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Quantum weirdness in technology

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Presentation SURF Research and Innovation Event 2013
February 28, The Hague University of Applied Sciences
Leo Kouwenhoven is Professor of Physics at the Delft University of Technology. He is also head of the research group Quantum Transport of the Kavli Institute of Nanoscience at the Delft University of Technology.

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Quantum weirdness in technology

  1. 1. Quantum weirdness in technology from molecules via teleportation to a quantum computerLeo Kouwenhoven
  2. 2. CLASSICAL WORLDQUANTUMMECHANICAL WORLD
  3. 3. fm pm nm µm mm m
  4. 4. Quantum mechanics,the theory for small objects Solvay conference 1927, Brussels
  5. 5. Quantum mechanics,absurd behaviour in big objects Quantum Transport Group 2012, Delft
  6. 6. Quantum superposition CH4 methanechemical bonds are quantum glue from electron superpositions.
  7. 7. Quantum superpositionTwo different positions at the same time! Colliding with itself (interference)
  8. 8. Entanglement
  9. 9. Entanglement“Properties remain entangled over long distances.” Teleportation !
  10. 10. Entanglement A measurement HERE also changesthe thing THERE ……instantaneously! Einstein: “Haha… Spooky action at a distance. You see, quantum is wrong.”
  11. 11. Entanglement A measurement HERE also changesthe thing THERE ……instantaneously! Feynman: “Shut up and calculate!”
  12. 12. Entanglement A measurement HERE also changesthe thing THERE ……instantaneously! Me: “Let’s do it!”
  13. 13. Entanglement Teleportation
  14. 14. Entanglement Teleportation
  15. 15. Entanglement Teleportation Quantum Teleportation“Transfer information over a large distance without going there”
  16. 16. PhilosophyWhat does it mean?
  17. 17. Feynman: “Shut up and calculate!”Quantum theory gives extremely accurate predictionsè Quantum theory is the best tested theory!!è We know how it works but not why it works this way.
  18. 18. Single photon light bulb 100 nm"
  19. 19. Single photon light bulb 100 nm"
  20. 20. Majorana particles on a chip
  21. 21. quantum DiCarlo group @ TUDelftatom gadget nm µm mm m
  22. 22. quantum DiCarlo group @ TUDelftatom gadget nm µm mm m
  23. 23. Can we extend quantum behaviour to even larger systems?
  24. 24. Hanson group @ TUDelft
  25. 25. Can we make quantum behaviour more complex?
  26. 26. quantum quantum classical atom transistor circuit gadget nm µm mm mPhoto’s © Miraceti, Luigi Chiesa, T137, Yukata Tsutano used under a Creative Commons license: www.creativecommons.org
  27. 27. Why a quantum computer?
  28. 28. Klassieke bits 0 of 1 ofQuantum bits = qubits 0 en 1 = |0> + |1> en =
  29. 29. What is a quantum computer good for? 15 = 3 x 5 200 digits 1 day (onmogelijk vandaag) 91 = ... x ... ? 201 2 days 437 = ... x ... ? 202 4 days ??? 203 8 days 210 1024 days ~ 3 years 220 3.000 years 230 3.000.000 yearsThere exits no classicalalgorithm to factorizenumbers efficiently !The problem increasesexponentially in time withthe number of digits.
  30. 30. “hard problems” take an exponentialy long time to solve time to factor a product of two primes bits van Meter et al 2006 Classical computers are useless! Quantum computers could do it!
  31. 31. Complexity of Quantum Systemen grows exponential 1 qubit n qubits |0〉 α| 0 〉 + β | 1 〉 2n degrees-of-freedom ! |1〉 | ψ 〉 = c1 | 000 〉 + c2 | 001 〉 + … + c8 | 111 〉 Parallel computing: Classsical: speed ∝ n Quantum: speed ∝ 2n Example: for n = 100 the quantum speed 2100 = 1030
  32. 32. © U. Geneva Quantum information: - encode information in photons - in quantum mechanics it is impossible to measure the information without changing it. => internet security. A prototype quantum intranet exists! Quantum computer: - more complex circuitshttp://www.idquantique.com - prototype quantum circuit in 2020 - a full scale quantum computer in ~15 to 20 years

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