Nowadays we communicate via radio signals and send electrical pulses through long cables. However, this could soon change. Scientists are working intensively on developing methods for quantum information transfer. This would enable tap-proof data transfer or perhaps even the linking of quantum computers one day.
In order for this to happen, quantum information transfer requires reliable information transfer from one quantum system to the other, which is extremely difficult to achieve. Independently, two research teams, one at the University of Innsbruck and the other at the Vienna University of Technology, have simultaneously developed a new quantum communication protocol. This protocol enables reliable quantum communication even despite contaminating noise. Both research groups work with the same basic concept. To make the protocol immune to the noise, they add an additional element, a so-called quantum oscillator, at both ends of the quantum channel.
Superconducting qubits, in particular, are promising elements for future quantum technologies. They are tiny circuits that can assume two different states at the same time. Contrary to conventional light switches that can be either turned on or turned off, the laws of quantum physics allow a qubit to assume any combination of these states, which is called quantum superposition.
To transfer this quantum state from one superconducting qubit to another requires microwave photons, which are already used today for classic signal transfer. Reliably transferring quantum information via a microwave regime has been considered impossible up until now, due to the fact that the constant thermal noise completely superposes the weaker quantum signal.
New transfer protocol
The two research groups from the Vienna University of Technology and the University of Innsbruck have now demonstrated that these obstacles are not impossible to overcome as previously assumed. In collaboration with teams from Harvard and Yale (USA) they have been able to develop a transfer protocol that is immune to the inevitable noise.