Spin-photon systems for scalable quantum processors

Lead Research Organisation: University of Bristol
Department Name: Electrical and Electronic Engineering

Abstract

Optical technologies are key to many communications, measurement and sensing tasks. In fact optical communication (in low loss fibres) underpins the global economy, supporting the near instantaneous transmission of terabits of information worldwide. However all-optical switching and computing have not developed dramatically despite optimism in the 1990's. This is primarily because of the problem of weak optical nonlinearity leading to high power requirements and low switching speeds. In this proposal I will develop a new optical switching technology based on the coupling of atom like defects in solid state hosts. The technology promises a high speed low power optical switch which could revolutionise all optical networks with routing and many other signal conditioning tasks performed in the all-optical domain.

The more recent developments of quantum photonic technologies such as quantum secured key distribution and the vision of quantum computing are also limited by the lack of a non-linearity at the single photon level. The missing component is in fact a deterministic entangler capable of inducing strong correlations between separate photons or between separate solid state realisations of quantum bits. This project aims to develop such gates based on our earlier invention a spin photon entangler which uses a singly charged quantum dot or colour centre strongly coupled to a microcavity. It turns out this element is a universal gate for quantum computation and experimental realisation of this gate is a key target here. Once such a component is available it will pave the way to a long range 'quantum internet' and to the development of a scalable quantum computer technology allowing both circuit and measurement based quantum computing realisations to be envisaged.

The end goal is to develop a technology that addresses both classical and quantum applications using single atom-like light emitters embedded in wavelength scale optical cavities (or waveguides) configured as either attojoule optical switches or high-fidelity efficient spin-photon entangling gates.

Planned Impact

Photonics technologies underlie the transfer of many terabits per second of information across the globe and are key to the global digital economy enabling trillions of dollars of online business to be carried out each day. The development of a switching technology operating at energy levels orders of magnitude below present capabilities at orders of magnitude faster switching speeds will have dramatic impact on the architecture and power consumption of future all optical networks. The long-term potential impact of the quantum technologies themselves could be immense, opening up a whole new branch of technology promising unprecedented sensing sensitivity, measurement accuracy, computational potential and quantum secured internet as well as many yet to be discovered applications. Its potential has been recognised by the government's decision to invest £270 million in quantum technologies over the next 5 years. The PI is heavily involved in hub bids for quantum imaging and quantum communications and will thus actively feed out results to these or the successful hubs when announced. This proposal targets two primary bottlenecks of optical quantum technology, providing potential solutions to both the quantum memory requirement and a deterministic gate technology. Success of this project will thus ensure that the UK is a world leader in the development and application of this new and emerging science and technology. I will continue to identify and write up key commercial patents as they arise within the project and actively engage with companies to develop this technology. We have established links with major players including E6, Toshiba and Nokia and Bristol start-ups Qumet and Venture photonics. To guide the switch development we will actively engage with communications systems engineers, noting the recent addition of a high performance a quantum networks group in Bristol. I will meet regularly with our collaborators face to face and online. In addition, I will organise a Quantum Switching Workshop in the 3rd year of the fellowship involving collaborators, world leading groups and industry to guide future developments. The fellowship will develop strong links with the newly funded Bristol Quantum Engineering Centre for Doctoral Training helping to develop the next generation of researchers. The primary form of written dissemination will be through publication in the best journals in engineering, physics, photonics and Nanoscience accompanied by timely presentations at major conferences and wider engagement of the general public through outreach activities both live and on-line.

Publications

10 25 50
 
Description We have developed ways of writing a reading out information from the spins of electrons and nuclei associated with colour centres in diamonds. Further these electron spins are strongly affected by their immediate environment thus can be used as sensors for magnetic and electric fields. Paper to be submitted in early 2018. We have discovered that simple polymer waveguides may be used to guide light on the surface of a dielectric mirror exploiting Bloch surface waves. We have also collaborated with groups doing Hamiltonian learning providing our spin system as a test for a Hamiltonian learning algorithm (Nature Physics 2017)).

