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Quantum Technology:

Quantum Technology:. Putting Weirdness to Use. Chris Monroe. University of Maryland Department of Physics. National Institute of Standards and Technology. Quantum mechanics and computing. atom-sized transistors. molecular-sized transistors. 2025 . 2040 .

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Quantum Technology:

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  1. Quantum Technology: Putting Weirdness to Use Chris Monroe University of Maryland Department of Physics National Institute of Standards and Technology

  2. Quantum mechanics and computing atom-sized transistors molecular-sized transistors 2025 2040

  3. “There's Plenty of Room at the Bottom” (1959) Richard Feynman “When we get to the very, very small world – say circuits of seven atoms - we have a lot of new things that would happen that represent completely new opportunities for design. Atoms on a small scale behave like nothing on a large scale, for they satisfy the laws of quantum mechanics…”

  4. A new science for the 21st Century? Information Theory Quantum Mechanics 20th Century 21st Century Quantum Information Science

  5. Alan Turing (1912-1954) universal computing machines Claude Shannon (1916-2001) quantify information: the bit Computer Science and Information Theory Charles Babbage (1791-1871) mechanical difference engine

  6. ENIAC (1946)

  7. The first solid-state transistor (Bardeen, Brattain & Shockley, 1947)

  8. Quantum Mechanics: A 20th century revolution in physics • Why doesn’t the electron collapse onto the nucleus of an atom? • Why are there thermodynamic anomalies in materials at low temperature? • Why is light emitted at discrete colors? • . . . . Erwin Schrödinger (1887-1961) Albert Einstein (1879-1955) Werner Heisenberg (1901-1976)

  9. The Golden Rules of Quantum Mechanics • Rule #1: Quantum objects are waves and can • be in states of superposition. • “qubit”:|0and |1 Rule #2:Rule #1 holds as long as you don’t look! • |0and |1 or |0 |1 probabilityp 1-p

  10. …BAD NEWS… Measurement gives random result f(x) e.g.,  |101 GOOD NEWS… quantum parallel processing on 2N inputs Example: N=3 qubits  = a0|000 + a1|001 + a2|010 + a3|011 a4|100 + a5|101 + a6|110 + a7|111 f(x) N=300 qubits: more information than particles in the universe!

  11. …GOOD NEWS! quantum interference depends on all inputs

  12. …GOOD NEWS! quantum interference depends on all inputs quantum logic gates quantum NOT gate: |0  |0 + |1 |1  |1 -|0 |0 |0  |0 |0 |0 |1  |0 |1 |1 |0  |1 |1 |1 |1  |1 |0 quantum XOR gate: ( ) e.g., |0 + |1 |0  |0|0 + |1|1 superposition  entanglement

  13. John Bell (1964) Any possible “completion” to quantum mechanics will violate local realism just the same • Quantum State: [0][0]& [1][1]

  14. H H Entanglement: Quantum Coins Two coins in a quantum superposition • [H][H] & [T][T] 11

  15. T T Entanglement: Quantum Coins Two coins in a quantum superposition • [H][H] & [T][T] 11 00

  16. T T Entanglement: Quantum Coins Two coins in a quantum superposition • [H][H] & [T][T] 11 00 00

  17. H H Entanglement: Quantum Coins Two coins in a quantum superposition • [H][H] & [T][T] 11 00 00 11

  18. H H Entanglement: Quantum Coins Two coins in a quantum superposition • [H][H] & [T][T] 11 00 00 11 11

  19. H H Entanglement: Quantum Coins Two coins in a quantum superposition • [H][H] & [T][T] 11 00 00 11 11 11

  20. T T Entanglement: Quantum Coins Two coins in a quantum superposition • [H][H] & [T][T] 11 00 00 11 11 11 00 .. .. ..

  21. Application: quantum cryptographic key distribution plaintext KEY ciphertext + ciphertext KEY plaintext +

  22. Quantum Superposition From Taking the Quantum Leap, by Fred Alan Wolf

  23. Quantum Superposition From Taking the Quantum Leap, by Fred Alan Wolf

  24. Quantum Superposition From Taking the Quantum Leap, by Fred Alan Wolf

  25. Quantum Entanglement “Spooky action-at-a-distance” (A. Einstein) From Taking the Quantum Leap, by Fred Alan Wolf

  26. Quantum Entanglement “Spooky action-at-a-distance” (A. Einstein) From Taking the Quantum Leap, by Fred Alan Wolf

  27. Quantum Entanglement “Spooky action-at-a-distance” (A. Einstein) From Taking the Quantum Leap, by Fred Alan Wolf

  28. Quantum Entanglement “Spooky action-at-a-distance” (A. Einstein) From Taking the Quantum Leap, by Fred Alan Wolf

  29. David Deutsch • “When a quantum measurement is made, the universe bifucates!” • Many Universes • Multiverse • Many Worlds

