Leader of the group Algorithms and Complexity: Harry Buhrman.

Our research group designs software for the computing technology of the future, especially quantum computing. Based on the laws of quantum mechanics, which tell us that systems and particles can be in multiple states at once, quantum computing is radically different from computing as we know it. Our quantum software requires fundamentally different techniques and approaches based on superposition, interference and entanglement. Ultimately, our research will result in better, faster and more reliable computer systems for society. Our research group is involved in QuSoft, the new Dutch research centre for quantum software.




Postdoc / Postdoctoral Researcher on the subject of the computer-science aspects of quantum computing and quantum information theory

This position involves research into the computer-science aspects of quantum computing and quantum information theory, in close cooperation with Prof. Ronald de Wolf. Specifically, the project will focus on the development of new quantum algorithms and the analysis of their complexity, development of new quantum communication protocols and the role entanglement plays in such protocols, and applications of quantum techniques to problems in classical computer science and mathematics.

Postdoc / Postdoctoral Researcher on the subject of the computer-science aspects of quantum computing and quantum information theory - Read More…



‘Paradiso lecture’ Harry Buhrman and Yfke Dulek

  • 2017-06-18T11:00:00+02:00
  • 2017-06-18T13:00:00+02:00
June 18 Sunday

Start: 2017-06-18 11:00:00+02:00 End: 2017-06-18 13:00:00+02:00

Paradiso, Weteringschans 6, 1017 SG Amsterdam

On 18 June, Harry Buhrman and Yfke Dulek will give a ‘Paradiso lecture’. These lectures, which take place in music venue and cultural centre Paradiso in Amsterdam, are intended for a broad audience. Harry Buhrman is leader of the Algorithms and Complexity group, director of QuSoft and professor at the University of Amsterdam. Yfke Dulek is a PhD student in the A&C research group. Their lecture is about artificial intelligence and quantum computers. Buhrman and Dulek will address the question: will computers take over in the future?

Please note that the Paradiso lectures are in Dutch.

PhD Defence Florian Speelman (A&C)

  • 2016-11-16T11:00:00+01:00
  • 2016-11-16T13:30:00+01:00
November 16 Wednesday

Start: 2016-11-16 11:00:00+01:00 End: 2016-11-16 13:30:00+01:00

Agnietenkapel, Oudezijds Voorburgwal 231, Amsterdam

Everyone is invited to attend the public defence of Florian of his thesis "Position-based
Quantum Cryptography and Catalytic Computation".

Promotor: Prof.dr. Harry Buhrman

PhD Defence Teresa Piovesan (N&O/A&C)

  • 2016-10-27T08:00:00+02:00
  • 2016-10-27T11:00:00+02:00
October 27 Thursday

Start: 2016-10-27 08:00:00+02:00 End: 2016-10-27 11:00:00+02:00

Agnietenkapel, Oudezijds Voorburgwal 231, Amsterdam

Everyone is welcome to attend the public defence of Teresa Piovesan, of her thesis "Quantum entanglement: insights via graph parameters and conic optimization"

Promotors:  Prof.dr. Harry Buhrman and Prof.dr. Monique Laurent

More information: see the news item 'Quantum entanglement can make some communications more efficient'.

CWI Lectures on Quantum Computing

  • 2015-12-03T08:45:00+01:00
  • 2015-12-03T17:00:00+01:00
December 3 Thursday

Start: 2015-12-03 08:45:00+01:00 End: 2015-12-03 17:00:00+01:00



ATTENTION: Registration is closed

We cordially invite you to attend the 'CWI Lectures on Quantum Computing' on 3 December 2015 at Centrum Wiskunde & Informatica in Amsterdam. This day is dedicated to the launch of the QuSoft research centre for quantum software. Several internationally renowned speakers will bring you up to date on the exciting topic of quantum computing. The symposium is aimed towards a general academic public.

QuSoft is an initiative of Centrum Wiskunde & Informatica (CWI), the University of Amsterdam (UvA) and the VU University Amsterdam. It will focus on developing software and finding applications that exploit the extraordinary power of quantum computers. The new centre will be headed by Harry Buhrman, Algorithms and Complexity Group Leader at CWI and Professor of Computer Science at UvA, and Kareljan Schoutens, Professor of Theoretical Physics at UvA.

