CityUHK Physics
Building Bridges to the Future for Science and Society
The world is clearly on the cusp – not only in science, but throughout society. The fundamental nature of physics has made it the foundation for novel advances in technology, and exciting new concepts are unlocking innovative ways to tackle the natural and man-made crises our planet faces. With a growing reputation for pushing the frontiers of knowledge, the Department of Physics at City University of Hong Kong (CityUHK Physics) is perfectly positioned to make a difference across the theoretical and applied physics landscape.
My philosophy on how to approach new challenges in physics is to first build a solid foundation. Offering unwavering support to students and faculty empowers them to better direct their energy towards what is most important: expressing their passions, exploring creative ideas, and striving towards their aspirations. Building a community of curious and collaborative peers will allow us to reach greater heights. With this approach, I believe that achievements, recognition, and accolades will naturally follow.
Encouraging broader collaborative links with top institutions around the world is also of the utmost importance. I am confident that forging closer ties with the international physics community through research collaborations, facilities sharing, student exchanges, and participating in global conferences, will deliver significant long-term scientific and financial dividends.
One of the Department’s most outstanding attributes is a faculty that includes very bright and dynamic young professors. Nurturing this advantage by promoting professional growth and recruiting more internationally renowned scholars and talented home-grown academics is among our most critical strategic goals. So is attracting gifted undergraduate physicists, master’s students, and PhD candidates. We are actively updating courses and creating an exceptional portfolio of high-quality international research opportunities. These and other initiatives will help to increase intake and enhance engagement.
This is undoubtedly an exciting time. While it is impossible to predict the future, I am certain it will be filled with exceptional growth and innovation. The next breakthrough could be unfathomable to us now – something completely revolutionary and unprecedented – and I have no doubt that CityUHK Physics will be at the forefront of it all.
In the meantime, I look forward with confidence as we continue the journey towards becoming a respected and popular partner – not only in Asia, but throughout the global physics community.
Professor Ren Yang Head and Chair Professor of Physics CityUHK Physics
CityUHK Physics –Pioneering Discoveries and Transformative Innovations
As we reflect on a remarkable two years, it is satisfying to see CityUHK Physics continuing to lead the way in pushing the boundaries of scientific knowledge and making significant contributions to the field of physics.
Launched in 2017, CityUHK Physics is one of Asia’s most agile and innovative physics departments. With an internationally recognised faculty and state-of-the-art facilities, including Hong Kong’s only lab for neutron scattering (operated jointly with the Chinese Academy of Sciences), we are becoming a centre of gravity for physics excellence. In fact, in its most recent assessment, the Research Grants Council of Hong Kong ranked CityUHK Physics as No.1 in world-leading (four-star) research output in physics and astronomy.
In addition to being a regional leader in five key research areas (Atomic, Molecular and Optical Physics; Quantum Materials; Soft Matter and Biophysics; Spectroscopy and Imaging; and Theoretical and Computational Physics), CityUHK Physics recently established a new research cluster: Astrophysics and Particle Physics. It represents a significant step towards our ambition of excelling in every major area of modern physics research.
Research Excellence: Revealing the Secrets of the Universe
CityUHK Physics faculty members are at the forefront of groundbreaking research that unravels the mysteries of the universe. Our esteemed team has made remarkable strides in a diverse range of research areas, from quantum computing and nanomaterials to astrophysics and biophysics.
One of our recent breakthroughs involves the development of a revolutionary lithiumion battery electrode material that has the potential to revolutionise renewable energy storage. By harnessing the material’s unique
properties, we can significantly enhance the capacity and endurance of lithiumion batteries, paving the way to a more sustainable future.
On another exciting scientific and technical frontier, our researchers have made significant advancements in the field of quantum science. Through cutting-edge experiments and theoretical investigations, we are unpacking the complexities of quantum entanglement and molecular quantum chemistry. This brings us closer to leveraging the full potential of the quantum mechanical nature of fundamental particles in our modern world.
CityUHK Physics faculty members are at the forefront of groundbreaking research.
Educational Excellence: Nurturing the Next Generation of Physicists
Our commitment to providing a world-class education remains unwavering. We take pride in nurturing the next generation of physicists who will shape the future of scientific discovery and technological innovation.
The undergraduate programme offers a rigorous and comprehensive curriculum, equipping students with a solid foundation in fundamental physics principles. We have introduced new courses that delve into emerging areas, such as quantum technologies and machine learning, preparing our students for the exciting challenges of an AI and quantum-driven future.
Furthermore, our postgraduate programmes continue to attract exceptional talent from around the world. Our PhD candidates engage in cutting-edge research projects, collaborate with renowned scientists, and make breakthroughs in their respective fields. The Department’s vibrant research environment and state-of-the-art facilities provide the perfect platform for their intellectual growth and professional development.
Collaborative Endeavours: Bridging Disciplines and Cultivating Partnerships
At CityUHK Physics, we recognise the importance of collaboration and interdisciplinary research in tackling complex scientific challenges. Accordingly,
we actively foster partnerships with leading institutions – both locally and internationally – to leverage diverse expertise and resources. These valuable connections, enable our faculty members to play an active role in international research collaborations, working alongside esteemed scientists from renowned institutions across the globe. Such partnerships not only enhance our research capabilities, but also enrich the educational experiences of our students by exposing them to a global scientific community.
The Department has established numerous joint memorandums of understanding with overseas institutions, focusing on unique collaborative research adventures. For example, using large, multi-billion dollar scientific facilities, including synchrotron light sources, as well as collectively nurturing young talents. These new bonds bring our Department to the centre of the research
frontier, consolidating our role as a key player in the search for innovative solutions and increasing the pace of discovery.
Looking Ahead: A Future of Boundless Possibilities
As we embark on a new chapter, we remain steadfast in our commitment to extending the frontiers of knowledge and nurturing the next generation of physicists. With our dedicated faculty, talented students, and collaborative partnerships, we are poised to make even greater strides in the years to come.
CityUHK Physics continues to shine as a beacon of scientific excellence, illuminating the path towards a better future. We invite you to join us on this exciting journey as we explore the wonders of the universe and shape a world driven by scientific innovation.
Professor Ren Yang encourages students to express their passions and strive towards their aspirations.
Embarking on a Journey of Scientific Excellence
Marching into a future of scientific research and technological advancement, CityUHK Physics is driven by a compelling vision. This is supported by a clear mission built on an unwavering commitment to excellence in physics education and research.
Staffed by an energetic, internationally recognised faculty, CityUHK Physics strives to be a beacon of scientific discovery, innovation, and academic excellence, standing at the forefront of cutting-edge research and technological advancements. By nurturing a vibrant and inclusive community of scholars and learners, we aim to inspire future generations to explore the wonders of physics and push the boundaries of knowledge.
Vision
• To become a leading physics department in the Asia-Pacific region, known for our professional curriculum and signature research
Mission
• To provide rigorous training that prepares students for competitive job opportunities or advanced studies
• To become a recognised international leader in specific areas of research
• To serve as a central resource for physics education at CityUHK
A Snapshot of Success
Leveraging Hong Kong’s unique culture, the strengths and resources of the university, and growing opportunities in the Greater Bay Area, CityUHK Physics has firmly established five key research areas:
• Atomic, Molecular, and Optical Physics
• Quantum Materials
• Soft Matter and Biophysics
• Spectroscopy and Imaging
• Theoretical and Computational Physics
The emerging field of Astrophysics and Particle Physics research, also has roots in the elegance of science and the curiosity of mankind. CityUHK Physics is seeking to answer some of the deepest mysteries of the universe, enhance our understanding of the laws of nature, and pave the way to tomorrow’s technological advancements.
This research programme is led by a remarkable, 28-strong research team with deep expertise in their respective specialties. Five members of the internationally
recognised faculty are Fellows of the American Physical Society, and another recently won the prestigious C. N. Yang Award.
CityUHK Physics students are also doing well. For example, Fan Jingyi, an undergraduate in the Joint Bachelor’s Degree Programme with Columbia University, was recently awarded the Dr. & Mrs Yeung Kin Man Scholarships. Tse Wai-chuen, an undergraduate student in the Department, also won the HKSAR Government Scholarship in 2024.
Our vision and mission statements reaffirm our commitment to advancing the frontiers of physics, nurturing the next generation of scientists, and making a lasting impact on society. CityUHK Physics will continue to pursue excellence, inspire innovation, and illuminate the path towards a bright future underpinned by scientific discovery.
Exploring the Frontiers of Knowledge
One of CityUHK Physics’ greatest strengths is our world-class faculty. It includes experienced professors who have built internationally recognised reputations, and a growing number of brilliant young academics producing high-level research that appears in the pages of respected academic journals. The Department is determined to build on this advantage by recruiting more top local and international scholars to explore the frontiers of knowledge and redraw the face of physics.
