Nanotechnology Now







Heifer International

Wikipedia Affiliate Button


DHgate

Home > Press > Spin Doctors: Opening the door to studying new, very fast quantum processes

Ames Lab theoretical physicist Viatcheslav Dobrovitski was recently part of a team that produced and controlled rotations of a single quantum spin at rates less than one trillionth of a second.
Ames Lab theoretical physicist Viatcheslav Dobrovitski was recently part of a team that produced and controlled rotations of a single quantum spin at rates less than one trillionth of a second.

Abstract:
For many exciting applications - from someday building quantum computers to developing ultra-precise magnetometry and improving quantum communication across fiber-optic networks - scientists need to better understand really fast and really small quantum systems. Theoretical physicist Viatcheslav Dobrovitski of DOE's Ames Laboratory recently worked with researchers at Lawrence Berkeley National Laboratory and the University of California Santa Barbara to take a significant step forward in the study of quantum processes.

Spin Doctors: Opening the door to studying new, very fast quantum processes

Ames, IA | Posted on May 11th, 2010

The team produced and controlled coherent rotations of a single quantum spin at rates less than one trillionth of a sec­ond. The group's discoveries, which appeared in a recent issue of Science, open the window to study­ing new, very fast quantum processes that were previ­ously impossible to detect and analyze.

Dobrovitski and his colleagues studied quantum spins in diamond, which can contain imperfections called nitrogen-vacancy, or N-V, centers, using sam­ples grown and characterized by researchers at Law­rence Berkeley National Laboratory. Since atoms in diamond sit very tightly in their positions and respond very weakly to heat or other excitation, the spin of an isolated N-V center can be studied with very little inter­ference from the rest of the world.

Isolating quantum spins is important, because to use spins in applications like quantum communication they must rotate smoothly and predictably to retain their quantum properties. When spins are exposed to outside forces, they can get bumped off their path.

"If we want a spin to go from position ‘a' to position ‘b,' an­other way for us to prevent interference from the outside world is to induce the spin rotation as fast as possible so it doesn't have time to interact with other forces," says Dobrovitski.

So researchers at UCSB, who performed the optical and magnetic measurements for the project, applied short and ex­tremely strong pulses of magnetic field to the spins. Similar, but weaker, pulses are used in conventional electron and nuclear magnetic resonance.

As power was increased, the spins started to exhibit a pattern of fast rotations and stallings, caused by the fast changes of the magnetic field during the pulse.

In conventional resonance experiments, the power of a pulse begins low for a short time, reaches a higher and consistent, level for the majority of the pulse and then drops down for a short time. In that case, the affect of pulses' "heads" and "tails" is not very noticeable compared to the even body of the pulse.

But when the magnetic resonance pulse is large and lasts less than a nanosecond, as occurred in the research by Dobrovitski and his colleagues, the pulse is mostly made up of heads and tails.

"If we want to rotate a spin very fast, we necessarily have to deal with the heads and tails," says Dobrovitski. "Our short, strong pulses will consist of mostly just edges. There's no time for a body of the pulse."

The finding that very fast rotations could be induced using these short pulses was a significant discovery in itself.

"We showed that controlled, coherent spin rotation is pos­sible outside the standard framework of nicely defined, long pulses," says Dobrovitski.

In principle, scientists can create much shorter pulse. But these pulses cannot induce a smooth, coherent rotation of a single spin. The pulses' large power excites a plethora of differ­ent degrees of freedom, and the precious quantum coherence of the spin is lost. Thus, the pulses have to be strong but not too strong. Dobrovitski and his colleagues at UCSB found the "sweet spot" for short, strong pulses.

The research team went on to determine experimentally and theoretically that the spins were most controllable when the short pulses had gradual increases and decreases in power.

"Those kinds of pulses seem to gradually awaken the spin processes," says Dobrovitski. "It's most controllable that way, and we can rotate the spins smoothly and coherently but still do re­ally fast rotations."

Next up for Dobrovitski and the team is studying other fast processes in N-V centers using these fast pulses.