We have discovered that a charged quantum dot in a suitably designed low quality factor (Q-factor) pillar microcavity can be used for a deterministic spin photon interface. Our experiments (Androvitsanaeas etal PRB) indicate that we achieve a large spin dependent phase shift leading to a Faraday rotation of linear polarised light. By looking only when the dot is on resonance we confirm that this large phase shift is in fact pi, enough to construct a deterministic spin photon entangling gate (paper submitted ). This work is continuing as our simple pillar cavity approach can also be used to show non-linearity at the single photon level, essentially a photon in the cavity can block the entry of a second photon into the cavity. This work has just appeared in ACS Photonics. In latest work we are developing a rapid way of detecting spin lifetime by linking it to optical coherence of scattered light. The results encourage us to look for photon-photon correlations mediated by the electron spin. In related work using NV centres in diamond we have developed a waveguide technology based on nanodiamonds embedded in SiN waveguides. We see single photon emission and initial spin photon effects in in this highly scalable platform,
Exploitation Route We will place our NV-centres in optical cavities to enhance the read out. We are now developing cavities on multilayer dielectric mirrors and also using Bloch surface wave cavities.

We are developing a better (more stable) optics to better understand our dot cavity systems so that these can be engineered for realising a spin photon interface. Others will realise that their cavity design constraints can be relaxed to lower Q-values.
Sectors Digital/Communication/Information Technologies (including Software),Electronics,Healthcare

URL https://www.bristol.ac.uk/qet-labs/
 
Description European Research Council
Amount £2,250,000 (GBP)
Funding ID 247462 QUOWSS 
Organisation European Research Council (ERC) 
Sector Public
Country Belgium
Start 02/2010 
End 02/2015
 
Description Future Photonics Hub, Innovation Partnership Fund, Southampton University
Amount £10,000,000 (GBP)
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 04/2017 
End 03/2018
 
Description IL6 Russia - Non Newton
Amount £146,078 (GBP)
Funding ID 352345416 
Organisation British Council 
Sector Charity/Non Profit
Country United Kingdom
Start 02/2018 
End 02/2021
 
Description QuantIC - The UK Quantum Technology Hub in Quantum Imaging
Amount £21,586,672 (GBP)
Funding ID EP/T00097X/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 12/2019 
End 11/2024
 
Description The EPSRC Quantum Communications Hub
Amount £23,961,861 (GBP)
Funding ID EP/T001011/1 
Organisation Engineering and Physical Sciences Research Council (EPSRC) 
Sector Public
Country United Kingdom
Start 12/2019 
End 11/2024
 
Title Supporting Data for "Optimal simultaneous measurements of incompatible observables of a single photon" 
Description EPSRC fellowship project Data will include electromagnetic simulations, raw spectroscopic data, processed data and details of processing code. 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
 
Title Twin-beam sub-shot-noise raster-scanning microscope 
Description Open access data relating to the publication J. Sabines-Chesterking et al. "Twin-beam sub-shot-noise raster-scanning microscope " Optics Express 27, 30810-30818 (2019) / arXiv-quant-ph:1906.05331 (2019) 
Type Of Material Database/Collection of data 
Year Produced 2019 
Provided To Others? Yes  
 
Description MSPU 
Organisation Moscow State University
Department Physics Department
Country Russian Federation 
Sector Academic/University 
PI Contribution Developing SiON waveguide technology for coupling light for nanodiamond
Collaborator Contribution Provision of complementary waveguide technology. Liason with SCONTEL on detector technologies
Impact Information exchange and visits to Moscow in October 2018
Start Year 2018
 
Description RS-MOST travel grant 
Organisation National Cheng Kung University
Country Taiwan, Province of China 
Sector Academic/University 
PI Contribution We are characterising the light scattered by Blue phase liquid crystals and investigating the improved stability of crystals in microstructures fabricated in our two photon lithography sysem
Collaborator Contribution Providing Blue phase liguid crystal samples and collaborative advice
Impact We have discovered a new way to stabilise Blue phase liquid crystal and are writing a paper on this.
Start Year 2017
 
