A challenge launched some 60 years ago by theoretical physicist Richard Feynman has been solved.
A team of quantum computing physicists from UNSW Sydney managed to mimic the structure and energy states of a specific organic compound. Scientists have designed a quantum system on an atomic scale. Your mission? Simulate the behavior of a small organic molecule called polyacetylene.
Specifically, these Australian scientists have created a circuit that could be defined as the first quantum processor. To understand the scope of this invention, let’s start with some definitions.
Understand the basics
A processor can be compared to the brain of the computer. It is responsible for managing data exchanges between the different components. That is, between the hard drive, RAM and graphics card. In addition, it is he who performs the calculations that allow the device to interact with the user and display information on the screen. For their part, quantum technologies represent the methods and systems created to invent tools whose operation is based on one of the quantum properties. Namely, the quantum superposition of states of a physical object and quantum entanglement. We are talking about particle physics of the infinitely small, in which Rydberg atoms interact, typical of quantum computers.
In short, quantum technology makes it possible to solve highly complex problems and process series of information on a massive scale. This is because, unlike conventional computers that store and process data in the form of binary bits (0 or 1), quantum machines use “qubits,” also called “quantum bits.” They have extraordinary computing power.
Finally, polyacetylene is a repeating chain of carbon and hydrogen atoms. It is distinguished by the alternation of single and double carbon bonds. A double bond is a bond between chemical elements that involves four electrons, against two for a single bond.
A big step for quantum physics
This processor represents a significant step in the race to build the first quantum computer. Clearly, these physicists have managed to control the quantum states of electrons and atoms in silicon to a level never before achieved. In fact, quantum states are very sensitive to external interference. A defect that can cause errors and that limits its scope and use so far.
Specifically, in Nature magazine articleThe researchers describe how they successfully mimicked the structure and energy states of the organic compound polyacetylene. “If you go back to the 1950s, Richard Feynman said that you can’t understand how nature works unless you can build matter on the same length scale”Professor Simmons recalls in the article. This is how the researchers built material that mimics the polyacetylene molecule. And this, “placing atoms in silicon with the exact distances that represent carbon-carbon single and double bonds”. He concludes that this means that it is now possible to begin to understand more and more complicated molecules, “put the atoms in their place as if they were imitating the real physical system”.
Towards a quantum computer
This is how the team announced that they had achieved an error rate of less than 1%. In fact, their silicon-based systems make it possible to contemplate the production of quantum machines using existing infrastructures. “Now we can make larger devices that are beyond what a typical computer can model”Professor Simmons rejoices. In other words, it is now possible to observe molecules that have not been simulated before, and therefore “understand the world in a different way, addressing fundamental questions that we have never been able to answer before”he adds.
As we have seen, quantum systems need qubits. It is a structure in the device, which helps to form the quantum state. In the processor discussed in this article, the atoms themselves create these qubits. “We only needed six metal gates to control the electrons in our 10-point system. In other words, we have fewer gates than active components of the device.”says the researcher. This reduces the elements previously needed in the circuits. In fact, most quantum computing architectures typically need at least twice as many control systems to move the electrons in the qubit architecture.