News & Events

Five talented secondary school students from Hong Kong had outstanding results at the 8th European Physics Olympiad (EuPhO 2024) held in Kutaisi, Georgia from 15-19 July 2024 and hosted by the Kutaisi International University. The Hong Kong EuPhO team members were Hayden Cheng (Baptist Lui Ming Choi Secondary School), Edison Fu (Queen's College), Hui Pok-shing (Queen Elizabeth School), Qiao Lok-hei (St. Paul's Co-educational College), and Yeung Yeung (St. Mark's School). Competing among 256 students from 54 countries and regions, the team members won four gold medals (Cheng, Fu, Qiao, Yeung) and one silver medal (Hui). With these outstanding individual performances, the team ranked 2nd among all the teams at the competition. The team was trained and mentored this year by Prof. Man Fung Cheung, Prof. Yilong Han, and Dr. Ting-Pong Choy of the HKUST Department of Physics, with the support of the Education Bureau and the Hong Kong Academy for Gifted Education.   The HKUST Department of Physics has been providing training to about 90 secondary school students to prepare for various regional (Asian, European, Pan-Pearl River Delta) Physics Olympiad competitions and the global International Physics Olympiad dating back to 2003. The year-long training program offered to these gifted students covers a wide range of topics, from Newtonian mechanics to modern physics, both in theory and experiment. The students who are eventually chosen to represent Hong Kong at competitions earn their selection based on their performance in a series of selection tests and competitions during their training. Participation in Physics Olympiad training and at formal competitions develops students’ potential and serves as a springboard for pursuing interests in physics and many other subjects at top universities and beyond.  Accompanying photo (left to right): Dr. Ting Pong Choy (HKUST), Edison Fu (Queen's College), Yeung Yeung (St. Mark's School), Qiao Lok-hei (St. Paul's Co-educational College), Hui Pok-shing (Queen Elizabeth School), Hayden Cheng (Baptist Lui Ming Choi Secondary School), Prof. Yilong Han (HKUST), Mr. Cheung Shi (Sing Yin Secondary School). Press release:
The Government of the HKSAR press release (Chinese)
The Government of the HKSAR press release (English) Read more

University press release: RGC Fellowship 2024 Read more

Eight talented secondary school students from Hong Kong achieved excellent results at the 24th Asian Physics Olympiad (APhO 2024) held in Malaysia from 3-10 June 2024. The Hong Kong APhO team members were Chan Hoi-chi (Hong Kong Chinese Women's Club College), Edison Fu (Queen's College), Leung Chi-fung (Evangel College), Liu Lincoln (Sha Tin College) Matthew Mui (The Hong Kong Sze Yap Commercial and Industrial Association Wong Tai Shan Memorial College), Marcus Poon (Po Leung Kuk Choi Kai Yau School), Michael Tang (St. Joseph's College), and Yan King-yiu (Queen Elizabeth School). Competing among over 200 students from 27 countries or cities, the team won one gold medal (Liu), three silver medals (Leung, Fu, Yan), two bronze medals (Mui, Tang), and two honourable mentions (Chan, Poon), and was ranked 8th among all teams at the competition. The team was trained and mentored this year by Dr. Ting-Pong Choy, Prof. Adrian Po, and Prof. Jensen Li of the HKUST Department of Physics, with the support of the Education Bureau and the Hong Kong Academy for Gifted Education.   The HKUST Department of Physics has been providing training to about 90 secondary school students to prepare for the Asian Physics Olympiad since 2007 and the International Physics Olympiad since 2003. The year-long training program offered to these gifted students covers a wide range of topics, from Newtonian mechanics to modern physics, both in theory and experiment. The team members that eventually participate in the APhO and IPhO competitions are chosen based on their performance in a series of selection tests and competitions during their training. The Hong Kong teams under the mentorship of the Department faculty were awarded an aggregate of 148 gold, silver and bronze medals in APhO and IPhO competitions up to and including 2024. Participation in Physics Olympics training and competition develops students’ potential and serves as a springboard for pursuing interests in physics and many other subjects at top universities and beyond. Accompanying photo (left to right): Mr Yu Kam Fung (Tak Nga Secondary School), Dr. Ting-Pong Choy (HKUST), Liu Lincoln (Sha Tin College), Matthew Mui (The Hong Kong Sze Yap Commercial and Industrial Association Wong Tai Shan Memorial College), Yan King-yiu (Queen Elizabeth School), Marcus Poon (Po Leung Kuk Choi Kai Yau School), Michael Tang (St. Joseph's College), Chan Hoi Chi (Hong Kong Chinese Women's Club College), Edison Fu (Queen's College), Leung Chi-fung (Evangel College), Prof. Adrian Po (HKUST). News and announcements:
The Government of the HKSAR press release (Chinese)
The Government of the HKSAR press release (English)
The Standard Read more

