They are billed as machines that will change the future, but quantum computers themselves are still in the future. All the same, scientists have been working on developing a working quantum computer for years now, and the frenzied competition to be the first has yielded a new record -- a 53-qubit quantum simulator.
From afar, it looks like a steampunk chandelier. It is, in fact, one of the most sophisticated quantum computers ever built. The processor inside has 50 quantum bits, or qubits, that process tasks in a (potentially) revolutionary way. Normally, information is created and stored as a series of ones and zeroes. Qubits can represent both values at the same time (known as superposition), which means a quantum computer can theoretically test the two simultaneously. Add more qubits and this hard-to-believe computational power increases.
That might not sound like much, but in the quantum computing arms race, several groups are edging past one another as they aim to eventually make a universal quantum computer. A group of researchers at the Joint Quantum Institute has created a quantum simulator using 53 quantum bits, or qubits. Earlier this month, IBM announced a 50-qubit prototype, though its capabilities are unclear. With this 53-qubit device, the researchers have done scientific simulations that don't seem to be possible
Successful protocols for quantum information processing and quantum computation depend on the reliable storage and manipulation of the quantum state of a qubit. Qubits, however, are prone to errors because complete isolation from the environment is not possible. Methods for correcting these errors must also contend with the fact that direct measurement of a qubit destroys it. Xue et al. describe a repetitive quantum nondemolition method on a two-qubit system in which the state of the main qubit is mapped onto a second qubit that acts as an ancilla. Repeated measurement of the ancilla qubit allows the main qubit to be maintained and read out with higher fidelity.
And so quantum computing, one of the jazziest and most mysterious concepts in modern science, struggles to come of age. It's been a century since scientists discovered that, on the most intimate scales, nature operates according to principles that boggle our poor ape brains. Randomness and uncertainty rule, causes are not guaranteed to be linked to effects, and an electron or other subatomic entity can be everywhere or nowhere, a wave or a particle, until someone measures it. Most of modern technology, from transistors and lasers to the gadgets in our pockets, runs on this quantum weirdness. Lately technophiles, politicians and journalists have been worrying out loud that China is pulling ahead in the effort to harness said weirdness for industry and power, better spying and better computing.