Leo Kouwenhoven

Last updated

Leo Kouwenhoven
Leo Kouwenhoven at the SingularityU The Netherlands Summit 2016 (29011185724).jpg
Leo Kouwenhoven in 2016
Born (1963-12-10) 10 December 1963 (age 61)
Alma mater TU Delft
Awards Spinoza Prize (2007)
Scientific career
Fields Physics
Quantum computing
Institutions TU Delft
Website qutech.nl/lab/kouwenhoven-lab/

Leo Kouwenhoven (born 10 December 1963) is a Dutch physicist known for his research on quantum computing, specifically in topological quantum computing experiments.

Contents

Kouwenhoven grew up in Pijnacker, a village near Delft, where his parents ran a farm. After losing the admission lottery for veterinary medicine he decided to study physics at Delft University of Technology (TU Delft). [1]

In 1992 he received his PhD cum laude at TU Delft; his promoter was Hans Mooij  [ de ]. In 1999 he became a professor at TU Delft. [1] In 2007 he received the Spinoza Prize, the highest Dutch academic award. In April 2012 his TU Delft research group presented experimental results that provided potential "signatures" of Majorana fermion quasiparticles. [2] [3] [4] These Majorana quasiparticles would be very stable, and therefore suitable for building a quantum computer. [5]

In 2018 his research group claimed to have proved the definitive existence of Majorana particles in a Nature publication. [6] However, the results could not be reproduced by other scientists, and the article had to be retracted in 2021 due to "insufficient scientific rigour". [7] [8] [9] [10] The researchers had excluded data points that contradicted their claims, with the complete data not supporting their conclusions. [11]

Two of the Majorana research papers involving Leo Kouwenhoven's group at QuTech were retracted due to data irregularities, leading to a couple of investigations by the TU Delft's Research Integrity Committee (CWI) and the Dutch Body for Scientific Integrity (LOWI) between 2020 and 2023. [a] While Kouwenhoven was found partly negligent in one case, no scientific integrity violations were confirmed. [12]

Kouwenhoven was reappointed as university professor at TU Delft in 2024. [12]

Personal life

Kouwenhoven has six sisters and is married to Vrije Universiteit Amsterdam professor Marleen Huysman. [1]

Notes

  1. CWI and the LOWI led a first investigation between 2020 and 2022. The CWI conducted a second investigation from 2022 to 2023

Related Research Articles

<span class="mw-page-title-main">Quantum computing</span> Computer hardware technology that uses quantum mechanics

A quantum computer is a computer that exploits quantum mechanical phenomena. On small scales, physical matter exhibits properties of both particles and waves, and quantum computing leverages this behavior using specialized hardware. Classical physics cannot explain the operation of these quantum devices, and a scalable quantum computer could perform some calculations exponentially faster than any modern "classical" computer. Theoretically a large-scale quantum computer could break some widely used encryption schemes and aid physicists in performing physical simulations; however, the current state of the art is largely experimental and impractical, with several obstacles to useful applications.

<span class="mw-page-title-main">Delft University of Technology</span> Dutch university

The Delft University of Technology is the oldest and largest Dutch public technical university, located in Delft, The Netherlands. It specializes in engineering, technology, computing, design, and natural sciences.

<span class="mw-page-title-main">Spin network</span> Diagram used to represent quantum field theory calculations

In physics, a spin network is a type of diagram which can be used to represent states and interactions between particles and fields in quantum mechanics. From a mathematical perspective, the diagrams are a concise way to represent multilinear functions and functions between representations of matrix groups. The diagrammatic notation can thus greatly simplify calculations.

<span class="mw-page-title-main">Timeline of quantum computing and communication</span>

This is a timeline of quantum computing.

Microsoft Research (MSR) is the research subsidiary of Microsoft. It was created in 1991 by Richard Rashid, Bill Gates and Nathan Myhrvold with the intent to advance state-of-the-art computing and solve difficult world problems through technological innovation in collaboration with academic, government, and industry researchers. The Microsoft Research team has more than 1,000 computer scientists, physicists, engineers, and mathematicians, including Turing Award winners, Fields Medal winners, MacArthur Fellows, and Dijkstra Prize winners.

<span class="mw-page-title-main">Topological quantum computer</span> Hypothetical fault-tolerant quantum computer based on topological condensed matter

A topological quantum computer is a theoretical type of quantum computer proposed by Russian-American physicist Alexei Kitaev in 1997. It utilizes quasiparticles, known as anyons, in two-dimensional systems. These anyons' world lines intertwine to form braids in a three-dimensional spacetime. These braids act as the logic gates of the computer. The primary advantage of using quantum braids over trapped quantum particles is enhanced stability. While small, cumulative perturbations can cause quantum states to decohere and introduce errors in traditional quantum computations, such perturbations do not alter the topological properties of the braids. This stability is akin to the difference between cutting and reattaching a string to form a different braid versus a ball colliding with a wall.

