Electrical engineers from Australia’s University of New South Wales (UNSW) have demonstrated the last building blocks needed to make silicon quantum computing a reality. They built a quantum logic gate in silicon for the first time, making calculations between two qubits of information possible. The researchers described their work as a “game changer” and “a triumph of electrical engineering.” Their quantum code is based on a phenomenon called entanglement, which has stumped physicists—including Albert Einstein—for decades. The premise of quantum entanglement is that the measurement of one particle will instantly influence another, no matter how far apart they may be. Einstein was skeptical of entanglement, and he famously called it “spooky action at a distance.” However, the researchers have now proved that entanglement exisits by achieving the highest score ever recorded in a Bell test, which is used to verify if two particles are entangled.
In today’s computers, data is rendered as binary bits, which are always in one of two states: 0 or 1. However, a quantum bit (or ‘qubit’) can exist in both of these states at once. This condition of “superposition” allows a computer code to contain many more words with the same number of bits, which leads to much more powerful computing.
Now, engineers have all the physical building blocks they need to build a computer that takes quantum computing beyond theory into reality. “What we have is a game changer,” said team leader Andrew Dzurak. “We’ve demonstrated a two-qubit logic gate – the central building block of a quantum computer – and, significantly, done it in silicon. Because we use essentially the same device technology as existing computer chips, we believe it will be much easier to manufacture a full-scale processor chip than for any of the leading designs, which rely on more exotic technologies.”