  30. Nature Quantum Computers and Computing Institute of Computer Science Russian Academy of Science ISSN 1607-9817 Science Phys. Rev. Lett. Phys. Rev. David Deutsch (1985) Peter Shor (1994) Lov Grover (1996) fast number factoring N = pq fast database search 3000 # articles mentioning “Quantum Information” or “Quantum Computing” 2500 2000 1500 1000 500 0 2010 1990 1995 2000 2005

  31. application: cryptanalysis(N ~ 10200) Quantum Factoring P. Shor, SIAM J. Comput. 26, 1474 (1997) A. Ekert and R. Jozsa, Rev. Mod. Phys. 68, 733 (1996) Look for a joint property of all 2N inputs e.g.: the periodicity of a function x2x2x (Mod 15) 0 1 1 1 2 2 2 4 4 3 8 8 4 16 1 5 32 2 6 64 4 7 128 8 8 256 1 etc… p = period r = period (a = parameter) A quantum computer can factor numbers exponentially faster than classical computers 15 = 3  5 38647884621009387621432325631 = ?  ?

  32. Error-correction Shannon (1948) Redundant encoding to protect against (rare) errors potential error: bit flip 0/1 0/1 unprotected p(error) = p 1/0 potential error: bit flip 000/111 000/111 protected 010/101 etc.. take majority better off whenever p < 1/2

  33. |0 + |1  /4{|00000 + |10010 + |01001 + |10100 + |01010 -|11011 - |00110 -|11000 - |11101 -|00011 -|11110 -|01111 - |10001 -|01100 -|10111 + |00101 } + /4{|11111 + |01101 + |10110 + |01011 + |10101 -|00100 - |11001 -|00111 - |00010 -|11100 -|00001 -|10000 - |01110 -|10011 -|01000 + |11010 } 5-qubit code corrects all 1-qubit errors to first order Shor (1995) Steane (1996) Quantum error-correction P0 C C* P1 r = |0 + |1 Decoherence

  34. Trapped Atomic Ions Yb+ crystal ~5 mm C.M. & D. J. Wineland, Sci. Am., 64 (Aug 2008) R. Blatt& D. J. Wineland, Nature453, 1008 (2008)

  35. Quantum bit inside an atom: States of relative electron/nuclear spin State | State | N S N S N S S N

  36. laser laser atom remains dark atom fluoresces 108 photons/sec 0.2 1 Probability 0 0 0 10 20 30 0 20 30 10 # photons collected in 200ms # photons collected in 200ms >99% detection efficiency! “Perfect” quantum measurement of a single atom state | state |

  37. Internal states of these ions entangled Trapped Ion Quantum Computer Cirac and Zoller, Phys. Rev. Lett. 74, 4091 (1995)

  38. AntiferromagneticNéel order of N=10 spins 2600 runs, a=1.12 All in state  All in state  AFM ground state order 222 events 219 events 441 events out of 2600 = 17% Prob of any state at random =2 x (1/210) = 0.2%

  39. (see K. Brown) a (C.O.M.) b (stretch) c (Egyptian) Mode competition – example: axial modes, N = 4 ions d (stretch-2) mode amplitudes 60 d b+c c b c-a 2b,a+c a+b b-a 2a c-a b-a b+c cooling beam 2b,a+c a a+b Fluorescence counts 40 2a d a b carrier axial modes only c 20 -15 -10 -5 0 5 10 15 Raman Detuning dR (MHz)

  40. 1 mm

  41. Maryland/LPS GaAs/AlGaAs GaTech Res. Inst. Al/Si/SiO2 NIST-Boulder Au/Quartz Sandia Nat’l Lab: Si/SiO2

  42. Photonic Quantum Networking Linking ideal quantum memory (trapped ion) with ideal quantum communication channel (photon) optical fiber trapped ions trapped ions

  43. Single atom here Single atom here

  44. unknown qubituploaded to atom #1 | + | qubittransfered to atom #2 |&| Quantum teleportation of a single atom S. Olmschenk et al., Science 323, 486 (2009).

  45. we need more time.. and more qubits..

  46. Large scale vision (103 – 106 atomic qubits)

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