Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Tunable diamond string may hold key to quantum memory

23.05.2018

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.


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.

Credit: Second Bay Studios/Harvard SEAS

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 is that qubits are extremely sensitive to their environment, even the vibrations of nearby atoms can disrupt their ability to remember information.

So far, researchers have relied on extremely low temperatures to quiet vibrations but, achieving those temperatures for large-scale quantum networks is prohibitively expensive.

Now, researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) and the University of Cambridge have developed a quantum memory solution that is as simple as tuning a guitar.

The researchers engineered diamond strings that can be tuned to quiet a qubit's environment and improve memory from tens to several hundred nanoseconds, enough time to do many operations on a quantum chip.

"Impurities in diamond have emerged as promising nodes for quantum networks," said Marko Loncar, the Tiantsai Lin Professor of Electrical Engineering at SEAS and senior author of the research.

"However, they are not perfect. Some kinds of impurities are really good at retaining information but have a hard time communicating, while others are really good communicators but suffer from memory loss. In this work, we took the latter kind and improved the memory by ten times."

The research is published in Nature Communications.

Impurities in diamond, known as silicon-vacancy color centers, are powerful qubits. An electron trapped in the center acts as a memory bit and can emit single photons of red light, which would in turn act as long-distance information carriers of a quantum internet. But with the nearby atoms in the diamond crystal vibrating randomly, the electron in the center quickly forgets any quantum information it is asked to remember.

"Being an electron in a color center is like trying to study at a loud marketplace," said Srujan Meesala, a graduate student at SEAS and co-first author of the paper. "There is all this noise around you. If you want to remember anything, you need to either ask the crowds to stay quiet or find a way to focus over the noise. We did the latter."

To improve memory in a noisy environment, the researchers carved the diamond crystal housing the color center into a thin string, about one micron wide -- a hundred times thinner than a strand of hair -- and attached electrodes to either side. By applying a voltage, the diamond string stretches and increases the frequency of vibrations the electron is sensitive to, just like tightening a guitar string increases the frequency or pitch of the string.

"By creating tension in the string, we increase the energy scale of vibrations that the electron is sensitive to, meaning it can now only feel very high energy vibrations," said Meesala. "This process effectively turns the surrounding vibrations in the crystal to an irrelevant background hum, allowing the electron inside the vacancy to comfortably hold information for hundreds of nanoseconds, which can be a really long time on the quantum scale. A symphony of these tunable diamond strings could serve as the backbone of a future quantum internet."

Next, the researchers hope to extend the memory of the qubits to the millisecond, which would enable hundreds of thousands of operations and long-distance quantum communication.

The Harvard Office of Technology Development has protected the intellectual property relating to this project and is exploring commercialization opportunities.

###

The research was co-first authored by Young-Ik Sohn and Srujan Meesala from Marko Loncar's group at Harvard, and Benjamin Pingault from Mete Atature's group at the University of Cambridge. Researchers from Harvard SEAS, Harvard Physics, Sandia National Laboratories also contributed to the manuscript.

The research was supported by the National Science Foundation-sponsored Center for Integrated Quantum Materials, Office of Naval Research Multidisciplinary University Research Initiative on Quantum Optomechanics, NSF Emerging Frontiers in Research and Innovation ACQUIRE, the University of Cambridge, the ERC Consolidator Grant PHOENICS, and the EPSRC Quantum Technology Hub NQIT.

Media Contact

Leah Burrows
lburrows@seas.harvard.edu
617-496-1351

 @hseas

http://www.seas.harvard.edu/ 

Leah Burrows | EurekAlert!
Further information:
https://www.seas.harvard.edu/news/2018/05/tunable-diamond-string-may-hold-key-to-quantum-memory

More articles from Physics and Astronomy:

nachricht New method gives microscope a boost in resolution
10.12.2018 | Rudolf-Virchow-Zentrum für Experimentelle Biomedizin der Universität Würzburg

nachricht A new 'spin' on kagome lattices
10.12.2018 | Boston College

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

Im Focus: Three components on one chip

Scientists at the University of Stuttgart and the Karlsruhe Institute of Technology (KIT) succeed in important further development on the way to quantum Computers.

Quantum computers one day should be able to solve certain computing problems much faster than a classical computer. One of the most promising approaches is...

Im Focus: Substitute for rare earth metal oxides

New Project SNAPSTER: Novel luminescent materials by encapsulating phosphorescent metal clusters with organic liquid crystals

Nowadays energy conversion in lighting and optoelectronic devices requires the use of rare earth oxides.

Im Focus: A bit of a stretch... material that thickens as it's pulled

Scientists have discovered the first synthetic material that becomes thicker - at the molecular level - as it is stretched.

Researchers led by Dr Devesh Mistry from the University of Leeds discovered a new non-porous material that has unique and inherent "auxetic" stretching...

Im Focus: The force of the vacuum

Scientists from the Theory Department of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science (CFEL) in Hamburg have shown through theoretical calculations and computer simulations that the force between electrons and lattice distortions in an atomically thin two-dimensional superconductor can be controlled with virtual photons. This could aid the development of new superconductors for energy-saving devices and many other technical applications.

The vacuum is not empty. It may sound like magic to laypeople but it has occupied physicists since the birth of quantum mechanics.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

Expert Panel on the Future of HPC in Engineering

03.12.2018 | Event News

 
Latest News

Small but ver­sat­ile; key play­ers in the mar­ine ni­tro­gen cycle can util­ize cy­anate and urea

10.12.2018 | Life Sciences

New method gives microscope a boost in resolution

10.12.2018 | Physics and Astronomy

Carnegie Mellon researchers probe hydrogen bonds using new technique

10.12.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>