A quantum computer does not usually bring musical instruments to mind. Yet inside a chip developed at ETH Zurich, information is stored in vibrations that behave somewhat like notes resonating through a guitar.
These movements cannot be heard. They occur at extremely high frequencies inside microscopic mechanical resonators, where packets of vibrational energy called phonons carry quantum information. The entire experimental chip measures about 7.5 millimeters long, 2.5 millimeters wide, and 1 millimeter thick (0.30 inches long, 0.10 inches wide, and 0.04 inches thick), making it roughly as wide as a small fingernail.
Led by quantum physicist Yiwen Chu, the team used these tiny resonators as a working memory connected to a superconducting quantum processor. Their results, published in Science, demonstrate a different way to organize a quantum computer, one that more closely resembles the basic structure of the classical computers used today.
“The interaction between the quantum processor and the quantum memory provides a crucial foundation with a view to establishing quantum computers as a powerful and reliable way to perform computations that are not feasible with conventional computers,” says Yiwen Chu.
Borrowing the CPU and RAM Model
Most quantum systems do not clearly separate calculation from memory. Processing and information storage are often closely integrated into the same hardware, which can make it difficult to expand the machine without adding more bulky components.
Chu’s team instead borrowed a familiar idea from conventional computing. In a digital computer, a central processing unit (CPU) performs calculations while data is temporarily held in random access memory (RAM). Separating those jobs allows the processor to retrieve information when needed rather than forcing every part of the system to perform every task.
The experimental quantum architecture follows a similar principle. A superconducting qubit serves as the processor and control unit, while mechanical resonators hold quantum information during the calculation.
“In our quantum working memory, however, information is not stored electromagnetically, as is usually the case today, but rather in the form of mechanical vibrations,” explains Chu.
Source: SciTechDaily
@EverythingScience
