The new quantum “fridge”
A tiny new quantum “fridge” is capable of correcting the calculations of a quantum computer – without the need for supervision or new hardware.
A small cooling device is capable of automatically replacing faulty components of a quantum computer.
This innovation is based on superconducting circuits and is powered by ambient heat. It can autonomously cool qubits to record low temperatures, paving the way for more reliable quantum computers.
The innovation was revealed in a study this Thursday in Nature Physics.
As a note, quantum computers are not yet fully practical because make too many mistakes. If the qubits – key components of this type of computer – accidentally heat up and become too energetic, they could end up in the wrong state before the calculation begins.
One way to “reset” the qubits to their correct states is cool them down. Apart from the new study, this cooling task was delegated, for the first time, to a autonomous quantum “fridge”. And successfully.
As New Scientist explains, researchers built two qubits and one “cut”which can store more complex information than a qubit, using small superconducting circuits. The qutrit and one of the qubits formed a refrigerator for the second target qubit, which could eventually be used for computation.
The researchers carefully engineered the interactions between the three components to ensure that when the target qubit had too much energy, causing errors, heat automatically flowed out of it and into the other two elements. This process lowered the temperature of the target qubit and reset it.
Since this process was autonomous, the qubit-e-qutrit cooler could correct the errors without any external control.
Mohammed Aamir Alicorresponding author of the study, praised that this approach to resetting the qubit did not require new hardware, unlike more conventional methods – and produced better results.
Without any significant remodeling of the quantum computer or introduction of new wires, the initial state of the qubit was correct 99.97% of the time. In contrast, other reset methods typically only achieve 99.8%, Aamir Ali told New Scientist.
Researchers are already developing this discovery, being able, for example, to create a autonomous quantum clock or design a quantum computer with other functions automatically controlled by temperature differences.
Additionally, the new experiment paves the way for many similar projects that have been proposed but never tested, such as using qubits to build autonomous quantum engines.
“It’s good to see this machine implemented and useful. The fact that it is autonomous, that is, it does not need any external control, should make it efficient and versatile”, he told New Scientist, Nicolas Brunnerfrom the University of Geneva (Switzerland), who did not participate in the study.
