Quantum information tagged posts

Quantum bits, or -qubits, can hold quantum information much longer now thanks to efforts by an international research team. The researchers have increased the retention time, or coherence time, to 10 milliseconds – 10,000 times longer than the previous record – by combining the orbital motion and spinning inside an atom...

Team identifies dark trions as the next carrier of quantum information. Move aside, electrons; it’s time to make way for the trion. A research team led by physicists at the University of California, Riverside, has observed, characterized, and controlled dark trions in a semiconductor – ultraclean single-layer tungsten diselenide (WSe2) – a feat that could increase the capacity and alter the form of information transmission.

In a semiconductor, such as WSe2, a trion is a quantum bound state of three charged particles. A negative trion contains two electrons and one hole; a positive trion contains two holes and one electron...

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...

A representation of the quantum state in the new Yale device. Crucial to its success, the researchers say, is the ability to successfully detect and sort errors. Credit: Yale University

Yale researchers have crossed the “break even” point in preserving a bit of quantum information for longer than the lifetime of its constituent parts. They have created a novel system to encode, spot errors, decode, and correct errors in a quantum bit, ie “qubit.” The development of such a robust method of Quantum Error Correction (QEC) has been one of the biggest remaining hurdles in quantum computation.

“This is the first error correction to actually detect and correct naturally occurring errors,” said Robert Schoelkopf, Sterling Professor of Applied Physics and Physics at Yale...