Quantum information tagged posts

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...

The wavelike pattern at the top shows the accordion-like structure of a proposed quantum material—an artificial crystal made of light—that can trap atoms in regularly spaced nanoscale pockets. These pockets can be made to hold a large collection of ultracold “host” atoms (green), slowed to a standstill by laser light, and individually planted “probe” atoms (red) that can be made to transmit quantum information in the form of a photon (particle of light). The lower panel shows how the artificial crystal can be reconfigured with light from an open (hyperbolic, in orange) geometry to a closed (elliptical, in green) geometry, which greatly affects the speed at which the probe atom can release a photon. Credit: Pankaj K. Jha/UC Berkeley

Scientists have devised a way to build a “quan...

Some rare atoms can store quantum information, an important phenomenon for scientists in their ongoing quest for a quantum Internet. New research exploits a system that has the potential to transfer optical quantum information to locally stored solid-state quantum format, needed for quantum communication.

“Our research aims at creating a quantum analog of current fiber optic technology in which light is used to transfer classical information — bits with values zero or one — between computers,” said author Dirk Bouwmeester, a professor in UCSB’s Department of Physics. “The rare earth atoms we’re studying can store the superpositions of 0 and 1 used in quantum computation. In addition, the light by which we communicate with these atoms can also store quantum information.”

Rare earth element...