In the wake of big data analytics, artificial intelligence and cognitive computer, the search for tiny and powerful computer chips has been on the rise lately. IBM admitted to have spent a whooping sum of $3 billion on computer chip development and research and I am sure other OEM especially Intel is not also sleeping.

 I was going through my google search results for the tiniest and most powerful computer chip ever built and the first search result landed me to IBM’s site which spots their latest 7 nanometer transistor which they claimed to be the world’s tiniest and most powerful chip and would not be commercialized any time soon. The normal process of manufacturing chips which is photolithography was taken to another level in the research and development of the chip and this process is known as extreme ultraviolet lithography. 

![](https://steemitimages.com/DQmZ7Be6FBp4tvJLUNSJVsWthrmzbwn5hvLb63LF54G7NfF/image.png)
<sup>[credit: <a href="https://www.flickr.com/photos/christiaancolen/20607701226">pixabay</a>. CC BY-SA 2.0 license. Author: <a href="https://www.flickr.com/photos/christiaancolen/">Christiaan Colen</a>]</sup>

Computer has greatly helped man in the course of solving his problems but the transformations it brings which I jokingly calls a “curse” is unmatched. I call it a curse because computer has shown us all how insatiable our wants are and this can be seen in the demand for stronger, faster, smarter and smaller computers. 

The quest for “better” computing experience has led scientists and technologists into the world of quantum computing and before I go into explaining what quantum computing is all about, let’s take a brief look at the limitations of your costly latest computer you just purchased. 

<h6>Limitations of classical computers</h6>
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When it comes to classical computing, there’s a man I respect so much and he is the co-founder of Intel and goes by the name Gordon Moore. After observing the trend of even in the history of computer chip development (by the way, a computer is as powerful as its chip and just as we can’t grower bigger than our dreams, a computer cannot do better than its chip, hence, the chip is the computer itself), put forward a “law” which says that transistor integration in a chip (the more transistor a chip contains, the more chance the chip has in performing operations) will double every eighteen months (18). You can check out a plot of transistor integration from the year 1970 to 2016 by Wikipedia <a href=”https://en.wikipedia.org/wiki/Moore%27s_law”>here</a>.

Well, there is a problem with Moore’s law as we approach 1 nanometer integration scale. As valid as Moore’s law is all these years, the behavior of electrons in the transistors changes as we approach atomic scale. This is due to the atomic <a href="https://en.wikipedia.org/wiki/Quantum_tunnelling">quantum tunneling</a> effect electrons has on its barriers at atomic level. 

![](https://steemitimages.com/DQmXe2q8FGbb1o1MueX1Gsk9izUbkaAv7UY1djMSiyY3pnp/image.png)
<sup>[credit: <a href="https://commons.wikimedia.org/wiki/File:TunnelEffektKling1.png">wikimedia</a>. CC3.0 creative commons license. Author: <a href="https://commons.wikimedia.org/w/index.php?title=User:DeepKling&action=edit&redlink=1">Felix Kling</a>]</sup>

Someone might ask, why would this be a limitation to computing today? Well, it’s no news saying that the computer is a digital machine. But that implies that the computer is also a binary machine which also implies that the basic unit of classical computing is the bit which can only hold either of two values, which is either 1 or zero. The computer functions by constantly making decisions in the form of switching. The component that enables the computer to perform this switching action is the transistor and this is why we have billions of transistors in today’s chips. 

But as we keep reducing the size of these transistors in order to make more powerful and portable computers, we will definitely reach a point where the transistors will no longer be able to function as switches thereby defeating its purpose in the first place. The quantum tunneling effect makes it possible for electrons to still pass through a closed circuit by the miniaturized transistor at atomic scale. 

In order to escape the problem of quantum tunneling, we must have to keep the size of the transistors large enough which means that in order to continue developing powerful computers in the future, our computer would be cumbersome making it practically unappealing. 

