Experimental physicists have succeeded for the first time in controlling protected quantum states – so-called dark states – in superconducting quantum bits. The entangled states are 500 times more robust and could be used, for example, in quantum simulations.
The team built four superconducting quantum bits into a microwave waveguide and attached control lines via two lateral inlets. Using microwave radiation via these wires, the dark states can be manipulated. Together, the four superconducting circuits form a robust quantum bit with a storage time about 500 times longer than that of the individual circuits. Multiple dark states exist simultaneously in this quantum bit, which can be used for quantum simulation and quantum information processing.
The concept developed by the team to control dark states can in principle be implemented not only with superconducting quantum bits, but also on other technological platforms.
The paper has been published in Nature Physics.