Description SCONTEL 
Organisation SCONTEL
Country Russian Federation 
Sector Private 
PI Contribution We have contributed knowledge on SiON waveguides for collection of single photons from NV-centres
Collaborator Contribution Provision of superconducting detectors on SiON material for testing in our cryostat
Impact None yet, ongoing
Start Year 2018
 
Description University of Wurzburg 
Organisation University of Wurzburg
Country Germany 
Sector Academic/University 
PI Contribution Design of pillar microcavity samples for characterisation in Bristol
Collaborator Contribution Growth and fabrication of microcavity samples
Impact Successful samples showing a spin dependent response. High efficiency single photon source samples.
Start Year 2010
 
Description York Quantum communications Quantum Technology Hub 
Organisation University of York
Country United Kingdom 
Sector Academic/University 
PI Contribution Integrated quantum photonics for quantum communication. Hand held QKD for financial transactions. Demonstration of quantum networks in Bristol Entanglement networks Various contributions to annual quantum technology hubs
Collaborator Contribution Co-ordination of research and various quantum communications schemes and Cambridge and UK quantum networks.
Impact KETS quantum security spin-out Various publications in the list
Start Year 2014
 
Company Name QLM TECHNOLOGY LTD 
Description QLM uses Bristol developed single photon sensing technology for gas sensing. In this early stage QLM Technology sets out to tackle the global problem of natural gas (methane) leaks from well-heads and pipeline transportation, which currently cost the industry greater than $6bn annually. The quantum remote sensing solution is capable of remotely detecting and quantifying the lowest leak rate required by the industry, out to a 100-metre operational distance. It is lightweight and low power and when mounted on a drone can deliver an 30 mph full coverage surveying speed. 
Year Established 2017 
Impact Raised £150K of venture capital and some £300K of Innovate UK funding to develop prototype systems
Website https://www.qlmtec.com/
 
Description BQIT (Bristol Quantum Information Technologies) Workshop 2017 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact The BQIT (Bristol Quantum Information Technologies) Workshop presents a programme of speakers and panellists bringing together recent and current events and research from the emerging field of Quantum Technology.

Since the workshop's conception in 2014 they have had 143 speakers and panellists who have presented their work and opinions on a range of topics from Quantum Sensing and Metrology to Quantum Communications and Networks, Quantum Algorithms to Quantum Hardware and Quantum Computation.
Year(s) Of Engagement Activity 2014,2015,2016,2017
URL http://www.bristol.ac.uk/physics/research/quantum/conferences/bqit-workshop/
 
Description BQIT (Bristol Quantum Information Technologies) Workshop 2018 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact This is the annual quantum information workshop organised by Bristol, chared again this year by Prof John Rarity
Year(s) Of Engagement Activity 2018
URL https://www.flickr.com/photos/cqpbristol/sets/72157694318687751
 
Description BQIT (Bristol Quantum Information Technologies) Workshop 2019 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact International workshop on quantum information technologies.
Year(s) Of Engagement Activity 2019
URL http://www.bristol.ac.uk/physics/research/quantum/conferences/bqit-workshop/
 
Description BQIT2019 1-3April 2019 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact 150 attendees to BQIT 2019. Promoted research in Bristol and created new relationships with external parties
Year(s) Of Engagement Activity 2019
URL http://www.bristol.ac.uk/physics/research/quantum/conferences/bqit-workshop/
 
Description CLEO Europe 23-27 June 2019 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact International Conference with 500 plus attendees. John Rarity chaired sessions on Quantum Information Processing and Nanoclassical Light. Conference raised discussions on Quantum related activity.
Year(s) Of Engagement Activity 2019
 
Description Cheltenham Science Festival 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact About the Science Festival
How long is a piece of string? What makes the world turn? And why does chocolate taste so good? From the state of the planet, to the latest stem cell research, to the secrets of the perfect cup of tea - nothing is off limits at Cheltenham Science Festival. We'll be joined by some of the world's greatest scientists, big thinkers and comedy geniuses to help us answer some pretty big questions.

