1. Quantum Computer Chris Monroe University of Maryland Department of Physics National Institute of Standards and Technology Hardware

2. “There's Plenty of Room at the Bottom” (1959) “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…” Richard Feynman Quantum Mechanics and Computing 20402025 atom-sized transistors molecular-sized transistors

3. A new science for the 21 st Century 20 th Century Quantum Information Science 21 st Century 0 1 1 0 0 0 1 1… Quantum Mechanics Information Theory

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

5. ENIAC (1946)

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

7. The classical NAND Gate ABAB out V0V0 AB 001 011 101 110 32-level NAND-based flash memory

8. The Golden Rules of Quantum Mechanics of Quantum Mechanics Rule #2: Rule #1 holds as long as you don’t look! or probability

9. GOOD NEWS… quantum parallel processing on 2 N inputs Example: N=3 qubits  =a 0 |000  + a 1 |001  + a 2 |010  + a 3 |011  a 4 |100  + a 5 |101  + a 6 |110  + a 7 |111  f(x) …BAD NEWS… Measurement gives random result e.g.,   |101  f(x) N=300 qubits: more information than particles in the universe! N=300 qubits: more information than particles in the universe!

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

11. |0   |0  + |1  |1   |1   |0  quantum  NOT gate: e.g., |0  + |1  |0   |0  |0  + |1  |1  superposition  entanglement ( ) |0  |0   |0  |0  |0  |1   |0  |1  |1  |0   |1  |1  |1  |1   |1  |0  quantum XOR gate: depends on all inputs …GOOD NEWS! quantum interference quantum logic gates

12. Quantum State: |0  |0  + |1  |1  John Bell (1964) Any possible “completion” to quantum mechanics will violate local realism just the same

13. Citations to John Bell’s 1964 paper J. Bell, "On the Einstein Podolsky Rosen Paradox," Physics 1, 195 (1964)

14. Quantum Computers and Computing Institute of Computer Science Russian Academy of Science ISSN 1607-9817 Quantum Computers and Computing Institute of Computer Science Russian Academy of Science ISSN 1607-9817 0 500 1000 1500 2000 2500 3000 # articles mentioning “Quantum Information” or “Quantum Computing” Nature Science Phys. Rev. Lett. Phys. Rev. 2005200019951990 2010 Shor’s Quantum Factoring Algorithm Moore’s Law of Publishing

15. (Classical) Error-correction Shannon (1948) Redundant encoding to protect against (rare) errors better off whenever p < 1/2 unprotected protected 0/1 potential error: bit flip p(error) = p 0/1 1/01/0 000/111 potential error: bit flip 010/101 etc.. take majority

16. Decoherence Quantum error-correction Shor (1995) Steane (1996) 5-qubit code corrects all 1-qubit errors to first order

17. N=10 28 N=1

19. Aarhus Amherst Basel Berkeley Bonn Citadel Clemson Denison Duke Erlangen ETH-Zurich Freiburg Georgia Tech Griffith Hannover Honeywell Indiana Innsbruck Lincoln Labs Lockheed Maryland/JQI Mainz MIT Munich NIST-Boulder Northwestern NPL-Teddington Osaka Oxford Paris Pretoria PTB-Braunschweig Saarbrucken Sandia Siegen Simon Fraser Singapore Sussex Sydney Tokyo Tsinghua-Beijing UCLA Washington-Seattle Weizmann Williams Trapped Atomic Ions Yb + crystal ~5  m

21. 2 S 1/2 (600 Hz/G @ 1 G)  HF /2  = 12 642 812 118 + 311B 2 Hz |  = |0,0  |  = |1,0  171 Yb + hyperfine qubit

22. 2 S 1/2 2 P 1/2 369 nm 2.1 GHz  = 20 MHz |  |  171 Yb + qubit detection (600 Hz/G @ 1 G)  HF /2  = 12 642 812 118 + 311B 2 Hz # photons collected in 800  s 0510152025 0 1 Probability |z|z

23. 2 S 1/2 2 P 1/2 369 nm  = 20 MHz |  |  2.1 GHz 171 Yb + qubit detection >99% detection efficiency # photons collected in 500  s 0510152025 0 1 Probability |z|z |z|z (600 Hz/G @ 1 G)  HF /2  = 12 642 812 118 + 311B 2 Hz

24. (600 Hz/G @ 1 G)  HF /2  = 12 642 812 118 + 311B 2 Hz 2 S 1/2 2 P 1/2 |  |  171 Yb + qubit manipulation  = 33 THz 355 nm (10 psec @ 100 MHz) 2 P 3/2  = 20 MHz

25. t (ms) 0 0.2 0.4 0.6 0.8 1 050100150200250300350400 prepare ↓ t laser beams measure P(↑) (bright or dark) :: increment t Combination of coherence and perfect measurement Prob(↑|↓) averaged data.

