̽��ֱ�� of Cambridge - Mete Atature

Five hubs launched to ensure UK benefits from quantum future

sc604 — Fri, 26 Jul 2024 06:30:07 +0000

̽��ֱ��hub, called Q-BIOMED, is one of 5 quantum research hubs announced on 26 July by Peter Kyle MP, the Secretary of State for Science, Innovation and Technology, supported by £160 million in funding.

̽��ֱ��hub will exploit advances in quantum sensors capable of detecting cells and molecules, potentially orders of magnitude more sensitively than traditional diagnostic tests.

This includes developing quantum-enhanced blood tests to diagnose infectious diseases and cancer quickly and cheaply using portable instruments, and sensors measuring tiny changes to the magnetic fields in the brain that have the potential to detect early markers of Alzheimer’s disease before symptoms occur.

Other research will include quantum-enhanced MRI scans, heart scanners and surgical and treatment interventions for early-stage and hard-to-treat cancers.

“Quantum technologies harness quantum physics to achieve a functionality or a performance which is otherwise unattainable, deriving from science which cannot be explained by classical physics,” said Hub Co-Director Professor Mete Atatüre, Head of Cambridge’s Cavendish Laboratory. “Q-BIOMED will be delivered by an outstanding team of researchers from academia, the NHS, charities, government and industry to exploit quantum-enhanced advances for human health and societal good.”

“Our hub aims to grow a new quantum for health innovation ecosystem in the UK, and has already shaped the UK's new Quantum Mission for Health,” said Hub Co-Director Professor Rachel McKendry, from the London Centre for Nanotechnology and Division of Medicine at UCL. “Our long-term vision is to accelerate the entire innovation pipeline from discovery research, to translation, adoption and implementation within the NHS and global health systems, for the benefit of patients and societal good.”

“Quantum sensing allows us to gather information at cellular and molecular levels with unprecedented sensitivity to electric and magnetic fields," said Dr Ljiljana Fruk from the Department of Chemical Engineering and Biotechnology, a member of the Q-BIOMED team. "I look forward to learning from colleagues and engaging in challenging discussions to develop more sensitive, affordable tools for doctors and patients, advancing the future of healthcare.”

Cambridge researchers are also involved in three of the other newly-announced hubs:

̽��ֱ��UK Hub for Quantum Enabled Position, Navigation and Timing (QEPNT), led by the ̽��ֱ�� of Glasgow, will develop quantum technologies which will be key for national security and critical infrastructure and sectors such as aerospace, connected and autonomous vehicles (CAVs), finance, maritime and agriculture. Luca Sapienza (Engineering), Louise Hirst (Materials Science and Metallurgy/Cavendish Laboratory) and Dave Ellis (Cavendish Laboratory) are part of the QEPNT team.
QCI3: Hub for Quantum Computing via Integrated and Interconnected Implementations, led by the ̽��ֱ�� of Oxford, aims to develop the technologies needed for the UK to play a key role in the development of quantum computers, a market estimated to be worth $1.3 trillion by 2030. Ulrich Schneider (Cavendish Laboratory), Helena Knowles (Cavendish Laboratory), and Chander Velu (Institute for Manufacturing) are part of the QCI3 team.
̽��ֱ��Integrated Quantum Networks (IQN) Quantum Technology Research Hub, led by Heriot-Watt ̽��ֱ��, will undertake research towards the ultimate goal of a ‘quantum internet’, globally interlinked quantum networks connecting multiple quantum computers to produce enormous computational power. Richard Penty, Adrian Wonfor and Qixiang Cheng (Engineering), Atatüre and Dorian Gangloff (Cavendish Laboratory) are part of the IQN team.

̽��ֱ��fifth hub, UK Quantum Technology Hub in Sensing, Imaging and Timing (QuSIT), is led by the ̽��ֱ�� of Birmingham.

̽��ֱ��five hubs are delivered by the UKRI Engineering and Physical Sciences Research Council (EPSRC), with a £106 million investment from EPSRC, the UKRI Biotechnology and Biological Research Council, UKRI Medical Research Council, and the National Institute for Health and Care Research. Added to this are contributions from industry and other partners worth more than £54 million.

Peter Kyle, Secretary of State for Science, Innovation and Technology, said: “We want to see a future where cutting-edge science improves everyday lives. That is the vision behind our investment in these new quantum technology hubs, by supporting the deployment of technology that will mean faster diagnoses for diseases, critical infrastructure safe from hostile threats and cleaner energy for us all.

