'Cavity protection effect' helps to conserve quantum information

The quantum system studied at TU Wien (Vienna): a black diamond (center) contains nitrogen atoms, which are coupled to a microwave resonator. Credit: TU Wien

The electronics we use for our computers only knows two different states: zero or one. Quantum systems on the other hand can be in different states at once, they can store a superposition of “zero” and “one”.

This phenomenon could be used to build ultrafast quantum computers, but there are several technological obstacles that have to be overcome first. The biggest problem is that quantum states are quickly destroyed due to interactions with the environment. At TU Wien (Vienna), scientists have now succeeded in using a protection effect to enhance the stability of a particularly promising quantum system.

A Quantum Computer Made of Two Systems

There are various concepts for possible quantum computers. “What we use is a hybrid system of two completely different quantum technologies”, says Johannes Majer. Together with his team, he couples microwaves and atoms, investigating and building a new type of quantum memory.

The theorists Dmitry Krimer and Stefan Rotter developed a theoretical model describing the complex dynamics in such hybrid quantum systems.

In a microwave resonator, photons are created. They interact with the spin of nitrogen atoms, which are built into a diamond. The microwave resonator can be used to quickly transport quantum information.

The atomic spins in the diamond can store it – at least for a period of several hundred nanoseconds, which is long compared to the time scale on which photons move in the microwave resonator.

“All nitrogen atoms are completely identical. But when they are placed in slightly different surroundings, they have slightly different transition frequencies”, says Stefan Putz, PhD-student at Vienna University of Technology. The atomic spins behave like a room full of pendulum clocks. Initially they may oscillate in sync, but as they can never be precisely identical, they eventually lose their rhythm, creating random noise.

Coupling Causes Order

“By creating a strong coupling between the atomic spins and the resonator, it is possible to dramatically prolong the time during which the spins oscillate in strict time – if their energy levels obey the right distribution”, says Dmitry Krimer. The atomic spins do not directly interact with each other, but the mere fact that they are collectively coupled to the microwave resonator prevents them from changing into a state in which they cannot be used for processing quantum information any longer. This protection effect considerably enhances the duration in which quantum information can be read out from the atomic spins.

“Improving the quantum coherence time with this cavity protection effect opens up many promising applications for our hybrid quantum system”, says Johannes Majer. The paper has now been published in Nature Physics.

Further information
Dr. Johannes Majer
Institute for Atomic and Subatomic Physics
TU Wien
Stadionallee 2, 1020 Wien
T: +43-1-58801-141838
johannes.majer@tuwien.ac.at

Media Contact

Florian Aigner Eurek Alert!

More Information:

http://www.tuwien.ac.at

All latest news from the category: Physics and Astronomy

This area deals with the fundamental laws and building blocks of nature and how they interact, the properties and the behavior of matter, and research into space and time and their structures.

innovations-report provides in-depth reports and articles on subjects such as astrophysics, laser technologies, nuclear, quantum, particle and solid-state physics, nanotechnologies, planetary research and findings (Mars, Venus) and developments related to the Hubble Telescope.

Back to home

Comments (0)

Write a comment

Newest articles

Lighting up the future

New multidisciplinary research from the University of St Andrews could lead to more efficient televisions, computer screens and lighting. Researchers at the Organic Semiconductor Centre in the School of Physics and…

Researchers crack sugarcane’s complex genetic code

Sweet success: Scientists created a highly accurate reference genome for one of the most important modern crops and found a rare example of how genes confer disease resistance in plants….

Evolution of the most powerful ocean current on Earth

The Antarctic Circumpolar Current plays an important part in global overturning circulation, the exchange of heat and CO2 between the ocean and atmosphere, and the stability of Antarctica’s ice sheets….

Partners & Sponsors