Contents
Background
Quantum Characteristics
Applications
Quantum Computer Design
Current Challenges
Predictions For The Future
Background
Moore’s Law. Predicted that the
number of transistors on a chip will double every 18-24 months.
The Wall! Transistors can only be
so small. It is believed this will
happen in the next 20 years.
Background
The idea of the quantum computer first immerged in 1982 by Richard Feynman.
In 1994, Peter W. Shor of AT&T Shor’s algorithm to factorize big number
Basic Idea
A quantum computer uses the physical characteristics of atoms to represent 0 and 1.
For example, spin of electrons.
Qubits
Quantum Bits
A normal bit can be either 0 or 1.
Because of superposition, a qubit can be both 0 and 1 at the same time.
There is no equivalency of superposition in classical world.
Qubits
An n-qubit register can store 2n
numbers at the same time, or do 2n
operations at one shot.
It’s exponentially faster!
Application(1)
Cryptography :perfectly secure communication Factorizing large numbers very rapidly
(Shor’s algorithm) Today’s computers would take about a billion years to
factor a 400-digit number. Using this new algorithm, a 400 digit number is
estimated to take about a year to factor.
Application(2)
Searching : especially algorithmic searching (Grover’s algorithm) To search 10,000 items
Classical algorithm uses 5,000 queries average
Grover’s algorithm takes 100 queries
Application(3)
Simulating quantum-mechanical system efficiently
Quantum computers will be able to model certain systems better. David Cory at MIT was the first to simulated a
quantum mechanical process. He simulated a “truncated harmonic oscillator” in July of 1999.
NMR (Nuclear Magnetic Resonance)
Developed at IBM by Issac Chaung in 1996.Protons and Neutrons have spin.Use magnetic field to control the spins.
Ion Traps
Ions in a radio frequency trap interact by exchanging vibrational excitations. Each ion can be controlled by a polarized, properly focused laser beam.
Picture shows the electrode structure.
The electrode is 1mm thick.
Current Challenges
Number of bits in a word. 7-qubit machine is the most advanced to date. All the atoms interact with each other and cause
undesirable results.
Physical size of the machines. Current machines are too large to be of practical use to
everyday society.
Error correction. Many advance have been made but this is still an area
of intense research.
Predictions For The Future
In the next 20 years more research will be devoted to quantum computers.
A working version for specific purposes should be ready to be released on the market by in 20 years.
Very little of our population knows of quantum computers. This will change a great deal also in the next 20
years.
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