Leadership
Chair Professors
Chair Professor of Materials Engineering
Prof. Paul Chu Kim-ho PhD Cornell University, USA
Chair Professors
Assistant Professors
Shaping the Future of Physics Research and Education
In the last two years, CityUHK Physics has made remarkable achievements in research, education, and professional services. These accomplishments are actively contributing to the development of Hong Kong society and propelling us towards the goal of becoming a world-leading physics institution.
The following highlights showcase some of the milestones that demonstrate the Department’s dedication, expertise, and innovative spirit as it shapes the future of physics research and education.
Dr. Muhammad Naeem (Postdoc) was awarded the AONSA Young Research Fellowship 2022 from the Asia-Oceania Neutron Scattering Association.
Prof. Alain Aspect was awarded the Nobel Prize in Physics 2022.
Prof. Bao Wei was awarded the Zhejiang Science and Technology Second-class Award and elected as the 2022 PSHK Fellow of the Physical Society of Hong Kong (PSHK).
Prof. Condon Lau was awarded the Gold Medal with Congratulations from the Jury at the 48th International Exhibition of Inventions Geneva (IEIG).
• Prof. Paul Chu Kim-ho, Dr. Huang Chao (Postdoc) and Ruan Qingdong (PhD student) received the Gold Medal at the 48th International Exhibition of Inventions Geneva (IEIG).
• Prof. Dai Liang and Prof. Liu Qi were honoured with the Faculty Service Awards in 2022 from the Department of Physics.
The project team led by Prof. Wang Xunli won the Second-class Award in the Higher Education Outstanding Scientific Research Output Awards (Science and Technology) 2022.
Prof. Wang Shubo was recognised by the Excellent Young Scientists Fund (Hong Kong and Macau) by the National Natural Science Foundation of China in 2023.
Prof. Denver Li Danfeng was awarded the AAPPS-APCTP Chen-Ning Yang Award 2023 (C.N. Yang Award 2023).
• Prof. Ma Junzhang received the 20232024 Early Career Award from the Research Grants Council.
Prof. Sunny Wang Xin received the 2023 Star of Tianhe Award at the Chinese National Supercomputer Center in Guangzhou.
Prof. Ren Yang discovered the key technology that enables negligible voltage decay in
• Prof. Dai Liang revealed the universal mechanisms of DNA and RNA deformation.
The Department has succeeded in acquiring major external funding support. For example: Prof. Denver Li Danfeng (Project Coordinator) and Prof. Ma Junzhang (leading Co-PI) received a Collaborative Research Fund grant from Hong Kong’s Research Grants Council; Prof. Rosie Chu Xiangqiang received significant funding under the Joint Funds of the National Natural Science Foundation of China. Prof. Li also received ANRRGC Joint Research Scheme funding from the Research Grants Council.
This life-changing Decision Could Change the World
Cherry Chan Cheuk-ying is the Research Manager for ITsci – a technology startup developing advanced, AI-based cancer diagnostic solutions for veterinary applications. She has certainly come a long way since her days as a CityUHK undergraduate studying for a Bachelor of Science in Applied Physics (BScAP). Fortunately, she didn’t have to travel very far to get there.
“Although I was already interested in the fundamentals of science, you could almost say CityUHK Physics chose me. My secondary school was close to Festival Walk, and whenever I passed by the CityUHK campus, the atmosphere and vibe among the students always felt great. It’s also a young, fast-growing university that has built a good reputation, which made the decision easy,” she said.
“I hope we can be successful as possible. Maybe we can change the world a little bit, just like CityUHK Physics has changed my life.”
According to Cherry, CityUHK Physics is different. “While other universities are more interested in theory, CityUHK is focussed on applied science and how it can be used.” During her final year, a simple enquiry about working on research projects proved that theory and transformed her career plans.
“I reached out to Prof. Condon Lau, who asked if I was interested in learning something new. He introduced me to Virtual Immunostaining for Veterinary Pathology, which became the AIstain technology on which ITsci is based,” she said.
Soon after graduation in 2021, Cherry officially joined the company, moving from CityUHK physics student to a new role as a high-tech entrepreneur in a single jump.
With a unique product and strong technological advantages over competitors, ITsci expects to expand rapidly in the multibillion USD veterinary diagnostics market. While AIstain is designed diagnose cancers in dogs and cats, Cherry is hopeful that it could potentially help people in future.
Cherry Chan Cheuk-ying CityUHK Physics BSc Graduate (2021)
Prof. Condon Lau (second from left), Cherry Chan Cheuk-ying (far right), and other ITsci team members.
CityUHK Paves the Way from High School to Ivy League
“I picked CityUHK because it is a young, fast-growing university, which has built a reputation – in Hong Kong and overseas – for dynamic research. The achievements of other graduates, coupled with Hong Kong’s combination of Chinese and Western culture, also made CityUHK an attractive choice.”
for kick-starting a career in condensed matter physics.
In addition to an exciting curriculum, Zezhu believes CityUHK Physics’ major advantage is a faculty that includes many ambitious and successful young research professors. Their insights and approachability led to one of the most valuable experiences in his academic career – the chance to present his research at one of the Department’s first ever symposiums.
“I learned a lot from other researchers and junior professors. They gave me valuable advice and incredible opportunities, such as taking advanced classes that are normally intended for post-graduates,” he explained.
This enabled him to leapfrog the usual Master’s requirement and secure a place in the PhD Physics programme at Brown immediately after receiving his BSc.
The diverse CityUHK community also taught Zezhu to communicate and collaborate with people from different countries and backgrounds. “That’s the most important social skill I learned in my undergrad years, and definitely helped in pursuing my PhD,” he said.
After his doctorate, Zezhu aims to continue towards the dream of becoming a tenured professor or a senior scientist at a research institute. Although he is uncertain whether he will remain in the United States or return to Hong Kong, he is convinced of one thing. “Wherever curiosity takes me, everything I learned at CityUHK Physics will pay dividends.”
Wei Zezhu
CityUHK Physics BSc Graduate (2019)
Wei Zezhu accepts an award from Prof. Chan Kwok-sum.
Global Reputation
CityUHK Physics has gained international recognition for its pursuit of excellence and its vision of becoming a leading physics department in the Asia-Pacific region. With cutting-edge facilities, a world-class faculty, and a bright student body, the Department has earned prestigious awards and accolades for academic excellence and trailblazing research. An enviable reputation and a commitment to pushing the boundaries of knowledge have consolidated the Department’s position as a global leader in physics.
Experience and Exposure Prepare Students to Face the Future
CityUHK Physics fulfils the University’s philosophy of delivering a “learning centred education” by offering access to a rich variety of extracurricular activities and exchange programmes. Exposure to a wide range of local and international experiences provides students with a broader perspective and valuable life lessons, including an appreciation of different ideas and the importance of competition.
Exchange Programmes
While CityUHK Physics welcomes inbound exchanges, its outbound programmes offer students dynamic opportunities to expand their horizons at partner institutions. Students can apply to have credits earned at a host university transferred to their CityUHK academic programmes.
phenomena in nonlinear physics and enjoying a host of international cuisines.
opportunity to gain practical skills and develop a deep knowledge of state-of-theart research techniques.
During her exchange at Toronto Metropolitan University, Ho Yuen-ting took medical physics courses closely related to her academic goals. Immersing herself in the city’s vibrant cultural scene also broadened her understanding of cultural diversity and instilled a sense of global citizenship. Applied Physics undergraduate He Siwei explored an entirely different discipline from her major when she joined a course on the Chinese Economy at Peking University. She believes the experience taught her to adapt, communicate and be resilient in the face of adversity.
International Research & Competitions
The Department recognises the vital role that participating in research at world-class research institutions plays in nurturing young talent. For example, CityUHK Physics students have probed the structure and properties of matter at renowned facilities in Europe. They include the Swiss Light Source (SLS), the Berlin Electron Storage Ring Society for Synchrotron Radiation (BESSY) in Germany, and the MAX-IV Laboratory in Sweden. Synchrotron Soleil in France also offered students a unique
Such experiences significantly enhance their competitiveness for future studies and job opportunities in academia, industry, and national laboratories. They help CityUHK Physics students succeed in prestigious scientific competitions, like taking second place in the “SpinQ Cup” at the Greater Bay Area Quantum Computing Challenge Camp. CityUHK Physics students also represented Hong Kong in the final round of PLANCKS 2023 – which is short for the Physics League Across Numerous Countries for Kick-ass Students – held in Milan. Also known as the Physics Olympics, the contest attracts the world’s best undergraduate and master’s level physics students.
