Quantum randomness from multi-pixel optical detection
Lead Research Organisation:
Imperial College London
Department Name: Physics
Abstract
Random numbers have many uses in science, statistics, cryptography, gaming, and other
fields. Quantum random number generators are developed with certified randomness.
Randomness in this thesis is characterized by the unpredictability of outcomes. Bell
inequality violation, min-entropy bound, and entropy estimation are the three methods for
randomness certification. Different methods of implementing quantum random number
generators are introduced and compared with their scheme and challenges.
Two-mode certification is discussed with separable two-mode input and two detectors
at the output of a beam splitter, where Fock state input achieves the maximum optimal
guessing probability. The binomial distribution model is employed to describe the twomode
outcomes and a guessing probability confidence interval is obtained.
Multi-pixel certification is introduced with spatial transformation. The guessing probability
for joint pixel detection number is calculated. The optimum beam radius for a
Gaussian illumination is 0:56 times of the detector size. Multiple trials with the same
total photon number are discussed with both Gaussian illumination and uniform illumination.
A Gaussian illumination is more convenient and economic for building the
RNG.
A CMOS detector from a Samsung Galaxy S7 phone is used in the experiment to
verify both two-mode certification and multi-pixel certification. The optimal guessing
probability and min-entropy are calculated with two-mode certification and 81200-pixel
certification. The min-entropy is estimated with experimental measurements. A minentropy
of around 300 000 bits can be reached with 81200 pixels and it will be larger
with 12 million pixels on CMOS.
fields. Quantum random number generators are developed with certified randomness.
Randomness in this thesis is characterized by the unpredictability of outcomes. Bell
inequality violation, min-entropy bound, and entropy estimation are the three methods for
randomness certification. Different methods of implementing quantum random number
generators are introduced and compared with their scheme and challenges.
Two-mode certification is discussed with separable two-mode input and two detectors
at the output of a beam splitter, where Fock state input achieves the maximum optimal
guessing probability. The binomial distribution model is employed to describe the twomode
outcomes and a guessing probability confidence interval is obtained.
Multi-pixel certification is introduced with spatial transformation. The guessing probability
for joint pixel detection number is calculated. The optimum beam radius for a
Gaussian illumination is 0:56 times of the detector size. Multiple trials with the same
total photon number are discussed with both Gaussian illumination and uniform illumination.
A Gaussian illumination is more convenient and economic for building the
RNG.
A CMOS detector from a Samsung Galaxy S7 phone is used in the experiment to
verify both two-mode certification and multi-pixel certification. The optimal guessing
probability and min-entropy are calculated with two-mode certification and 81200-pixel
certification. The min-entropy is estimated with experimental measurements. A minentropy
of around 300 000 bits can be reached with 81200 pixels and it will be larger
with 12 million pixels on CMOS.
Planned Impact
The main impact of the proposed Hub will be in training quantum engineers with a skillset to understand cutting-edge quantum research and a mindset toward developing this innovation, and the entrepreneurial skills to lead the market. This will grow the UK capacity in quantum technology. Through our programme, we nurture the best possible work force who can start new business in quantum technology. Our programme will provide multi-level skills training in quantum engineering in order to enhance the UK quantum technologies landscape at several stages. Through the training we will produce quantum engineers with training in innovation and entrepreneurship who will go into industry or quantum technology research positions with an understanding of innovation in quantum technology, and will bridge the gap between the quantum physicist and the classical engineer to accelerate quantum technology research and development. Our graduates will have to be entrepreneurial to start new business in quantum technology. By providing late-stage training for current researchers and engineers in industry, we will enhance the current landscape of the quantum technology industry. After the initial training composed of advanced course works, placements and short projects, our students will act as a catalyzer for collaboration among quantum technology researchers, which will accelerate the development of quantum technology in the UK. Our model actively encourages collaboration and partnerships between Imperial and national quantum tehcnology centres and we will continue to maintain the strong ties we have developed through the Centre for Doctoral Training in order to enhance our on-going training provisions. The Hub will also have an emphasis on industrial involvement. Through our new partnerships students will be exposed to a broad spectrum of non-academic research opportunities. An important impact of the Hub is in the research performed by the young researchers, PhD students and junior fellows. They will greatly enhance the research capacity in quantum technology. Imperial College has many leading engineers and quantum scientists. One of the important outcomes we expect through this Hub programme is for these academics to work together to translate the revolutionary ideas in quantum science to engineering and the market place. We also aim to influence industry and policy makers through our outreach programme in order to improve their awareness of this disruptive technology.
Organisations
People |
ORCID iD |
| William Steven Kolthammer (Primary Supervisor) | |
| Mengbo Long (Student) |
| Description | The random numbers generated from multipixel detection is proved to be unpredictable both theoretically and experimentally. The unpredictability is verified to be intrinsic randomness. And the random level is scaled with the pixel number given that the detectors are not saturated. It demonstrates an approach that does not need assumptions about the light source, which can cut down the cost of random number generators. Apart from the above topic, we also developed the theory for cavity-enhanced squeezed state generation. In this project, we focus on generating squeezed states with high squeezing parameter as well as high purity. |
| Exploitation Route | The random number generation can be used in quantum communication, cryptography, and scientific simulations. The cavity-enhanced squeezed state generation can be applied as the key component of quantum information and quantum communication. |
| Sectors | Digital/Communication/Information Technologies (including Software),Security and Diplomacy |
| Description | National Quantum Showcase |
| 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 | Our QRNG demo has received great popularity at the National Quantum Showcase for two consecutive years. There are policymakers and industry who show enthusiasm to our QRNG demo. Some ask about the industrialisation of the QRNG. |
| Year(s) Of Engagement Activity | 2018,2019 |
| URL | https://nqit.ox.ac.uk/event/national-quantum-technologies-showcase-2019 |
| Description | Quantum in the City: the shape of things to come |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Public/other audiences |
| Results and Impact | The public showed a lot of interest in our QRNG demo and our research about quantum information. There are a lot of families attending the event. The questions and discussions during the event helped to connect our research to the general public. |
| Year(s) Of Engagement Activity | 2019 |
| URL | https://www.rigb.org/whats-on/events-2019/november/public-quantum-in-the-city |
| Description | Schools challenge STEM Market |
| Form Of Engagement Activity | Participation in an activity, workshop or similar |
| Part Of Official Scheme? | No |
| Geographic Reach | Regional |
| Primary Audience | Schools |
| Results and Impact | This event is the culmination of The Schools Challenge 2018, which is run as a collaboration between Imperial College London and J.P. Morgan. Since October, year 9 students (13-14 years old) have been challenged to come up with solutions to some of London's most pressing environmental issues: air pollution, making London more sustainable or improving London's biodiversity - a challenge set by the Mayor of London's Office. Working in teams of eight, the teams have been asked to design a product that can solve one of these issues, conduct market research, create a prototype to demonstrate their ideas, develop a brand and ideas on how to market the product, devise a basic business plan and present their ideas using a posterboard and a seven minute spoken presentation. The students explored our STEM market place, where we exhibited our demo. The STEM market place becomes a great opportunity to inspire students to continue to pursue their interests in Science, Technology, Engineering and Maths, through interactive exhibits and the opportunity to interact with STEM specialists. |
| Year(s) Of Engagement Activity | 2019 |
| URL | https://www.imperial.ac.uk/news/190274/london-school-students-science-solve-city/ |