An atomic scale integrated quantum circuit propels us toward quantum computers

premiere mondiale circuit integre quantique echelle atomique couv

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There has always been a strong motivation for scientists to search for superior computer performance. Tomorrow’s computers will be quantum, which allows for faster and more complex calculations, complete simulation of molecules, or the development of innovative materials. However, before accessing it, it is first necessary to create the components of these supercomputers. Recently, engineers in Sydney demonstrated a quantum integrated circuit made of 10 phosphorus atoms made of silicon. This is an important step in the development of quantum computing that is effective under real conditions. By precisely controlling the quantum states of atoms – different energy levels Electrons Atomic – The new silicon processor can simulate the structure and properties of an organic molecule with astonishing accuracy.

The culmination of 20 years of research led by Michael Simmons of Cynthia, founder of UNSW start-up Silicon Quantum Computing (SQC), is the integrated circuit milestone on the nuclear scale. In 2012, his team developed the first “quantum transistor”.

The திரிதடையம் Small electronic components that store information snippets. They are made of semiconductor materials, which allows a switching effect and encryption of information. This occurs because semiconductors have a large group of electrons. However, according to quantum mechanics, a Counter electronics Can only occupy certain energy levels. The amounts of electrons that make up the semiconductor correspond to variations in “bands” or allowable energy values. When a transistor is turned on – the mains voltage is in the power band – the current flows and the system detects a value of “1”. When a transistor is in off-mode the voltage will be outside the allowable energy band – the current will no longer flow and the system will specify a value of “0”.

Note that a Quantum computer Similar to classical computers, but does its calculations directly using the laws of quantum physics. A classical computer handles bits of information, either 0V or 1V, using a quantum computer Quits. These are generalizations of classical bits that are simultaneously superpositions of these two levels.

So recently, a team of quantum computing physicists from UNSW Sydney, in conjunction with start-up silicon quantum computing, simulated the behavior of a small organic molecule and designed a nuclear-scale quantum processor to reflect its structure and energy levels. It represents an important milestone in the race to create the world’s first quantum computer, and demonstrates the team’s ability to control the quantum positions of electrons and atoms in the world. Silicon, On an unprecedented scale. Their results are published in the journal Natural.

Follow nature, but in the most demanding way

This technological breakthrough addresses the challenge first posed by pioneering theoretical physicist Professor Richard Feynman in his famous 1959 lecture. Lots of room downstairs. During this lecture, Feynman emphasized that in order to understand how nature works, it is necessary to control matter at the same lengths as it is structured – that is, to control matter at the atomic level.

Science professor Michelle Simmons, a leading researcher in the study, says in an Was contacted : ” That’s why we do, we create it from bottom to top, where we reflect the polyacetylene molecule by placing atoms in silicon at the exact distances representing single and double carbon-carbon bonds. “. This molecule has a well-known advantage over researchers so they can immediately determine the stability of the result and the reliability of the chip by extension.

To design the first quantum integrated circuit, the team had to make three unique technological breakthroughs in nuclear engineering, in a complete vacuum. In fact, at this level, the entire manipulation of a hydrogen atom can be compromised.

The first achievement is to create small dots of atoms of the same size so that their energy levels are in order and the electrons can easily pass through them. These points, called quantum points (QD), are the points of phosphorus atoms. By configuring their layouts, they can function like real quantum transistors. In the present study, the quantum integrated circuit consists of a chain of 10 quantum points to simulate the exact location of the atoms in the polyacetylene chain.

Nevertheless, the bearing power band is very small as mentioned earlier for conventional transistors. This is where the second technological breakthrough comes in, the ability to adjust the power levels of each point individually, but collectively adjust all points. Therefore, using a nanometric precision system, six control electrodes (G1 to G6 in the figure below) were added to adjust the energy levels. It completely controls where the electrons are in the polyacetylene chain. By adding the source (S) and drain (D) conductors, it is possible to measure the current flowing through the device as electrons pass through a string of 10 quantum points.

Quantum circuit model1
The scanning tunneling microscope image of the 10 quantum dot quantum analog simulator represents a polyacetylene molecule. © SM Simmons et al., 2022

Finally, the third technical challenge is to achieve the ability to control the distance between points with sub-nanometer accuracy. If they are too close, the energy produced is too powerful to pass. If they are far apart, the connections between them are dangerous. The points must therefore be close enough, but independent, to allow the coherent transport of electrons through the chain.

To double this consistency of the circuit-generated results, the researchers simulated two different strands of polymer chains at 10 points on the molecule.

In the first device 10 peaks were given to the current and finally a part of the chain was cut so as to leave double bonds. In the second device, cut different pieces of chain so as to leave single bonds at the end and only two peaks are available in the current. The current through each chain is completely different due to the different bond lengths of the atoms at the end of the chain.

Comparative circuit models
Theoretical comparison and scanning tunneling microscopy of two different strands of polymer chains at 10 points of the molecule. Above (device I), the chain ends with a double bond; Below (Device II), it ends with a simple binding. © SM Simmons et al., 2022 (Replaced by Larry Henry for Trust My Science)

Professor Simmons explains: ” What this shows is that you can actually reflect what is really going on in the molecule. It’s exciting because the signatures of the two chains are so different. Most other quantum computing structures do not have the ability to engrave atoms with sub-nanometer accuracy or allow atoms to be that close. This means that we can begin to understand increasingly complex molecules by placing atoms in place as if they represent a real physical structure. “.

And now? Quantum biology …

According to Professor Simmons, the choice of a carbon chain of 10 atoms is not accidental because it is within the range of a typical computer’s computational size, up to 1024 unique contacts of electrons in this system. Increasing it to a chain of 20 points would see the number of potential contacts increase exponentially, making it difficult for a common system to solve.

She says: ” We are approaching the limit of what conventional computers can do, so this is like a step unknown. […] We are going to understand the world differently by answering basic questions that we have not yet been able to answer. “.

Also, we are talking about quantum biology. This latest regulatory field deals with the study of the mechanisms by which organisms function, including the laws of quantum physics. Photosynthesis, orientation or bioluminescence of migratory birds are governed by quantum processes. Understanding these phenomena will lead to many innovations in the field of biomimetry.

The team believes that the development of quantum computers is on a path comparable to the evolution of classical computers – from a transistor in 1947 to an integrated circuit in 1958, and then small computer chips were integrated into commercial products, such as calculators. Five years later. Coincidentally, this atomic scale integrated circuit, which acts as an analog quantum processor, came less than a decade after the team announced the creation of the world’s first transistor (in 2012). Before the schedule.

Finally, the use of fewer components in the circuit to control quilts reduces the amount of any interference in the quantum states and allows devices to be measured to create more complex and powerful quantum systems.

Source: Natural

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