can be read using resistance measuring equipment. Stored record can be changed easily. Scientists assume that on this principle arise very effective and powerful rewriting permanent storage elements with a high stability of the record. Its density is just 16 x 1010 bits per square centimeter. Thermodynamic stability of the media should ensure legibility of data over a period of about a billion years.
The nano-world with its quantum state must go ahead. The real apparel we’ll use in the future, however, we could only suppose.
Sources:
Physical Review Letters 94 (23): Art. No. 230401
http://www.physics.berkeley.edu/research/zettl/