With past speakers including Brian Cox, Robert Winston, Alice Roberts and Richard Dawkins, the festival is the perfect place to pose your most burning questions and expand your mind. Join us for six jam-packed-days of debate, discovery, experiments, enjoyment and hands on fun and take a fresh look at the world around you.
Year(s) Of Engagement Activity 2017
URL https://www.cheltenhamfestivals.com/science
 
Description Frontiers in Optics/Laser Science Conference (FiO+LS) 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact International Conference taking place between 15-19 September 2019, Washington DC. Sparked research debates and lively Qnad A session. John Rarity presided over a session on Quantum Communications and the Future Quantum Internet.
Year(s) Of Engagement Activity 2019
 
Description IOP Quantum Dot Day, Oxford 6 Jan 2020 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Industry/Business
Results and Impact The Quantum Dot Day aims at bringing together researchers working on quantum optics, Spectroscopy, spin physics, transport, devices and applications, synthesis and growth of semiconductor quantum dots.
Year(s) Of Engagement Activity 2020
URL https://events.iop.org/events/search_process/Spectroscopyoldoldold/56123*34355*35476*31572*31553*184...
 
Description International Conference on Optics of Excitons in Confined Systems, University of Bath 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact The International conference on Optics of Excitons in Confined Systems (OECS 2017) took place at the University of Bath on 10-15 September 2017.

The event brings together internationally leading scientists and many young researchers collaborating in a broad range of scientific topics related to optics of excitons in confined systems. The main goal of this conference was to discuss in-depth new important results, ideas and future directions in the existing as well as in the emerging areas of research.
Year(s) Of Engagement Activity 2017
 
Description Invited talk at INL Workshop, Braga 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Invited talk at INL Workshop, Braga, Portugal, 3rd-5th October 2017
Year(s) Of Engagement Activity 2017
 
Description Invited to Taiwan, National Cheng Kung University, Lecture on Pohotonic Quantum Technologies 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact Invited to Taiwan, National Cheng Kung University, Lecture on Pohotonic Quantum Technologies: Metrology, spins and photons, 12/01/2018
Year(s) Of Engagement Activity 2017
 
Description Invivation to Summer School "Interaction between Radiation and Quantum Matter" Moscow 2-5July 2020 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Undergraduate students
Results and Impact Visit to Federal State Budgetary Educational Institution of Higher education "Moscow Pedagogical State University" 3-5 July 2019. Approx. 100 students attended the summer school. Engaging Q and A session.
Year(s) Of Engagement Activity 2019
 
Description NIST Single Photon Workshop - Boulder Colorado 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact on July 31 - August 4, 2017, NIST hosted the Single Photon Workshop 2017, at the University of Colorado in Boulder, Colorado (USA). SPW2017 was the eighth installment in a series of international workshops on single-photon generation and detection technology and applications.
Year(s) Of Engagement Activity 2017
URL https://www.nist.gov/news-events/events/2017/07/single-photon-workshop-2017
 
Description Nano Meta 2017 Conference 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact NANOMETA 2017 aimed to bring together the international Nanotechnology, Photonics and Materials research communities where most recent and challenging results and plans were discussed in the informal setting on a glorious mountaineering resort. The technical programme included invited and selected contributed papers in the areas of:

• Plasmonics, Metamaterials and Metadevices
• Quantum and Topological Nanophotonics
• New Materials for Nanophotonics
• Optical Super-resolution

The conference was organised in two oral parallel sessions (Nanophotonics and Metamaterials) and will feature joint plenary, tutorial and post-deadline sessions. The conference timetable was arranged in a way that permits mid-day breaks for recreational activities and informal contact between participants.

