Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Molecular engineers record an electron's quantum behavior

These images show a diamond sample with a hemispherical lens (right and lower left), and the location of a single electron spin/quantum state visible through its light emission (upper left). The scale bar on the image at upper left measures five microns, the approximate diameter of a red blood cell.

Credit: Courtesy of Awschalom Lab/University of Chicago
These images show a diamond sample with a hemispherical lens (right and lower left), and the location of a single electron spin/quantum state visible through its light emission (upper left). The scale bar on the image at upper left measures five microns, the approximate diameter of a red blood cell.

Credit: Courtesy of Awschalom Lab/University of Chicago

Abstract:
A team of researchers led by the University of Chicago has developed a technique to record the quantum mechanical behavior of an individual electron contained within a nanoscale defect in diamond. Their technique uses ultrafast pulses of laser light both to control the defect's entire quantum state and observe how that single electron state changes over time. The work appears in this week's online Science Express and will be published in print later this month in Science.

Molecular engineers record an electron's quantum behavior

Chicago, IL | Posted on August 14th, 2014

This research contributes to the emerging science of quantum information processing, which demands that science leave behind the unambiguous universe of traditional binary logic—0 or 1—and embrace the counterintuitive quantum world, where behavior is radically different from what humans experience every day. While people are generally content being in one place at a time, electrons can be in many states at once.

The team researches a quantum mechanical property of the electron known as spin. Much like conventional computers use the charge state of electrons to constitute bits of information, a quantum computer would use the spin state of a single electron as its quantum bit, or qubit. The work could accelerate development of quantum computing devices, and the extra computing power that would come with them, because it will be easier to identify materials that have appropriate quantum properties.

The spin system studied is known as the nitrogen-vacancy (NV) center, an atom-sized defect that occurs naturally in diamond, consisting of a nitrogen atom next to a vacant spot in the crystal lattice. "These defects have garnered great interest over the past decade, providing a test-bed system for developing semiconductor quantum bits as well as nanoscale sensors," said team leader David Awschalom, the Liew Family Professor of Molecular Engineering at UChicago. "Here, we were able to harness light to completely control the quantum state of this defect at extremely high speeds."

Quantum snapshots

In this new technique, the researchers locate a single NV center and then illuminate it with a pair of extremely short pulses of laser light. Each pulse lasts less than a picosecond (or a millionth of a millionth of a second). The first pulse excites the quantum states of the defect-bound electron, which then change or evolve in characteristic ways. The second pulse stops that evolution, capturing a picture of the quantum state at that elapsed time.

By progressively extending the elapsed time between the two pulses, the team creates a sequence of quantum-state snapshots—a movie of how the quantum state changes in time. The elapsed time can be as short as femtoseconds (a billionth of a millionth of a second) or as long as nanoseconds (a thousandth of a millionth of a second). On the human scale, this range of time is like the difference between an hour and a century.

Having this vast range of timescales makes the technique especially valuable. The electron is susceptible and interacts with its complex local environment in many different ways, each with a characteristic timescale. Being able to test a wide range of these timescales gives a far more complete picture of the dynamics of the NV center than has been obtained previously.

"Our goal was to push the limits of quantum control in these remarkable defect systems," explained Lee Bassett, co-lead author on the paper and now an assistant professor of electrical and systems engineering at the University of Pennsylvania, "but the technique also provides an exciting new measurement tool. By using pulses of light to direct the defect's quantum dynamics on super-short timescales, we can extract a wealth of information about the defect and its environment."

"It's quite a versatile technique, providing a full picture of the excited state of the quantum defect," said F. Joseph Heremans, a postdoctoral scholar at UChicago, the other co-lead author on the paper. "Previous work on the nitrogen-vacancy center has hinted at some of these processes, but here, simply through the application of these ultrafast pulses, we get a much richer understanding of this quantum beast."

Spin control

It's not just a matter of observation, though. "This technique also provides a means of control of the spin state—an important precursor for any quantum information system," said Evelyn Hu, a professor of applied physics and electrical engineering at Harvard University, who is not connected with the new work.

In addition, the method is not limited to investigating this particular defect. It could be applied to quantum states of matter in a host of materials and technologies, including many semiconductor materials. "You only have to be able to use light to transfer an electron between a ground state and an excited state," said Awschalom.

Professor Guido Burkard, theoretical physicist at the University of Konstanz and a co-author on the paper, remarked, "This technique offers a path toward understanding and controlling new materials at the atomic level."

Hu agrees that the technique opens many new avenues. "Each new system will pose new challenges to understanding the energy levels, local environments, and other properties, but the general approach should provide an enormous step forward for the field," said Hu.