“This isn’t just about research; it’s about putting that research to work. These hubs will bridge the gap between brilliant ideas and practical solutions. They will not only transform sectors like healthcare and security, but also create a culture of accelerated innovation that helps to grow our economy.”

EPSRC Executive Chair Professor Charlotte Deane said: “Technologies harnessing quantum properties will provide unparalleled power and capacity for analysis at a molecular level, with truly revolutionary possibilities across everything from healthcare to infrastructure and computing.

“ ̽��ֱ��5 Quantum Technology Hubs announced today will harness the UK’s expertise to foster innovation, support growth and ensure that we capitalise on the profound opportunities of this transformative technology.”

A major new research hub led by the ̽��ֱ�� of Cambridge and UCL aims to harness quantum technology to improve early diagnosis and treatment of disease.

James Tye/UCL

L-R: Professor John Morton (UCL), Professor Rachel McKendry (UCL), Professor Mete Atatüre (Cambridge), Professor Eleni Nastouli (UCL)

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes

Diamonds and rust help unveil ‘impossible’ quasi-particles

sc604 — Tue, 05 Dec 2023 10:02:43 +0000

Researchers led by the ̽��ֱ�� of Cambridge used a technique known as diamond quantum sensing to observe swirling textures and faint magnetic signals on the surface of hematite, a type of iron oxide.

̽��ֱ��researchers observed that magnetic monopoles in hematite emerge through the collective behaviour of many spins (the angular momentum of a particle). These monopoles glide across the swirling textures on the surface of the hematite, like tiny hockey pucks of magnetic charge. This is the first time that naturally occurring emergent monopoles have been observed experimentally.

̽��ֱ��research has also shown the direct connection between the previously hidden swirling textures and the magnetic charges of materials like hematite, as if there is a secret code linking them together. ̽��ֱ��results, which could be useful in enabling next-generation logic and memory applications, are reported in the journal Nature Materials.

According to the equations of James Clerk Maxwell, a giant of Cambridge physics, magnetic objects, whether a fridge magnet or the Earth itself, must always exist as a pair of magnetic poles that cannot be isolated.

“ ̽��ֱ��magnets we use every day have two poles: north and south,” said Professor Mete Atatüre, who led the research. “In the 19th century, it was hypothesised that monopoles could exist. But in one of his foundational equations for the study of electromagnetism, James Clerk Maxwell disagreed.”

Atatüre is Head of Cambridge’s Cavendish Laboratory, a position once held by Maxwell himself. “If monopoles did exist, and we were able to isolate them, it would be like finding a missing puzzle piece that was assumed to be lost,” he said.

About 15 years ago, scientists suggested how monopoles could exist in a magnetic material. This theoretical result relied on the extreme separation of north and south poles so that locally each pole appeared isolated in an exotic material called spin ice.

However, there is an alternative strategy to find monopoles, involving the concept of emergence. ̽��ֱ��idea of emergence is the combination of many physical entities can give rise to properties that are either more than or different to the sum of their parts.

Working with colleagues from the ̽��ֱ�� of Oxford and the National ̽��ֱ�� of Singapore, the Cambridge researchers used emergence to uncover monopoles spread over two-dimensional space, gliding across the swirling textures on the surface of a magnetic material.

̽��ֱ��swirling topological textures are found in two main types of materials: ferromagnets and antiferromagnets. Of the two, antiferromagnets are more stable than ferromagnets, but they are more difficult to study, as they don’t have a strong magnetic signature.

To study the behaviour of antiferromagnets, Atatüre and his colleagues use an imaging technique known as diamond quantum magnetometry. This technique uses a single spin – the inherent angular momentum of an electron – in a diamond needle to precisely measure the magnetic field on the surface of a material, without affecting its behaviour.

For the current study, the researchers used the technique to look at hematite, an antiferromagnetic iron oxide material. To their surprise, they found hidden patterns of magnetic charges within hematite, including monopoles, dipoles and quadrupoles.

“Monopoles had been predicted theoretically, but this is the first time we’ve actually seen a two-dimensional monopole in a naturally occurring magnet,” said co-author Professor Paolo Radaelli, from the ̽��ֱ�� of Oxford.

“These monopoles are a collective state of many spins that twirl around a singularity rather than a single fixed particle, so they emerge through many-body interactions. ̽��ֱ��result is a tiny, localised stable particle with diverging magnetic field coming out of it,” said co-first author Dr Hariom Jani, from the ̽��ֱ�� of Oxford.

