This presentation discusses the history and concepts of quantum computing. It introduces quantum computers, which perform calculations using quantum bits that can represent more than one value at a time. Operations on quantum computers use quantum gates rather than classical logic gates. One example covered is Shor's algorithm, which can factor large numbers efficiently. Some challenges with quantum computing are decoherence issues and the difficulty of measuring quantum states without destroying superposition. While still in early research stages, quantum computers may one day be able to solve problems exponentially faster than classical computers.

1. CS 1 with Robots
UNIVERSITE DE STRASBOURG
UFR Physique & Ingénierie
English Presentation:
Presented on : December 16, 2015
English professor:
Mrs Sabine Roth
Realized by :
HADDAD ANIS

2. 2
• Overview
• Introduction and History
• Data Representation (Qubits)
• Operations on Data
• Quantum Computer Languages (Shor’s Algorithm)
• Problems and disadvantages
• Conclusion and Open Questions
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3. 3
• Overview
• Introduction and History
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4. 4
• Introduction and History
Moore’s Law
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5. 5
• Introduction and History
Richard Feynman 1982
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Feynman proposed the
idea of creating
machines based on the
laws of quantum
mechanics instead of
the laws of classical
physics.

6. 6
• Introduction and History
David Deutsch 1985
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developed the
quantum Turing
machine, showing that
quantum circuits are
universal.

7. 7
• Introduction and History
What is a quantum computer?
A quantum computer is a machine
that performs calculations based
on the laws of quantum
mechanics, which is the behavior
of particles at the sub-atomic
level.
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“I think I can safely say
that nobody understands
quantum mechanics” -
Feynman

8. 8
• Introduction and History
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Applications:
 Cryptography
 Artificial intelligence
 Teleportation
 Quantum Communication

9. 9
• Overview
• Data Representation
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10. 10
• Data Representation
How can we represent data on
computers ?
Classical computers  Bit
 Can only take ‘0’ or ‘1’
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Ideal for classical
mechanics application

11. 11
• Data Representation
What’s about quantum computers?
Quantum computers  two levels
quantum system  Qubit
 Can take more than one value
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Dosn’t work with
classical mechanics
applications

12. 12
• Data Representation
Qubit
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Physical implementation  must use the two
energy levels of an atom
Ground state Excited state

13. 13
• Data Representation
Qubit
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Qbit in superposition 
Ground State |0>
Excited State |1>

14. 14
• Overview
• Operations on Data
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15. 15
• Operations on Data
Operations on Data
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Classical Computers  Classical Gates
A
B
C
A B C
0 0 0
0 1 0
1 0 0
1 1 1
Input Output
For Example :
The AND Gate

16. 16
• Operations on Data
Operations on Data
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Quantum Computers  Classical Gates ???
A
B
C
A B C
0 0 0
0 1 0
1 0 0
1 1 1
Input Output
The AND Gate
The answer is No !

17. 17
• Operations on Data
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A
B
C
The AND Gate
A B C
0 0 0
0 1 0
1 0 0
1 1 1
Input Output
In these 3 cases,
information is
being destroyed
gate will cause heat
to be evolvedDestruction of Qubits Superposition
Quantum physics nature

18. 18
• Operations on Data
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We must use Quantum Gates
H
State |0> State |0> + |1>
H
State |1>
Hadamard Gate:
The original input state can be derived from the
output state They must be reversible.

19. 19
• Overview
• Quantum Computer
Languages (Shor’s Algorithm)
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20. 20
• Quantum Computers Languages (Shor’s Algorithm)
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Peter Shor (1994)
A quantum computer is capable of
factoring very large numbers in
polynomial time.
F(a) = x^a mod N is a periodic function
7 mod 15 = 1
7 mod 15 = 7
7 mod 15 = 4
7 mod 15 = 13
7 mod 15 = 1
0
1
2
3
4
.
.
.

21. 21
• Overview
• Problems and disadvantages
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22. 22
• Problems and disadvantages …
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 Decoherence  must be isolated
 Uncertainty Principle  Can’t measure without disturb
 Ability to crack passwords
 Can Break every level of encryption
 Complex Hardware Schemes
 Cost

23. 23
• Overview
• Conclusion
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24. 24
• Conclusion
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 In 2001, a 7 qubit machine was built and
programmed to run Shor’s algorithm to
successfully factor 15.
 In December 8, 2015
The D-Wave 2X quantum computer at NASA's
Advanced Supercomputer Facility in Silicon Valley
Quantum chip 1,097 Qubits

25. 25
• Conclusion
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A quantum computer outperformed a
conventional machine by 100 million times
Can quantum computers solve Complete
problems in polynomial time?

26. 26
• References
- How quantum computers work: YouTube video
https://www.youtube.com/watch?v=g_IaVepNDT4
- Quantum Computers. Retrieved on December 1st, 2002 from:
http://www.ewh.ieee.org/r10/bombay/news4/Quantum_Comput
ers.htm
- “The Physics of Quantum Mechanics” James Binney and
David Skinne.
- Quantum Computers: What are They and What Do They
Mean to Us? Retrieved on December 1st, 2002 from:
http://www.carolla.com/quantum/QuantumComputers.htm
- Google: Our quantum computer is 100 million times faster
than a conventional system.
http://www.extremetech.com/extreme/219160-googles-
quantum-computer-is-100-million-times-faster-than-a-
conventional-system
December 16, 2015

27. 27
• Keywords
Quantum mechanics, Qubit, D-wave, Algorithm,
Nanotechnology, Processors, Engineering, Applied physics,
Microsystems, Silicon, Research, Electronic, Performance,
Computers, Binary, Hack, Prototypes, High-Tech revolution,
Quantum processors, Cryptography
December 16, 2015

28. Thank you :
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