<h6>What then is Quantum Computing?</h6>
<hr/>
Quantum computing is the application of the principles of mathematics and quantum mechanics in the production of more portable, faster, smarter, cheaper and powerful computer. The laws of classical physics is not entirely the same with the laws of quantum physics. As already stated, the classical computer makes intelligent decisions by performing binary operations (1 or 0), but the quantum computer makes even a more intelligent decision is a shorter period of time by combining both 1 and 0  in another unit of computing called QUBIT. 

<h6>The Qubit</h6>
To understand Qubit, I will use our normal switch to the bulbs in our rooms as an example. When we toggle the switch lever, the light either comes “on” or goes “off”. 

<div class="pull-right"><center><img src="https://steemitimages.com/0x0/![](https://steemitimages.com/DQmZSG5cKAB9zuvvjxYAwqJ9VBBghngm2XFPpAPxfNGwuYZ/image.png))" /><br /><em><sup>[qubit notation and representation <a href="https://commons.wikimedia.org/wiki/File:Simple_qubits.svg" rel="noopener">credit: wikimedia</a> CC3.0 license. Author: Clemens Adolphs]</sup></em></center></div> 


At the “on” state, one dare not touch the terminals of our lamp holders because there are movement of electrons. In classical computers, this is represented by a “1”. In the “off” state, the bulb fails to come up and we can play with the lamp holders, this is because there are little or no movement of electrons in the lamp holder terminals. This state is represented by “0” in classical computers.

Qubits stands for quantum bits and represents both “on” and “off” states of the classical computers and more space to hold more variables. This means that in quantum computing, a bus (a connecting wire) can hold no electron and still hold electron at the same time! Using the home switch example, it means that the bulb can be on and off at the same time. When many qubits are employed in computations, it allows for more multiple options and process information in a space of time even the fastest conventional computer cannot achieve. The enabling properties of the quantum computer are the Qubits which I have already explained, the principle of superposition, Entanglement and Quantum Parallelism. Let’s get to know them in detail.

<h6>Principle of Superposition</h6>
At the atomic level which is the operating level of the quantum computers, it is very possible to have multiple states of the electron. That is to say that something can be at the top and also be down at the same time. Mathematically, at the atomic level, the ground state and the excited states of electron can be suitably represented using Dirac form of notation as ├ |0⟩ and ├ |1⟩ for computation. If the above notation can represent the two quantum states of electron (ground and excited states), according to quantum mechanics the electronic states of an atom is equivalent to the superposition of the primary states,  |0> and |1> and can be represented as:

Ψ = α|0> + β|1>
Where Ψ is a wave function while both β and α are vectors of the complex form satisfying the mathematical condition:
|α|^2 + |β|^2 = 1

<div class="pull-left"><center><img src="https://steemitimages.com/0x0/![](https://steemitimages.com/DQmZPpk7HA54hdqu76vhcWF1LLaBTYHcbe7ok56133k1Ddd/image.png))" /><br /><em><sup>[superposition of qubit <a href="https://commons.wikimedia.org/wiki/File:Quantum_computer.svg" rel="noopener">credit: wikimedia</a> CC3.0 license. Author: <a href="https://commons.wikimedia.org/wiki/User:WhiteTimberwolf">WhiteTimberwolf</a>]</sup></em></center></div> 

Hence the qubit which the basic unit of the quantum computation can exist in the superposition of both 1 and 0. This implies that the qubit can store a 1, 0, both 1 and 0, and can store unlimited number of values in between these combinations. Also increasing the number of qubits exponentially increases the computational ability of the quantum computer instead of linear relationship offered by the conventional transistors. 

The normal transistor used in classical computing requires several electrons (hundreds of electrons) to perform its switching functions but the quantum computer employs what is known as SET (Single Electron Transistors) transistors which requires just a single electron to perform its switching operations.

<h6>Quantum Parallelism</h6>

The quantum microprocessor which will power the quantum computers are direct products of quantum parallelism and the principle of superposition already discussed. The concept of parallelism is comparable to the concept of instruction pipelining of the classical computer instructions. Quantum parallelism allows the quantum computers to carry out multiple operations simultaneously using atoms.