<span class="mw-page-title-main">Majorana fermion</span> Fermion that is its own antiparticle

A Majorana fermion or Majorana particle is a fermion that is its own antiparticle. They were hypothesised by Ettore Majorana in 1937. The term is sometimes used in opposition to Dirac fermion, which describes fermions that are not their own antiparticles.

<span class="mw-page-title-main">Deltar</span> Analogue computer used in the Dutch Delta Works project

The Deltar was an analogue computer used in the design and execution of the Delta Works from 1960 to 1984. Originated by Johan van Veen, who also built the initial prototypes between 1944 and 1946, its development was continued by J.C. Schönfeld and C.M. Verhagen after van Veen's death in 1959.

Lorenza S. Colzato is an Italian cognitive psychologist who is best known for the attention she received in the mainstream media in the Netherlands for multiple incidents of scientific misconduct. Her research "aims to understand the neural and neuromodular underpinnings of cognitive control in humans."

<span class="mw-page-title-main">Shoucheng Zhang</span> Chinese-American physicist (1963–2018)

Shoucheng Zhang was a Chinese-American physicist who was the JG Jackson and CJ Wood professor of physics at Stanford University. He was a condensed matter theorist known for his work on topological insulators, the quantum Hall effect, the quantum spin Hall effect, spintronics, and high-temperature superconductivity. According to the National Academy of Sciences:

He discovered a new state of matter called topological insulator in which electrons can conduct along the edge without dissipation, enabling a new generation of electronic devices with much lower power consumption. For this ground breaking work he received numerous international awards, including the Buckley Prize, the Dirac Medal and Prize, the Europhysics Prize, the Physics Frontiers Prize and the Benjamin Franklin Medal.

<span class="mw-page-title-main">Stephanie Wehner</span> German physicist and computer scientist

Stephanie Dorothea Christine Wehner is a German physicist and computer scientist.

<span class="mw-page-title-main">Quantum oscillations</span> Experiments used to map the Fermi surface

In condensed matter physics, quantum oscillations describes a series of related experimental techniques used to map the Fermi surface of a metal in the presence of a strong magnetic field. These techniques are based on the principle of Landau quantization of Fermions moving in a magnetic field. For a gas of free fermions in a strong magnetic field, the energy levels are quantized into bands, called the Landau levels, whose separation is proportional to the strength of the magnetic field. In a quantum oscillation experiment, the external magnetic field is varied, which causes the Landau levels to pass over the Fermi surface, which in turn results in oscillations of the electronic density of states at the Fermi level; this produces oscillations in the many material properties which depend on this, including resistance, Hall resistance, and magnetic susceptibility. Observation of quantum oscillations in a material is considered a signature of Fermi liquid behaviour.

<span class="mw-page-title-main">Jan in 't Veld</span> Dutch engineer (1925–2005)

Jan in 't Veld was a Dutch aerospace engineer and professor of industrial organization at the Mechanical Engineering Department of the Technical University of Delft. In the Netherlands he was one of the pioneers of the application of systems theory in business administration and management.

Claudia Felser is a German solid state chemist and materials scientist. She is currently a director of the Max Planck Institute for Chemical Physics of Solids. Felser was elected as a member into the National Academy of Engineering in 2020 for the prediction and discovery of engineered quantum materials ranging from Heusler compounds to topological insulators.

Andrew MacGregor Childs is an American computer scientist and physicist known for his work on quantum computing. He is currently a professor in the department of computer science and Institute for Advanced Computer Studies at the University of Maryland. He also co-directs the Joint Center for Quantum Information and Computer Science, a partnership between the University of Maryland and the National Institute of Standards and Technology.

Barbara M. Terhal is a theoretical physicist working in quantum information and quantum computing. She is a professor in the Delft Institute of Applied Mathematics at TU Delft, as well as leading the Terhal Group at QuTech, the Dutch institute for quantum computing and quantum internet, founded by TU Delft and the Netherlands Organisation for Applied Scientific Research (TNO). Her research concerns many areas in quantum information theory, including entanglement detection, quantum error correction, fault-tolerant quantum computing and quantum memories.

<span class="mw-page-title-main">Pierre Malotaux</span>

Pierre Charles-André Malotaux was a Dutch organizational theorist, business consultant, and Professor of Business Administration at the Delft University of Technology. His is known with Jan in 't Veld for developing a specific systems approach to organizational problems, called the Delft Systems Approach.