###

In addition to researchers from UChicago's Institute for Molecular Engineering, the team included collaborators at the University of California, Santa Barbara (co-lead author Lee Bassett is now at the University of Pennsylvania), and the University of Konstanz, Germany.

####

For more information, please click here

Contacts:
Steve Koppes
773-702-8366

Copyright © University of Chicago

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

Supersonic waves may help electronics beat the heat May 18th, 2018

New blood test rapidly detects signs of pancreatic cancer May 17th, 2018

Disability Can Be a Superpower in Space Disabled astronauts offer unique solutions to emergencies in space May 17th, 2018

Deeper understanding of quantum chaos may be the key to quantum computers May 16th, 2018

Spintronics

Diamonds show promise for spintronic devices: New experiments demonstrate the potential for diamond as a material for spintronics January 30th, 2018

Researchers from TU Delft combine spintronics and nanophotonics in 2-D material January 25th, 2018

ICN2 researchers compute unprecedented values for spin lifetime anisotropy in graphene November 17th, 2017

Spin current detection in quantum materials unlocks potential for alternative electronics October 15th, 2017

Quantum Computing

Deeper understanding of quantum chaos may be the key to quantum computers May 16th, 2018

New qubit now works without breaks: A universal design for superconducting qubits has been created April 19th, 2018

Quantum shift shows itself in coupled light and matter: Rice University scientists corral, quantify subtle movement in condensed matter system April 16th, 2018

When superconductivity disappears in the core of a quantum tube: By replacing the electrons with ultra-cold atoms, a group of physicists has created a perfectly clean material, unveiling new states of matter at the quantum level April 16th, 2018

Discoveries

Supersonic waves may help electronics beat the heat May 18th, 2018

New blood test rapidly detects signs of pancreatic cancer May 17th, 2018

Deeper understanding of quantum chaos may be the key to quantum computers May 16th, 2018

Making carbon nanotubes as usable as common plastics: Researchers discover that cresols disperse carbon nanotubes at unprecedentedly high concentrations May 15th, 2018

Materials/Metamaterials

Making carbon nanotubes as usable as common plastics: Researchers discover that cresols disperse carbon nanotubes at unprecedentedly high concentrations May 15th, 2018

Mining for gold with a computer: Texas A&M team gleans new insights on key material May 3rd, 2018

'Exceptional' research points way toward quantum discoveries: Rice University scientists make tunable light-matter couplings in nanotube films April 30th, 2018

The first PE blown films with nanotubes hit the Chinese market April 26th, 2018

Announcements

Supersonic waves may help electronics beat the heat May 18th, 2018

New blood test rapidly detects signs of pancreatic cancer May 17th, 2018

Disability Can Be a Superpower in Space Disabled astronauts offer unique solutions to emergencies in space May 17th, 2018

Deeper understanding of quantum chaos may be the key to quantum computers May 16th, 2018

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

Supersonic waves may help electronics beat the heat May 18th, 2018

New blood test rapidly detects signs of pancreatic cancer May 17th, 2018

Deeper understanding of quantum chaos may be the key to quantum computers May 16th, 2018

Making carbon nanotubes as usable as common plastics: Researchers discover that cresols disperse carbon nanotubes at unprecedentedly high concentrations May 15th, 2018

Photonics/Optics/Lasers

A micro-thermometer to record tiny temperature changes May 15th, 2018

Strain improves performance of atomically thin semiconductor material May 11th, 2018

A powerful laser breakthrough: Lehigh research team demonstrates terahertz semiconductor laser with record-high output power May 2nd, 2018

'Exceptional' research points way toward quantum discoveries: Rice University scientists make tunable light-matter couplings in nanotube films April 30th, 2018

Research partnerships

Deeper understanding of quantum chaos may be the key to quantum computers May 16th, 2018

Nanoscale measurements 100x more precise, thanks to improved two-photon technique May 8th, 2018

Hematene joins parade of new 2D materials: Rice University-led team extracts 3-atom-thick sheets from common iron oxide May 8th, 2018

Harvesting clean hydrogen fuel through artificial photosynthesis May 3rd, 2018

Quantum nanoscience

Nanoscale measurements 100x more precise, thanks to improved two-photon technique May 8th, 2018

'Exceptional' research points way toward quantum discoveries: Rice University scientists make tunable light-matter couplings in nanotube films April 30th, 2018

New qubit now works without breaks: A universal design for superconducting qubits has been created April 19th, 2018

Quantum shift shows itself in coupled light and matter: Rice University scientists corral, quantify subtle movement in condensed matter system April 16th, 2018

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



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project