A paper co-authored by Matthias C. Caro has been featured on the cover of PRX Quantum. PRX Quantum is a premier journal for quantum information science and technology research. The work was a collaboration with Haimeng Zhao (Caltech & Tsinghua), Laura Lewis (Caltech & Google), Ishaan Kannan (Caltech), Yihui Quek (Harvard & MIT) and Hsin-Yuan Huang (Caltech, Google & MIT).

Characterizing a quantum system by learning its state or unitary evolution is a key tool in developing quantum devices, with applications in practical quantum machine learning, benchmarking, and error mitigation. However, in general, this task requires exponentially many resources. Prior knowledge is required to circumvent this exponential bottleneck. The paper pinpoints the complexity for learning states and unitaries that can be implemented by quantum circuits with a bounded number of gates, a broad setting that is topical for current quantum technologies. When measuring efficiency with respect to the number of accesses to the unknown quantum state or unitary, the paper presents and implements algorithms that are provably optimally efficient. Thereby, this work establishes the equivalence between the complexity of learning quantum states or unitaries and the complexity of creating them. However, it also shows that the data processing necessarily requires exponential computation time under reasonable cryptographic assumptions.

We are happy to announce that an academic from our department, Dr Sayan Bhattacharya, is among the winners of ERC Consolidator Grants 2024. According to the European Research Council: "These grants, totalling €678 million, aim to support outstanding scientists and scholars as they establish their independent research teams and develop their most promising scientific ideas. The funding is provided through the EU's Horizon Europe programme."

Sayan Bhattacharya has been awarded a €2million ERC Consolidator grant for a 5-year project entitled "Towards a Dynamic Algorithms Centric Theory of Linear Programming" (DYNALP). The project aims to build a new theory exploring the interplay between two key concepts, Linear Programming and Dynamic Algorithms, which, in turn, will pave the way towards attacking outstanding open questions in the field of Theoretical Computer Science.

In the 2024 round, this was the only project from the United Kingdom that was awarded an ERC Consolidator Grant in Computer Science and Informatics (PE6 panel). The press release contains more information about the ERC funding programme.

We are delighted to announce that Martin Costa, a PhD student at the Theory and Foundations research division, has received a highly competitive Google PhD Fellowship for his work on designing clustering algorithms for dynamic datasets. The Fellowship comes in the form of an unrestricted gift from Google, of 60,000 USD per year, for up to two years. Under the category of "Algorithms and Theory", besides Martin only two other PhD students in Europe (from University of Cambridge and ETH Zurich) received a Google PhD Fellowship this year. Many congratulations to Martin for this achievement!