Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Fast track control accelerates switching of quantum bits

16.12.2016

From laptops to cellphones, today’s technology advances through the ever-increasing speed of directing electric charges in circuits. Similarly, speeding up control over quantum states in atomic and nanoscale systems could lead to leaps for the emerging field of quantum technology.

An international collaboration between physicists at the University of Chicago, Argonne National Laboratory, McGill University, and the University of Konstanz recently demonstrated a new framework for faster control of a quantum bit. First published online Nov. 28, 2016, in Nature Physics, their experiments on a single electron in diamond could create quantum devices that are less to prone to errors when operated at high speeds.


Intricately-shaped pulses of light pave a speedway for the accelerated dynamics of quantum particles, enabling faster switching of a quantum bit. Image courtesy Peter Allen.


Brian Zhou, postdoctoral scholar at the University of Chicago, aligns the lasers onto the diamond chips used in the experiments. Image courtesy Awschalom Lab.

Accelerating quantum dynamics
To understand their experiment, one can look to the ultimate setting for speed in classical dynamics: the oval racetracks at the Indianapolis or Daytona 500. To enable the racecars to navigate the turns at awesome speeds, the racetrack’s pavement is “banked” by up to 30 degrees. A student in Newtonian mechanics could explain that this inward slope of the pavement allows the normal force provided by the road to help cancel the car’s centrifugal acceleration, or its tendency to slide outward from the turn. The greater the speed, the greater the bank angle that is required.

“The dynamics of quantum particles behaves analogously,” said Aashish Clerk, professor of theoretical physics at McGill University. “Although the equations of motion are different, to accurately change the state of a quantum particle at high speeds, you need to design the right track to impart the right forces.”

Clerk, together with colleagues Alexandre Baksic and Hugo Ribeiro, formulated a new technique to enable faster quantum dynamics by deftly absorbing detrimental accelerations felt by the quantum particle. These accelerations, unless compensated, would divert the particle from its intended trajectory in the space of quantum states, similar to how the centrifugal acceleration deflects the racecar from its intended racing line on the track.

Through conversations with members of his own group and the Clerk group, David Awschalom, professor in spintronics and quantum information at the Institute for Molecular Engineering in the University of Chicago, realized that the new theory could be used to speed up the diamond-based quantum devices in his labs. However, just as constructing the banked speedways presented challenges in civil engineering, experimentally executing the control sequences envisioned by Clerk and co-workers presented ones in quantum engineering.

Building the quantum fast track required shining intricately-shaped, synchronized laser pulses on single electrons trapped at defects inside their diamond chips. This experimental feat was achieved by lead author Brian Zhou, working with Christopher Yale, F. Joseph Heremans, and Paul Jerger.

“We demonstrated that these new protocols could flip the state of a quantum bit, from ‘off’ to ‘on,’ 300% faster than conventional methods,” said Awschalom, also a senior scientist at Argonne National Laboratory. “Shaving every nanosecond from the operation time is essential to reduce the impact of quantum decoherence,” he explained, referring to the process by which quantum information is lost to the environment.

Professor Guido Burkard and Adrian Auer from the University of Konstanz joined the Awschalom and Clerk groups to examine the data from the experiments. A leading expert in diamond-based quantum systems, Burkard remarked, “What is promising for translating these techniques beyond the laboratory is that they are effective even when the system is not perfectly isolated.”

The researchers anticipate that their methods can be further applied for fast and accurate control over the physical motion of atoms or the transfer of quantum states between different systems, and convey benefits to quantum applications, such as secure communications and simulation of complex systems.

Citation: doi:10.1038/nphys3967
Funding: US Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division; Air Force Office of Scientific Research; National Science Foundation; German Research Foundation.

Contact
University of Konstanz
Communications and Marketing
Phone: + 49 7531 88-3603
E-Mail: kum@uni-konstanz.de

Julia Wandt | idw - Informationsdienst Wissenschaft
Further information:
http://www.uni-konstanz.de

More articles from Physics and Astronomy:

nachricht Magnetic nano-imaging on a table top
20.04.2018 | Georg-August-Universität Göttingen

nachricht New record on squeezing light to one atom: Atomic Lego guides light below one nanometer
20.04.2018 | ICFO-The Institute of Photonic Sciences

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: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Magnetic nano-imaging on a table top

20.04.2018 | Physics and Astronomy

Start of work for the world's largest electric truck

20.04.2018 | Interdisciplinary Research

Atoms may hum a tune from grand cosmic symphony

20.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>