The structures of biological materials, commonly called “living matter”, such as DNA, proteins, bacterial flagella, and flower petals to name a few, are predominately chiral. However, the origin of the prevalence of one type of handedness over the other in this part of nature  remains a mystery, despite knowledge of its existence for hundreds or thousands of years. When living matter self-propel, they also exhibit handedness, a notable example of which is the tendency of bacteria to swim in a circle near a surface. Therefore, understanding how self-propelling or active chiral living matter self-organize, navigate, and transport in complex environments will help us decipher the mechanisms of living systems. Moreover, identifying and sorting different cells or microorganisms according to their degree of activity and chirality holds great promise for applications such as diagnostics, omics, and drug delivery. However, the interactions between these chiral active matter and their environment are notoriously difficult to examine, which impedes their further study. Prof. Rui Zhang and Prof. Yilong Han and members of their research groups in the HKUST Department of Physics, Chung Wing Chan, Daihui Wu, Kaiyao Qiao, and Kin Long Fong, explored the intriguing behavior exhibited by chiral active matter using a simple platform with the help of Prof. Zhiyu Yang of the same department. Prof. Han  discovered that  Echinochloa crus-galli grass seed has chiral surface ridges that  give rise to  circular or linear motion when it is propelled under the application of external vibrations. Careful studies of the seed particle motion on a vibrating stage performed by Dr. Wu, Mr. Qiao, and Mr. Chan under the guidance of Prof. Han and Prof. Yang revealed that an active Brownian dynamics model can capture the seed dynamics well. Mr. Fong and Mr. Chan developed a simulation model with Prof. Zhang’s guidance, which they used to examine the dynamics of chiral active particles in an obstacle array that mimics the complex environment of the experiment. Similar to opotaxis of active particles or cells that describes the tendency to move to regions with less dense obstacles, chiral active particles can also migrate according to the obstacle density. Surprisingly, it was  found in this work that at certain conditions a particle tends to be trapped in a triangular obstacle lattice but exhibits fast diffusion in a square obstacle lattice with the same obstacle density. Furthermore, this tendency can be reversed by changing the particle chirality. The remarkable ability to differentiate obstacle lattice structure exhibited by chiral particles is not observed for achiral active particles. Interestingly, further studies also revealed that left-handed and right-handed particles exhibit different effective diffusivities in a parallelogram lattice with broken mirror symmetry. Such a difference can be understood by a pure geometric quantity, which was defined to characterize how far a lattice deviates from mirror symmetry. The key simulation findings were confirmed by experiments. This work demonstrates that the chiral motions of active particles can sense lattice configurations. Therefore, the work facilitates applications of active matter in chirality-based separation and therapeutic delivery, and also paves the way toward novel applications such as using chiral active matter as environmental sensors. The work has been recently published in Nature Communications 15, 1406 (2024) and highlighted by the Editor in the “Applied physics and mathematics” section. This work is financially supported by the Research Grants Council via no. 26302320 (R.Z.) and no. 16305822 (Y.H.). This research also highlights research opportunities for outstanding undergraduate (UG) students in the Department of Physics. Mr. Kin Long Fong, who initiated the work, was a student in the elite International Research Enrichment (IRE) undergraduate program at HKUST between 2017 – 2021. He was involved in research projects under Prof. Rui Zhang’s supervision during his final year of UG study and he is now working towards his Ph.D. degree at the Technical University of Berlin. Mr. Chung Wing Chan was the lead author of publication about the work. He initiated the project during his fourth year as a UG student in the Department of Physics and completed the work during his M.Phil. studies in Prof. Zhang’s group. Mr. Chan is now pursuing his Ph.D. degree in the Department of Physics at Kyoto University, where he is focusing on soft condensed matter physics. Read more

