To program a quantum computer, one must first formulate the problem to be solved as a spin model by mapping it to a set of interacting quantum bits or qubits. The problem is encoded into the states and interactions of the qubits. The connectivity between qubits is defined according to the problem graph. This graph and the interaction weights are then transferred to the quantum computer to find the optimal qubit configuration that solves the given problem. Some potential applications include using quantum annealing to solve optimization problems or running quantum circuits for applications like machine learning. Programming quantum computers is currently challenging but may become simpler over time as the technology develops further.

1. How to program a
Quantum Computer?

2. Early computers were
BIG
Custom
tailoredbritannica.com
HARD to PROGRAM
expensive
useless

3. Think you know how to code ?
Go
britannica.com
program
the
ENIAC!

4. Modern computers are
muuuuuuch “better”...
Code in
Python for
food!
dogstable.com

5. simulate the
Can we
NATURE?

6. e- e-
Few Electrons in a
chunk of metal
# of configurations
# of atoms in the universe!
>

7. ...you’d better
make it
QUANTUM
MECHANICAL!
Richard Feynman,1981

8. Bit Qubitvs
0 or 1 0 or 1
or
everything
inbetween
0
1
0
1
x
x

9. For N Qubits Explore ALL 2^N
configurations at the same time!

10. Explore ALL 2^N
at the same time!

11. In practice allows:
quick search
parallel
computations
solve
optimization
problems
iStockphoto.com/slobo
mobile.ecs.soton.ac.uk

12. Quantum computers
BIG
Custom
tailoreddwavesys.com
HARD to PROGRAM
expensive
useless

13. How to program it?
Quantum annealers Universal
solves a single
problem!
executes
quantum
circuits
ibm.com

14. Quantum annealers
Quantum annealers
cbc.ca

15. H =
X
ij
JijSiSj +
X
i
hiSi
Map your problem to a spin model
...to program it

16. ~512/1000 qubits (spins) out there

17. Example problem:
Satisfy all employees with the
3 types of presents

18. Formulate a problem
Cost =
X
ij
Jij
J > 0 0
min(Cost)

19. Encode states with qubits
3 states 256 states

20. Encode states with qubits
3 states 2^3=8 states
Give Cost
extra states!

21. Encode states with qubits
3 states 3 lowest states
t12 t13
h1
h2 h3
t23
Cost =
X
ij
tijSiSj +
X
i
hiSi

22. Encode states with qubits
3 lowest states3 states
Physical
qubits

23. Interconnect qubits acording to
problem graph

24. Interconnect qubits acording to
problem graph

25. Interconnect qubits acording to
problem graph

26. Transfer graph to computer
and get optimal qubit
configuration

27. Transfer weights to computer
and get optimal qubit
configuration

28. Any real world applications?

29. Any real world applications?

30. Any real world applications?

31. Any real world applications?

32. And it will Eventually get
muuuuuuch simpler...
Code in
Quipper
for food!
dogstable.com

33. Thank you!

34. Quantum Moor’s Law