“We’ve shown how diamond quantum magnetometry could be used to unravel the mysterious behaviour of magnetism in two-dimensional quantum materials, which could open up new fields of study in this area,” said co-first author Dr Anthony Tan, from the Cavendish Laboratory. “ ̽��ֱ��challenge has always been direct imaging of these textures in antiferromagnets due to their weaker magnetic pull, but now we’re able to do so, with a nice combination of diamonds and rust.”

̽��ֱ��study not only highlights the potential of diamond quantum magnetometry but also underscores its capacity to uncover and investigate hidden magnetic phenomena in quantum materials. If controlled, these swirling textures dressed in magnetic charges could power super-fast and energy-efficient computer memory logic.

̽��ֱ��research was supported in part by the Royal Society, the Sir Henry Royce Institute, the European Union, and the Engineering and Physical Sciences Research Council (EPSRC), part of UK Research and Innovation (UKRI).

Reference:
K C Tan, Hariom Jani, Michael Högen et al. ‘Revealing Emergent Magnetic Charge in an Antiferromagnet with Diamond Quantum Magnetometry.’ Nature Materials (2023). DOI: 10.1038/s41563-023-01737-4.

For more information on energy-related research in Cambridge, please visit the Energy IRC, which brings together Cambridge’s research knowledge and expertise, in collaboration with global partners, to create solutions for a sustainable and resilient energy landscape for generations to come.

Researchers have discovered magnetic monopoles – isolated magnetic charges – in a material closely related to rust, a result that could be used to power greener and faster computing technologies.

If monopoles did exist, and we were able to isolate them, it would be like finding a missing puzzle piece that was assumed to be lost

Mete Atatüre

Anthony Tan and Michael Hoegen

Magnetic monopoles in hematite

̽��ֱ��text in this work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes

Two-dimensional material could store quantum information at room temperature

sc604 — Fri, 11 Feb 2022 11:01:00 +0000

Quantum memory is a major building block to be addressed in the building of a quantum internet, where quantum information is securely stored and sent via photons, or particles of light.

Researchers from the Cavendish Laboratory at the ̽��ֱ�� of Cambridge, in collaboration with colleagues from UT Sydney in Australia, have identified a two-dimensional material, hexagonal boron nitride, that can emit single photons from atomic-scale defects in its structure at room temperature.

̽��ֱ��researchers discovered that the light emitted from these isolated defects gives information about a quantum property that can be used to store quantum information, called spin, meaning the material could be useful for quantum applications. Importantly, the quantum spin can be accessed via light and at room temperature.

̽��ֱ��finding could eventually support scalable quantum networks built from two-dimensional materials that can operate at room temperature. ̽��ֱ��results are reported in the journal Nature Communications.

Future communication networks will use single photons to send messages around the world, which will lead to more secure global communication technologies.

Computers and networks built on the principles of quantum mechanics would be both far more powerful and more secure than current technologies. However, in order to make such networks possible, researchers need to develop reliable methods of generating single, indistinguishable photons as carriers of information across quantum networks.

“We can send information from one place to another using photons, but if we’re going to build real quantum networks, we need to send information, store it and send it somewhere else,” said Dr Hannah Stern from Cambridge’s Cavendish Laboratory, the study’s co-first author, along with Qiushi Gu and Dr John Jarman. “We need materials that can hold onto quantum information for a certain amount of time at room temperature, but most current material platforms we’ve got are challenging to make and only work well at low temperatures.”

Hexagonal boron nitride is a two-dimensional material that is grown by chemical vapour deposition in large reactors. It’s cheap and scalable. Recent efforts have revealed the presence of single photon emitters and the presence of a dense ensemble of optically accessible spins, but not individually isolated spin-photon interfaces operating under ambient conditions.

“Usually, it’s a pretty boring material that’s normally used as an insulator,” said Stern, who is a Junior Research Fellow at Trinity College. “But we found that there are defects in this material that can emit single photons, which means it could be used in quantum systems. If we can get it to store quantum information in spin, then it’s a scalable platform.”

Stern and her colleagues set up a hexagon boron nitride sample near a tiny gold antenna and a magnet of set strength. By firing a laser at the sample at room temperature, they were able to observe lots of different magnetic field-dependent responses on the light being emitted from the material.

