Engineers have discovered a new way to precisely control single electrons (A new technique brings quantum chips closer to billions of qubits) embedded in quantum dots that run logic gates. The new system is also smaller and requires fewer components, which could be essential to making large-scale silicon quantum computers a reality.
The discovery, made by engineers from quantum computing startup Diraq at UNSW, is described in the journal Nature Nanotechnology.
“It’s a completely new feeling that we haven’t seen before, and we didn’t really understand before,” author Dr. Will Gilbert, a quantum processor engineer at Diraq, a company based at UNSW said. His Kensington School. . “But it turns out that this is a powerful new way to control spins and quantum dots. But it’s a lot of fun.
The calculator is the cornerstone of any computer. They allow “bits” – or binary numbers (0 and 1) – to work together to process information. However, a quantum bit (or qubit) exists in both these states at once – a condition known as “superposition“.
This allows for many computational processes – some running faster, others working simultaneously – that bypass ordinary computers. Qubits themselves are made of “quantum dots” – small nanodevices that can trap one or a few electrons. Accurate control of electrons is essential for calculations to occur.
Use electricity rather than magnetic fields
By experimenting with different geometrical devices as small as a billionth of a billionth of a meter in size that control quantum dots, and different types of magnets and small antennae that work with them, Dr Tuomo Tanttu of UNSW Engineering obtained amazing feeling.
Dr Tanttu, who is also a measurement engineer at Diraq, said, “I have been trying to work with two qubit gates, going through many different devices, slightly different geometries, different packages and control systems available. separately.” “Then this strange trap appeared. It looked like the rotation of a group of qubits was happening very quickly, something I had never seen in four years of doing these experiments.
What he discovered, the engineers later realized was a new way to manipulate the quantum state of a qubit by using an electric field, rather than the magnetic fields they used to use. Since its discovery in 2020, engineers have been perfecting this process – which has become another tool in their arsenal to achieve Diraq’s goal of building billions of qubits in a single chip.
“It’s a new way to manipulate qubits, and it’s very small to build – you don’t need to make cobalt micro-magnets or antennas around the qubits to create a control effect.” Dr. Gilbert said. “This eliminates the need to place other structures around each door. Therefore, there is less clutter. »
Controlling single electrons without disturbing others nearby is important for quantum information processing in silicon. There are two established methods: electron spin resonance (ESR) using an on-chip microwave antenna and electric dipole spin resonance (EDSR), which relies on a magnetic field gradient. This newly discovered technique is known as “Intrinsic spin-orbit EDSR”.
“Ultimately, we design our microwave antenna to provide a magnetic field,” said Dr Tanttu. new effects we can use to manipulate qubits. It’s a happy coincidence for you.
Making quantum computing on silicon a reality
“This is a new system, a gem, which only adds to the wealth of technologies that we have developed in the last 20 years of research,” said Professor Andrew Dzurak, Professor of Scientia and quantum engineering at UNSW and CEO and the findings of Diraq. . . Professor Dzurak led the team that built the first silicon quantum gate in 2015.
“It builds on our work to make quantum computing on silicon a reality, based on the same semiconductor chip technology as current computer chips, rather than relying on special materials.
Since it is based on the same CMOS technology as today’s computer industry, our approach will make scaling up commercial production easier and faster and achieve our goal of producing billions of qubits on a single chip.
CMOS (or complementary metal-oxide-semiconductor, pronounced “see-moss”) is the manufacturing process at the heart of modern computers. It is used for all kinds of integrated circuit components – including microprocessors, microcontrollers, memory chips and other digital logic circuits, as well as analog circuits such as image sensors and data converters.
The computer is also called “the space race of the 21st century” – a very difficult and serious challenge that can provide critical tools to calculate impossible calculations, such as the creation of complex drugs and substances, high, or quick search of large unstructured databases.
“We often think of the moon landing as man’s greatest technological marvel,” Professor Dzurak said. “But the truth is that today’s CMOS chip – and the billions of electronic devices that run like a musical instrument, and carry around in your pocket – is a marvel of engineering and evolution. Modern life Quantum computing will be very amazing.
