With the basics out of the way, how do you model some more complex quantum algorithms.

1. PROGRAMMING COMPLEX FLOWS
ON QUANTUM COMPUTERS
Rolf Huisman
IT Architect
Rolf.Huisman@ .com
@rlrhuisman

2. What did you learn ?
How would you model a more
complex scenario ?

3. Picture by Rolf Huisman / CC0 Creative Commons

4. Picture by Rolf Huisman / CC0 Creative Commons

5. Picture by Rolf Huisman / CC0 Creative Commons

6. Picture by Rolf Huisman / CC0 Creative Commons

7. Internet
Of
Stuffed
Animals
(IOSA)
Picture by Rolf Huisman / CC0 Creative Commons

8. Picture by Rolf Huisman / CC0 Creative Commons
Living Room
Attic
Bedroom
Stuffed animal problem

9. Stuffed animal problem
Living Room
Attic
Bedroom
Picture by Rolf Huisman / CC0 Creative Commons

10. Stuffed animal problem
Living Room
Attic
Bedroom
Picture by Rolf Huisman / CC0 Creative Commons

11. Stuffed animal problem
Living Room
Attic
Bedroom
Picture by Rolf Huisman / CC0 Creative Commons

12. Stuffed animal problem
Living Room
Attic
Bedroom
Picture by Rolf Huisman / CC0 Creative Commons

13. Stuffed animal problem
Living Room
Attic
BedroomSearch Path
Optimization
Picture by Rolf Huisman / CC0 Creative Commons

14. Same problem as other fields
Picture by Geralt / CC0 Creative Commons

15. Traveling Salesman problem
• NP Hard
Pictures by Saurabh harsh / CC BY-SA 3.0
O(2n*2n)

16. Using the gates to describe
• Optimized Traveling Salesman Problem 5 Cities:
Details: Phys. Rev. A 95, 032323 – Published 22 March 2017

17. Using the gates to describe
• Optimized Traveling Salesman Problem 5 Cities:
Details: Phys. Rev. A 95, 032323 – Published 22 March 2017
Homework, lets use a simpler version for now …

18. Told Qubits are waves

19. Radio waves

20. Radio waves
Radio stations:
E.g. Q-Music, 538, Radio 4

21. Radio waves
Radio stations:
E.g. Q-Music, 538, Radio 4

22. Tuning specific waves

23. Tuning specific waves
Oracle Function

24. Grover (and other amplifications)
Oracle Function

25. Grover (and other amplifications)
Original Amplitudes Negate Amplitude
Average of all Amplitudes Flip all Amplitudes around Avg

26. Radio stations
Step 1: Create our state space

27. Stuffed animal problem
Simplified version
• 4 places
• 2 options per place

28. Stuffed animal problem

29. Stuffed animal problem
Attic
Bedroom

30. Stuffed animal problem
Attic
Bedroom

31. Stuffed animal problem

32. Stuffed animal problem

33. Stuffed animal problem

34. “Stairway to Attic Rock FM”

35. “Going down Beats FM”

36. Stuffed animal problem

37. Stuffed animal problem
• Add another Qubit
CNOT

38. In Code
Q#
Qiskit

39. Result
firstChoice location]
One
(Go Up)
One
(Attic)
Zero
(Go Down)
Zero
(Living Room)

40. Stuffed animal problem

41. Stuffed animal problem

42. Stuffed animal problem

43. Model the stairs
Q#
Qiskit

44. Model the stairs
choice1 choice2 “Location”
One
(Up)
One
(Up)
Roof
One
(Up)
Zero
(Down)
Bedroom
Zero
(Down)
Down
(Up)
Bedroom
Zero
(Down)
Zero
(Down)
Basement

45. Waffie on the roof ?

46. Dirty solution
Q#
Qiskit

47. Dirty solution
• But my basement is now gone 
choice1 choice2 “Location”
One
(Up)
Zero
(Down)
Bedroom
Zero
(Down)
One
(Up)
Bedroom

48. Controlled Hadamard
H H
Q1 Q2
One One
One Zero
Zero Zero

49. Controlled Hadamard
Using Q# functor:
(Controlled H)(Qubit[], Qubit)
H H H
Q1 Q2
One One
One Zero
Zero Zero

50. Put the basement back
Qiskit
Q#

51. Put the basement back
choice1 choice2 “Location”
One
(Up)
Zero
(Down)
Bedroom
Zero
(Down)
One
(Up)
Bedroom
Zero
(Down)
Zero
(Down
Basement

52. Keep on going
• For this example, still pretty simple (2 paths)
• Real version of my house is more complex
Choice 1 Choice 2 Choice 3 Choice 4 Choice 5 Choice 6 …
One
(Up)
Zero
(Down)
Zero
(Down)
Zero
(Down)
One
(Up)
One
(Up)
…
Zero
(Down)
Zero
(Down)
One
(Up)
One
(Up)
One
(Up)
Zero
(Down)
…
…. …. …. … … … …

53. This gives us our state space
Now we need to tune the frequency
Our Oracle function

54. Stuffed animal problem
• Oracle Function
• (Loss function, cost function)

55. Attic
Bedroom
Stuffed animal problem
• Oracle Function, Flag Qubit

56. Attic
Bedroom
Stuffed animal problem
• Oracle Function, Flag Qubit

57. Attic
Stuffed animal problem
• Oracle Function, Flag Qubit

58. Attic
Stuffed animal problem
• Oracle Function, Flag Qubit

59. Stuffed animal problem
• Oracle Function, Flag Qubit
Bedroom

60. Library Functions
Q#
Qiskit
Aqua

61. Grover (and other amplifications)
Original Amplitudes Negate Amplitude
Average of all Amplitudes Flip all Amplitudes around Avg
Grover execution:
informally 𝑠𝑡𝑎𝑡𝑒𝑠

62. Chance amplification
• When you have more options than 2 and places than 4
Choice 1 Choice 2 Choice 3 Chance
Zero Zero … 0.00.. %
Zero One … 49.99.. %
One Zero … 49.99.. %
One One … 0.00… %
Simplification

63. The real device is not the same
• Real vs Simulated for x + y = 1

64. Many hours and code lines later
Traditional Quantum
Naive O(𝑛!) O( 𝑛!)
With effort O(2n*2n) O(( 𝑛)!)

65. Many hours and code lines later
Traditional Quantum
Naive O(𝑛!) O( 𝑛!)
With effort O(2n*2n) O(( 𝑛)!)
Choice 1 Choice 2 Choice 3 Choice 4 …
… … … … …
Zero One One Zero …
… … … … …

66. Living Room
Attic
Bedroom
Stuffed animal solution

67. Low-Tech Solution
Picture by Rolf Huisman / CC0 Creative Commons

68. Conclusions
•Quantum Computing
1. If you want a challenge,
2. And change the world,
3. Because its cool to program for
4. And it works on real hardware ☺

69. So be part of the quantum future !
• Rolf Huisman
• Rolf.Huisman@infosupport.com
• @rlrhuisman
Questions ?
• For more internals, please visit the stand