Keynote speakers:
- Prof. Gilles Brassard (Université de Montréal)
- Prof. Ronald Hanson (Delft University of Technology)
- Prof. Richard Jozsa (University of Cambridge)
- Prof. Serge Massar (Université Libre de Bruxelles)
- Prof. Mario Szegedy (Rutgers University)

Quantum Show 'Wereld in trilling'
by Huub Rutjes and Yuri van Nieuwkerk (Dutch)


09.45 - 10.15    Doors open & Coffee

10.15 - 10.30    Welcome and introduction
10.30 - 11.15    Keynote Ronald Hanson: From a loophole-free Bell test to a quantum Internet
11.15 - 12.00    Keynote Serge Massar: Certified Quantum Randomness

12.00 - 13.00    Lunch break

13.00 - 13.45    Keynote Gilles Brassard: Cryptography in a Quantum World
13.45 - 14.30    QuSoft launch

14.30 - 15.00    Champagne break

15.00 - 15.45    Keynote Mario Szegedy: The Area Law and The Nature of Quantum Entanglement
15.45 - 16.30    Keynote Richard Jozsa: Complexity in Computation and in Physics
16.30 - 16.45    Wrap-up

16.45 - 18.00    Reception


Due to high demand, the registration has been closed.


For further information and questions concerning the CWI Lectures, contact Susanne van Dam (
More information on QuSoft can be found at




Ronald Hanson
QuTech, Delft University of Technology
Title: From a loophole-free Bell test to a quantum Internet

In fall 2014 the Dutch government elected the new Delft institute QuTech as one of 4 National Icon projects. After a brief introduction to the institute and its mission, I will present our work towards the realization of a highly connected network of quantum bit registers for quantum information processing and long-distance quantum communication. Diamond spins associated with NV centers are promising building blocks for such a network as they combine a coherent optical interface (similar to that of trapped atomic qubits) [1] with a local register of robust and well-controlled nuclear spin qubits [2]. We can now exploit these features simultaneously to achieve new functionalities such as unconditional remote quantum teleportation [3].
Here we present our latest progress towards scalable quantum networks, including the first loophole-free violation of Bell’s inequalities [4]. I will discuss how the techniques developed in these experiments may enable the realization of a network of quantum bit registers for quantum computation and communication. In the long run, such networks may lead to a quantum Internet secured through device-independent protocols – reaching the ultimate physical limits of privacy [5].

[1] H. Bernien et al., Nature 497, 86 (2013).
[2] T. H. Taminiau et al., Nature Nanotechnology 9, 171 (2014).
[3] W. Pfaff et al., Science 345, 532 (2014).
[4] B. Hensen et al., Nature 526, 682 (2015).
[5] A. Ekert and R. Renner, Nature 507, 443 (2014).


Serge Massar
Title: Certified Quantum Randomness

Abstract: Randomness is a phenomena which we are confronted with all the time. Will it rain today? Will the train be on time? What present will I receive at Christmas? But are such phenomena truly random? Good randomness is essential for many applications. For instance, cryptography, the art of hiding information from malicious parties, is only as good as the source of randomness that underlies it. Quantum mechanics, the theory of microscopic phenomena, can only predict the probability of events. For instance quantum theory can only predict the probability that a radioactive nucleus will decay, not when the nucleus will decay. Does this mean that microscopic phenomena are truly random?
By studying systems of two entangled particles, it can be shown both theoretically and experimentally, that events at the microscopic scale are truly random, truly unpredictable. Beyond its philosophical implications, this result also has important potential applications. Indeed it implies that one can build random number generators that certify that they work correctly. That is, if the random number generator malfunctions in some way, if the numbers it produces cease to be random, this will automatically be detected. By extending this idea, one could also build quantum cryptographic systems and quantum computers that certify that they work correctly. We discuss the perspectives for practical implementations.

Gilles Brassard
Title: Cryptography in a Quantum World

Abstract: Although practised as an art and science for ages, cryptography had to wait until the mid-twentieth century before Claude Shannon gave it a strong mathematical foundation. However, Shannon's approach was rooted is his own information theory, itself inspired by the classical physics of Newton and Einstein. When quantum physics is taken into account, new vistas open up both for codemakers and codebreakers. Is this blessing or a curse for the protection of privacy? As we shall see, the jury is still out! No prior knowledge in cryptography or quantum physics will be assumed.
Reference: arXiv:1510.04256 [quant-ph] .

Mario Szegedy
Title: The Area Law and The Nature of Quantum Entanglement

Abstract: Unlike classical states, quantum states cannot be given qubit by qubit. When one gives a state on sub-systems A and B, one may miss a great deal of information about the state on the entire (A,B). The missing information can be measured in various ways. Of particular interest for physicists, chemists and engineers are ground states of many-particle systems. What can be said about the missing information when we know the state in question only on smaller sub-systems? The Area Law is a sweeping conjecture that upper bounds the missing information. We explain what the conjecture states, how it may or may not be helpful for computing the state on the whole system and give a glimpse into the remarkable attempts for proving it.

Richard Jozsa
DAMTP, University of Cambridge UK.
Title: Complexity in Computation and in Physics

We will begin with an introductory overview of quantum mechanical features, and their prospective significance for computation and complexity. Then we will discuss the question of the relation of NP to quantum computing and its possible significance for fundamental physics. Finally we will describe some recent results on the classical simulation of quantum computations, which suggest that the relationship between classical and quantum computing power is surprisingly rich and in fact so far, little understood.

