Quantum Computers 3
Transcript of Quantum Computers 3
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A quantum computer, if built, will be to an ordinary computer
as a hydrogen bomb is to gunpowder, at least for some types of
computations. Today no quantum computer exists, beyond
laboratory prototypes capable of solving only tiny problems, and
many practical problems remain to be solved.
Yet the theory of quantum computing has advanced
significantly in the past decade, and is becoming a significant
discipline in itself. This explains the concepts and basic
mathematics behind quantum computers and some of the
promising approaches for building them.
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The massive amount of processing power generated by
computer manufacturers has not yet been able to quench our
thirst for speed and computing capacity
In 1947, American computer engineer Howard Aiken said that
just six electronic digital computers would satisfy the computing
needs of the United States. Others have made similar errant
predictions about the amount of computing power that would
support our growing technological needs.
Of course, Aiken didn't count on the large amounts of data
generated by scientific research, the proliferation of personal
computers or the emergence of the Internet, which have only
fueled our need for more, more and more computing power.
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Will we ever have the amount of computing power we need or
want? If, as Moore's Law states, the number of transistors on a micro
processor continues to double every 18 months, the year 2020 or 2030will find the circuits on a microprocessor measured on a scale.
And the logical next step will be to create quantum computers,
which will harness the power of atoms and molecules to performmemory and processing tasks. Quantum computers have the potential
to perform certain calculations significantly faster than any silicon-
based computer.
Scientists have already built basic quantum computers that can
perform certain calculations; but a practical quantum computer is still
years away. In this article, you'll learn what a quantum computer is
and just what it'll be used for in the next era of computing
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You don't have to go back too far to find the origins of quantum
computing.While computers have been around for the majority of
the 20th century, quantum computing was first theorized less than30 years ago, by a physicist at the Argonne National Laboratory.
In 1982 - Feynman proposed the idea of
creating machines based on the laws of quantum
mechanics instead of the laws of classical physics.
Paul Benioff is credited with first applying
quantum theory to computers in 1981. Benioff
theorized about creating a quantum Turing
machine. Most digital computers, like the one you
are using to read this article, are based on the
Turing Theory
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The Turing machine, developed by Alan Turing in the 1930s, is a
theoretical device that consists of tape of unlimited length that is
divided into little squares. Each square can either hold a symbol (1or 0) or be left blank.
A read-write device reads these symbols and blanks, which
gives the machine its instructions to perform a certain program
Well, in a quantum Turing machine, the difference is that the tapeexists in a quantum state, as does the read-write head. This means that
the symbols on the tape can be either 0 or 1 or a superposition of 0 and
1; in other words the symbols are both 0 and 1 (and all points in
between) at the same time.
1985 - David Deutsch developed the quantum Turing
machine, showing that quantum circuits are universal
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Qubits represent atoms, ions, photons or electrons and their
respective control devices that are working together to act as
computer memory and a processor. Because a quantum computer
can contain these multiple states simultaneously, it has thepotential to be millions of times more powerful than today's
most powerful supercomputers.
Quantum computers aren't limited to two states; they encode
information as quantum bits, or qubits, which can exist insuperposition.
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A quantum Turing machine
can perform many calculations
at once
This superposition of
qubits is what gives quantum
computers their inherent
parallelism. According tophysicist David Deutsch, this
parallelism allows a quantum
computer to work on a
million computations at once,while your desktop PC works
on one.
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A 30-qubit quantum computer would equal the processing
power of a conventional computer that could run at 10
teraflops (trillions of floating-point operations per second).
Today's typical desktop computers run at speeds measured in
gigaflops (billions of floating-point operations per second).
Quantum computers could one day replace silicon chips, just
like the transistor once replaced the vacuum tube. But fornow, the technology required to develop such a quantumcomputer is beyond our reach. Most research in quantumcomputing is still very theoretical.
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The most advanced quantum computers have not gone beyond
manipulating more than 16 qubits, meaning that they are a far cry from
practical application. However, the potential remains that quantum
computers one day could perform, quickly and easily, calculations that
are incredibly time-consuming on conventional computers. Several keyadvancements have been made in quantum computing in the last few
years. Let's look at a few of the quantum computers that have been
developed
Forty qubits could have the same power as modern supercomputers.
According to Chuang a supercomputer needs about a month to find a
phone number from the database consisting of world's phone books,where a quantum computer is able to solve this task in 27 minutes
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1998
Los Alamos and MIT researchers managed to spread a single qubitacross three nuclear spins in each molecule of a liquid solution of
alanine
2000
In March, scientists atLos Alamos National Laboratory
announced the development of a 7-qubit quantum computer within
a single drop of liquid.
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2001
Scientists from IBM and Stanford University successfullydemonstrated Shor's Algorithm on a quantum computer. Shor's
Algorithm is a method for finding the prime factors of numbers
(which plays an intrinsic role in cryptography). They used a 7-qubit
computer to find the factors of 15. The computer correctly deducedthat the prime factors were 3 and 5.
2005
The Institute of Quantum Optics and Quantum Information at the
University of Innsbruck announced that scientists had created the
first qubyte, or series of 8 qubits.
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2006Scientists inWaterloo and Massachusetts devised methods for
quantum control on a 12-qubit system. Quantum control becomes
more complex as systems employ more qubits.
2007
Canadian startup company D-Wave demonstrated a 16-qubit
quantum computer. The computer solved asudokupuzzle and otherpattern matching problems. The company claims it will produce
practical systems by 2008.
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Our current methods of encryption are simple compared to the
complicated methods possible in quantum computers. Quantumcomputers could also be used to search large databases in a
fraction of the time that it would take a conventional computer.
Other applications could include using quantum computers to
study quantum mechanics, or even to design other quantum
computers.
If functional quantum computers can be built, they will bevaluable in factoring large numbers, and therefore extremely
useful for decoding and encoding secret information. If one were
to be built today, no information on the Internet would be safe
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It is important that making a practical quantum computing is still far in
the future. Programming style for a quantum computer will also be quite
different. Development of quantum computer needs a lot of money. Even
the best scientists cant answer a lot of questions about quantum physics.
Quantum computer is based on theoretical physics and some experiments
are already made.
Building a practical quantum computer is just a matter of time. Quantum
computers easily solve applications that cant be done with help of todays
computers. This will be one of the biggest steps in science and will
undoubtedly revolutionize the practical computing world
COCLUSION
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