The Computer Systems, Imagery & media (CSI) research programme performs research on methods and techniques for the design, implementation and application of advanced computer systems, in particular parallel, distributed and embedded computer systems.

In this thesis, Quantum computing, norms, and polynomials, we investigate the interplay between quantum mechanics, complexity theory, and functional analysis, three central areas of physics, computer science, and mathematics, respectively.

We see computer programming as an essential skill. It enables you to be self-sufficient in building tools, processing data, visualizing research output, communicating research results, etc. Moreover, it empowers you to make beautiful things.

Research in the natural computing group covers theoretical foundations, the development of new algorithms, and interdisciplinary applications of natural computing methods.

Computational linguistics uses computational methods to help answer linguistics questions across a variety of topics.

In this theme you will be supplied with a firm background in the core of current computational linguistics and a solid comprehension of its neighboring fields.

Computational thinking, programming, and algorithms form the basic of many of the things that are shaping our world, the way we work, interact, organize ourselves, and even spend our free time with social networks, streaming media, and games. And this transformation is far from being complete, it is…

This dissertation focused on computational methods based on first principles calculations using the Density Functional Theory (DFT) framework. Emphasis was laid on affordable methods that can provide a tradeoff between computational expense and accuracy.

Are you thinking about studying Computer Science? Learn more and watch the videos. Note: As of September 2025 you can also combine this master programme with the Business Studies specialisation.

Promotor: Prof.dr. S. Haring

This thesis covers several aspects of quantum algorithms for near-term quantum computers and its applications to quantum chemistry and material science.

In this work we describe three methods to improve the performance of Quantum Field Theory calculations.

Projects within the theme ‘Computational Biology’ aim to employ mathematical or computational dynamical modelling approaches to discover novel concepts that are important for drug development.

PhD candidates carry out a programme of independent research and additional (limited) course work, culminating in production of a PhD thesis in typically 4 years.

This thesis probes under what conditions quantum computing presents an advantage over classical computing.

Beowulf clusters looking for new frontiers.

The two-year master’s programme in Computer Science at Leiden University offers seven specialisations ranging from AI to Bioinformatics and Data Science. The programme combines excellent theoretical teaching with possibilities for applied work with industrial relevance.

The master's specialisation Bioinformatics at Leiden University focuses on research, development and application of computational tools and approaches for expanding the use of biological, medical, behavioral and health data.

We investigate reaction systems, a novel computational model gleaned from the biochemical reactions taking place in living cells and information processing in nature.

A high performance computer or supercomputer owes its massive processing capacity to the fact that it chops a single overarching task into a whole series of smaller tasks. It simultaneously tackles each of those smaller problems.

We are becoming ever more dependent on automation systems in our daily lives. Computer Science is more than programming; you integrate maths and logic into the development of systems and solutions that can be applied in all fields - from business to healthcare.

Promotor: S.J. Edixhoven, L.D.J. Taelman

Natural Computing investigates algorithms and phenonema based on nature to create better and new computer science innovations.

Met de bachelorspecialisatie Informatica & Economie aan de Universiteit Leiden leer je waardevolle inzichten in de economie te combineren met (programmeer)vaardigheden en kennis uit de informatica.

Research in the Natural Computing and Optimization cluster covers theoretical foundations, the development of new algorithms, and interdisciplinary applications of natural computing methods.

The Computer Support group provides dedicated support for the computing infrastructure of Leiden Observatory

Research in this group, headed by Gerard van Westen, focusses on computational methods integrated in different parts of the drug discovery process. More specifically, topics include innovative treatments for cancer, selectivity modeling, translational research, allosteric modulation, drug resistance…

The master's specialisation Bioinformatics at Leiden University focuses on research, development and application of computational tools and approaches for expanding the use of biological, medical, behavioral and health data.

The master’s specialisation Computer Science and Education at Leiden University prepares students to teach the subject of biology to secondary school students. The programme comprises a one-year Computer Science component, followed by an education component in the second year.

The master's specialisation Data Science: Computer Science at Leiden University provides students thorough knowledge and understanding of statistical and computational aspects of data analysis, including their application in databases, advances in data mining, networks, pattern recognition, and deep…

High Performance Computing (HPC) is becoming ever more important as a research tool in many research areas across all research domains. A University facility, providing serious computational capabilities, combined with easy and flexible local access, is a strong advantage for these research areas. It…

This dissertation investigates Extended Lexical Units (ELUs), elements that are bigger than just one word and which are stored in the Lexicon.

Quantum computing represents a fundamentally new computational paradigm, capable of addressing problems that are intractable for classical computers.

Large-scale computing infrastructure, such as supercomputers, cluster, and clouds, are already pervasive, most members of our society interact with them daily: social networks, government services, media streaming services--all systems heavily interfacing with the members of our society--are powered…

This thesis investigates the contribution of quantum computers to machine learning, a field called Quantum Machine Learning. Quantum Machine Learning promises innovative perspectives and methods for solving complex problems in machine learning, leveraging the unique capabilities of quantum computers…

Leiden Institute of Advanced Computer Science (LIACS)

Promotor: Roeland M.H. Merks

This thesis is a collection of theoretical works aiming at adjusting quantum algorithms to the hardware of quantum computers.

Sewer pipes are an essential infrastructure in modern society and their proper operation is important for public health. To keep sewer pipes operational as much as possible, periodical inspections for defects are performed.

In the master’s specialisation Computer Science and Business Studies, you combine high quality research in Computer Science with training in management and entrepreneurship. You will expand your knowledge of computer science and develop business and organisational skills that are essential to become…

The master’s specialisation Computer Science and Science Communication and Society at Leiden University bridges the gap between experts and the public by combining high quality research in computer science with extensive training in science communication.

Epithelial-mesenchymal plasticity (EMP) and tumor cell migration play an important role in cancer progression, and an improved understanding of the mechanisms underlying these concepts is essential for developing new targeted approaches.

The NEASQC project brings together academic experts and industrial end-users to investigate and develop a new breed of Quantum-enabled applications that can take advantage of NISQ (Noise Intermediate-Scale Quantum) systems in the near future. NEASQC is use-case driven, addressing practical problems…

The first book ever on information-theoretically secure multiparty computation

An algorithm is discussed to compute the exponential representation of principal units in a finite extension field F of the p-adic rationals.