̽��ֱ��researchers found that when they shone the laser on the material, they were able to manipulate the spin, or inherent angular momentum, of the defects, and use the defects as a way of storing quantum information.

“Typically, the signal is always the same in these systems, but in this case, the signal changes depending on the particular defect we’re studying, and not all defects show a signal, so there is a lot to still discover,” said co-first author Qiushi Gu. “There’s a lot of variation across the material, like a blanket draped over a moving surface – you see lots of ripples, and they’re all different.”

Professor Mete Atature, who supervised the work, adds “now that we have identified optically accessible isolated spins at room temperature in this material, the next steps will be to understand their photophysics in detail and explore the operation regimes for possible applications including information storage and quantum sensing. There will be a stream of fun physics following this work.”

̽��ֱ��research was supported in part by the European Research Council. Mete Atature is a Fellow of St John's College, Cambridge.

Reference:
Hannah L. Stern, Quishi Gu, John Jarman, et al. ‘Room-temperature optically detected magnetic resonance of single defects in hexagonal boron nitride.’ Nature Communications (2022). DOI: 10.1038/s41467-022-28169-z

Researchers have identified a two-dimensional material that could be used to store quantum information at room temperature.

There are defects in this material that can emit single photons, which means it could be used in quantum systems

Hannah Stern

Qiushi Gu

Artistic rendition of isolated spins on hexagonal boron nitride under an optical microscope

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. Images, including our videos, are Copyright © ̽��ֱ�� of Cambridge and licensors/contributors as identified. All rights reserved. We make our image and video content available in a number of ways – as here, on our main website under its Terms and conditions, and on a range of channels including social media that permit your use and sharing of our content under their respective Terms.

Yes

Light used to detect quantum information stored in 100,000 nuclear quantum bits

sc604 — Mon, 15 Feb 2021 15:18:20 +0000

̽��ֱ��researchers, from the ̽��ֱ�� of Cambridge, were able to inject a ‘needle’ of highly fragile quantum information in a ‘haystack’ of 100,000 nuclei. Using lasers to control an electron, the researchers could then use that electron to control the behaviour of the haystack, making it easier to find the needle. They were able to detect the ‘needle’ with a precision of 1.9 parts per million: high enough to detect a single quantum bit in this large ensemble.

̽��ֱ��technique makes it possible to send highly fragile quantum information optically to a nuclear system for storage, and to verify its imprint with minimal disturbance, an important step in the development of a quantum internet based on quantum light sources. ̽��ֱ��results are reported in the journal Nature Physics.

̽��ֱ��first quantum computers – which will harness the strange behaviour of subatomic particles to far outperform even the most powerful supercomputers – are on the horizon. However, leveraging their full potential will require a way to network them: a quantum internet. Channels of light that transmit quantum information are promising candidates for a quantum internet, and currently there is no better quantum light source than the semiconductor quantum dot: tiny crystals that are essentially artificial atoms.

However, one thing stands in the way of quantum dots and a quantum internet: the ability to store quantum information temporarily at staging posts along the network.

“ ̽��ֱ��solution to this problem is to store the fragile quantum information by hiding it in the cloud of 100,000 atomic nuclei that each quantum dot contains, like a needle in a haystack,” said Professor Mete Atatüre from Cambridge’s Cavendish Laboratory, who led the research. “But if we try to communicate with these nuclei like we communicate with bits, they tend to ‘flip’ randomly, creating a noisy system.”

̽��ֱ��cloud of quantum bits contained in a quantum dot don’t normally act in a collective state, making it a challenge to get information in or out of them. However, Atatüre and his colleagues showed in 2019 that when cooled to ultra-low temperatures also using light, these nuclei can be made to do ‘quantum dances’ in unison, significantly reducing the amount of noise in the system.

Now, they have shown another fundamental step towards storing and retrieving quantum information in the nuclei. By controlling the collective state of the 100,000 nuclei, they were able to detect the existence of the quantum information as a ‘flipped quantum bit’ at an ultra-high precision of 1.9 parts per million: enough to see a single bit flip in the cloud of nuclei.

“Technically this is extremely demanding,” said Atatüre, who is also a Fellow of St John’s College. “We don’t have a way of ‘talking’ to the cloud and the cloud doesn’t have a way of talking to us. But what we can talk to is an electron: we can communicate with it sort of like a dog that herds sheep.”

