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spin up (we know it after done a measurement). Then without have to measure it, we can
directly know that the other qubit has spin down. Because of this ability, communication in
quantum computation can reach a very high speed because information can be transferred
instantly, very fast like it overmatch the speed of light.
As quantum computing is on its way to becoming an established discipline of computing
science, much effort is being put into the development of new quantum algorithms. One
of quantum algorithms is Grover algorithm, which is used for searching an element in an
unstructured list of N elements with quadratic speed-up over classical algorithms. Today,
there are some quantum programming languages which can be used to simulate quantum
mechanical and quantum algorithm without having a real quantum computer. In this work,
Quantum Computer Language (QCL) will be used to make a Grover’s quantum search
simulation in a classical computer.
B. Position of the Research
This research is related to an invention of a quantum search algorithm by Lov K. Grover
[1]. His invention presents an algorithm, which is known as Grover algorithm, that is signifi-
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cantly faster than any classical algorithm can be. This quantum search algorithm can search
for an element in an unsorted database containing N elements only in O(√N) steps, while
in the models of classical computation, searching an unsorted database cannot be done in
less than linear time (so merely searching through every item is optimal), which will be done
in O(N) steps. Also, this research is related with Paramita et al work, where their paper
presented a pseudo code for better understanding about Grover algorithm, and Freddy P.
Zen et al work [2], who provide an example simulation of Grover algorithm in their paper.
This research will also try to simulate Grover algorithm in a classical computer using one of
quantum programming languages, Quantum Computer Language (QCL)[3, 4].
C. Significance of the Research
Inpractice, thisresearchcanbeusedasthefastestknownmethodorsolutionforsearching
an element in an unsorted database containing N elements. By using the method in this
research, the searching process can speed-up quadratically over classical algorithms.
D. Problem
Considered points in this work are:
1. Is it possible to simulate Grover algorithm in a classical computer?
2. How many qubits and iterations the program needed to search an element?
3. How minimum and maximum the size of elements in the database that the program
can hold?
E. Objective
The objective of this work is to to make a simulation of Grover algorithm using Quantum
Computer Language (QCL), to know how many qubits and iterations needed for the search-
ing process, and to know how minimum and maximum the size of elements in the database
that can be hold by the program.
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F. Scope
This thesis concern on simulating Grover algorithm in a classical computer using Quan-
tum Computer Language (QCL). The program can search a desired element in an unsorted
database of N elements.
G. Working Methodology
This work begins with designing pseudo code and flowchart for Grover algorithm. Then,
the design will be implemented by using Quantum Computer Language. After that, there
will be several test to know how many qubits and iterations needed forthe searching process,
also to know how minimum and maximum the size of elements in the database that can be
hold by the program.
II. LITERATURE REVIEW
Computer science has grown faster, made an evolution in computation. Research has
already begun on what comes after our current computing revolution. This research has
discovered the possibility for an entirely new type of computer, one that operates according
to the laws of quantum physics - a quantum computer.
1. Way to Quantum Computation
Quantum computers were first proposed in the 1970s and 1980s by theorists such as
Richard Feynman, Paul Benioff, and David Deutsch. At that times, many scientists doubted
that they could ever be made practical. Richard Feynman was the first to suggest, in a talk
in1981,thatquantum-mechanical systems might bemorepowerfulthanclassical computers.
In this lecture [5], reproduced in the International Journal of Theoretical Physics in 1982,
Feynman asked what kind of computer could simulate physics and then argued that only
a quantum computer could simulate quantum physics efficiently. He focused on quantum
physics rather than classical physics. He said that nature isn’t classical, and if we want
to make a simulation of nature, we’d better make it quantum mechanical, because it does
not look so easy. Around the same time, in a paper titled "Quantum mechanical models
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of Turing machines that dissipate no energy" [6] and related articles, Paul Benioff demon-
strated that quantum-mechanical systems could model Turing machines. In other words, he
proved that quantum computation is at least as powerful as classical computation. But is
quantum computation more powerful than classical computation? David Deutsch explored
this question and more in his 1985 paper "Quantum theory, the Church-Turing principle and
the universal quantum computer" [7]. First, he introduced quantum counterparts to both
the Turing machine and the universal Turing machine. He then demonstrated that the uni-
versal quantum computer can do things that the universal Turing machine cannot, including
generate genuinely random numbers, perform some parallel calculations in a single register,
and perfectly simulate physical systems with finite dimensional state spaces. In 1989, in
"Quantum computational networks" [8], Deutsch described a second model for quantum
computation: quantum circuits. He demonstrated that quantum gates can be combined
to achieve quantum computation in the same way that Boolean gates can be combined to
achieve classical computation. He then showed that quantum circuits can compute anything
that the universal quantum computer can compute, and vice versa.
A. Quantum Computers Development
Quantum computers could one day replace silicon chips, just like the transistor once
replaced the vacuum tube. But for now, the technology required to develop such a quantum
computer is beyond our reach. Most research in quantum computing is still very theoretical.
Themostadvancedquantumcomputershavenotgonebeyondmanipulatingmorethan16
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 key advancements
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.
In 1998, Los Alamos and MIT researchers managed to spread a single qubit across
three nuclear spins in each molecule of a liquid solution of alanine (an amino acid used
to analyze quantum state decay) or trichloroethylene (a chlorinated hydrocarbon used
for quantum error correction) molecules. Spreading out the qubit made it harder to
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corrupt, allowing researchers to use entanglement to study interactions between states