1. Quantum Information Processing Raymond Laflamme www.iqc.ca Fundación Bunge y Born and University of Buenos Aires, August 2010

2. Curiosity Understanding ControlTechnology Societal impact

3. Fire Steam Electromagnetism

4. What are the properties of Nature that will charaterise the 21 st century?

5. Plan Why now? What is it? Major successes – and a little bit about IQC Conclusion

6. Towards the quantum world The size of transistors decreases by half every eighteen months Intel’s 20 and 45 nm transistor We have learn that QM is powerful for information processing

7. The Quantum World: some unusual properties -The Uncertainty principle Observing quantum systems cannot be done without perturbing them: quantum cryptography and sensors MIT Technology Review -The Superposition principle Quantum systems can be in more than one state at once: quantum computing

8. Interference A coherent light source such as a laser is shined through 2 slits, the result of each independent slit do not add up to the final result when both slits are open due to interference effects.

9. . Quantum Information Processing Computation Communication Sensors

10. # of quantum bitsquantum states# of classical bits 1 2 3 50 … 0,1 00,01,10,11 000,001,…111 000000000000… 2 1 =2 2 2 =4 2 3 =8 2 50 =1P … The power of quantum computation

11. Applications Understanding and Test Quantum Mechanics Increase the speed of computer simulations Material Science – Simulation of new material Chemistry – Chemical reactions, molecules – Drug design Searching Cryptography …

12. Quantum Cryptography (Quantum key distribution) How do we exchange the key?

13. RSA cryptography: using pseudo-randomness Bank: p x q=2701 You: F(2701, #) = 101111011101111111 G(p,q, 101111011101111111) = # You: Login to a bank web site http -> https 2701 2701, 101111011101111111

16. Major successes of quantum information science and technology Discovery that QM is powerful for information processing: challenging strong Turing’s thesis Discovery of quantum error correction Demonstration of control in the laboratory of control of up to a dozen quantum bits

17. Algorithms Factoring and breaking codes Searching Random Walks Communication Simulation of Quantum Physics Physics, e.g. High Tc Superconductivity Chemistry Material science Two exciting new results: Hastings: non-addivity of quantum channel capacity Watrous: QIP=PSPACE

18. Quantum Error Correction Without QEC, if error per gate is p, n gates can lead to a fidelity of (1-p) n Accuracy threshold theorem:

19. Laboratory demonstrations …

20. The People  18 faculty, 9 associates, 24 pdfs, 83 grads and undergrads  17 staff Aim: 30 faculty, 50 pdfs, 125 grads Started in 2002 Raised more than $240M, from Feds/Province/Private Lead 2 National QIP networks Collaborative grad program Building on its way including fabrication/metrology facility www.iqc.ca Quantum Computing: Theory and Experiment – Optics/Superconducting/Quantum Dots/NMR Quantum Communication: – Quantum Cryptography: Prototype, ETSI, Certification Quantum Sensors: – Optics, NMR, spin-based The institute for Quantum Computing

21. IQC Collaborations with Sponsors IQC Waterloo

22. Testing Born’s rule

23. Interference orders Two possible paths Probability Interference B Sum Rules From N. Bohr 1949/1983: Discussions with Einstein on Epistemological Problems in Atomic Physics, p. 27

24. Testing the 2 nd Sum Rule So we have to measure these seven probabilities to detect a particle at a certain point behind the slits plus the background probability (leakage, dark count) Calculate ● In practice, we can’t easily measure a probability, so we use a normalization ●  measures the “amount of interference”

25. Results U. Sinha, C. Couteau, T. Jennewein, R.Laflamme, G. Weihs Science 23 July 2010: Vol. 329. no. 5990, pp. 418 - 421 We got  < 10 -2

26. Conclusion Quantum Information Science will deliver better understanding of QM and has the potential to deliver new technologies for the 21 st century Present success – Theoretical: Power of Quantum Information Control of quantum systems, quantum error correction – Experimental: Demonstration of control of small quantum systems and of counterintuitive properties of quantum mechanics