Using the light from a laser, the researchers are able to communicate with an electron, which then communicates with the spins, or inherent angular momentum, of the nuclei.

By talking to the electron, the chaotic ensemble of spins starts to cool down and rally around the shepherding electron; out of this more ordered state, the electron can create spin waves in the nuclei.

“If we imagine our cloud of spins as a herd of 100,000 sheep moving randomly, one sheep suddenly changing direction is hard to see,” said Atatüre. “But if the entire herd is moving as a well-defined wave, then a single sheep changing direction becomes highly noticeable.”

In other words, injecting a spin wave made of a single nuclear spin flip into the ensemble makes it easier to detect a single nuclear spin flip among 100,000 nuclear spins.

Using this technique, the researchers are able to send information to the quantum bit and ‘listen in’ on what the spins are saying with minimal disturbance, down to the fundamental limit set by quantum mechanics.

“Having harnessed this control and sensing capability over this large ensemble of nuclei, our next step will be to demonstrate the storage and retrieval of an arbitrary quantum bit from the nuclear spin register,” said co-first author Daniel Jackson, a PhD student at the Cavendish Laboratory.

“This step will complete a quantum memory connected to light – a major building block on the road to realising the quantum internet,” said co-first author Dorian Gangloff, a Research Fellow at St John’s College.

Besides its potential usage for a future quantum internet, the technique could also be useful in the development of solid-state quantum computing.

̽��ֱ��research was supported in part by the European Research Council (ERC), the Engineering and Physical Sciences Research Council (EPSRC) and the Royal Society.

Reference:
D. M. Jackson et al. ‘Quantum sensing of a coherent single spin excitation in a nuclear ensemble.’ Nature Physics (2021). DOI: 10.1038/s41567-020-01161-4

Researchers have found a way to use light and a single electron to communicate with a cloud of quantum bits and sense their behaviour, making it possible to detect a single quantum bit in a dense cloud.

We don’t have a way of ‘talking’ to the cloud and the cloud doesn’t have a way of talking to us. But what we can talk to is an electron: we can communicate with it sort of like a dog that herds sheep

Mete Atatüre

Gerd Altmann from Pixabay

Quantum particles

Yes

Cambridge researchers awarded European Research Council funding

sc604 — Wed, 01 Apr 2020 13:19:46 +0000

One hundred and eighty-five senior scientists from across Europe were awarded grants in today’s announcement, representing a total of €450 million in research funding. ̽��ֱ��UK has 34 grantees in this year’s funding round, the second-most of any ERC participating country.

ERC grants are awarded through open competition to projects headed by starting and established researchers, irrespective of their origins, who are working or moving to work in Europe. ̽��ֱ��sole criterion for selection is scientific excellence.

ERC Advanced Grants are designed to support excellent scientists in any field with a recognised track record of research achievements in the last ten years.

Professors Mete Atatüre and Jeremy Baumberg, both based at Cambridge’s Cavendish Laboratory, work on diverse ways to create new and strange interactions of light with matter that is built from tiny nano-sized building blocks.

Baumberg’s PICOFORCE project traps light down to the size of individual atoms which will allow him to invent new ways of tugging them, levitating them, and putting them together. Such work uncovers the mysteries of how molecules and metals interact, crucial for creating energy sustainably, storing it, and developing electronics that can switch with thousands of times less power need than currently.

"This funding recognises the huge need for fundamental science to advance our knowledge of the world – only the most imaginative and game-changing science gets such funding," said Baumberg.

Atatüre’s project, PEDESTAL, investigates diamond as a material platform for quantum networks. What gives gems their colour also turns out to be interesting candidates for quantum computing and communication technologies. By developing large-scale diamond-semiconductor hybrid quantum devices, the project aims to demonstrate high-rate and high-fidelity remote entanglement generation, a building block for a quantum internet.

" ̽��ֱ��impact of ERC funding on my group’s research had been incredible in the last 12 years, through Starting and Consolidator grants. I am very happy that with this new grant we as UK scientists can continue to play an important part in the vibrant research culture of Europe," said Atatüre.

Professor Judith Driscoll from Cambridge’s Department of Materials Science & Metallurgy was also awarded ERC funding for her work on nanostructured electronic materials. She is also spearheading joint work of her team, as well as those of Baumberg and Atatüre, on low-energy IT devices.

