Transcript A brief introduction to Quantum computer Alri Moore`s law the

A brief introduction
to
Quantum computer
Alri
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
speed and computing
capacity
physical limits
atomic level
quantum theory
classical computer
——>
quantum computer?
Qubit
a linear superposition of basis states
both states at the same time
two-state quantum-mechanical system
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
Faster-than-light
Quantum mechanics
not true communication
two observers in different locations see the
same system simultaneously
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?
Reversible computing
the relation of the mapping from states to their
successors must be one-to-one
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
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))
Universality and Toffoli
gate
Boolean functions：
OR, AND，NOT gates
NOR gates
NAND gates
Toffoli gate
NAND(a,b)=Toffoli′(a,b,1)
NOT(x)=Toffoli′(1,1,x)
AND(a,b)=Toffoli′(a,b,0)
basic quantum computers that can perform
certain calculations
D-Wave Systems
512-qubit
D-Wave Two quantum computer
new era
References
https://en.wikipedia.org/wiki/Moore%27s_law
https://en.wikipedia.org/wiki/Qubit#Bit_versus_qubit
https://en.wikipedia.org/wiki/Quantum_entanglemen
t
http://www.technologyreview.com/view/422511/th
e-fantastical-promise-of-reversible-computing/
https://en.wikipedia.org/wiki/Toffoli_gate
http://www.dwavesys.com/quantum-computing
Thank you!