"Before our most recent research, people could not see these processes," says Dobrovitski. "Now that we can see them, it's my job as a theoretical physicist to explain what we see."

####

About Ames Laboratory
Ames Laboratory is a government-owned, contractor-operated research facility of the U.S. Department of Energy that is run by Iowa State University.

For more than 60 years, the Ames Laboratory has sought solutions to energy-related problems through the exploration of chemical, engineering, materials, mathematical and physical sciences. Established in the 1940s with the successful development of the most efficient process to produce high-purity uranium metal for atomic energy, the Lab now pursues a broad range of scientific priorities.

For more information, please click here

Contacts:
Ames Laboratory
111 TASF
Ames, IA 50011-3020
(515) 294-9557

Copyright © Ames Laboratory

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

How to maximize the superconducting critical temperature in a molecular superconductor: International team led by Tohoku University opens new route for discovering high Tc superconductors April 19th, 2015

Engineer improves rechargeable batteries with MoS2 nano 'sandwich' April 18th, 2015

Nanocomposites Play Effective Role in Production of Smart Fibers April 18th, 2015

Dais Analytic Corporation Appoints Eliza Wang to Board of Directors: Company's Newest Director Brings Expertise in Commercial and Legal Matters Both in the United States and China; Joins on the Heels of Successful Business Development Trade Mission to China April 18th, 2015

Quantum Computing

NIST tightens the bounds on the quantum information 'speed limit' April 13th, 2015

Electrical control of quantum bits in silicon paves the way to large quantum computers: Breakthrough by Australian-led team should make the construction of large-scale quantum computers more affordable April 11th, 2015

OU physicists first to create new molecule with record-setting dipole moment April 4th, 2015

Quantum teleportation on a chip: A significant step towards ultra-high speed quantum computers April 1st, 2015

Discoveries

How to maximize the superconducting critical temperature in a molecular superconductor: International team led by Tohoku University opens new route for discovering high Tc superconductors April 19th, 2015

Optical resonance-based biosensors designed for medical applications April 18th, 2015

Iranian Foodstuff, Agricultural Industries Welcome Nanotechnology Packaging Bags April 18th, 2015

Nanocomposites Play Effective Role in Production of Smart Fibers April 18th, 2015

Announcements

How to maximize the superconducting critical temperature in a molecular superconductor: International team led by Tohoku University opens new route for discovering high Tc superconductors April 19th, 2015

Iranian Foodstuff, Agricultural Industries Welcome Nanotechnology Packaging Bags April 18th, 2015

Nanocomposites Play Effective Role in Production of Smart Fibers April 18th, 2015

Dais Analytic Corporation Appoints Eliza Wang to Board of Directors: Company's Newest Director Brings Expertise in Commercial and Legal Matters Both in the United States and China; Joins on the Heels of Successful Business Development Trade Mission to China April 18th, 2015

Research partnerships

Beyond the lithium ion -- a significant step toward a better performing battery April 18th, 2015

Light in a spin: Researchers demonstrate angular accelerating light April 15th, 2015

Graphene pushes the speed limit of light-to-electricity conversion: Researchers from ICFO, MIT and UC Riverside have been able to develop a graphene-based photodetector capable of converting absorbed light into an electrical voltage at ultrafast timescales April 14th, 2015

Scientists create invisible objects without metamaterial cloaking April 14th, 2015

Quantum nanoscience

Quantization of 'surface Dirac states' could lead to exotic applications April 15th, 2015

Electrical control of quantum bits in silicon paves the way to large quantum computers: Breakthrough by Australian-led team should make the construction of large-scale quantum computers more affordable April 11th, 2015

Quantum physics -- hot and cold at the same time: Measurements at the Vienna University of Technology show that a cloud of quantum particles can have several temperatures at once; the experiment provides new insight into the behavior of large quantum systems April 9th, 2015

A glass fiber that brings light to a standstill: By coupling photons to atoms, light in a glass fiber can be slowed down to the speed of an express train; for a short while it can even be brought to a complete stop April 9th, 2015

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More










ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2015 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE