Russian physicists have developed a new way to cool a quantum computer

A group of scientists described the technology of remote control of the entropy of specific qubits, which actually locally violates the second law of thermodynamics in the system. The device can be applied to point cooling of quantum computers, to create nanocoolers or heaters.

One of the basic laws of physics states that disorder of an energetically isolated system cannot spontaneously decrease. However, researchers from the Moscow Institute of Physics and Technology with colleagues from the United States and Switzerland have presented a device that allows you to manipulate this state, changing it on demand. To be precise, they described the spatially-separated quantum demon Maxwell, acting at a distance of up to 5 meters.

As a qubit, the scientists used a tiny superconducting device made up of thin layers of aluminum on a silicon chip. The system is called an artificial atom because, under ultra-low temperature conditions, it behaves like an elementary particle with two energy levels. Once connected, the qubits begin to exchange virtual photons, which leads to a change in their state.

The second device (demon), brought to a clean state, transfers it to the first, and itself becomes «dirty». In this case, the working qubit decreases its entropy, while maintaining the same energy. Essentially the second device «eats» disorder.

An example is billiard balls, which, after being hit with a cue, fly in all directions. The described technology makes all the balls return to their original state, in fact, turning back the clock..

Since qubits are in a pure state for only a fraction of a second, manipulations can be performed many times. In practice, this can be used to develop algorithmic cooling of a quantum computer, a subroutine that can purposefully cool individual qubits, reducing the amount of noise and errors..

You can also create a microscopic refrigerator that affects not the entire volume, but specific points. Since the process can be started in the opposite direction, not only cooling is possible, but also heating..

When working with two qubits, the effect was achieved in 85% of cases, and with the addition of the third, the effect was only 50%. However, scientists plan to reduce the error rate by improving the equipment used..

Russian physicists have developed a new way to cool a quantum computer

Physicists have recently developed an equally amazing device – a photoacoustic pump. laser-driven that is capable of moving fluids in any direction without moving parts or electrical contacts.

text: Ilya Bauer, photo: Getty Images

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