Quantum Drum Stores Quantum States for Record Times

Researchers at the Niels Bohr Institute, University of Copenhagen, dramatically improved the coherence time of a previously developed quantum membrane. The membrane can store sensitive quantum information for further processing in a quantum computer or network with a coherence time of one hundred milliseconds. The results are published in Nature Portfolio.

Researchers have combined the membrane with a superconducting microwave circuit, enabling precise read-outs from the membrane. It has become “plugged in,” as required for virtually any application. With this development, the membrane can be connected to various other devices that process or transmit quantum information.

Since the environment’s temperature determines the level of random forces disturbing the membrane, a sufficiently low temperature must be reached to prevent the quantum state of motion from being washed out. The researchers achieved this with a helium-based refrigerator. Using the microwave circuit, they can then control the quantum state of the membrane motion. In their recent work, the researchers could prepare the membrane in the quantum ground state, meaning that quantum fluctuations dominate its motion. The quantum ground state corresponds to an effective temperature of 0,00005 degrees above absolute zero, which is −273.15 °C.