Recently, the research team of Southern University of Science and Technology has successively published articles in Nature and Science, 1 each in physics, environment, chemistry and biology.
Nature
On March 22, Yu Dapeng, Xu Yuan, Zheng Shibiao of Fuzhou University and Luyan Sun of Tsinghua University jointly published a research paper entitled "Beating the break-even point with a discrete-variable-encoded logical qubit" in Nature Online, which demonstrated the QEC process in a circuit quantum electrodynamic architecture. Among them, the logic qubits are encoded in the photon number state of the microwave cavity, and the dispersion is coupled to the auxiliary superconducting qubits.
Paper Link:
https://www.nature.com/articles/s41586-023-05784-4
One of the main hurdles to building quantum computers is environment-induced decoherence, which destroys quantum information stored in qubits. Errors caused by decoherence can be corrected by repeatedly applying a quantum error correction (QEC) program in which logical qubits are encoded in a high-dimensional Hilbert space so that different errors project the system into different orthogonal subspaces and can therefore be unambiguously identified and corrected without disturbing the stored quantum information. In a traditional QEC scheme, the codeword of a logical qubit consists of two highly symmetrical entangled states of several physical qubits encoded with some discrete variable.
Over the past two decades, experimental demonstrations of this QEC code in different systems have made significant progress, including nuclear spin, nitrogen vacancy centers in diamonds, trapped ions, photonic qubits, silicon spin qubits, and superconducting circuits. However, in these experiments, the lifetime of the logic qubits needs to be greatly extended to reach the lifetime of the best physical component available, which is seen as a break-even point for judging whether the QEC code is beneficial for quantum information storage and processing.
Schematic diagram of the QEC process with lowest-order binomial coded logic qubits (Figure from Nature)
Another QEC coding scheme is to utilize the large space of the oscillator, which can be used to encode continuous or discrete variable qubits. Both types of code can tolerate errors due to the loss and gain of energy quanta, allowing QEC to execute in a hardware-efficient manner. Circuit quantum electrodynamics (QED) systems represent an ideal platform for implementing this coding scheme: by distributing quantum information over the infinite-dimensional Hilbert space of a continuous variable-encoded photonic qubit, the deposit-even point has been exceeded in two breakthrough experiments, but the codeword of this photonic qubit is not strictly orthogonal.
This inherent limitation can be overcome with discrete variable coding schemes, where the codewords of logical qubits are encoded with the mutually orthogonal Fokker states of the oscillator. This property, combined with their intrinsic compatibility with error correction and their usefulness in logically connecting modules in quantum networks, makes such discrete variable qubits promising in fault-tolerant quantum computing. These advantages can only be translated into practical benefits in true quantum information processing when the lifetime of the encoded logical qubit exceeds the break-even point, however, this is still a difficult outcome to achieve, despite the sustained efforts that have been made to achieve it.
Frequency comb control measurement error symptoms (Figure from Nature)
This study demonstrates that a discrete variable photonic qubit in a microwave cavity corrects for exceeding the QEC break-even point by real-time feedback, and its codewords remain orthogonal to each other and can be clearly distinguished. The main error of the logical qubit, single-photon loss, is mapped to the state of a nonlinear oscillator based on a Josephson junction that dispersively couples to the cavity and acts as an auxiliary qubit, implemented by a continuous pulse involving a cleverly customized frequency component comb.
Perturbations on the logical qubits are highly suppressed in the encoded logical space when the driving frequency points to the error space where photon loss events occur. Another inherent advantage of this false symptom detection is that the continuous drive protects the system from the phase-out noise of the auxiliary qubits. The researchers demonstrated this process with the lowest-order binomial code and extended the lifetime of stored quantum information by 16 percent, 16 percent longer than the best physical qubits, encoded in the two lowest Fock states, known as Fock qubits. A more important feature associated with this error detection process is that there is no need for explicit parity in either the logical space or the error space, which allows the implementation of QEC code to tolerate the loss of multiple photons.
Nature
On March 20, the team of Professor Liu Xinyuan of Southern University of Science and Technology published a research paper entitled Enantioconvergent Cu-catalyzed N-alkylation of aliphatic amines online in Nature, which reported the chemical selectivity and enantioconvergence of aliphatic amines and α-oxylalkyl chlorides catalyzed by copper-catalyzed N-alkylation using chiral tricarboxylic acid anionic ligands.
Paper Link:
https://www.nature.com/articles/s41586-023-05950-8
The researchers observed excellent enantioselectivity and functional group tolerance. This method directly converts raw material chemicals, including ammonia and pharmaceutical-related amines, into unnatural chiral α-aminoamides under mild, stable conditions. It has good enantioselectivity and functional group tolerance. The ability of this method has been demonstrated in many complex settings, including late functionalization and accelerated synthesis of different amine drug molecules. Current methods suggest that "polydental" anionic ligands are a general solution to overcome transition metal catalyst poisoning.
Liu Xinyuan, the corresponding author of this paper, is a chair professor of Southern University of Science and Technology, a recipient of the National Natural Science Outstanding Youth Fund, a winner of the National Natural Science Outstanding Youth Fund, and a distinguished professor (youth) of the Ministry of Education. Since the independent work of SUSTech, Liu Xinyuan's team has carried out in-depth and systematic research on the scientific problem of "asymmetric radical catalytic chemistry", proposed a unique new strategy of "chiral anion-metal single-electron catalyst", developed an asymmetric radical catalytic reaction with the participation of simple chemical raw materials, solved the problem of chiral control of highly active radicals, and expanded its application demonstration research in the efficient utilization of resource molecules and chiral drug synthesis.
