Tuesday , June 15 2021

Tech: To design future quantum technologies, scientists determine how microwaves interact with matter – (Report)



Small moving particles make up everything in our physical world – including modern electronics, whose function depends on the movement of negatively charged electrons. Physicists seek to understand the forces that push these particles in motion in order to master their strength in new technologies. Quantum computers, for example, use a fleet of precision-controlled electrons to handle goliath computational tasks. Recently, OIST researchers have demonstrated how a form of light, called microwaves, reduces the movement of electrons. Findings can help improve quantum computations.

Normal computers work with zeros and units, and this binary code limits the volume and type of information that machines can process. Subatomic particles can exist in more than two discrete states, so quantum computers compel electrons to crush complex data and perform functions at impact velocity. To preserve electrons in uncertainty, scientists capture the particles and expose them to forces that change their behavior.

In a new study, published on December 18, 2018, Physical Review BOIST researchers held the electrons in a refrigerated, vacuum-sealed chamber and subjected them to microwaves. Particles and light change the movement and the exchange of energy, which implies that the sealed system can potentially be used to store quantum information – a microchip of the future.

"This is a small step towards a project that requires a lot more research," said Jiabao Chen, the first author of the article and a graduate student at the OIST Quantum Dynamics Unit, led by Professor Dennis Konstantinov. Creating new states of electrons for quantum computation and quantum information storage. "

Transmitting electrons

The light, made up of fast, oscillating electric and magnetic fields, can push around the charged matter it encounters in the environment. If the light vibrates at the same frequency as the electrons, the light and the particles can exchange energy and information. When this happens, the movement of light and electrons is "connected". If energy is exchanged faster than other light interactions in the environment, the movement is "strongly connected". strongly connected state using microwaves.

"Achieving strong bonding is an important step towards quantum mechanical control of light-using particles," Chen said. "This may be important if we want to generate a non-classical state of matter."

To see a strong connection clearly, this helps to isolate the electrons from a misleading "noisy signal" in their environment that occurs when electrons collide with nearby matter or interact with heat. Scientists have studied the influence of microwaves on electrons in semiconductor interfaces – where the semiconductor encounters an isolator, thus limiting the electron movement to a plane. But the semiconductors contain impurities that impede the natural movement of electrons.

No material is completely devoid of defects, so Quantum Dynamics Unit chooses an alternative solution by isolating their electrons in refrigerated vacuum enclosures equipped with two metal mirrors that reflect microwaves.

Cameras, small cylindrical containers called cells, contain a pool of liquid helium maintained at a temperature close to absolute zero. Helium remains liquid at this extreme temperature, but any impurities floating inside the substance freeze and stick to the sides of the cage. The electrons bind to the surface of the helium, thus forming a two-dimensional sheet. Researchers can then expose waiting electrons to electromagnetic radiation, such as microwaves, by capturing the light between the two mirrors in the cell.

This relatively simple system revealed the influence of microwaves on electron rotation – an effect that is invisible in semiconductors.

"In our organization, we can more clearly define the course of the physical phenomenon," says Dr. Olexius Zajorjko, author of the report and post-doctorate at Quantum Dynamics Unit. "We have found that microwaves have a significant impact on electron movement."

Quantum Calculation Power Supply

Physicists describe their findings mathematically and find that fluctuations in the velocity, location or total charge of individual electrons have little effect on the strong coupling effects. Instead, the average movement of particles and microwaves, massively, seems to cause an exchange of energy and information between them.

Researchers hope that in the future the liquid helium system will give them precise control of the electrons, allowing them to read, write and process quantum information similar to how we store standard hard disk data. With an improved understanding of this system, the Quantum Dynamics Unit aims to improve the industry standard for cubes – bits of quantum information. Their efforts can lead to the development of faster and more powerful quantum technologies.


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