26. ~5  m      r Entangling Trapped Ion Qubits Cirac and Zoller (1995) Mølmer & Sørensen (1999)  ~ 10 nm e  ~ 500 Debye “dipole-dipole coupling” for full entanglement

27. 355nm Raman beams High NA objective Individual Beams kk Global Beam 5-segment linear Paul trap High NA objective (0.37) Tightly focused Raman beams 32ch AOM and PMT for indiv. addressing/detection Diffractive optic (х10) Harris Corp 32channel AOM 2μm pixels 355nm pulsed laser Programmable Quantum Computer… in the lab

28. QFT circuit (n=5 qubits) controlled phase gate Quantum Fourier Transform (QFT) input amplitudes output amplitudes

29. Controlled phase gate Controlled-Phase Gate ± phase of Ising coupling

30. state preparation results e.g. state with period 8 = 7 15 2331 Quantum Fourier Transform (QFT)

31. F = F 0 | ↑  ↑ | F 0 | ↓  ↓ | Physics: global spin-dependent force

32. ↑↓↑↓↑↓↑↓↑↓↑↓↑↓↑↓↑↓↓↑↓↑↓↑ ↑ ↓↑↓↑↓↑↓↑↓↑↓↑↓↑↓↑↓↓↑↓↑↓↑ |  |  ADD: Independent spin flips B F = F 0 | ↑  ↑ | F 0 | ↓  ↓ | Physics: global spin-dependent force F = F 0 | ↑  ↑ | F 0 | ↓  ↓ |

33. Adiabatic Quantum Simulation from S. Lloyd, Science 319, 1209 (2008) Initialization: spins along x Detection: measure spins along z Time (<1 0 msec ) Transverse Ising model

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

35. First Excited States (Pop. ~ 2% each)

36. Second Excited States (Pop. ~ 1% each)

37. AFM order of N=14 spins (16,384 configurations)

38. N=22 spins initial state at t=0 state measured at J 0 t = 36  B. Neyenhuis et al., in preparation (2015)

39. a (C.O.M.) b (stretch) c (Egyptian) d (stretch-2) Mode competition – example: axial modes, N = 4 ions Fluorescence counts Raman Detuning  R (MHz) -15-10-5051015 20 40 60 a b c d a b c d 2a c-a b-a 2b,a+c b+c a+b 2a c-a b-a 2b,a+c b+c a+b carrier axial modes only mode amplitudes cooling beam Kielpinski, Monroe, Wineland, Nature 417, 709 (2002) Medium scale vision (>100 atomic spins)

40. Univ. of Maryland Boulder

41. 2 S 1/2 2 P 1/2 R B |  |  171 Yb + Mapping qubits from atoms to photons Given photon is collected success probability

42. Simon & Irvine, PRL 91, 110405 (2003) L.-M. Duan, et. al., QIC 4, 165 (2004) Y. L. Lim, et al., PRL 95, 030505 (2005) D. Moehring et al., Nature 449, 68 (2007) Doubling down: remote link through photons D. Hucul, et al., Nature Phys. 11, 37 (2015) state of the art: Upon coincidence detection! 171 Yb + ion optical fiber 50/50 BS /4 171 Yb + ion

43. Single atom here

44. unknown qubit uploaded to atom #1  |  +  |  qubit transfered 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. CM et al., Phys. Rev. A 89, 022317 (2014) Large scale modular Architecture (10 3 - 10 6 atomic spins?) 0.001 Hz before ~ 10 Hz now ~ 1 kHz soon D. Hucul, et al., Nature Phys. 11, 37 (2015)

48. 1947: first transistor2000: integrated circuit 2015: qubit collectionLarge scale quantum network? single module N ion trap modules

49. # particles control & configurability molecules trapped ions Implementation of Quantum Hardware Cannot model Verification? quantum materials by design complex optimization “big quantum data” quantum computing NV Q-dots superconductors neutral atoms

50. Superconducting Circuits Leading Quantum Computer Hardware Candidates CHALLENGES short (10 -6 sec) memory 0.05K cryogenics all qubits different not reconfigurable Superconducting qubit: right or left current FEATURES & STATE-OF-ART connected with wires fast gates 5-10 qubits demonstrated printable circuits and VLSI Atomic qubits connected through laser forces on motion or photons individual atoms lasers photon Trapped Atomic Ions Others: still exploratory FEATURES & STATE-OF-ART very long (>>1 sec) memory 5-20 qubits demonstrated atomic qubits all identical connections reconfigurable CHALLENGES lasers & optics high vacuum 4K cryogenics engineering needed NV-Diamond Semiconductor quantum dots Atoms in optical lattices Investments: IARPALockheed GTRIUK Gov’t Sandia LARGE Investments: Google/UCSBIBM Lincoln Labs Intel/Delft

51. D-Wave:superconducting circuits venture capital funding great advertising but is it quantum?

53. N=10 28 N=1

55. Grad Students David Campos Clay Crocker Shantanu Debnath Caroline Figgatt David Hucul (  UCLA) Volkan Inlek Kevn Landsman Aaron Lee Kale Johnson Harvey Kaplan Antonis Kyprianidis Lexi Parsagian Chris Rickerd Crystal Senko (  Harvard) Ksenia Sosnova Jake Smith Ken Wright Undergrads Eric Birckelbaw Kate Collins Micah Hernandez ARO LPS/NSA Postdocs Paul Hess Marty Lichtman Norbert Linke Brian Neyenhuis (  Lockheed) Guido Pagano Phil Richerme (  Indiana) Grahame Vittorini (  Honeywell) Jiehang Zhang Res. Scientists Jonathan Mizrahi Kai Hudek Marko Cetina Trapped Ion Quantum Information www.iontrap.umd.edu Collaborators Luming Duan (Michigan) Philip Hauke (Innsbruck) David Huse (Princeton) Alexey Gorshkov (JQI/NIST) Alex Retzker (Hebrew U)

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

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

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

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

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

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

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