Tag: computers

Quantum computers in silicon

Quantum computers in silicon

Development of a new European quantum technology begins

The EQUSPACE consortium (Enabling New Quantum Frontiers with Spin Acoustics in Silicon) has received 3.2 million euros from the European Innovation Council’s (EIC) Pathfinder Open funding program to advance the development of silicon-based quantum technologies. In addition to the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), the project brings together four other partners from three EU countries and convenes experts from the fields of spin qubits, optomechanics and atomic silicon modifications to develop a novel silicon-based quantum platform.

Although silicon is the central material for classic computers, it does not play a key role in the currently favored quantum computer concepts. However, it would make a lot of sense to use the multi-billion euro silicon infrastructure already developed with semiconductor technology to process qubits – the quantum mechanical information units. Researchers have shown that so-called donor spin qubits are actually particularly well suited for this endeavor. These qubits use a property of impurity atoms, their spin, to process information. Compared to other quantum systems, they are characterized by long periods of time over which they remain stable in order to perform quantum mechanical computing operations. Currently, however, they are not the workhorse of commercial quantum computers, as there are no suitable coupling and readout mechanisms that could be used to scale them up to a practically usable level.

EQUSPACE now aims to create a long-term future for silicon-based donor spin qubits in Europe. The platform makes an effort to connect the qubits, which are based on tiny atomic spins, via sound waves in vibrating structures. Lasers and single-electron transistors will also be used to electrically read out the result at the end of the quantum mechanical calculation. The project seeks to provide a scalable solution for all important aspects of a quantum platform: the control and readout of the result, the spin-spin coupling between qubits, and the transmission of quantum information between computing units on the chip. The final outcome could be a complete quantum information platform that includes qubits, interconnects and scalable control and readout electronics.

HZDR expertise in silicon quantum technology

A team from the Institute of Ion Beam Physics and Materials Research at HZDR will contribute its expertise in the atomic modification of silicon for quantum applications and further develop the materials science methods required as a basis for the project. The team will use a focused ion beam to locally enrich ultra-pure silicon with the isotope silicon-28. Compared to many other materials, silicon-28 has the advantage that its atomic nuclei have no spin that could interact with magnetic fields or the spin of other particles and thus interfere with the calculations. “Through the targeted enrichment with special isotopes, the quantum state remains stable for longer timespans. This allows more complex quantum operations, and the platform could thus outperform classical computers and other quantum computer systems in the future,” says HZDR project manager Dr. Nico Klingner.

In addition to isotope purification, the team is developing the single-ion implantation of donor atoms. The aim is to implant individual bismuth atoms whose spin forms a two-state system that can point either “up” or “down”. The special feature of qubits is that at very low temperatures, both states can exist simultaneously in superpositions: the spin can be in a combination of the “up” and “down” states at the same time. This allows quantum computers to perform many calculations in parallel, which can drastically increase their computing power.

One of the main advantages of donor spin qubits is their relative stability compared to other types of qubits, for example those based on superconducting circuits. The spin in a donor atom is less susceptible to perturbations from the environment, so the quantum state can be maintained over longer periods of time. This stability is essential for scaling quantum computers to a larger number of qubits without losing coherence or precision of computations. “These contributions from HZDR, especially in the areas of isotope purification, implantation and strain engineering in semiconductors, are fundamental to the success of the EQUSPACE project,” states Professor Juha Muhonen, the coordinator of the project.

Read more on HZDR website

Image: In the single ion implanter TIBUSSII (Triple Ion Beam UHV System for Single Ion Implantation), individual dopants can be implanted atom by atom into a material, for example to generate qubits.