Study Tours
Face to face interactions remain vital. In CityUHK’s first academic expedition of the post-pandemic period, a group of 12 undergraduate students completed an eyeopening study tour of prominent scientific institutions in Japan. Led by Prof. Denver Li Danfeng, and Prof. Rosie Chu Xiangqiang,
and J-PARC, where they explored cuttingedge research and fostered international collaborations. The visits provided an invaluable opportunity to interact with eminent researchers and gain insights into original work.
Encouraging Initiative
CityUHK students are encouraged to take the initiative in creating new opportunities. The PHY Student Chapter recruits passionate students to co-host the Department’s learning support network and brand promotion initiatives. In addition to meeting prestigious scholars and visitors from around the world, Student Chapter members
also develop leadership, presentation and interpersonal skills, and receive valuable recognition and recommendations that improve their prospects during academic and employment interviews.
It’s not “all work, no play” at CityUHK. PHY Student Connect organises regular gatherings to bring students and faculty members together to exchange ideas in an informal environment.
“It was a profound experience that left an indelible mark on my personal and academic growth.”
“I could really feel what I had learned and contributed in a real research group … things normal undergraduate students may not have a chance to do or experience.”
Xu Wenxuan
CityUHK Physics student on his NUS exchange
CityUHK Physics student on his research at Synchrotron Soleil
Xu Wenxuan (first from left)
Lee Kai-fai (left)
Learning for Lifelong Success
The BSc Physics programme is designed to develop logical thinking and problemsolving skills that benefit students throughout their entire lives. Our continually enhanced curriculum provides a solid foundation in fundamental physics, which enables students to explore more specialist disciplines, such as solid-state physics, optics, medical physics, financial engineering and soft matter physics.
Encouraging Excellence
The programme assigns each new student a faculty member as a personal academic advisor, and pairs them with a senior-year peer to help navigate the ins and outs of university life. Students can also connect with fellow classmates at events organised by the Department.
Students are invited to participate in the Undergraduate Research Attachment Scheme, which offers opportunities to join research teams and gain valuable investigative experience. They can also broaden their horizons through the Outbound Student Exchange Programme, which offers the chance to study at partner universities overseas.
Following the explosion of interest in A.I., we have strengthened our computational physics training and introduced machine learning for physical sciences. Undergraduates can now pursue A.I.-related research projects, building valuable knowledge in a fast-changing field.
Such comprehensive support positions CityUHK Physics graduates to embark on further studies, or pursue professional careers in a variety of sectors, from scientific research and technological development to medical physics, data science, finance, and STEM education.
Undergraduates are also encouraged to participate in outreach activities such as Information Days, and join the Department’s student chapter to develop useful interpersonal skills and increase their understanding and connections with the community. In summer 2023, a number of students joined a study tour of research institutes in Japan to gain a more global perspective.
Doubling Down
CityUHK offers a variety of programmes to help elite students develop their talents. For example, undergraduates who demonstrate excellent academic performance in their first two years of study can apply to the Joint Bachelor’s Degree Programme between CityUHK and Columbia University in New York. Successful candidates spend their third and fourth years studying in the United States, earning a BSc from CityUHK and a BA from Columbia University. Participants include Wu Peilin, who continued his studies with an MSc in Theoretical Physics at King’s College London after completing his double degree.
“Studying in the Joint Bachelor’s Degree Programme was an extremely rewarding journey … both academically and personally. The biggest lesson that I’ve learned [was the] personal paradigm shift after the expansion of my horizon. Every conversation with a great mind around the campus turned out to be inspiring. Even though a two-year study [at Columbia] might be a bit short in time, it was enough to peek through the cultural, social, political, and religious differences, and those discrepancies really lifted me out of the normal plane of comprehension in a local perspective and granted me a glimpse of the whole picture.”
Wu Peilin BSc, BA, MSc
Transforming Talent Development
CityUHK Physics recently enriched its talent development portfolio with a new Undergraduate plus Master’s Degree Programme. It is designed to nurture students through integrated learning that includes access to courses that are normally only taught at the postgraduate level, and participating in advanced research projects. Successful candidates receive two degrees –a BSc in Physics and an MSc in Physics with Data Modelling and Quantum Technology.
Cutting- edge Courses
The CityUHK Master of Science in Applied Physics Programme has gained a worldwide reputation. Applications have more than doubled, with candidates coming from as far afield as Europe and North America, as well as mainland China and Hong Kong. Many obtained their bachelor’s degrees from prestigious international schools, including the University of Toronto, the University
University, the University of Science and Technology of China, Hong Kong Polytechnic University and CityUHK.
Their background is equally diverse, covering physics, chemistry, materials science, mechanical engineering, bioengineering, and computer science. However, they all share an intense commitment to succeeding academically and professionally.
To attract high-quality applicants, the MSc Programme is constantly adding new opportunities. The majority of graduates employment, with more than half taking jobs in the Greater Bay Area, including Shenzhen and Hong Kong, in organisations ranging from education and high-tech industries to the public sector.
The faculty is involved in a broad range of advanced research projects that challenge MSc students, teach them to think critically
and solve problems, and provide a smooth transition to future studies. Every year a number of graduates receive PhD scholarshipsfromtopuniversities.
Inresponsetoanincreasingmarketdemand for a modern curriculum, and to prepare studentsforthehighlytechno-centricworld ofthefuture,thecurrentMScProgrammeis undergoingamajorreform.Itwillbecomean MScinPhysicsprogramme,withafocuson DataModellingandQuantumTechnologies.
“Throughout the MSc Programme, I enjoyed exploring cutting-edge research alongside faculty members and combining relevant experimental techniques with theory. The knowledge gained from the programme enabled me to successfully apply for and receive a PhD scholarship to continue my research journey.”
Ding
Xiaoqi CityUHK Physics MSc graduate and PhD candidate
The formula for PhD Success
Much of the PhD programme’s success is due to our talented faculty. This internationally recognised team now includes 7 Chair Professors, 3 Professors, 10 Associate Professors, and 8 Assistant Professors.Theyarefocussedonfivemain researchareas.
• Atomic, Molecular, and Optical Physics
• Quantum Materials
• Soft Matter and Biophysics
• Spectroscopy and Imaging
• Theoretical and Computational Physics
The programme covers a host of “hot” topics, ranging from topological insulators to Dirac and Weyl semimetals, superconductivity, neutron scattering, quantum computation and information, machine learning, and molecular machines. This cutting-edge research is supported by significant funding from a variety of channels, including the Hong Kong SAR Research Grants Council’s Areas of Excellence Scheme, the Collaborative Research Fund, and the General Research Fund, as well as the National Natural Science Foundation of China’s Excellent Young Scientists Fund.
The Department produces a steady stream of outstanding research results, and its findings are regularly published in highprofile academic journals, such as Science, Physical Review Letters, Nature Materials, and Nature Communications
Creating Rewarding Careers
In addition to encouraging academic development, the CityUHK Physics PhD programme provides a solid foundation for rewarding careers.
Outstanding Faculty Attracts Awards and Funding
CityUHK Physics fosters an environment that encourages pioneering research across a variety of subfields. This dedication to excellence has enabled our faculty to secure prestigious awards and attract substantial research funding, reinforcing our position as a leading centre for transformative physics research.
In the past two years, the Department has excelled in securing research funding from a range of sources, such as the Early Career Scheme (ECS) and the General Research Fund (GRF) organised by the Research Grants Council. This reflects our faculty’s strong research capabilities and potential.
ECS Prof. Ma Junzhang
ECS Prof. Bastien Michon
GRF Prof. Dai Liang
GRF Prof. Hoi Io-chun
Liu Qi
GRF Prof. Zhang Ruiqin
Prof. Wang Shubo
Prof. Wang Xunli GRF Prof. Yu Wing-chi
Breakthroughs and Novel Theories Take Physics to the Next Level
CityUHK Physics is at the forefront of unravelling the fundamental principles that govern our universe. Our research teams bridge the gap between cutting-edge theoretical knowledge and transformative real-world applications, creating innovative solutions that enhance the quality of life and promote sustainability. Through our interdisciplinary approach and commitment to excellence, we aim to make significant contributions that resonate far beyond academia.
World-First Battery Technology With Negligible Voltage Decay Developed at CityUHK
A pivotal breakthrough in battery technology, with profound implications for our energy future, has been made by a CityUHK Physics research team. The new development overcomes the persistent challenge of voltage decay, and could lead to significantly higher energy storage capacity.
Lithium-(Li) and manganese-rich (LMR) layered oxides are a promising class of cathodes for Lithium-ion batteries. Due to their low cost and high capacity, they are widely used in electronic devices. However, the long-standing problem of voltage decay hinders their application.
