Xanadu, a Canadian quantum computer (computer) research and development company, and the U.S. National Institute of Standards and Technology (NIST) have collaborated to build an optical quantum chip with eight quantum digits.
The materials and supporting technologies used to make the quantum bits, the core component of a quantum computer chip, are now one of the keys to quantum computer research, with some using superconductors, which require atoms to be cooled to extremely low temperatures, and others using photons. Each technology has its own advantages and disadvantages.
Optical quantum chips came later?
For a long Time, optical quantum chips were not well received. Several high-profile quantum chips demonstrated by IBM, Google and other companies in the past few years were not based on optical quantum technology.
Recently, Xanadu has developed a chip that seems to have made a lot of progress. The magazine Physics World describes this achievement under the title “Programmable photonic chip lights up the field of quantum computers”; Ars Technica says “New optical quantum computer technology overcomes previous limitations and looks like a winner. It looks like a winner”.
The chip uses a “squeeze” method that sends photons into a miniature circuit, saying that “its quantum uncertainty is minimized.
The company said the chip consists of three units: squeezers (Squeezers), interferometers (Interferometer) and photon detectors (Photon Detectors). The squeezers are the input units that feed the photons and “squeeze” them; the interferometers are the logic units; and finally the photon detectors are the measurement and output units.
Programming performance demonstration
The chip uses a Python-like looking code as the programming interface to communicate with the hardware. The researchers used it to demonstrate running three programs ranging from simple to complex.
The first program is the simplest, simulating itself and showing how many different states can be produced in a given amount of time. Any quantum chip can now do this. The second program calculates the vibrational state of an ethylene molecule (a compound of two carbon atoms and four hydrogen atoms), followed by a bit more complexity, the vibrational state of phenylvinylacetylene. A third program calculates the most popular names for newborns in 2021.
These programs were carefully selected by the developers and aptly demonstrate the performance of this quantum chip with only eight digits.
Small size
The very small size is another highlight of this chip. It is less than the size of a fingertip, as seen in the pictures shown by the company.
Shuntaro Takeda, a physicist at the University of Tokyo who was not involved in the research, says that previous experiments using squeezed photon technology required mirrors, lenses and other optical components that would have taken several tables to set up. He believes that Xanadu’s ability to build such a small chip has laid the necessary foundation for future expansion.
Connecting to cloud services
Another colleague, Zheshen Zhang, a quantum information researcher at the University of Arizona, said that previous similar optical quantum chips could not perform tasks from different users at the same time, and that the chip’s ability to perform multiple operations at the same time is a big step forward. In addition, Xanadu’s chip can be connected to cloud services, which is another advantage.
Loss of photons
The research team said that currently, due to process difficulties, many photons are lost in the process of passing through the chip. This will be the direction of their improvement. There is still a lot of work to be done to build quantum computers that can be of comparable scale to modern computers.
A paper describing the chip was published in the journal Nature on March 3.
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