One of the major limitations of the classical computers is its inability to perform complex computations like factorization of big integers, discrete logarithms and even the search problem associated with databases. With the help of quantum parallelism, quantum computers can easily solve this problems much faster. Take for instance it will take a supercomputer which is one of the most powerful classical computer billions of years to factorize a number with 500 digits whereas the quantum computer can do this in just a year!

<h6>Entanglement</h6>

The major building block of the quantum computing are entanglement and the principle of superposition. Entanglement is a term used to describe the strong relationship which exists between different quantum particles. In quantum computing, many particles are linked in such a way that it is impossible to describe one without the other there by making their quantum states inseparable. 

![](https://steemitimages.com/DQmYwxf5WjNoFumeM5z2bRjkBxwLLuE8JfdCjABUZ3zXeLy/image.png)
<sup>[A representation of two qubits in phi minus entangled state. credit: <a href="https://commons.wikimedia.org/wiki/File:Representation_of_the_two-qubit_Phi-minus_entangled_state.svg">wikimedia</a>. CC4.0 license. Author: <a href="https://commons.wikimedia.org/w/index.php?title=User:DavidBoden&action=edit&redlink=1">David Boden</a>]</sup>

Entanglement raises the security of quantum computing to a whole new level because it enables the atoms to spin in unison in one direction and can only be disturbed by an external force (like eavesdropping) and when this happens, the system becomes aware automatically and can initiate counter measures. 

<h6>Problems facing quantum computing</h6>
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<div class="pull-right"><center><img src="https://steemitimages.com/0x0/![](https://steemitimages.com/DQmZLeXc33k633wmtTYEWULWyCwCD33ZGvC5pRakEAujZ4v/image.png)
)" /><br /><em><sup>[quantum decoherence <a href="https://commons.wikimedia.org/wiki/File:DecoherenceQuantumClassical_en.svg" rel="noopener">credit: wikimedia</a> CC3.0 license. Author: Belsazar]</sup></em></center></div> 


The major problem facing quantum computing is the de coherence problem which is the loss of information from the quantum computer to its environment. This is due to the unstable nature of the qubits because once the quantum particles are entangled, a little disturbance disrupts the whole system. Microsoft systems went into the search of a more stable qubit and came up with a type of qubit called Topology Qubits which are more stable than the traditional qubits. 

Apart from the problem of de coherence, quatum computing also faces the problem of quantum factorization of numbers. Quantum factorization requires large number of operation on the coherent qubits in order to factor numbers that can then be processed using the classical methods. Two methods have been proven to solve this problem and these are:
<li>Thermal isolation and</li>
<li>Laser cooling</li>

Research carried out on these two methods shows they are capable of solving the problem of quantum factoring but another problem arises because it is difficult to make such devices without introducing considerable noise during processing of information. 

<h6>Conclusion</h6>
<hr>

As useful classical computing is, it has limited problem solving ability especially in the field of complex computations like the prime factoring of integers with enormous lengths. This would have been possible with the classical computers but we are approaching the limit of transistor integration, hence the need to find better processors which operates at the atomic level. 

<h6>REFERENCES</h6>
<hr>

<ol>
<li><a href="https://en.wikipedia.org/wiki/Quantum_computing">Quantum computing -wikipedia</a></li>
<li><a href="https://www.ibm.com/developerworks/library/l-quant/index.html">introduction to quantum computing-IBM</a></li>
<li><a href="https://xn--https-nw3b//en.wikipedia.org/wiki/Moore%27s_law%E2%80%9D">Moore's Law -wikipedia</a></li>
<li><a href="https://quantum-algorithms.herokuapp.com/433/shor-par/node11.html">Quantum Parallelism-quatum-algorithms</a></li>
<li><a href="https://en.wikipedia.org/wiki/Quantum_entanglement">Quantum entanglement-wikipedia</a></li>
</ol>

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