1. A brief introduction to Quantum computer
Alri

2. Moore's law
the number of transistors in a dense integrated circuit has doubled approximately every two years
——- Gordon E. Moore, the co-founder of Intel
晶体管

4. speed and computing capacity

5. physical limits
atomic level

6. quantum theory

7. classical computer ——> quantum computer?

8. two-state quantum-mechanical system
Qubit
a linear superposition of basis states
both states at the same time
two-state quantum-mechanical system
量子比特，线性 叠加态

9. Quantum entanglement system as a whole
one particle of an entangled pair "knows" what measurement has been performed on the other, and with what outcome

10. Faster-than-light Quantum mechanics
not true communication
two observers in different locations see the same system simultaneously

11. Energy and computing Landauer's principle:
the erasure of n bits of information must always incur a cost of
n k T ln(2)
in thermodynamic entropy
erasure of information — necessary?

12. Reversible computing
the relation of the mapping from states to their successors must be one-to-one

13. Toffoli gate CCNOT gate "controlled-controlled-not" gate
any reversible circuit can be constructed from Toffoli gates
3-bit inputs and outputs : if the first two bits are set, it inverts the third bit, otherwise all bits stay the same

14. (a,b,c)=Toffoli(Toffoli(a,b,c))
Toffoli gate
The Toffoli gate is reversible (but the Toffoli' used above is not). This means that any computation did with it can be undone. This is:
(a,b,c)=Toffoli(Toffoli(a,b,c))

15. Universality and Toffoli gate
Boolean functions：
OR, AND，NOT gates
NOR gates
NAND gates
若知道一个封闭物理系统的最终状态，则可以求出该系统的最初状态，这样导致在不擦除信息的前提下可进行计算

16. Toffoli gate NAND(a,b)=Toffoli′(a,b,1) NOT(x)=Toffoli′(1,1,x)

17. basic quantum computers that can perform certain calculations

18. D-Wave Systems
512-qubit
D-Wave Two quantum computer
1000万美元

19. new era

20. References https://en.wikipedia.org/wiki/Moore%27s_law t
e-fantastical-promise-of-reversible-computing/

21. Thank you!