Last updated: 1 December 2015

Robin Adams (Radboud University)
Carmina Almudever (TU Delft)
Martine Anholt (CWI)
Claudiu Antonovici (CWI)
Harold Aptroot (UvA)
Srinivasan Arunachalam (CWI)
Jasmijn Baaijens (CWI)
Jos Baeten (CWI)
Tom Bannink (CWI)
Debarati Bhaumik (CWI / FOM)
Marcel Beemster (Solid Sands)
Alexander Belov (CWI)
Kees van Berkel (TU Delft)
Nikolaos Bezirgiannis (CWI)
Daniëlle Bijl (University of Amsterdam)
Krzysztof Bisewski (CWI)
Joke Blom (CWI)
Jan de Boer (IoP)
Marcello Bonsangue (LIACS -Leiden University)
Joost Bosman (ING)
Jordy Bottelier (UvA)
Nicandro Bovenzi (Leiden University)
Susan Branchett (Netherlands eScience Center)
Dick Broekhuis (CWI)
Benjamin Bruhn (WZI / IoP / UvA)
Harry Buhrman Sr (retired)
Sabine Burgdorf (CWI)
Jan-Willem Buurlage (Utrecht University)
Pablo César (CWI)
Mandar Chandorkar (CWI)
Kenta Cho (Radboud University)
Alessio Ciamei (University of Amsterdam)
Tyler Cools (UvA)
Tim Coopmans (ILLC)
Philippe Corboz (UvA)
Daan Crommelin (CWI)