Prof. Ren Yang, Head and Chair Professor of CityUHK Physics, Prof. Liu Qi, and their team, have unlocked the potential of LMR cathode materials by stabilising the unique honeycomb-like internal structure. This has resulted in longer lasting and more efficient batteries. These insights are likely to transform the way we power our devices and take the development of high-energy cathode materials to the next level.
CityUHK Physicists Reveal the Universal Mechanisms of DNA and RNA Deformations
Physics, and their team have achieved a pivotal breakthrough in battery technology.
[Source] Luo, D., Zhu, H., Xia, Y., Yin, Z., and Qin, Y. et al., ‘A Li-rich layered oxide cathode with negligible voltage decay.’ Nature Energy 8, 1078–1087 (2023). They
DNA and RNA, the two main types of nucleic acid and the building blocks of life, are susceptible to environmental stimuli, which can cause them to deform, bend or twist. These deformations can significantly affect gene regulation and protein functions, but are extremely difficult to measure using traditional techniques. Recently, a research team co-led by a physicist from CityUHK, accurately measured the change in a nucleic acid induced by salt, temperature change and stretching force. Their findings help reveal the underlying universal deformation mechanisms of DNA and RNA.
“The latest findings can be applied to better understand DNA packaging in cells and the related deformation energy cost. The results also provide insights into how proteins recognise DNA and RNA and induce deformations, which are the key steps in gene expression and regulation.”
Prof. Dai Liang Associate Professor at CityUHK Physics who co-led the research
[Source] Zhang, Z.D., Nie, X.Y., Lei, D.Y., and Mukamel, S., Physical Review Letters 130, 103001 (2023).
New Quantum Theory of Light-Induced Matter
A team led by a physicist from CityUHK, recently developed a new quantum theory that explains the “light-induced phase” of matter and predicts some novel functionalities.
“The ultrafast processes of photoactive molecules, such as electron transfer and energy redistribution, which are typically at the femtosecond scale (10 -15s), are of extensive importance for light-harvesting devices, energy conversion and quantum computing. However, the research on these processes is full of obscurities. Most of the existing theories related to light-induced phases are bottlenecked by time and energy scales, and therefore cannot explain the transient properties and ultrafast processes of molecules when short laser pulses come into play. These impose a fundamental limit for exploring the light-induced phases of matter.”
Prof. Zhang Zhedong Assistant Professor at CityUHK Physics who led the study
To tackle these difficulties, Prof. Zhang and his collaborators developed a novel quantum theory for the optical signals of the light-induced phases of molecules, which is a world first. Through mathematical analysis in conjunction with numerical simulations, the new theory explains the excited state dynamics and optical properties of molecules in real time, overcoming the bottlenecks resulting from existing theories and techniques.
GdV6Sn6 kagome crystal structure: (i) unit cell; (ii) top view along the c-axis showing the kagome layer of V3Sn.
Simulated constant-energy contours showing reversal of spin chirality (green arrows) of surface electrons, from (i) clockwise in pristine GdV6Sn6 to (ii) anticlockwise after surface electron doping with potassium.
[Source] Hu, Y., Wu, X. X., Gao, S. Y., Plumb, N. C., Schnyder, A. P. et al., Science Advances 8, eadd2024 (2022).
“Kagome” Metallic Crystal Adds New Spin to Electronics
A multinational team of researchers, co-led by a physicist from CityUHK, has found a novel metallic crystal that displays unusual electronic behaviour on its surface, thanks to its unique atomic structure. Their findings open up the possibility of using the material to develop smaller and faster microelectronic devices.
“Our team unambiguously observed for the first time that a kagome metal can exhibit altered electronic energy-band structures, known as topologically non-trivial Dirac surface states. Because of their intrinsic spin and charge, electrons create their own magnetic fields and behave like tiny gyroscopes that have both rotation and an angled tilt that points in a certain direction. We demonstrated that in GdV6Sn6, the surface electrons become reordered or ‘spin-polarised’, and their tilts reorient themselves around a common axis that is perpendicular to the surface.”
Prof. Ma Junzhang Assistant Professor at CityUHK Physics
Prof. Zhang Zhedong (2nd from right) and his research group at CityUHK.
Schematic illustration of time-resolved spectroscopy for the light-induced phase of molecules, based on the new quantum theory.
Simple Physics Model Understands Complex Biological Processes
The double-helix structure of DNA deforms under environmental stimuli, which then affects gene expression, and eventually triggers a sequence of cellular processes. A team led by CityUHK Physics Assistant Professor, Prof. Dai Liang, has observed substantial DNA deformations by ions and temperature changes. The researchers also developed a simple physical model to explain DNA deformations. These results provide new insights into the molecular mechanisms of cellular responses to ions and temperature changes, and can be used to control gene expression by ions and temperature.
The research, which was conducted in collaboration with Wuhan University, focuses on the changes of DNA twist during DNA deformations, because the twist is a key structural parameter of the DNA double-helix. Increasing the DNA twist angle (overwinding) not only leads to the formation of DNA supercoils, but also enhances the energy cost of DNA unzipping and, hence, suppresses gene expression.
“Active control of DNA twist angle, or DNA supercoils, is employed by bacteria for regulating gene expression.”
Prof. Dai Liang
Associate Professor at CityUHK Physics
Prof. Dai and his team proposed a unified mechanism to explain four scenarios: stretching can induce the increase and decrease of DNA and RNA twists, depending on the situation of DNA and RNA.
[Source] Qiang, X. W., Zhang, C, Dong, H.-L., Tian, F.-J., Dai, L. et al., Physical Review Letters 128, 108103 (2022).
Effects of twist changes on gene expression.
Cutting-Edge Research is Unlocking the Mysteries of the Universe
In the most recent Research Assessment Exercise (RAE2020) conducted by the University Grants Council of Hong Kong, an independent panel ranked 38% of the research output by the Department of Physics at City University of Hong Kong as four-star – its highest possible rating. Signifying ‘world-leading’ quality, this outstanding result puts CityUHK Physics at the forefront of research excellence in Hong Kong, and ahead of every other physics department in the city. The exceptional performance also highlights the Department’s strong commitment to cutting-edge research and the significant contributions it has made to the advancement of physics.
Principal Investigator
Prof. Chai Yu Soft Matter Group
Led by Prof. Chai Yu, the Soft Matter Lab at CityUHK is dedicated to exploring the exotic behaviours of various soft matter systems, particularly those at or near surfaces or interfaces. Over the past year, the lab’s research group has focused on the controlled assembly and potential applications of a range of soft matter materials – including nanoparticles, small molecules, and polymers – at liquid-liquid interfaces. Utilising advanced in-situ characterisation techniques, it has successfully locked the shape of ferrofluids remotely, without the need for external magnetic fields, through the interfacial assembly and jamming of solid colloidal particles[1]. Additionally, it has identified a novel “single particle-aggregation-single particle” mechanism for transferring solid colloidal particles from one liquid phase to another[2]. These findings, among others, underscore the significance of soft matter at surfaces and interfaces[3].
[1] Zhao, S., Zhang, J., Fu, Y., Zhu, S., Shum, H. C. et al., Nano Lett., 22, 5538-5543 (2022).
[2] Fu, Y., Zhao, S., Fan, Y., Ho, Y. Y. L., Wang, Y. et al., Angew. Chem. Int. Ed. 62, e202308853 (2023).
[3] Fu, Y., Zhao, S., Chen, W., Zhang, Q., and Chai, Y., Nano Today, 54, 102073 (2024).
Principal Investigator
Prof. Chu Sai-tak
The aim of Prof. Chu Sai-tak’s research is to develop integrated optical devices for novel applications in linear, nonlinear and quantum optics.
In the past two years, his group has focused on the hybrid integration of its high-index doped glass platform with other platforms such as SiN, and the improvement of the nonlinear optical effect via dispersion engineering. It has also explored the application of integrated optical devices in microcomb generation, along with AI and quantum optics.
A., Cecconi, V., Hanzard, P. H., Rowley, M., Das, D. et al., Commun. Phys. 6, 259 (2023). Li, G., Li Y., Ye, F., Li, Q., Wang, S. H. et al., Laser & Photonics Rev. 17, 2200754 (2023). Zhu, X., Li, G., Wang, X., Li, Y., Davidson, R. et al., Opt. Express 31, 10525-10532 (2022).
The assembly of soft matter at liquid interfaces with different stimuli. Supercontinuum (SC) generation in different slot waveguides: (a-c) SC evolution vs input pulse energy; (d-f) output spectra
Cutrona,
Principal Investigator
Prof. Oscar Dahlsten
Quantum Information and Intelligent Energy Harvesting Group
Established in January 2023, Prof. Oscar Dahlsten’s Quantum Information and Intelligent Energy Harvesting Group currently comprises two PhD students and two postdoctoral researchers. They are engaged in three main areas of theoretical physics research: (i) quantum computing and machine learning, (ii) the theory of energy efficiency, and (iii) quantum foundations.
