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

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

With the help of quantum mechanics, digital quantum hardware may be able to tackle some of the problems that are too difficult for ordinary computers. But despite these expectations and the ongoing effort of the research community, reliable quantum computers are not yet realized in a lab setting.

Grenzen van quantum-theorieën verleggen, dat is precies waar de natuurkundigen van de Universiteit Leiden goed in zijn. Leidse onderzoekers starten acht nieuwe quantum-onderzoeksprojecten binnen het consortium Quantum Limits.

This thesis covers various applications of topology in condensed matter physics and quantum information.

Tessa de Wekker van het Leidsch Dagblad interviewde Julia Cramer over quantum computers, quantuminformatie en de maatschappelijke impact die van de toepassingen.

Quantum Information Science & Technology (QIST) encompasses the understanding, design, construction and investigation of quantum information processing systems, such as quantum computers, quantum communication networks, and quantum sensors.

Why do black holes emit thermal radiation? And how does a closed quantum system thermalize?

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…

Quantum annealing belongs to a family of quantum optimization algorithms designed to solve combinatorial optimization problems using programmable quantum hardware. In this thesis, various methods are developed and tested to understand how to formulate combinatorial optimization problems for quantum…

Thermodynamics is one of the founding scientific pillars that has helped us better understand heat engines, biology, ecosystems, and even black holes. While it fundamentally describes large systems by examining the bulk behavior of their constituents, it is anchored in the statistical equivalence of…

Divide & Quantum (D&Q) biedt verschillende oplossingen om de kracht van quantumcomputers op korte termijn te benutten, en stelt volledige pipelines voor, van theoretisch onderzoek, via implementatie tot real-world case studies in verschillende disciplines, tot wetenschapscommunicatie naar een bredere…

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

Quantummechanica voor iedereen

Onderzoeksgroepen in het Quantum Matter & Optics onderzoeksprogramma onderzoeken elektronische eigenschappen van interacties van materie en lichtmaterie, met de nadruk op quantuminformatie.

This thesis addresses questions on effectively using variational quantum circuits for machine learning tasks.

Promotor: Ronald Cramer, Co-promotor: Serge Fehr

Promotor: Prof.dr. D. Bouwmeester

A single self-assembled semiconductor quantum dot in a high-finesse optical microcavity - the subject of this thesis - is an interesting quantum-mechanical system for future quantum applications. For instance, this system allows trapping of an extra electron and thus can serve as a spin quantum memory,…

Optical cavities are useful tools to enhance the interaction between light and matter, which is important to make good quantum emitters. However, it turns out that the cavities themselves (without any quantum emitters) are already interesting objects to study.

Promotor: C. W. J. Beenakker, Co-promotor: J. K. Asboth

Quantum computers are a proposed fundamentally new type of computer. They aim to perform some computations much faster than previously possible by exploiting phenomena at the quantum scale, called superposition and entanglement.

Quantum hardware comes with a different computing paradigm and new ways to tackle applications. Much effort has to be put into understanding how to leverage this technology to give real-world advantages in areas of interest for industries such as combinatorial optimization or machine learning.

Quantum computing is an emerging technology, which holds the potential to simulate complex quantum systems beyond the reach of classical numerical methods.Despite recent formidable advancements in quantum hardware, constructing a quantum computer capable of performing useful calculations remains challenging.In…

Promotor: R. Gill, Co-promotor: P. Massart

The aim of this thesis is to present novel techniques for proving cryptographic schemes secure against quantum adversaries. Most results are within the context of an idealized model called the ‘quantum random-oracle model’.

Hoogwaardige technologische innovatie voor bedrijfsleven en consumenten dankzij toponderzoek naar het heelal en de quantumwereld.

Kiemproject: Hoe kunnen metaforen bijdragen aan betere maatschappelijke betrokkenheid bij quantumwetenschap en -technologie, en welke factoren beïnvloeden de acceptatie of weerstand tegen metaforen bij zowel experts als leken?

This thesis advances automata learning, a key area in computer science, with applications in software verification, biological analysis, and autonomous technologies. It explores three main themes: first, it introduces a passive learning algorithm for generating compact probabilistic models from positive…

This thesis investigates how quantum, quantum-inspired, and hybrid quantum-classical computation can enhance key points of the automated machine learning (AutoML) pipeline under the constraints of noisy intermediate-scale quantum (NISQ) devices.

Hoe quantum-ready ben jij? Want geloof het of niet, ook jouw toekomst is quantum. Nieuwe quantum-technologieën gaan onze samenleving meer beïnvloeden dan we ons nu realiseren. Hoe precies? Op deze pagina ontdek je meer over quantum.

Wat weet het grote publiek over quantum en wat vindt men ervan? Ook daar denken onderzoekers binnen Quantum Leiden over na.

Bedrijven met wie Quantum Leiden samenwerkt: Shell, TotalEnergies, Google, Volkswagen en Qu&Co. En met de volgende overheden en publieke organisaties: CERN, ESA, SURF, Gemeente Leiden, Provincie Zuid-Holland, Quantum Delta NL en InnovationQuarter.

De organisatie van het onderzoek binnen Quantum Leiden is in handen van onderstaande onderzoekers.

Wie zijn de mensen achter Quantum Leiden? Dat zijn natuurlijk de bevlogen en enthousiaste onderzoekers die nu keihard bezig zijn met onze quantumtoekomst. Maar vergeet ook niet hun voorgangers. En daarbij zitten onderzoekers van wereldfaam.

During my PhD research, I studied the photon statistics of light emitted by a microcavity that contains a single quantum dot (QD) on resonance.

Quantum, machine learning, AI en qubits. Quantum Leiden bundelt onderzoek en onderwijs van Universiteit Leiden naar supercomputers of quantumcomputers

In my research, we developed a method to distinguish knots. A knot is a mathematical depiction of the everyday knot that occurs in ropes and cords.

Promotor: Prof.dr. C.W.J. Beenakker

Leiden is sterk in het ontwikkelen van algoritmen. Verder zijn quantumnetwerken en quantumsensing belangrijke onderzoeksthema's. Als ook onderwijs en communicatie over quantum.

Natuurkundige Julia Cramer krijgt 50 duizend euro financiering voor 'Let's talk about quantum', een onderzoek naar communicatie over quantumcomputers. Een project met scholieren van onderwijs-expert Henk Buisman valt onder dezelfde NWA ELSA-toekenning.

Promotor: Prof.dr. C.W.J. Beenakker

Promotor: Prof.dr.ir. J.W.M. Hilgenkamp, Prof.dr. J. van den Brink

In this dissertation, we work towards an experiment in which we aim to bring a micrometer sized magnet at the tip of a soft cantilever into a superposition.

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

Ice, the solid state of water, plays an important role on our planet as well as the entire universe.Despite the fact that an individual water molecule has a very simple structure, its chemical bonding in the solid phase can be surprisingly complex.