The Department of Chemistry of Southern University of Science and Technology, where Professor Liu Xinyuan of Southern University of Science and Technology works, has independently undertaken more than 400 national and local scientific research projects, including 150 projects of the National Natural Science Foundation of China, with a total competitive scientific research fund of more than 440 million yuan. The full-time teachers of the Department of Chemistry have published more than 1500 SCI papers as the first or corresponding author with SUSTech as the supporting unit, including more than 370 papers in journals with an impact factor of more than 10 such as top journals in chemistry, and some of the research results have been recommended or highlighted by Nature, Angewandte Chemie International Edition and other journals.
Science
On March 9, Professor Du Jiamu's research group of the School of Life Sciences of Southern University of Science and Technology further conducted research on the unique properties of Pol V downstream of RdDM and made a major breakthrough, and the relevant research results were published online in Science with the title "Structure and mechanism of the plant RNA polymerase V".
Xie Guohui, a doctoral student in the School of Life Sciences of SUSTech, Du Xuan, a senior research scholar, and Hu Hongmiao, a visiting scholar, were co-first authors of the paper, SUSTech was the first unit of the paper, and Du Jiamu was the corresponding author of the paper, Steven E. Jacobsen, an academician of UCLA, Cao Xiaofeng, an academician of the Institute of Genetics and Development, Chinese Academy of Sciences, and Li Sisi, a professor of Shenzhen University, participated in the project.
Paper Link:
https://www.science.org/doi/10.1126/science.adf8231
In general, this work analyzes the functional mechanism of the last eukaryotic RNA polymerase, Pol V, which is structurally unknown, and proposes a working model for recruiting downstream agents to cause DNA methylation and gene silencing by retention on chromatin. This work was supported by Shenzhen Science and Technology Innovation Commission, China Postdoctoral Foundation, National Natural Science Foundation of China and Chinese Academy of Sciences, and cryo-EM data acquisition and mass spectrometry experiments were supported by the Cryo-EM Center and the Analysis and Testing Center of Southern University of Science and Technology, respectively.
Nature
On March 1, the team of Feng Lian, associate professor of the School of Environmental Science and Engineering of Southern University of Science and Technology, made up for the current cognitive shortcomings of the current trend of algal blooms in the global coastal zone by using the observation advantages of long-time, periodicity and large-scale observation of satellite remote sensing. The team's research revealed the overall increase trend of algal blooms in the global coastal zone from 2003 to 2020, and quantified the potential relationship between the frequency of algal blooms and sea surface temperature, marine mesoscale circulation, and human activities such as agricultural fertilizer application and aquaculture, and its findings were based on "Coastal phytoplankton blooms expand and intensify in the 21st century" The title was published in Nature magazine and was selected as the cover article of the current issue.
Nature magazine cover
The research team constructed an automatic classification algorithm for algal blooms based on chlorophyll fluorescence and CIE color space, and used 760,000 sun-scale MODIS satellite remote sensing data from 2003 to 2020 to achieve consistent dynamic monitoring of algal blooms in coastal zones around the world. The results showed that coastal algal blooms were frequent in the eastern ocean current region, the northeastern coast of the United States, the coast of Latin America, the Baltic Sea, the northern Black Sea, and the Arabian Sea. Of the 153 coastal countries covered, 126 had outbreaks of algal blooms in coastal zones.
Distribution map of phytoplankton algal blooms in the global coastal zone during 2003~2020. a: Spatial distribution map of the global average annual algal bloom occurrence based on MODISAqua remote sensing day-scale observation data; b: statistical results based on the occurrence of algal blooms globally and continentally (SA: South America, AF: Africa, EU: Europe, NA: North America, AS: Asia, AU: Australia); c: Multi-year average statistical results of the area affected by algal blooms on all continents. Among them, the percentage figure indicates the proportion of algal blooms in the world by continent.
Between 2003 and 2020, the global impact area and frequency of coastal algal blooms increased by 13.2% and 59.2%, respectively.
Trends in phytoplankton blooms in coastal zones around the world between 2003 and 2020. a: Spatial distribution of the frequency trend of algal blooms at the global 1°×1° grid scale; b: Interannual changes and trends in algal bloom frequency and total global algal bloom area.
The article also analyzes the potential causes affecting the formation of algal blooms from a quantitative point of view:
- Changes in ocean temperature and circulation alter ocean stratification and nutrient transport, which in turn affects phytoplankton growth and algal bloom formation.
- Global extreme weather also has a certain impact on global coastal algal blooms.
- Changes in nutrient salts caused by such activities may also be a factor influencing the trend of algal blooms in coastal zones.
SUSTech is a new type of public research university established by Shenzhen with a high starting point and high positioning under the background of China's higher education reform and development. On February 14, 2022, the Ministry of Education and other three ministries and commissions announced the second round of the list of "Double First-class" construction universities and construction disciplines, and Southern University of Science and Technology and mathematics were selected into the list of "Double First-class" construction universities and construction disciplines.
Southern University of Science and Technology draws on the discipline setting and school-running mode of world-class science and engineering universities, focuses on science, engineering and medicine, and carries out research in a series of new discipline directions, making the school a think tank leading social development and a source of new knowledge and new technologies.