The group has demonstrated how a thermodynamic enhancement, known as a quantum switch, can be achieved without violating the , and recent experimental findings have corroborated this analysis. Additionally, in a preprint, the group presented a quantum algorithm for information compression using quantum neural networks, which can in principle extract significantly more energy than classical methods, under specific conditions.
Principal Investigator
Prof. Dai Liang
Computational Soft Matter and Biophysics Group
In the last three years, Prof. Dai Liang’s Computational Soft Matter and Biophysics Group has measured and explained the deformations of DNA and RNA induced by ions, stretching force, temperature changes, and methylation. It also developed a simple and unified physical model to quantitively explain many deformations. Furthermore, the group has elaborated the impacts of these DNA/RNA deformations on DNA packaging, DNA/RNA-protein interactions, and gene expression. Considering the unique functions achieved by the DNA double-helix, the group designed artificial double-helix structures through the selfassembly of simple polymer models using computational methods.
[1]
[2]
[3]
It has also developed a generalised theory of energy, unifying the classical and quantum cases[2]. In collaboration with industry, the group established a new approach for guaranteeing the quality of computation outputs based on simulated annealing[3], and initiated a new industrial collaboration focused on physics-inspired computing.
Prof. Dahlsten’s team currently has nine papers undergoing peer review from the past year’s submissions. Exciting preliminary results from a key project indicate that a thermodynamics-inspired method can substantially reduce energy consumption in integrated circuits used for computation. The group is in the process of disseminating more of its machine learning research.
[2]
[3]
Information compression via quantum methods. Quantum processing extracts important features which constitute the compressed data. During the tuning of the quantum processing, the data is reconstructed at the end to ensure there is no significant loss due to compression. Such compression can be used to remove the entropy from a subsystem, from which energy can then be extracted.
DNA twist change with salt and the underlying mechanism.
[1] Liu, X. J., Ebler, D., and Dahlsten, O., Phys. Rev. Lett. 129, 230604 (2022).
Jiang, L. B., Terno, D., and Dahlsten, O., Phys. Rev. Lett. 132, 120201 (2024).
Luo, Y. T., Zhen, Y. Z., Liu, X. J., Ebler, D., and Dahlsten, O., Phys. Rev. E 108, L052105 (2023).
Tian, F., Zhang, C., Zhou, E., Dong, H., Tan, Z. et al., PNAS 120, e2218425120 (2023).
Zhang, C., Tian, F., Lu, Y., Yuan, B., Tan, Z. et al., Sci. Adv. 8, eabn1384 (2022).
Du, J., Yin, H., Zhu, H., Wan, T., Wang, B. et al., Phys. Rev. Lett. 128, 197801 (2022).
Principal Investigator
Prof. Condon Lau
Prof. Condon Lau is a pioneer in developing cutting edge, translatable imaging, and spectroscopy methods for biomedical applications, and using them to answer basic research questions and address educational and healthcare demands. Some of his most notable recent discoveries and innovations include FROZEN! multi-electrolyte analysis, AIstain AI-powered technology for diagnosing cancers in dogs and cats, and lithium treatment during breast feeding which inhibits thyroid iodine uptake and hormone production.
Gunawan, R., Imran, A., Ahmed, I., Liu, Y., Chu, Y. et al., Analyst 146, 5186–5197 (2021). Ahmed, I., Ma, V., Liu, Y., Khan, M. S., Liu, Z. et al., Bipolar Disord. 23, 615-625 (2021).
Principal Investigator
Prof. Li Haixing
Single Molecule Electronics Group
Prof. Li Haixing’s lab examines molecules and develops measurement tools at the single molecule level to spark advances in electronics and sustainability. Specifically, the lab creates single molecule circuits to probe charge transport processes at metal-moleculemetal junctions, while also focusing on uncovering the underlying physics and chemistry that dictate these nanoscale transport phenomena. By applying single molecule techniques to a variety of synthetic molecules, the lab aims to understand the structurefunction relationships of molecular materials and, ultimately, design and create novel functionalities that harness molecular properties.
[3] Lau, C., Li, X., and Hill, F.I., Recipients of the Gold Medal with Congratulations of the Jury at the 48th International Exhibition of Inventions Geneva, Apr 2023. Guo, W., Quainoo, T., Liu, Z., and Li, H., Chem. Comm. 60, 3393-3396 (2024).
user interface.
The inside front cover of the March 2024 edition of Chemical Communications, which featured the work “Robust Binding
AIstain’s
Principal Investigator
Prof. Li Xiao
Condensed Matter Theory Group
Prof. LI Xiao’s research group is focused on theoretical studies of quantum condensed matter physics. Currently, the group has two main research directions: nonequilibrium quantum dynamics, and novel electronic states in low-dimensional materials. Recent findings include a systematic investigation of how the range of electronelectron interactions affects the stability of many-body localisation[1], the discovery of an exactly solvable model for discrete-time crystal enforced by nonsymmorphic dynamical symmetry[2], and a study of nonlinear current response of a two-dimensional system under an
[1] Vu, D., Huang, K., Li, X., and Das Sarma, S., Phys. Rev. Lett. 128, 146601 (2022).
[2] Hu, Z., Fu, B., Li, X., and Shen, S.-Q., Phys. Rev. Res. 5, L032024 (2023).
[3] Huang, Y., Wang, Y., Wang, H., Xiao, C., Li, X. et al., Phys. Rev. B 108, 075155 (2023).
Principal Investigator
Prof. Liu Qi
Prof. Liu Qi’s group focuses on the fundamental investigation of layered cathodes with advanced synchrotron characterisation techniques. Recently, it reported a Lithium-rich manganese-based (LMR) layered oxide cathode with negligible voltage decay. The group designed the cathode with TM ions occupying the interlayer Li sites. Located just above or below the Li ions in the honeycomb structure, these TM ions serve as a “cap” to pin the oxygen ions around the honeycomb. As a result, the capped-honeycomb structure persists after high-voltage cycling and prevents TM migration and oxygen loss. The discovery demonstrates that the long-standing voltage decay problem in LMRs can be effectively mitigated by internally pinning the honeycomb structure. It opens an avenue to developing next-generation, high-energy cathode materials.
Many-body localisation phase diagram of various one-dimensional models under shortrange (SR) and long-range (LR) interactions. The horizontal and vertical parameters are the interaction strength U and the disorder strength V, respectively. The colour represents the inverse participation ratio (IPR).
Design of a honeycomb local structure pinned with interlayer TM ions to overcome the voltage decay of Li-rich layered oxides.
Luo, D., Zhu, H., Xia, Y., Yin, Z., Qin, Y. et al., Nat. Energy 8, 1078-1087 (2023).
Principal Investigator
Prof. Ma Junzhang ARPES Group
Kagome metals feature both VHS and flat bands in their electronic structure. In the last two years Prof. Ma Junzhang’s ARPES Group has investigated how VHS and density waves are related, and whether excitonic states can be induced by VHS in 166 type systems.
Using ARPES to study the 166-type kagome metal GdV6Sn6, the team 2 topology (Fig.a). In another work, using ARPES combined with Raman scattering measurements to investigate , which exhibits a CDW order (Fig.b), the team identified multiple VHS near the Fermi level. In addition, the team also found a signature of strong electron-phonon coupling
6 6
The research has established kagome systems as fertile ground, showcasing unique structures like flat bands, VHS, and Dirac points. They also serve as an ideal platform for probing a multitude of quantum states, including CDW, superconductivity, topological phenomena, and magnetism[3].
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(a) Doping evolution of the 3D band structure of GdV6Sn6. The spin chirality inversed during the process. (b) Observation of topological surface states and VHS in ScV6Sn6
Principal Investigator
Prof. Jeff Ou Zheyu Quantum Optics Group
The Quantum Optics Group uses new SU(1,1) quantum entangled interferometers on different platforms, such as in optical fibre, atomlight hybrid systems and integrated optical systems. They offer advantages over traditional interferometers, including sensitivity, tolerance to losses, and the mixing of different types of waves[1].
The group recently proposed deploying an SU(1,1) version of a Sagnac interferometer, which is widely used in rotational sensing applications, by inserting parametric amplifiers inside the Sagnac . This enables the loop to be divided into quantum and classical portions. The Quantum loop increases the interferometer’s sensitivity in proportion to the amplifier’s gain.
Quantum entangled Sagnac interferometer. Degenerate parametric amplifiers (DPA1,2’,1’,2) are inserted into a traditional Sagnac interferometer to measure rotational phase shift, with the quantum loop (Loop 2-q) providing enhanced sensitivity.
