Coupling atomic spins in diamonds to microwave resonators could lead to new quantum technologies. Researchers at the Vienna University of Technology (TU Wien) have now managed to dramatically prolong the time these systems can store information
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.
Dr. Johannes Majer
Institute for Atomic and Subatomic Physics
Stadionallee 2, 1020 Wien
Florian Aigner | Eurek Alert!
Breaking the optical bandwidth record of stable pulsed lasers
24.01.2017 | Institut national de la recherche scientifique - INRS
European XFEL prepares for user operation: Researchers can hand in first proposals for experiments
24.01.2017 | European XFEL GmbH
A Swedish-German team of researchers has cleared up a key process for the artificial production of silk. With the help of the intense X-rays from DESY's...
For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.
According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
24.01.2017 | Physics and Astronomy
24.01.2017 | Life Sciences
24.01.2017 | Health and Medicine