"My approach uses a different way of designing and creating oxide nano-scale film structures with different materials to both create new electronic device functions as well as much more reliable and uniform existing functions," she said. "Cambridge is a fantastic place that enables all our approaches to come together, driven by cohorts of inspirational young researchers in our UK-funded Centre for Doctoral Training in Nanoscience and Nanotechnology – the NanoDTC."

Professor John Robb from Cambridge’s Department of Archaeology was awarded an ERC grant for the ANCESTORS project on the politics of death in prehistoric Europe. ̽��ֱ��project takes the methods developed in the ‘After the Plague’ project and the taphonomy methods developed in the Scaloria Cave project and apply them to a major theoretical problem in European prehistory - the nature of community and the rise of inequality.

"This project is really exciting and I’ll be working with wonderful colleagues Dr Christiana ‘Freddi’ Scheib at the ̽��ֱ�� of Tartu and Dr Mary Anne Tafuri at Sapienza ̽��ֱ�� of Rome," said Robb. " ̽��ֱ��results will allow us to evaluate for the first time how inequality affected lives in prehistoric Europe and what role ancestors played in it."

Four researchers at the ̽��ֱ�� of Cambridge have won advanced grants from the European Research Council (ERC), Europe’s premier research funding body.

Yes

Physicists get thousands of semiconductor nuclei to do ‘quantum dances’ in unison

Anonymous — Fri, 22 Feb 2019 12:46:40 +0000

Quantum dots are crystals made up of thousands of atoms, and each of these atoms interacts magnetically with the trapped electron. If left alone to its own devices, this interaction of the electron with the nuclear spins, limits the usefulness of the electron as a quantum bit - a qubit.

Led by Professor Mete Atatüre from Cambridge's Cavendish Laboratory, the researchers are exploiting the laws of quantum physics and optics to investigate computing, sensing or communication applications.

“Quantum dots offer an ideal interface, as mediated by light, to a system where the dynamics of individual interacting spins could be controlled and exploited,” said Atatüre, who is a Fellow of St John's College. “Because the nuclei randomly ‘steal’ information from the electron they have traditionally been an annoyance, but we have shown we can harness them as a resource.”

̽��ֱ��Cambridge team found a way to exploit the interaction between the electron and the thousands of nuclei using lasers to ‘cool’ the nuclei to less than 1 milliKelvin, or a thousandth of a degree above the absolute zero temperature. They then showed they can control and manipulate the thousands of nuclei as if they form a single body in unison, like a second qubit. This proves the nuclei in the quantum dot can exchange information with the electron qubit and can be used to store quantum information as a memory device. ̽��ֱ��results are reported in the journal Science.

Quantum computing aims to harness fundamental concepts of quantum physics, such as entanglement and superposition principle, to outperform current approaches to computing and could revolutionise technology, business and research. Just like classical computers, quantum computers need a processor, memory, and a bus to transport the information backwards and forwards. ̽��ֱ��processor is a qubit which can be an electron trapped in a quantum dot, the bus is a single photon that these quantum dots generate and are ideal for exchanging information. But the missing link for quantum dots is quantum memory.

Atatüre said: “Instead of talking to individual nuclear spins, we worked on accessing collective spin waves by lasers. This is like a stadium where you don’t need to worry about who raises their hands in the Mexican wave going round, as long as there is one collective wave because they all dance in unison.

“We then went on to show that these spin waves have quantum coherence. This was the missing piece of the jigsaw and we now have everything needed to build a dedicated quantum memory for every qubit.”

In quantum technologies, the photon, the qubit and the memory need to interact with each other in a controlled way. This is mostly realised by interfacing different physical systems to form a single hybrid unit which can be inefficient. ̽��ֱ��researchers have been able to show that in quantum dots, the memory element is automatically there with every single qubit.

Dr Dorian Gangloff, one of the first authors of the paper and a Fellow at St John’s, said the discovery will renew interest in these types of semiconductor quantum dots. Dr Gangloff explained: “This is a Holy Grail breakthrough for quantum dot research – both for quantum memory and fundamental research; we now have the tools to study dynamics of complex systems in the spirit of quantum simulation.”

̽��ֱ��long term opportunities of this work could be seen in the field of quantum computing. Last month, IBM launched the world’s first commercial quantum computer, and the Chief Executive of Microsoft has said quantum computing has the potential to ‘radically reshape the world’.

Gangloff said: “ ̽��ֱ��impact of the qubit could be half a century away but the power of disruptive technology is that it is hard to conceive of the problems we might open up – you can try to think of it as known unknowns but at some point you get into new territory. We don’t yet know the kind of problems it will help to solve which is very exciting.”