Hu, Y., Wu, X., Yang, Y., Ga, S., Plumb, N. et al., Sci. Adv. 8, (2022).
[2] Hu, Y., Ma, J., Li, Y., Jiang, Y., Gawryluk, D. et al., Nat. Commun. 15, 1658 (2024).
[3] Ekahana, S., Soh, Y., Tamai, A., Gosálbez-Martínez, D., Yao, M. et al., Nature 627, 67–72 (2024).
[1] Ou, Z. Y. and Li, X., APL Photonics 5, 080902 (2020).
[2] Zhao, W., Tang X., Guo X., Li, X., and Ou, Z. Y., Appl. Phys. Lett. 122, 064003 (2023).
Principal Investigator
Prof. Ren Yang Energy & Materials Physics Group
Prof. Ren Yang’s research focuses on the development and fundamental understanding of advanced materials, and their applications for energy storage and conversion technologies. The team members frequently use state-of-the-art techniques at synchrotron X-ray and neutron scientific facilities worldwide to characterise and understand materials at various spatio-temporal scales. One of the main research areas is solid-state batteries, and several that use solidstate electrolytes with high ionic conductivity and good mechanical properties have been developed. The electrolyte/electrode interface has been designed to suppress lithium-dendrite growth, which improves the electrochemical performance of lithium-ion batteries. Solid-state batteries with polymer-based solid electrolytes have demonstrated outstanding cycling stability, excellent specific capacity, and high levels of safety, clearly illustrating the potential for practical applications. In addition, the team is working on magnetocaloric and elastocaloric materials for solid state magnetic refrigeration and related thermal conversion applications.
Principal Investigator
Prof. Wang Shubo Photonics Group
Prof. Wang Shubo leads the Photonics Group in investigating light manipulation by artificial structures. The team discovered an exact, universal connection between the topological properties of light and the real-space topology of structures. They showed that the number of “holes” in a smooth metallic structure decides the total index of the optical polarisation singularities in the near field[1]. The team also demonstrated that a simple nano helix particle can be exploited to realise a “Directional Dipole Dice,” enabling unidirectional coupling of light in three orthogonal directions. This can be used in integrated optical circuits for various on-chip applications[2]
Polarization singularity lines in the near field of a double-torus structure[1]
[1] Peng, J., Zhang, R. Y., Jia, S., Liu, W., and Wang, S., Sci. Adv. 8, eabq0910 (2022).
[2] Cheng, Y., Oyesina, K. A., Xue, B., Lei, D., Wong, A. M. H. et al., PNAS 120, e2301620120 (2023).
(Left) Folding test of polymer solid-state batteries. (Right) Magnetic entropy change (a) and reversible entropy change (b), and positron annihilation spectroscopy (PAS) results (c,d).
[1] Zhang, F., Wu, Z., Wang, J., Chen, W., Wu, Z. et al., Acta Mater. 265, 119595 (2024).
[2] Zhang, S., Liu, H., Liu, Z., Zhao, Y., Yan, J. et al., Adv. Funct. Mater. 34, 2401377 (2024).
Principal Investigator
Prof. Sunny Wang Xin
Quantum Theory Group
Prof. Sunny Wang Xin and the Quantum Theory Group study theoretical problems arising from the physical implementation of quantum computation. For example, Prof. Wang has developed optimised control protocols that mitigate noise in the manipulation and improve the accuracy of quantum hypothesis
Zhang, X. -M., Kong, W., Farooq, M. U., Yung, M. -H., Guo, G. et al., Phys. Rev. A 103, L040403 (2021).
Xu, H., Wang, B., Yuan, H., and Wang, X., New J. Phys. 25, 113026 (2023).
Principal Investigator
Prof. Wang Xunli
Applied Physics Group
The Applied Physics Group uses state-of-the-art neutron and synchrotron scattering techniques to study the structure and dynamics of advanced materials. Fundamental knowledge of the structure and dynamics – where atoms are and how they move – is essential to understanding the properties of materials. Broad topics of interest include phase transformation, deformation behaviours, and magnetism. In addition, the group is involved in several collaboration projects. Experiments are carried out at leading neutron and synchrotron sources worldwide by CityUHK Physics
[1] Lan, S., Zhu, L., Wu, Z., Gu, L., Zhang, Q. et al., Nat. Mater. 20, 1347 (2021).
[2] Naeem, M., He, H., Zhang, F., Huang, H., Harjo, S. et al., Sci. Adv. 6 eaax4002 (2020).
[3] Li, X. Y., Zhang, H. P., Lan, S., Abernathy, D. L., Otomo, T. et al., Phys. Rev. Lett. 124, 225902 (2020).
Photon dispersion relationship in Zr46Cu46Al8 metallic glass. (a) and (c) are the phonon density of states obtained via inelastic neutron scattering measurements and molecular dynamics simulations, respectively. (b) and (d) are the second derivatives of data in (a) and (c) respectively, which identified two phonon branches. The lower branch comes from the transverse phonons[2]
Optimal control protocols for quantum hypothesis testing.
Principal Investigator
Prof. Sam Wong Sung-ching
Black Hole and Cosmology Group
Answering key questions, such as where the universe came from and why its expansion is accelerating, is fundamental to understanding our entire existence. Prof. Sam Wong Sung-ching’s Black Hole and Cosmology Group is dedicated to studying these cosmological and astrophysical phenomena. They are uncovering underlying principles that dictate the properties of gravity in extreme scenarios, and providing insights that could redefine our perspective on reality itself.
Recent examples of the group’s diverse research programme include the study of parity violation using astrometry[1], the study of black hole tidal Love numbers beyond general relativity and its connection to , as well as the study of symmetries in effective field theories that govern superfluid and inflationary fluctuations.
[1] Liang, Q., Lin, M.-X., Trodden, M., and Wong S. S. C., Phys. Rev. D 109, 083028 (2024).
[2] De Luca, V., Khoury, J., and Wong S. S. C., Phys. Rev. D 108, 024048 (2023).
[3]
Principal Investigator
Prof. Yu Wing-chi
Prof. Yu Wing-chi’s group investigates a variety of topics related to quantum critical phenomena in many-body systems. The current focus is on dynamical quantum phase transitions, where a manybody system undergoes criticality in time when being brought out of equilibrium. The group has introduced different probes to understand the behaviour of the system around a dynamical , which is an open question in the field. By tracing the time evolution of the spin fluctuations, the researchers found that the system is usually in its least spin-squeezed state around the dynamical quantum phase transition. The spin correlations around a dynamical quantum phase transition were also found to be correlated with the postquenched phase of the system, suggesting a non-trivial relation of the dynamical criticality to the equilibrium phase diagram of the system[3]
[1] Wong, C. Y., Cheraghi, H., and Yu, W. C., Phys. Rev. B 108, 064305 (2023).
[2] Wong, C. Y. and Yu, W. C., Phys. Rev. B 105, 174307 (2022).
[3] Yu, W. C., Sacramento, P. D., Li, Y. C., and Lin, H. Q. Phys. Rev. B 104, 085104 (2021).
The dynamical free energy λ, the dynamical topological order parameter νD and spin squeezing parameter ξs 2 as a function of time in the quantum XY model quenched from the equilibrium critical point to the paramagnetic phase (left) and the ferromagnetic phase (right).
Hui, L., Joyce, A., Komissarov, I., Parmentier, K., Santoni, L. et al., JHEP 2023, 123 (2023).
Schematic of black holes.
Principal Investigator
Prof. Zhang Ge
Disordered solids possess many useful mechanical, thermal, and optical properties, but differ in their responses to large deformations. For example, shaving cream is ductile, and able to deform indefinitely. However, many disordered solids, such as window glass, are brittle, which limits their application. Empirical research has uncovered ways to improve ductility, but offers little insight into their success or how to generalise them to new materials.
Previous theoretical approaches have focused on interactions between plasticity with elasticity. Over the past three years, Prof. Zhang Ge and his research group have constructed models that incorporate structure into this interplay. The theory captures behaviours observed experimentally and by computer simulations, yielding insights into microscopic mechanisms underlying empirical strategies for tuning ductility.
[1] Xiao, H., Zhang, G., Yang, E., Ivancic, R., Ridout, S. et al., PNAS 120, e2307552120 (2023).
[2] Zhang, G., Xiao, H., Yang, E., Ivancic, R., Ridout, S. et al., Phys. Rev. Res. 4, 043026 (2022).
[3] Zhang, G., Ridout. S., and Liu, A. J., Phys. Rev. X 11, 041019 (2021).
