{"id":36016,"date":"2023-01-19T19:31:47","date_gmt":"2023-01-19T20:31:47","guid":{"rendered":"https:\/\/peymantaeidi.net\/stem-cell\/?p=36016"},"modified":"2023-01-19T20:36:10","modified_gmt":"2023-01-19T20:36:10","slug":"breakthrough-discovery-brings-billion-qubit-quantum-computing-chips-closer","status":"publish","type":"post","link":"https:\/\/peymantaeidi.net\/stem-cell\/2023\/01\/19\/breakthrough-discovery-brings-billion-qubit-quantum-computing-chips-closer\/","title":{"rendered":"Breakthrough Discovery Brings Billion-Qubit Quantum Computing Chips Closer"},"content":{"rendered":"
\"Intrinsic<\/p>\n

How multiple qubits may be controlled using the new \u2018intrinsic spin-orbit EDSR\u2019 process. Credit: Tony Melov<\/p>\n

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Discovery of previously unknown effect makes compact, ultra-fast control of spin qubits possible.<\/h3>\n

Australian engineers have discovered a new way of precisely controlling single electrons nestled in quantum dots that run logic gates. What\u2019s more, the new mechanism is less bulky and requires fewer parts, which could prove essential to making large-scale silicon quantum computers a reality.<\/p>\n

The serendipitous discovery, made by engineers at the quantum computing<\/p>\n

Performing computation using quantum-mechanical phenomena such as superposition and entanglement.<\/div>\n

” data-gt-translate-attributes=”[{"attribute":"data-cmtooltip", "format":"html"}]”>quantum computing<\/span> start-up Diraq and UNSW Sydney, is detailed on January 12 in the journal Nature <\/em>Nanotechnology<\/em>.<\/p>\n

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\u201cThis was a completely new effect we\u2019d never seen before, which we didn\u2019t quite understand at first,\u201d said lead author Dr. Will Gilbert, a quantum processor engineer at Diraq, a UNSW spin-off company based at its Sydney campus. \u201cBut it quickly became clear that this was a powerful new way of controlling spins in a quantum dot. And that was super exciting.\u201d<\/p>\n

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\"Single<\/p>\n

Artist\u2019s concept of a single qubit held within a quantum dot flips in response to a microwave signal. Credit: Tony Melov<\/p>\n<\/div>\n

Logic gates are the basic building block of all computation; they allow \u2018bits\u2019 \u2013 or binary digits (0s and 1s) \u2013 to work together to process information. However, a quantum<\/em> bit (or qubit) exists in both of these states at once, a condition known as a \u2018superposition\u2019. This allows a multitude of computation strategies \u2013 some exponentially faster, some operating simultaneously \u2013 that are beyond classical computers. Qubits themselves are made up of \u2018quantum dots\u2019, tiny nanodevices which can trap one or a few electrons. Precise control of the electrons is necessary for computation to occur.<\/p>\n

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Diraq engineers have discovered a new way of precisely controlling single electrons nestled in quantum dots that run logic gates, bringing the reality of achieving billion-qubit quantum chips closer. What\u2019s more, the new mechanism is less bulky and requires fewer parts, which could prove essential to making large-scale silicon quantum computers a reality. Credit: Diraq<\/em><\/p>\n

Using electric rather than magnetic fields<\/h4>\n

While experimenting with different geometrical combinations of devices just billionths of a meter in size that control quantum dots, along with various types of minuscule magnets and antennas that drive their operations, Dr. Tuomo Tanttu stumbled across a strange effect.<\/p>\n

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\u201cI was trying to really accurately operate a two-qubit gate, iterating through a lot of different devices, slightly different geometries, different materials stacks, and different control techniques,\u201d recalls Dr. Tanttu, a measurement engineer at Diraq. \u201cThen this strange peak popped up. It looked like the rate of rotation for one of the qubits was speeding up, which I\u2019d never seen in four years of running these experiments.\u201d<\/p>\n

What he had discovered, the engineers later realized, was a new way of manipulating the quantum state of a single qubit by using electric<\/em> fields, rather than the magnetic fields they had been using previously. Since the discovery was made in 2020, the engineers have been perfecting the technique \u2013 which has become another tool in their arsenal to fulfil Diraq\u2019s ambition of building billions of qubits on a single chip.<\/p>\n

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\"Accelerating<\/p>\n

Illustration of a single qubit as it begins to accelerate in response to a microwave signal, and the electron begins rattling within the quantum dot. Credit: Tony Melov<\/p>\n<\/div>\n

\u201cThis is a new way to manipulate qubits, and it\u2019s less bulky to build \u2013 you don\u2019t need to fabricate cobalt micro-magnets or an antenna right next to the qubits to generate the control effect,\u201d said Gilbert. \u201cIt removes the requirement of placing extra structures around each gate. So, there\u2019s less clutter.\u201d<\/p>\n

