quantum computer tagged posts

Scientists have developed a faster way to read information out of qubits, the basic building blocks of a quantum computer. The potential computing revolution that quantum computers have long promised is based on their weird property called superposition. Namely, qubits can take both logical states 0 and 1 simultaneously, on top of any value in between. By mastering superpositions of the whole quantum memory, quantum computers can quickly solve problems that would require too much computing time from regular computers working with simply 0s and 1s.

However, qubits are sensitive, and currently hold quantum information for less than a millisecond ...

Layout of IBM’s four superconducting quantum bit device.
Credit: IBM Research

Scientists have now demonstrated for the first time developed a quantum circuit that can solve a problem that is unsolvable using any equivalent classical circuit. Conventional computers obey the laws of classical physics. They rely on the binary numbers 0 and 1. These numbers are stored and used for mathematical operations. In conventional memory units, each bit – the smallest unit of information – is represented by a microscopic dot on a microchip. Each of these dots can hold a charge that determines whether the bit is set to 1 or 0.

In a quantum computer, however, a bit can be both 0 and 1 at the same time. This is because the laws of quantum physics allow electrons to be in multiple places at one time...

An IBM cryostat wired for a 50 qubit system. Credit: IBM

IBM has announced a milestone in its race against Google and other big tech firms to build a powerful quantum computer. Dario Gil, who leads IBM’s quantum computing and artificial intelligence research division, said it’s scientists have successfully built and measured a processor prototype with 50 qubits. Gil says it’s the first time any company has built a quantum computer at this scale.

This new processor expands upon the 20 qubit architecture and will be made available in the next generation IBM Q systems. Clients will have online access to the computing power of the first IBM Q systems by the end of 2017, with a series of planned upgrades during 2018...

1. Flow Ambiguity: A Path Towards Classically Driven Blind Quantum Computation. Physical Review X, 2017; 7 (3) DOI: 10.1103/PhysRevX.7.031004
2. Illustration of an exemplary run of Protocol 1

Researchers suggest you could operate a quantum computer in the cloud without revealing your data or the program you’re running. Here’s the scenario: you have sensitive data and a problem that only a quantum computer can solve. You have no quantum devices yourself. You could buy time on a quantum computer, but you don’t want to give away your secrets. What can you do? Writing in Physical Review X on 11 July, researchers in Singapore and Australia propose a way you could use a quantum computer securely, even over the internet. The technique could hide both your data and program from the computer itself...