Reference:
D. A. Gangloff et al. 'Quantum interface of an electron and a nuclear ensemble.' Science (2019). DOI: 10.1126/science.aaw2906

Originally published on the St John's College website.

A team of Cambridge researchers have found a way to control the sea of nuclei in semiconductor quantum dots so they can operate as a quantum memory device.

This is like a stadium where you don’t need to worry about who raises their hands in the Mexican wave going round, as long as there is one collective wave because they all dance in unison

Mete Atatüre

̽��ֱ�� of Cambridge

Theoretical ESR spectrum buildup as a function of two-photon detuning δ and drive time τ, for a Rabi frequency of Ω = 3.3 MHz on the central transition.

Yes

Cambridge partners in new €1 billion European Quantum Flagship

sc604 — Mon, 29 Oct 2018 11:00:00 +0000

̽��ֱ��Quantum Flagship, which is being officially launched today in Vienna, is one of the most ambitious long-term research and innovation initiatives of the European Commission. It is funded under the Horizon 2020 programme, and will have a budget of €1 billion over the next ten years.

̽��ֱ��Quantum Flagship is the third large-scale research and innovation initiative of this kind funded by the European Commission, after the Graphene Flagship – of which the ̽��ֱ�� of Cambridge is a founding partner – and the Human Brain Project. ̽��ֱ��Quantum Flagship work in Cambridge is being coordinated by Professor Mete Atature of the Cavendish Laboratory and Professor Andrea Ferrari, Director of the Cambridge Graphene Centre.

Quantum technologies take advantage of the ability of particles to exist in more than one quantum state at a time. A quantum computer could enable us to make calculations that are well out of reach of even the most powerful supercomputers, while quantum secure communication could power ‘unhackable’ networks made safe by the laws of physics.

̽��ֱ��long-term research goal is the so-called quantum web, where quantum computers, simulators and sensors are interconnected via quantum networks, distributing information and quantum resources such as coherence and entanglement.

̽��ֱ��potential performance increase resulting from quantum technologies may yield unprecedented computing power, guarantee data privacy and communication security, and provide ultra-high precision synchronisation and measurements for a range of applications available to everyone, locally and in the cloud.

̽��ֱ��new Quantum Flagship will bring together academic and industrial partners, with over 500 researchers working on solving these problems, and help turn the results into technological opportunities that can be taken up by industry.

In close partnership with UK, Italian, Spanish, Swedish universities and companies, Cambridge will develop layered quantum materials and devices for scalable integrated photonic circuits, for applications in quantum communication and networks.

Cambridge is investigating and refining layered semiconductors just a few atoms thick, based on materials known as transition metal dichalcogenides (TMDs). Certain TMDs contain quantum light sources that can emit single photons of light, which could be used in quantum computing and sensing applications.

These quantum light emitters occur randomly in layered materials, as is the case for most other material platforms. Over the past three years, the Cambridge researchers have developed a technique to obtain large-scale arrays of these quantum emitters in different TMDs and on a variety of substrates, establishing a route to build quantum networks on compact chips. ̽��ֱ��Cambridge team has also shown how to electrically control emission from these devices.

Additionally, the researchers have found that TMDs can support complex quasi-particles, called quintons. Quintons could be a source of entangled photons - particles of light which are intrinsically linked, no matter how far apart they are - if they can be trapped in quantum emitters.

These findings are the basis of the work being done in the Quantum Flagship, aimed at the development of scalable on-chip devices for quantum integrated photonic circuits, to enable secure quantum communications and quantum sensing applications.

“Our goal is to bring some of the amazing properties of the layered materials platform into the quantum technologies realm for a number of applications,” said Atature. “Achieving compact integrated quantum photonic circuits is a challenge pursued globally and our patented layered materials technology offers solutions to this challenge. This is a great project that combines quantum physics, optoelectronics and materials science to produce technology for the future.”

“Quantum technology is a key investment area for Europe, and layered materials show great promise for the generation and manipulation of quantum light for future technological advances,” said Ferrari. “ ̽��ֱ��Graphene Flagship led the way for these large European Initiatives, and we are pleased to be part of the new Quantum Flagship. ̽��ֱ��Flagships are the largest and most transformative investments in research of the European Union, and will cement the EU leadership in future and emerging technologies.”