Controlling single electrons without disturbing others nearby is essential for quantum information processing in silicon. There are two established methods: \u2018electron spin resonance\u2019 (ESR) using an on-chip microwave antenna; and electric dipole spin resonance (EDSR), which relies on an induced gradient magnetic field. The newly discovered technique is known as \u2018intrinsic spin-orbit EDSR\u2019.<\/p>\n

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\u201cNormally, we design our microwave antennas to deliver purely magnetic fields,\u201d said Dr. Tanttu. \u201cBut this particular antenna design generated more of an electric field than we wanted \u2013 and that turned out to be lucky, because we discovered a new effect we can use to manipulate qubits. That\u2019s serendipity for you.\u201d<\/p>\n

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\"Diraq<\/p>\n

Prof Andrew Dzurak, Dr. Will Gilbert, and Dr. Tuomo Tanttu of quantum computing company, Diraq. Credit: Grant Turner<\/p>\n<\/div>\n

Discovery brings silicon quantum computing closer<\/h4>\n

\u201cThis is a gem of new mechanism, which just adds to the trove of proprietary technology we\u2019ve developed over the past 20 years of research,\u201d said Prof Andrew Dzurak, CEO and Founder of Diraq, and a Professor in Quantum Engineering at UNSW, who led the team that built the first quantum logic gate in silicon<\/a> in 2015.<\/p>\n

\u201cIt builds on our work to make quantum computing in silicon a reality, based on essentially the same semiconductor component technology as existing computer chips, rather than relying on exotic materials,\u201d he added. \u201cSince it is based on the same CMOS technology as today\u2019s computer industry, our approach will make it easier and faster to scale up for commercial production and achieve our goal of fabricating billions of qubits on a single chip.\u201d<\/p>\n

\"Diraq<\/p>\n

Bird\u2019s eye view of one of Diraq\u2019s labs in Sydney, Australia. Credit: Shaun Dougherty<\/p>\n

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CMOS (or complementary metal-oxide-semiconductor, pronounced \u2018see-moss\u2019) is the fabrication process at the heart of modern computers. It is used for making all sorts of integrated circuit components \u2013 including microprocessors, microcontrollers, memory chips, and other digital logic circuits, as well as analog circuits such as image sensors and data converters.<\/p>\n

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Building a quantum computer has been called the \u201cspace race of the 21st century\u201d \u2013 a difficult and ambitious challenge with the potential to deliver revolutionary tools for tackling otherwise impossible calculations, such as the design of complex drugs and advanced materials, or the rapid search of massive, unsorted databases.<\/p>\n

\u201cWe often think of landing on the Moon as humanity\u2019s greatest technological marvel,\u201d said Dzurak. \u201cBut the truth is, today\u2019s CMOS chips \u2013 with billions of operating devices integrated together to work like a symphony, and which you carry in your pocket \u2013 that\u2019s an astounding technical achievement, and one that\u2019s revolutionized modern life. Quantum computing will be equally astonishing.\u201d<\/p>\n

Reference: \u201cOn-demand electrical control of spin qubits\u201d by Will Gilbert, Tuomo Tanttu, Wee Han Lim, MengKe Feng, Jonathan Y. Huang, Jesus D. Cifuentes, Santiago Serrano, Philip Y. Mai, Ross C. C. Leon, Christopher C. Escott, Kohei M. Itoh, Nikolay V. Abrosimov, Hans-Joachim Pohl, Michael L. W. Thewalt, Fay E. Hudson, Andrea Morello, Arne Laucht, Chih Hwan Yang, Andre Saraiva and Andrew S. Dzurak, 12 January 2023, Nature Nanotechnology<\/em>.
DOI: 10.1038\/s41565-022-01280-4<\/a><\/p>\n

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About Diraq
<\/strong><\/p>\n

Diraq aims to redefine scalable quantum computing by creating billions of qubits on a single chip, compared to the hundreds of qubits possible today. Relying on proprietary technology developed over 20 years of research and with over A$100 million in funding across nine patent families, Diraq\u2019s approach relies on the existing silicon manufacturing processes used by foundries to produce today\u2019s semiconductor components, known as CMOS, forging a faster and cheaper road to market. It aims to be an end-to-end quantum computing provider, creating quantum hardware and software as a full-stack, cloud-accessible service. <\/p>\n

About UNSW Engineering
<\/strong><\/p>\n

UNSW Engineering is the powerhouse of engineering research in Australia, made up of nine schools and 36 research centers. Ranked in the world\u2019s top 50 engineering faculties and equal fifth globally in sustainability (equal first in Australia); it\u2019s also ranked #1 in Australia for graduates who create start-ups. UNSW itself tops the list of Australian universities with the most millionaire graduates.<\/p>\n

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