Principal Investigator
Prof. Zhang Ruiqin
Computational Materials Physics Group
) gas pollutants create severe threats to human health, the ozone layer, and the global climate. Accordingly, finding suitable materials and methods to efficiently remove NOX has been a great concern for years. By studying related photocatalysis and surface reactions, Prof. Zhang Ruiqin and the Computational Materials Physics Group proposes to use graphitic carbon nitride (g-CN) film with N-vacancies (g-CNNV) to decompose NOX.
Comparison of the group’s theory and simulations of the deformation process of a ductile disordered solid (left) and a brittle one (right). Darker colours indicate more local deformation.
Based on density functional theory (DFT) and time-dependent DFT calculations, it has determined the decomposition mechanism of NO/ 2 gas on g-CNNV. The group has found that the N-O bond cleavage of NOX is usually accompanied by the N occupying the N-vacancy. Oxygen formation, and subsequent light excitation promotes oxygen desorption from the g-CN surface through the photochemical processes of intersystem crossing and conical intersection. It demonstrated that, under illumination the g-CNNV film can effectively decompose NOX into harmless oxygen. The work offers a deep understanding of the fundamental process of surface photocatalytic reactions, and suggests potential practical applications. For example, since sunlight and surface defects can synergistically affect the electronic states of adsorbates and facilitate their favourable transformation by gas-solid interaction, coating the outer walls of buildings or chimneys with the film could be an economical way to remove NOX from the environment.
CityUHK researchers propose coating buildings with a g-CN film with nitrogen vacancies (g-CNNV) to combat nitrogen oxides (NOX) released into the atmosphere from the combustion of fossil fuels. Allowing sunlight to decompose the NOX, in line with density functional theory (DFT) and time-dependent DFT calculations, offers a green and potentially economic anti-pollution solution.
Yang, Y. W., Zhao, Y. L., and Zhang, R. Q., J. Mater. Chem. A 12, 375–383 (2024).
Principal Investigator
Prof. Zhong Yiming
There is abundant evidence proving the existence of dark matter, yet its nature remains elusive. Prof. Zhong Yiming is committed to exploring the mysteries of dark matter and other invisible dark particles, through astrophysical observations and particle physics experiments. His research focuses on several key areas: Probing the self-interactions of dark matter by investigating the properties of dark matter halos and their potential connections to high-redshift ; Exploring particle production in the early universe through investigating cosmological correlators exploring the origin of the Galactic centre gamma-ray excess detected
[1] Zhong, Y.-M., Yang, D., and Yu, H.-B., MNRAS 526, 758-770 (2023).
[2] Wang, L., Xianyu, Z.-Z., and Zhong, Y.-M., JHEP 2022, 85 (2022).
[3] McDermott, S. D., Zhong, Y.-M., and Cholis, I., MNRAS 522, L21-L25 (2023).
Principal Investigator
Prof. Zhang Zhedong
Quantum Nonlinear Spectroscopy & Photonics Group
In the field of ultrafast spectroscopy, the Quantum Nonlinear Spectroscopy & Photonics Group led by Prof. Zhang Zhedong has developed a microscopic theory for the multidimensional coherent spectroscopy of molecular polaritons. It highlights the collective dynamics against the dark states, presenting a remarkable tradeoff with the localisation effect. In 2023 CityUHK’s Research News reported the group’s success indemonstrating a quantum femtosecond Raman spectra using entangled photons, capable of capturing ultrafast electron dynamics within 50fs beyond the Heisenberg limit for resolution. In the area of statistical mechanics, the group has developed a full quantum theory for an exciton-polariton condensate, which may offer a promising paradigm for quantum light sources. This is essential for a comprehensive understanding of nonequilibrium phase transitions.
[1] Zhang, Z. D., Nie, X., Lei, D. and Mukamel, S. Phys. Rev. Lett. 130, 103001 (2023).
[2] Zhang, Z. D., Peng, T., Nie, X., Agarwal, G. S. and Scully, M. O. LSA 11, 274 (2022).
[3] Zhang, Z. D., Zhao, S. and Lei, D. Phys. Rev. B 106, L220306 (2022).
Self-interacting dark matter halo benchmarks (red arrows) could explain the origin of high-redshift supermassive black holes (black and grey dots). The black curves indicate their Eddington accretion history. For each red arrow, the markers on higher and lower redshift ends denote initial halo and seed masses, respectively. The blue shaded regions indicate the ratio of the critical density fluctuation to the halo mass variance.
(A) Schematic illustration of time-resolved spectroscopy for the light-induced phase of molecules (i.e., a few molecules in an optical microcavity). Emission signals are collected in a detector after laser pulses excite the molecules, yielding a multidimensional image of exciton dynamics in real-time. (B) 2D optical signal for organic dyes in an optical cavity, where horizontal and vertical axes record the absorption and emission frequency, respectively.
World Class Facilities Powering New Ideas and Innovations
CityUHK Physics relies on cutting-edge facilities to fulfil its mission of serving as a central resource for physics education and research. The university is now a hub for scientific exchange and collaboration, which is constantly making new discoveries and innovations.
Joint Neutron Scattering Science and
Technology
Lab Receives Top Ranking
The CAS-CityUHK Joint Laboratory on Neutron Scattering Science and Technology is a joint laboratory programme conducted in conjunction with the Chinese Academy of Sciences (CAS). It was launched in February 2019, and has been managed by the Centre for Neutron Scattering (CNS) at CityUHK since 2021. In the latest assessment exercise commissioned by the CAS and the Research Grants Council (RGC) of Hong Kong at the end of 2023, it was ranked “Outstanding” – one of four joint labs to receive such recognition out of the 22 that were evaluated.
As the only research centre of its kind in Hong Kong, the CAS-CityUHK Joint Lab has tremendous potential to enhance the city’s role in developing science and technology in the Greater Bay Area. The CAS-CityUHK Joint Lab also works closely with the China Spallation Neutron Source (CSNS) in Dongguan on professional training, research programmes, instrumentation, and other projects.
Multi-Physics
Instrument Delivers Results in Record Time
In less than three years, the Multi-Physics Instrument (MPI) at the CSNS has produced a string of outstanding research findings.
Constructed in cooperation with Dongguan University of Technology and City University of Hong Kong, and funded by a Collaborative Research Fund equipment grant from the RGC, the MPI has generated over 77 research papers, including two in Nature and nine in Nature Energy and Nature Communications
When it was officially commissioned in January 2021, the MPI became the first neutron total scattering instrument in China. The CNS team played a leadership role in the instrument’s design and construction. They are delighted to see it delivering such outstanding insights, including high-quality pair-distributionfunction data, in so short a period of time.
Located in Dongguan, about 70 km north of Hong Kong, the CSNS was an international sensation when it was officially commissioned in August 2017. It marked the moment that China joined the US, UK, and Japan as the only nations capable of providing pulsed neutron sources for research and development. The CSNS recently received approval for Phase-2 of its development, which includes a 5x power upgrade to 500 kW, and the construction of 10 more instruments. With a total budget of RMB3 billion (~US$ 0.5 billion), the ground breaking ceremony for the latest phase of development was held in late March 2024.
(From left) Prof. Kuo Way, Prof. Wang Xunli, Prof. Chen Hesheng and Prof. Yang Chen-ning, officiated at the CAS-CityUHK Joint Laboratory on Neutron Scattering Science and Technology launch ceremony on 27 February 2019.
New World Class Facility –the Southern
Advanced
Photon Source – is On the Way
A state-of-the-art synchrotron facility, tentatively named the Southern Advanced Photon Source, is now being planned. Called SAPS for short, this next-generation medium-energy synchrotron radiation facility is designed to cover a broad range of scientific applications. Operating at 3.5 GeV, the 800 metre circumference storage ring will be optimised for high brilliance (reaching 1022phs/s/mm2/mrad2/0.1%BW).
SAPS will be located next to the CSNS in Dongguan, which means that Hong Kong’s scientific community will enjoy the benefits of two world class facilities.
Giant Step in Knowledge Transfer
In 2023, Prof. Liu Qi, Associate Professor of CityUHK Physics, and a core member of the CNS, launched a new battery technology company. Several of his research outcomes, including high-voltage LiCoO2 and singlecrystal Ni-rich cathode materials, have been licensed for commercialisation. The
start-up, called “Shenzhen Sufang New Energy Ltd.”, focuses on the development and manufacturing of Li-rich layered cathode materials for lithium-ion batteries. The business has already received US$2 million in investments from the Qingsong Fund – a leading early-stage venture capital entity in China, whose successes include the technology conglomerate Tencent.
New STEM Lab to Nurture the Next Generation of Researchers
The Head of CityUHK Physics, Prof. Ren Yang, has won funding from the Hong Kong Jockey Club to set up the JC STEM Lab for Energy and Materials Physics (EMP).