<span class="mw-page-title-main">Ronald Hanson</span> Dutch physicist

Ronald Hanson is a Dutch experimental physicist. He is best known for his work on the foundations and applications of quantum entanglement. He is Antoni van Leeuwenhoek Professor at the Kavli Institute of Nanoscience at Delft University of Technology and scientific director of QuTech. the Dutch Quantum Institute for quantum computing and quantum internet, founded by Delft University of Technology and the Netherlands Organisation for Applied Research.

<span class="mw-page-title-main">Pablo Jarillo-Herrero</span> Spanish physicist

Pablo Jarillo-Herrero is a Spanish physicist and current Cecil and Ida Green Professor of Physics at Massachusetts Institute of Technology (MIT).

In condensed matter physics, the Kitaev chain is a simplified model for a topological superconductor. It models a one dimensional lattice featuring Majorana bound states. The Kitaev chain have been used as a toy model of semiconductor nanowires for the development of topological quantum computers. The model was first proposed by Alexei Kitaev in 2000.

References

  1. 1 2 3 Hoeks, Louis (6 March 2016). "'Op de boerderij leerde ik dat wegduiken geen optie is'". Financieele Dagblad.
  2. Bob Yirka (13 April 2012). "Researchers find possible evidence of Majorana fermions". phys.org. Retrieved 28 May 2024.
  3. "Nanowetenschappers vinden langgezocht Majorana-deeltje". engineersonline.nl (in Dutch). 17 February 1999. Retrieved 28 May 2024.
  4. Mourik, V.; Zuo, K.; Frolov, S. M.; Plissard, S. R.; Bakkers, E. P. a. M.; Kouwenhoven, L. P. (25 May 2012). "Signatures of Majorana Fermions in Hybrid Superconductor-Semiconductor Nanowire Devices". Science. 336 (6084): 1003–1007. arXiv: 1204.2792 . Bibcode:2012Sci...336.1003M. doi:10.1126/science.1222360. ISSN   0036-8075. PMID   22499805. S2CID   18447180.
  5. Robert F. Service, Physicists Discover New Type of Particle — Sort Of, ScienceNOW, 12 April 2012
  6. Zhang, Hao; Liu, Chun-Xiao; Gazibegovic, Sasa; Xu, Di; Logan, John A.; Wang, Guanzhong; van Loo, Nick; Bommer, Jouri D. S.; de Moor, Michiel W. A.; Car, Diana; Op het Veld, Roy L. M. (2018). "RETRACTED ARTICLE: Quantized Majorana conductance". Nature. 556 (7699): 74–79. arXiv: 1710.10701 . doi:10.1038/nature26142. ISSN   1476-4687. PMID   29590094. S2CID   4613547. (Retracted, see doi:10.1038/s41586-021-03373-x, PMID   33686283,  Retraction Watch)
  7. Zhang, Hao; Liu, Chun-Xiao; Gazibegovic, Sasa; Xu, Di; Logan, John A.; Wang, Guanzhong; Van Loo, Nick; Bommer, Jouri D. S.; De Moor, Michiel W. A.; Car, Diana; Op Het Veld, Roy L. M.; Van Veldhoven, Petrus J.; Koelling, Sebastian; Verheijen, Marcel A.; Pendharkar, Mihir; Pennachio, Daniel J.; Shojaei, Borzoyeh; Lee, Joon Sue; Palmstrøm, Chris J.; Bakkers, Erik P. A. M.; Das Sarma, S.; Kouwenhoven, Leo P. (2021). "Retraction Note: Quantized Majorana conductance". Nature. 591 (7851): E30. Bibcode:2021Natur.591E..30Z. doi: 10.1038/s41586-021-03373-x . PMID   33686283. S2CID   232159790.
  8. "Landmark article by QuTech researchers under scrutiny". Landmark article by QuTech researchers under scrutiny | TU Delta (in Dutch). 19 May 2020. Retrieved 8 March 2021.
  9. Stan van Pelt (23 February 2021). "Hoe jonge onderzoekers het fundament wegsloegen onder de quantumdroom van een Delftse hoogleraar". de Volkskrant (in Dutch). Retrieved 8 March 2021.
  10. Brouwer, Piet; Ensslin, Klaus; Goldhaber-Gordon, David; Lee, Patrick (2021). "Nature paper 'Quantized Majorana conductance', report from independent experts". Zenodo. doi:10.5281/zenodo.4545812. S2CID   244959752.
  11. "Microsoft's Big Win in Quantum Computing Was an 'Error' After All". Wired.
  12. 1 2 "Timeline retracted Majorana papers". QuTech. Retrieved 23 October 2024.