“Winner! Seven.” A crowd gathers around the craps table cheering for the player who is preparing for the next crapshot. The player kisses the dice and people who are believed to jinx the game are sent away.
Remarkably, this attempt of favourably influencing the chances at winning is similar to what scientists try in quantum computing. But while rolling the dice is based on hope, scientists root their methods on the laws of physics. Candidates for quantum computers are based on networks of elements of two superconducting pieces separated by small gaps.
Superconductivity is a quantum-mechanical effect in which a material loses its electrical resistance and expels magnetic fields from its interior. Recent experimental progress enabled their use by ensuring that exactly one electric charge-carrier can hop from one piece to the other. Just like in classical computers, such charges carry information like a coin with its two faces.
Quantum computers differ because they operate by ‘spinning the coin’ much like the gambler rolls his dice. While a coin is spinning, it shows neither heads nor tails but it could be both. Quantum mechanical ‘coins’ can be influenced during the spin, such that certain outcomes become unlikely while others are prominent.
However, predicting the outcomes according to the laws of quantum mechanics becomes increasingly difficult with the number of ‘coins’ that are spun simultaneously and the number of actions taken until the ‘coins’ fall into the final state.
Google’s recent claim of having reached ‘quantum supremacy’ was achieved by setting 53 charges simultaneously in motion and employing 1500 actions on them for three million times within 10 minutes.
Besides scientific purposes, one possible short-term application is generating genuinely and certifiably random numbers to improve secure communication.
Google’s main competitor IBM questioned the claim and responded that if done wisely, the probabilities can be predicted within days and that ‘supremacy’ is an exaggeration for quantum computers outperforming classical computers at exactly one task. Nevertheless, technologies typically establish themselves with one so-called “killer application”.
If the gambler knew a sequence of angles at which he needs to blow at the two dice to certainly get a seven and win, most certainly he wouldn’t look for other applications.
Karl Andreas Pelka is Phd student, Quantumalta, HOT project.
Did you know?
• The electric charge-carrier of metals in the superconducting state is two electrons that follow each other, so-called a Cooper pair.
• Richard Feynman ignited the idea of quantum computing by noting that “it is impossible to represent the results of quantum mechanics with a classical [computer]”.
• The problem of prime number decomposition can be solved efficiently on a quantum computer.
• First quantum computations were performed with special molecules; each nucleus acts as a magnet which can align or anti-align with an external magnetic field.
For more trivia, see: www.um.edu.mt/think
Sound bites
• Superconductivity has the potential to reduce the carbon dioxide emissions of aviation as a key technology towards all-electric aircrafts. Superconducting elements weigh much less compared to regular counterparts and allow to distribute electrical power without losses, as shown in Essen, Germany. Essen has integrated the longest superconducting energy cable in their power grid. It is highly efficient and space-saving, transporting five times more power with low losses. This could potentially lead to a better energy system.
https://www.scientificamerican.com/article/for-low-emission-planes-try-superconductivity/
• The EU aims to invest one billion euros over the next ten years in quantum technologies in terms of the ‘Quantum Technologies Flagship’. It strives to bring together academic institutions, industrial companies and public funding to advance research results in quantum physics towards commercial technologies.
https://ec.europa.eu/digital-single-market/en/quantum-technologies
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