Qubits 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...

Tracks called waveguides guide photons in silicon. Spirals of these waveguides are used to generate photons that are routed around the processor circuit.
Credit: Xiaogang Qiang, University of Bristol

Light may be the missing ingredient in making usable quantum silicon computer chips, according to an international study featuring a University of Queensland researcher. The team has engineered a silicon chip that can guide photons along optical tracks, encoding and processing quantum-bits of information – ‘qubits’.

Professor Timothy Ralph from UQ’s Centre for Quantum Computation and Communication Technology said that the use of photons in this way could increase the number and types of tasks that computers can help us with...

Electrodes stretch diamond strings to increase the frequency of atomic vibrations to which an electron is sensitive, just like tightening a guitar string increases the frequency or pitch of the string. The tension quiets a qubit’s environment and improves memory from tens to several hundred nanoseconds, enough time to do many operations on a quantum chip. (Second Bay Studios/Harvard SEAS)

A process similar to guitar tuning improves storage time of quantum memory. A quantum internet promises completely secure communication. But using quantum bits or qubits to carry information requires a radically new piece of hardware – a quantum memory. This atomic-scale device needs to store quantum information and convert it into light to transmit across the network.

A major challenge to this vision i...