New component in the quantum electronics toolbox

August 29, 2013
Quantum electronics with atoms and superconductors: Rubidium atoms are magnetically suspended above a superconducting microchip, creating a new interface between superconducting nanoelectronics and the atoms. This means the advantages of both systems may be harnessed to process, transfer and store quantum information. Credit: CQ Center for Collective Quantum Phenomena/University of Tübingen

The coherence of quantum systems is the foundation upon which hardware for future information technologies is based. Quantum information is carried by units called quantum bits, or qubits. They can be used to secure electronic communications – and they enable very fast searches of databases. But qubits are also very unstable. Professors József Fortágh, Dieter Kölle and Reinhold Kleiner of Tübingen's Institute of Physics have developed a new electronic component which will help to deal with this problem. The researchers' long-term goal is to process, transfer and store superposition states such as the overlapping of the binary digits zero and one. The initial results of their work are to be published in the journal Nature Communications on 29 August 2013.

The researchers aim to link two systems and draw on the advantages of both. Superconducting circuits, which are structured on microchips using standard technology, can process quickly but cannot store it for very long. By contrast, atoms, nature's smallest , can serve as a natural quantum storage unit. "In the future, this combination will allow us to transfer information from into ensembles of atoms and store it," says Professor József Fortágh.

The atoms are trapped in a magnetic field above the surface of the microchip. Because superconductors allow an electric current to flow without resistance, the current does not become weaker in a superconducting ring. Institute of Physics PhD students Helge Hattermann and Daniel Bothner along with postdoctoral researcher Simon Bernon have made use of this to construct a complex superconducting ring-circuit and a particularly stable storage space for atoms. And the researchers can test how long atoms remain in the quantum superposition states within the system – by using the atoms themselves as a clock.

Today's definition of a second is given to us by the caesium atom, with a frequency of approximately nine billion Hertz per second, corresponding to the transition between its two ground states. Rubidium, the atom used for the experiments in Tübingen, is a secondary frequency standard. An atomic clock's precision is based on the constant transition between quantum states. Just like the swinging of the pendulum of a grandfather clock, an atomic clock's oscillations become weaker with time – when the quantum superpositions decay.

The atomic clock integrated into the superconducting chip indicates that the atoms suspended above the chip remain in their states for several seconds. By comparison, solid-state quantum storage retains coherence for only microseconds. "This result paves the way for new quantum electronic components for information processing systems," József Fortágh says. The researchers at the University of Tübingen's CQ Center for Collective Quantum Phenomena are now planning experiments on atoms in superconducting microwave resonators – which could serve as a shuttle for data between integrated circuits and atoms.

Explore further: Towards hybrid quantum systems

More information: Bernon, S. et al. Manipulation and coherence of ultra-cold atoms on a superconducting atom chip, Nature Communications, Online-Veröffentlichung. DOI: 10.1038/ncomms3380

Related Stories

Towards hybrid quantum systems

May 16, 2012

EU-funded scientists made advances in the development of a hybrid quantum system (HQS) by combining different quantum technologies.

Noise is not necessarily detrimental to quantum devices

February 4, 2013

The researches of the Aalto University and the University of Oulu have succeeded to simulate a phenomenon called motional averaging, which demonstrates that in certain conditions externally-induced fast fluctuations in energy ...

New method to generate Laughlin states with atomic systems

July 3, 2013

In 1998, the Nobel Prize in Physics was conferred to the discovery of a new type of quantum fluid with fractional charge excitations, known as Laughlin state. The production of this quantum state, which explains the behaviour ...

Recommended for you

Test racetrack dipole magnet produces record 16 tesla field

November 30, 2015

A new world record has been broken by the CERN magnet group when their racetrack test magnet produced a 16.2 tesla (16.2T) peak field – nearly twice that produced by the current LHC dipoles and the highest ever for a dipole ...

Turbulence in bacterial cultures

November 30, 2015

Turbulent flows surround us, from complex cloud formations to rapidly flowing rivers. Populations of motile bacteria in liquid media can also exhibit patterns of collective motion that resemble turbulent flows, provided the ...

'Material universe' yields surprising new particle

November 25, 2015

An international team of researchers has predicted the existence of a new type of particle called the type-II Weyl fermion in metallic materials. When subjected to a magnetic field, the materials containing the particle act ...

CERN collides heavy nuclei at new record high energy

November 25, 2015

The world's most powerful accelerator, the 27 km long Large Hadron Collider (LHC) operating at CERN in Geneva established collisions between lead nuclei, this morning, at the highest energies ever. The LHC has been colliding ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.