Credit: B. Schröder / HZDR

More Brain-like Computers Could Cut IT Energy Costs

More Brain-like Computers Could Cut IT Energy Costs

The dynamics of magnetic metamaterials offer a path to low-energy, next-gen computing

The public launch of OpenAI’s ChatGPT in November 2022 caused a media sensation and kicked off a rapid proliferation of similar Large Language Models (LLMs). However, the computing power needed to train and run these LLMs and other artificial intelligence (AI) systems is colossal, and the energy requirements are staggering. Training the GPT-3 model behind ChatGPT, for example, required 355 years of single-processor computing time and consumed 284,000 kWh of energy1. This is one example of a task that the human brain handles much more efficiently than a traditional computer, and researchers are investigating the potential of more brain-like (neuromorphic) computing methods that may prove to be more energy efficient. Physical reservoir computing is one such method, using the natural, complex responses of materials to perform challenging computations. Researchers from the University of Sheffield are investigating the use of magnetic metamaterials – structured at the nanoscale to exhibit complex and emergent properties – to perform such computations. In work recently published in Communications Physics, they have demonstrated an ability to tune the system to achieve state-of-the-art performance in different types of computation. Their results show that an array of interconnected magnetic nanorings is a promising architecture for neuromorphic computing systems.

Emergence Could Power More Brain-Like Computers

Anyone who has witnessed the majestic and mesmerising flight of a murmuration of starlings has no doubt wondered how a flock of birds can achieve such synchronised behaviour. This is an example of emergence, where the interactions of simple things lead to complex collective behaviours. But emergence doesn’t only occur in the natural world, and a group at the University of Sheffield is investigating how the emergent behaviour can be engineered in magnetic materials when they are patterned to have nanoscale dimensions.

Dr Tom Hayward, Senior Lecturer in Materials Physics at the University of Sheffield and author of this paper says,

Life is inherently emergent – with simple entities connecting together to give complex behaviours that a single element would not have. It’s exciting because we can take simple things – which hypothetically can be very energy efficient – and make them manifest the kind of complexity we see in the brain. Material computation relies on the fact that many materials that exhibit some form of memory can take an input and transform it into a different output – precisely the properties we need to perform computation. Our system connects a series of tiny magnetic rings into a big ensemble. One individual ring in isolation shows quite simple behaviours. But when we connect them, they interact with each other to give complex behaviours.

Magnets have a number of properties that make them interesting for these kinds of applications: 

  • Firstly, they are non-volatile, with inherent memory – if you stick a magnet to your fridge, it stays put.
  • Brains (and brain-like computers) need to have non-linear responses, taking simple information and performing complicated transforms, and that’s something magnets are naturally good at.
  • There are plenty of ways to make magnets change state and perform computations that use very little energy.
  • And magnets are a well-established technology (used, for example, in hard drives and Magnetoresistive random-access memory (MRAM)), and so there are existing routes to technology integration.

XPEEM Highlights the Underlying Magnetic Dynamics

Key to this research is understanding what’s happening to these magnetic nanorings when they’re connected together – the way that emergence changes the way they change magnetic states.

Read more on Diamond website

World changing science with precious photons

World changing science with precious photons

he 3.4 km long European XFEL generates extremely intense X-ray flashes used by researchers from all over the world. The flashes are produced in underground tunnels and they enable scientists to conduct a wide range of experiments including mapping atomic details of viruses, filming chemical reactions, and studying processes in the interior of planets.

Michael Schneider is a physicist at the Max Born Institute in Berlin. He uses synchrotrons and free electron lasers, such as the European XFEL, to study magnetism and magnetic materials. Michael’s fascinating #LightSourceSelfie takes you inside the European XFEL where he recalls the fact that it was large scale facilities themselves that first attracted him to his area of fundamental research. The work is bringing us closer to a new generation of computing devices that work more like the neurons in our brains that the transistors that we currently have in our computers. Michael captures the dedication of his colleagues and the facility teams, along with the type of work that you can get involved with at large scale facilities. He also gives a brilliant overview of the stages involved in conducting research at a light source. Michael is clearly very passionate about his science, but also finds time for some great hobbies too!