The JC STEM lab will focus on developing advanced materials for energy storage and conversion, other transformative technologies, and exploring materials physics. By applying cutting edge techniques, such as synchrotron radiation and neutron scattering, the EMP group aims to deepen the fundamental understanding of the structure-propertyfunctionality relationship in critical materials.
The new lab will embrace Prof. Ren’s philosophy of enhancing student education and talent development by engaging them in innovative research activities. This commitment will extend far beyond advancing the field of energy and materials science, to nurture the next generation of researchers and technology professionals.
The China Spallation Neutron Source (CSNS) and the proposed Southern Advanced Photon Source (SAPS) in Dongguan, about 70 km north of Hong Kong. The CSNS is entering Phase 2 of development with a 5x power upgrade and the construction of 10 more instruments. The proposed SAPS (upper right) is collocated with the CSNS (lower left) to create synergy.
A delegation from the Chinese Academy of Sciences visited the Centre for Neutron Scattering on 27 March 2024.
Inspiring Innovation and Maximising Social Progress
Conferences and workshops are vital for fostering scientific innovation, driving progress, and addressing the complex challenges facing our world. These gatherings provide a platform for scientists, researchers, and experts to share their discoveries and collaborate on cutting-edge solutions.
The goal of CityUHK Physics’ events programme is to create a nexus where diverse stakeholders converge to drive scientific advancements, inspire technological innovation, and maximise societal progress.
For example, scientists gain opportunities to showcase their research, receive critical feedback, and forge collaborations to accelerate the pace of discovery. Government agencies also benefit by staying informed about cutting-edge research, which enables evidence-based policymaking. Investment firms gain insights into emerging technologies and research trends, thus informing strategic investment decisions. And, on the commercial front, private enterprises find avenues for collaboration, innovation, and the recruitment of skilled talent by fostering a symbiotic relationship with the scientific community.
Exploring Quantum Frontiers and Complex Systems at CityUHK
The HK Tech Forum on Quantum Physics and Complex Systems, hosted by the Hong Kong Institute for Advanced Study at CityUHK, brought together leading researchers in quantum computation and related fields. The fifth in the HK Tech Forum series provided a multidisciplinary platform for scientists to discuss complex systems, including spin glasses, neural networks, proteins, and related issues.
PHY Annual Symposium 2023
Provides Platform to Share Research
The PHY Annual Symposium kicked off with a poster presentation showcasing 27 submissions from students across various academic levels. They included 3 Undergraduates (UG Category), 9 MSc Students (MSc Category), and 15 PhD Students (PhD Category).
Designed to be a “Celebration of Physics,” the June event served as a platform for students to share their year-long research findings with peers and faculty, and engage in meaningful face-to-face discussions on their respective topics.
CityUHK Hosts International Biophysics and Soft Matter Workshop
speakers from around the world, the Biophysics and Soft Matter Workshop offered a forum to share recent research findings and explore new directions. The discussions covered a wide range of topics, such as DNA and protein structures, polymer physics, colloids, and much more. The event received acclaim for its success, with participants enjoying scientific discussions and exploring the city’s many exciting attractions.
Exploring the Future of Energy Materials and Scattering Techniques
Backed by the Department of Physics and the Institute for Advanced Study (IAS) at CityUHK, the International Workshop on Energy Materials and Scattering Techniques enjoyed a successful
three-day run. With over 50 participants and 20 speakers from global universities, the workshop aimed to foster knowledge exchange, share recent findings, and explore new directions. Highlighting the university’s commitment to collaboration, it provided a platform for participants to share insights. The wide range of talks covered diverse topics, including battery materials, catalysts, and X-ray/ neutron scattering techniques.
CityUHK Physics Celebrates Successful YGA2023
The 2023 Joint Annual Conference of Physical Societies in the Guangdong-Hong Kong-Macao Greater Bay Area (YGA2023) took place at CityUHK. Attracting over 300 registered participants, YGA2023 proved to be a significant academic platform in the post COVID-19 period. CityUHK Physics played a crucial role in the conference, with faculty members holding key positions on the organising and scientific committees. The event won widespread praise for fostering communication among physicists in the Greater Bay Area.
Promoting Scientific Literacy and Welfare in Local Communities
The outreach and community service endeavours of CityUHK Physics stand as a testament to our commitment to fostering meaningful connections beyond the academic realm. Recognising the pivotal role science plays in society, we actively engage in initiatives that bridge the gap between the fascinating world of physics and the broader community.
Prof. Denver Li Danfeng told 40 Form 5 students at SKH Bishop Baker Secondary School (
Prof. Hoi Io-chun explained “Quantum Technology” to S.3 and S.5 students from Ying Wa College (英華書院
Prof. Sunny Wang Xin delivered popular science talks on “The Exotic Quantum World: Introduction to Quantum Computation” at several secondary schools in Hong Kong and Mainland China.
Prof. Sunny Wang Xin was the Chief Judge for the second “SpinQ Cup” Quantum Computing Challenge Camp.
Prof. Denver Li Danfeng, Prof. Li Xiao, Prof. Dai Liang, and Prof. Sunny Wang Xin served as jurors at the 2023 Hong Kong Young Physicists’ Tournament.
AI Advances Disease Diagnosis
Prof. Condon Lau conducted a workshop, entitled “Artificial Intelligence Powered Image-to-Image Translation for Disease Diagnosis,” as part of the Science in the Public Service (SIPS) 2023 programme held at the Hong Kong Science Museum’s Earth Science Gallery. The workshop introduced “AIstain” – a breakthrough generative AI tool designed for virtual tissue staining. It offers a faster, more affordable, and easier to use alternative to traditional veterinary pathology methods that can significantly enhance cancer diagnostics.
High School Students Visit CityUHK Physics
Some 60 students and teachers from Ying Wa College were invited to visit CityUHK Physics. Professor Bao Wei, the Chair
Professor of the Department, presented a lecture on neutron scattering and its relevance to quantum biology. During their lab visit, the group was impressed by the faculty’s enthusiasm and commitment to the pursuit of new research.
Science Summer Camp 2023
After taking place online for three years during the COVID-19 pandemic, the fifth Science Summer Camp at CityUHK was held face-to-face on campus from July 10 to 15, 2023. Some 52 selected campers from Mainland China, Germany, Russia, Singapore, Vietnam, the UK, and Hong Kong
participated in a diverse range of academic activities and explored Hong Kong’s local culture and heritage. The welcome ceremony emphasised Hong Kong’s strategic location and CityUHK’s international profile, which make it an ideal destination for research education.
CityUHK Physicists Interact with Other Institutes and Agencies
In July 2023, CityUHK Physics hosted a halfday visit from the South China University of Technology (SCUT), aimed at fostering academic exchange. As Head of Department, Prof. Ren Yang offered an overview of CityUHK Physics’ achievements in research and education, and faculty members discussed different research themes, including theoretical and computational physics, atomic, molecular, and optical physics, and quantum materials.
2023 Beijing Tour for Hong Kong Talents
Between September 18 and 22, Prof. Zhang Zhedong and Prof. Zhong Yiming represented City University of Hong Kong at the “2023 Beijing Tour for Hong Kong Talents.” The collaborative effort involved young and talented professors and students from six leading universities in Hong Kong.
(Left) A guided demonstration during the event. (Right) Prof. Lau interacting with workshop participants.
Visiting Professor Wins Nobel Prize
Described by colleagues as “just like a photon,” because he builds bridges between people, Alain Aspect is more than one of CityUHK Physics’ most respected Distinguished Visiting Professors. He is also a winner of the 2022 Nobel Prize for Physics, whose experiments with entangled photons established the violation of Bell inequalities and are pioneering quantum information science.
As a Senior Fellow at Hong Kong Institute for Advanced Studies (HKIAS) at CityUHK, Professor Aspect received an Honorary Doctor of Science from CityUHK in recognition of his significant contribution to education and society. While the breadth and depth of his research is breathtaking, he is also a popular teacher who always finds time to interact with students. On one of his first visits, his short course on Laser Science drew a full house of students and faculty members from Hong Kong and nearby regions in mainland China.
“Having Professor Aspect as a member of the CityUHK Physics community has been a tremendously rewarding experience. We could not be any happier about his recognition as one of the field’s newest Nobel laureates, and look forward to welcoming him back to CityUHK.”
Prof. Ren Yang Head and Chair Professor of Physics at CityUHK Physics
Prof. Aspect (second from right) poses with Prof. Chu Saitak (first from right) and CityUHK students.
The Nobel laureate shares his insights.
A packed audience of students and faculty members.
Department of Physics
City University of Hong Kong
Phone: (852) 3442-7831
Fax: (852) 3442-0538
Email: phy.go@cityu.edu.hk Website: www.cityu.edu.hk/phy