Benjamin Daiber (FOM Institute AMOLF)
Susanne van Dam (CWI)
André Deutz (Universiteit Leiden)
Bob Diertens (Universiteit van Amsterdam FNWI/IvI)
Maarten Dijkema (CWI)
Michail Dorgiakis (AIMMS B.V.)
Yfke Dulek (ILLC)
Derek Duncan (Lighthouse Instruments)
Ute Ebert (CWI)
Thomas Edwards (University of Amsterdam)
Lucas Ellerbroek (BCG)
Tim van Elsloo (University of Amsterdam)
Peter van Emde Boas (ILLC-FNWI-UvA - retired)
Serge Fehr (CWI)
Qian Feng (CWI)
Wan Fokkink (VU)
Malvin Gattinger (ILLC UvA)
Daniel Gebler (VU University Amsterdam)
Irene Giacomelli (Aarhus University)
Krasimir Georgiev (UvA-ILLC)
András Gilyén (CWI)
Kristina Gogoladze (ILLC)
Mark Golden (UvA-IoP)
Jeannette de Graaf (Universiteit Leiden)
Clemens Grelck (University of Amsterdam)
Sander Gribling (CWI)
Daniel Groen (University of Amsterdam)
Anton Groot (Qubits)
Peter Grünwald (CWI / Leiden University)
Peter van der Gulik (CWI)
Lynda Hardman (CWI)
Rianne de Heide (CWI)
Martijn Heijstek (UvA)
Erik van Heumen (WZI/UVA)
Michiel van den Hout (FOM)
Asparuh Hristov (CWI)
Jimmy Hutasoit (Lorentz Institute, Leiden University)
Irfan Ilgin (UvA)
Vincent Jacobs (De Breed & Partners)
Mahdi Jaghouri (AMC / CWI)
Stacey Jeffery (IQIM, Caltech)
Niek Kabel (UvA)
Laurens Kabir (University of Amsterdam)
Evangelos Kanoulas (University of Amsterdam)
Lucie Kattenbroek (Universitet Utrecht)
Rutger Katz (Capgemini)
Annette Kik (CWI)
Sandor Kisfaludi-Bak (TU/e)
Aleks Kissinger (Radboud University)
Pieter Kleer (CWI)
Paul Klint (CWI)
Henk Kox (KVL-EPR)
Karst Koymans (University of Amsterdam)
Bram Kraeima (Rijksuniversiteit Groningen)
Peter Kristel (Universiteit Utrecht)
Ivan Kryven (UvA)
Ruurd Kuiper (TU/e)
Ruurd Jan Anthonius Kuiper (TU Delft)
David de Laat (TU Delft)
Davy Landman (CWI)
Monique Laurent (CWI)
Timo Leemans (CWI)
Guido Legemaate (CWI / Fire Department Amsterdam)
Alvaro Leitao (CWI)
Robert van Liere (CWI)
Walter Lioen (SURFsara)
Guido Loupias (UvA)
Ad Mank (retired)
Shimon Machluf (UvA)
Joost van Mameren (UvA / Institute of Physics)
Philip Michgelsen (ILLC)
Leonardo Morelli (Leiden University)
Jelmer Neeven (Universiteit van Amsterdam)
Ludo Nieuwenhuizen (Institute of Physics, University of Amsterdam)
Margreet Nool (CWI)
Aad Offerman (Offerman Consulting)
Giulio Orecchia (Universiteit Leiden)
Peter van Ormondt (UvA-ILLC)
E.M. Peeters (TNO)
Steven Pemberton (CWI)
Rene Penning de Vries (Boegbeeld ICT)
D.R. Peperkamp (Saxion University of Applied Sciences)
Eleni Petraki (CWI)
Markus Pfundstein (University of Amsterdam)
Daniel Pijn (Universiteit van Amsterdam)
Teresa Piovesan (CWI)
Aske Plaat (Leiden University)
Femke van Raamsdonk (VU)
F.M. Reinshagen (UvA)
Mathys Rennela (Radboud University)
Lisanne Rens (CWI)
Boris Reuderink (Cortext)
Amin Rezaeian (TU Delft)
Andrea Roccaverde (Leiden University)
Carla Sanna (UvA)
Thomas Santoli (UvA)
Giada Scalpelli (CWI)
Guido Schaefer (CWI)
Christian Schaffner (University of Amsterdam / CWI)
Eddie Schoute (Delft University of Technology)
Kareljan Schoutens (UvA)
Florian Schreck (UvA)
Guus Schreiber (VU Computer Science)
René Schroder (Het Scheepvaartmuseum)
W.A. Schuur (VWS Triangulum)
Ana Silva (CWI)
Georgios Skantzaris (University of Amsterdam)
Florian Speelman (CWI)
Robert Spreeuw (UvA)
Menno van der Steen (Mediabrands)
Kees Stammes (Universiteit van Amsterdam)
Tom Sterkenburg (CWI / University of Groningen)
Simon Stuij (UvA)
Karthik Srinivasan (ING Bank)
Shin-ichi Tanigawa (CWI)
Gerard Tel (Utrecht University)
Jeroen Terstall (UvA)
Hans van Thiel (MyBusinessMedia)
Jos Timmermans (Comvote)
Ioannis Tzanellis (AIMMS B.V)
Sander Uijlen (Radboud Universiteit)
Jouko Vaananen (ILLC, University of Amsterdam)
Yde Venema (ILLC UvA)
Richard Versluis (QuTech Delft)
Stephan Verveen (Funnelvision)
Melle Vessies (UvA)
Marco Virgolin (CWI)
Frank Visser (iMMovator)
Maureen Voestermans (science journalist)
Marcel Vonk (UvA)
Tom Vonk (University of Amsterdam)
Johan Vos (Universiteit van Amsterdam)
Ivo van Vulpen (UvA/Nikhef)
Wouter Waalewijn (UvA)
Bas Westerbaan (Radboud Universiteit)
Frank Wetzels (CWI)
Kees Wevers (TN-ITS)
Jasper van Wezel (IOP)
Diderik van Wingerden (Think Innovation)
Abe Wits (Utrecht University)
Cees Witteveen (Delft University of Technology)
Ronald de Wolf (CWI)
Miro van der Worp (UvA)
Vladimir Zamdzhiev (University of Oxford)
Fabio Zanasi (Radboud University)
Tom van der Zanden (Universiteit Utrecht)
Ying Zhang (MonetDB Solutions / CWI)
Bonan Zhao (UvA)
Arkin Zoodsma (UvA)
Jeroen Zuiddam (CWI)
Astrid Zuurbier (NWO)

PhD Defence Thijs van Ommen (A&C)

  • 2015-06-10T13:15:00+02:00
  • 2015-06-10T16:00:00+02:00
June 10 Wednesday

Start: 2015-06-10 13:15:00+02:00 End: 2015-06-10 16:00:00+02:00

Academiegebouw of Leiden University, Rapenburg 73, Leiden

Everybody is invited to attend the PhD Defence of Thijs van Ommen. The dissertation is entitled 'Better Predictions when Models are Wrong or Underspecified'.

The informal talk about the thesis will start at 15:15. De defense itself starts at 16:15. 

Promotor: Prof. Dr. Peter Grunwald (CWI, A&C/Universiteit Leiden).

More information
Bayesian statistics not as robust as commonly thought

Members of Algorithms and Complexity


Current Projects

  • Distributed Ledger Services for Online Settlement (DLS OCS)
  • Position-Based Quantum Cryptography
  • Promotieonderzoek CWI-IoP
  • Quantum and classical data transmission
  • Networks
    Networks (eerste fase)
    Progress in quantum computing:Algorithms, communication, and applications
  • QSC
    Quantum Software Consortium
  • WISE
    WISE Women In Science Excel


  • Technische Universiteit Eindhoven
  • Technische Universiteit Delft
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