Read more

The Department of Physics is proud to welcome its newest faculty member: Assistant Professor Xueyang Song grew up in north China and attended the Asian Physics Olympiad at high school. She got her Bachelor of Science from Peking University, and PhD in physics from Harvard University, under the supervision of Ashvin Vishwanath. Before joining HKUST, she was a Moore postdoctoral fellow at Massachusetts Institute of Technology.  Professor Song is interested in theoretical condensed matter physics, in particular strongly correlated systems where free electron approximation fails. Quantum effects give rise to emergent phenomena there, such as particles with fractional charge and photon-like excitations in solid state systems. The interplay of symmetry, topology and correlations constrains the ground states, dynamics and kinematics of such systems, despite the absence of exact solution on the many-body systems. She studied effective descriptions and physical properties of frustrated magnetic systems, that fail to order at zero temperature. Instead, the magnetic moments conspire to form collective motions that are best captured by fractions of the elementary degrees of freedom and sometimes gauge structures. More recently, she focused on the exotic physics realized in 2d Moire systems, formed by a slight lattice misalignment among multiple atomic-thin layers stacked together. She investigated topological superconductivity and phase transitions relevant to these tunable platforms.  Her research makes extensive use of effective field theory, as well as lattice models, through a combination of analytical and numerical methods. Read more

Congratulations to Prof. Kam Tuen Law for being selected to receive the 2023 Achievement in Asia Award (AAA) Robert T. Poe Prize from the International Organization of Chinese Physicists and Astronomers (OCPA). The AAA is presented annually to a physicist/astronomer (or a team of Physicists/astronomers) of Chinese ethnicity working in Asia who has (have) made outstanding contributions in physics or astronomy. See the School of Science press release for more information. Read more

A groundbreaking study spearheaded by a team from The Hong Kong University of Science and Technology (HKUST) led by Prof. C. T. Chan, in collaboration with a team from Fudan University led by Prof. Jian Zi, has been published in Physical Review X. This study, titled "Imaging with an Ultrathin Reciprocal Lens", introduces a paradigm-shifting imaging mechanism—the "reciprocal lens." This novel lens performs imaging by shifting light rays rather than bending them like conventional lenses. It can directly produce upright real images. This research has potential for wide-ranging applications. Lenses are indispensable in imaging systems. Lenses like those used in optical systems including cameras and microscopes form images by bending light rays entering the lens structure. The rays originating from the object are altered in direction as they pass through the lens. The bent rays converge on a single point on the image plane to reconstruct the object's image. This relies on the lens having varying optical properties and thickness to properly deviate the rays' paths. In recent years, "metalenses" fabricated using micro- and nano- techniques utilize flat nanostructures to control phases and bend rays by imposing phase gradients. However, both conventional and metamaterial lenses share the fundamental mechanism of bending rays (Fig. 1). The reciprocal lens designed and implemented by the research team enables imaging through a different mechanism than bending rays. It controls the lateral shifts of rays based on their incidence angle (Fig. 1). The lens imposes an angle-dependent phase distribution that causes rays entering at different angles to shift laterally by varying amounts after passing through. This engineered angle-dependent ray shifting makes rays originating from a point source converge after exiting the lens, achieving the imaging functionality. The team utilized geometric optics theory to derive the conditions and phase modulation requirements for reciprocal lens imaging. Figure 1: Schematics comparing the mechanisms of the reciprocal lens and conventional/metalenses. For this study, research team members constructed an ultra-thin reciprocal lens operating in the microwave frequency range (28.5 GHz) using standard printed circuit boards (PCB) as shown in Fig. 2a. The lens consists of a core layer featuring a hexagonal lattice of holes and patches, sandwiched by two cladding layers. This structure supports multiple guided resonances that provide the necessary phase modulation effect. The researchers tested the propagation phase through the lens and confirmed it satisfies the phase distribution relationship needed for reciprocal lens imaging.  Experiments showed the 1 mm-thick core layer could produce focal lengths on the order of centimeters, enabling imaging (Fig. 2b). The team also tested imaging using objects of various shapes, demonstrating the reciprocal lens's imaging ability without shape constraints. Figure 2: Imaging of an "F" slit using the PCB-based reciprocal lens shown in (a). The upright real image obtained with the lens shows sharper edges and improved resolution compared to the reference image captured without any lens. The reciprocal lens realized in this study enables imaging without bending light rays, completely subverting the conventional imaging mechanism and providing a new choice for lens and imaging technologies. The reciprocal lens is ultra-thin and alignment-free, uniquely suited for constrained applications. This research outcome has expanded the theoretical foundations of imaging technology and has also opened up new directions for wavefront modulation. Research supported by the Research Grants Council of Hong Kong, Croucher Foundation, National Natural Science Foundation of China, and other agencies. Read more