Andrus Ansip, Commission Vice-President for the Digital Single Market, said: “Europe is determined to lead the development of quantum technologies worldwide. ̽��ֱ��Quantum Technologies Flagship project is part of our ambition to consolidate and expand Europe's scientific excellence. If we want to unlock the full potential of quantum technologies, we need to develop a solid industrial base making full use of our research.”

Inset images: Mete Atature and Andrea Ferrari; Artist’s impression of on-chip quantum photonics architecture with single photon sources and nonlinear switches on optical waveguides, credit Matteo Barbone.

̽��ֱ�� ̽��ֱ�� of Cambridge is a partner in the €1 billion Quantum Flagship, an EU-funded initiative to develop quantum technologies across Europe.

̽��ֱ��Flagships are the largest and most transformative investments in research of the European Union, and will cement the EU leadership in future and emerging technologies

Andrea Ferrari

panthermedia.net/agsandrew

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Ultra-thin quantum LEDs could accelerate development of quantum networks

sc604 — Fri, 07 Oct 2016 15:26:04 +0000

Ultra-thin quantum light emitting diodes (LEDs) – made of layered materials just a few atoms thick – have been developed by researchers at the ̽��ֱ�� of Cambridge. Constructed of layers of different ultra-thin materials, the devices could be used in the development of new computing and sensing technologies. ̽��ֱ��ability to produce single photons using only electrical current is an important step towards building quantum networks on compact chips.

̽��ֱ��devices are constructed of thin layers of different materials stacked together: graphene, boron nitride and transition metal dichalcogenides (TMDs). ̽��ֱ��TMD layer contains regions where electrons and electron vacancies, or holes, are tightly confined. When an electron fills an electron vacancy that sits at a lower energy than the electron, the energy difference is released as a photon, a particle of light. In the LED devices, a voltage pushes electrons through the device, where they fill the holes and emit single photons.

A computer built on the principles of quantum mechanics would be both far more powerful and more secure than current technologies, and would be capable of performing calculations that cannot be performed otherwise. However, in order to make such a device possible, researchers need to develop reliable methods of electrically generating single, indistinguishable photons as carriers of information across quantum networks.

̽��ֱ��ultra-thin platform developed by the Cambridge researchers offers high levels of tunability, design freedom, and integration capabilities. Typically, single photon generation requires large-scale optical set-ups with several lasers and precise alignment of optical components. This new research brings on-chip single photon emission for quantum communication a step closer. ̽��ֱ��results are reported in the journal Nature Communications.

“Ultimately, we need fully integrated devices that we can control by electrical impulses, instead of a laser that focuses on different segments of an integrated circuit,” said Professor Mete Atatüre of Cambridge’s Cavendish Laboratory, one of the paper’s senior authors. “For quantum communication with single photons, and quantum networks between different nodes, we want to be able to just drive current and get light out. There are many emitters that are optically excitable, but only a handful are electrically driven.”

̽��ֱ��layered nature of TMDs makes them ideal for use in ultra-thin structures on chips. They also offer an advantage over some other single-photon emitters for feasible and effective integration into nanophotonic circuits.

With this research, quantum emitters are now seen in another TMD material, namely tungsten disulphide (WS₂). “We chose WS₂ because we wanted to see if different materials offered different parts of the spectra for single photon emission,” said Atatüre, who is a Fellow of St John's College. “With this, we have shown that the quantum emission is not a unique feature of WS₂, which suggests that many other layered materials might be able to host quantum dot-like features as well.”

“We are just scratching the surface of the many possible applications of devices prepared by combining graphene with other materials,” said senior co-author Professor Andrea Ferrari, Director of the Cambridge Graphene. “In this case, not only have we demonstrated controllable photon sources, but we have also shown that the field of quantum technologies can greatly benefit from layered materials. Many more exciting results and applications will surely follow.”

Reference:
C. Palacios-Berraquero et al. ‘Atomically thin quantum light emitting diodes.’ Nature Communications (2016). DOI: 10.1038/ncomms12978

Researchers have developed all-electrical ultra-thin quantum LEDs, which have potential as on-chip photon sources in quantum information applications, including quantum networks for quantum computers.

Ultimately, we need fully integrated devices that we can control by electrical impulses.

Mete Atature

Microscope image of a quantum LED device showing bright quantum emitter generating a stream of single photons.

̽��ֱ��text in this work is licensed under a Creative Commons Attribution 4.0 International License. For image use please see separate credits above.

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