Nanometa 2017 presented plenary and breakthrough talks. The conference also featured a number of invited talks devoted to recent important advances in nanophotonics and metamaterials science.
Year(s) Of Engagement Activity 2017
URL http://www.nanometa.org/
 
Description PicoQuant Symposium - 22-24 May 2019 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact 2nd international symposium on "Single Photon based Quantum Technologies" planned for May 22-24, 2019 in Berlin, Germany. International audience. John Rarity spoke on "Single Photon based Quantum Technologies" and chaired a session on "Quantum Metrology." Raised the profile of Quantum Techonologies internationally.
Year(s) Of Engagement Activity 2019
 
Description QCrypt 2017, University of Cambridge 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Professional Practitioners
Results and Impact Quantum cryptography aims to achieve security from fundamental physical principles, such as the quantum mechanical phenomena of entanglement and Heisenberg's uncertainty principle. In the last few years, significant progress has been made in the theoretical understanding of quantum cryptography, and its technological feasibility has been demonstrated experimentally. Quantum cryptography is therefore regarded as one of the most promising candidates for a future quantum technology.

The annual conference on quantum cryptography (QCrypt) is a conference for students and researchers working on all aspects of quantum cryptography. The main goals of the conference are to represent the previous year's best results and to support the building of a research community in quantum cryptography. For more information on goals and structure, see QCrypt charter.
Year(s) Of Engagement Activity 2017
URL http://2017.qcrypt.net/
 
Description QUAMP 2017, Glasgow 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact QuAMP WAS a biennial international conference on Quantum, Atomic, Molecular and Plasma Physics.
QuAMP 2017 was held in Glasgow at the Hilton Glasgow Grosvenor Hotel, from 4-7 September 2017. The meeting covered quantum information and technology, quantum optics, ultra-cold matter, the interaction of light with molecules and plasmas. The format comprised of plenary talks by invited speakers as well as some contributed talks and posters.
Year(s) Of Engagement Activity 2017
URL http://quamp2017.iopconfs.org/Home
 
Description Quantum Graphic Novel 
Form Of Engagement Activity A magazine, newsletter or online publication
Part Of Official Scheme? No
Geographic Reach National
Primary Audience Public/other audiences
Results and Impact We wrote a graphic novel chapter detailing in an entertaining way the development of secure communications from ancient times until today where we research quantum secured communications
Year(s) Of Engagement Activity 2017,2018,2019
URL https://www.bristol.ac.uk/physics/research/quantum/engagement/light-keys/
 
Description Quantum Technology showcase November 2018 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Showcase of quantum technologies.
We have exhibited:
Hand held quantum key distributions
Chip-scalequantum key distribution
Quantum light sources for sub-shot noise measurement
Quantum pair photn sources for rangefinging
Remote gas sensing using single photon detection
Quantum network technologies
Year(s) Of Engagement Activity 2015,2016,2017,2018,2019
URL http://uknqt.epsrc.ac.uk/news-and-events/events/
 
Description Royal Society Theo Murphy Conference, Chicheley Hall 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Industry/Business
Results and Impact Lively participation. Title of my talk was on "Exploiting quantum correlations for spectroscopy, imaging and remote sensing."
Year(s) Of Engagement Activity 2019
 
Description Southampton Quantum Tech Lecture 8th November 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach Regional
Primary Audience Postgraduate students
Results and Impact Lecture at Southampton University
Year(s) Of Engagement Activity 2017
 
Description Summer school on Interaction between Radiation and Quantum matter, MSPU Moscow, 2-5 JUly 2019 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Summer school on interaction of radiation with quantum matter. Presented summary of the Bristol quantum efforts in communication, sensing and computation and then focussed of spin photon interfaces.
Year(s) Of Engagement Activity 2019
 
Description UIMP International Summer School and Workshop by Spanish Network of Quantum Technologies, Madrid 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Talk at UIMP International Summer School and Workshop by Spanish Network of Quantum Technologies in Madrid
Year(s) Of Engagement Activity 2017