from the it's-not-just-black-and-white dept.
Submitted via IRC for SoyCow6430
Schrödinger's Cat with 20 Qubits
"Qubits in the cat state are considered extremely important for the development of quantum technologies," explains Jian Cui. "The secret of the enormous efficiency and performance expected of future quantum computers is to be found in this superposition of states," says the physicist from the Peter Grünberg Institute at Jülich (PGI-8).
Classical bits in a conventional computer always only have one certain value, which is composed of 0 and 1, for example. Therefore, these values can only be processed bit by bit one after the other. Qubits, which have several states simultaneously due to the superposition principle, can store and process several values in parallel in one step. The number of qubits is crucial here. You don't get far with just a handful of qubits. But with 20 qubits, the number of superimposed states already exceeds one million. And 300 qubits can store more numbers simultaneously than there are particles in the universe.
The new result of 20 qubits now comes a little closer to this value, after the old record of 14 qubits remained unchanged since 2011. For their experiment, the researchers used a programmable quantum simulator based on Rydberg atom arrays. In this approach, individual atoms, in this case rubidium atoms, are captured by laser beams and held in place side by side in a row. The technique is also known as optical tweezers. An additional laser excites the atoms until they reach the Rydberg state, in which the electrons are located far beyond the nucleus.
This process is rather complicated and usually takes too much time, such that the delicate cat state is destroyed before it can even be measured. The group in Jülich contributed their expertise in Quantum Optimal Control to solve this issue. By cleverly switching the lasers off and on at the right rate, they achieved a speed up in the preparation process which made this new record possible.
