Introduction to Quantum Computing: Classical Mechanics vs Quantum Mechanics
Welcome Readers, after a long break from writing, I will be writing a series of blogs with detailed description of Quantum Computing, its applications and how it works.
Quantum Computing works on the principles of Quantum mechanics, so before moving towards the working of Quantum computing and its applications, it is important to know the difference between Classical Mechanics and Quantum Mechanics and the concepts based on which quantum computing works on.
So, in this blog, I will discuss what is the difference between Classical Mechanics and Quantum Mechanics and other basic terminologies in Quantum Mechanics in order to understand the concept of Quantum Computing.
Classical Mechanics vs Quantum Mechanics
In Classical Mechanics, all the normal sized moving bodies or objects can be accurately predicted using the basic laws of physics, those laws were coined by Sir Issaac Newton. This is can also be termed as Newtonian Mechanics.
But things will start to get change when it comes to very small particles called subatomic particles such as electrons or protons, which are moving at very high speed or moving nearing to the speed of light, as the results may be inaccurate. And in such cases, Newtonian Mechanics (Classical Mechanics) fails which gave rise to Quantum Mechanics.
Quantum Mechanics also known as quantum physics deals with understanding the behaviour of moving subatomic particles such as protons or electrons. We can define the behaviour of such subatomic particles.
For example, when a water molecule is broken down, then there are 2 hydrogen atoms and one oxygen atom, and when these atoms are broken down then there are protons, neutrons and electrons. So, Quantum mechanics is about understanding the movement and behaviour of these particles i.e. proton, neutrons and electrons.
Single Quantum Energy:
Quantum is a discrete packet of energy, discrete can be defined as whole packet, it cannot be a half quantum of energy or one third quantum of energy or quarter quantum of energy.
One photon of light carries exactly one quantum of energy, photon is a very small unit of light energy.
Characteristics of Quantum Objects:
Quantum Objects are weird because its predictions are dramatically unlike our everyday experience i.e. particles behaving like waves.
The effects involved gets larger as objects gets very smaller. We will see some weird some characteristics of Quantum Objects
- Wave Duality:
The dual nature of light means that, in some experiments, it behaves as a wave. In other experiments, light behaves as a particles.
This behaviour also demonstrated by double slit experiment.
In double slit experiment, if we pass a beam of light through only one slit then you can see particles of light on the screen, and when that beam of light is passed through two slits in plane then you can see the light is spread out across the screen.
2. Superposition:
Superposition of two state means a quantum system is in two state at a time unless and until observed. And this superposition is very useful in quantum computing. The concept of superposition is further explained by famous Austrian-Irish Physicist Erwin Schrödinger.
Schrödinger stated that if we place a cat and something that could kill the cat in a box and sealed it, we cannot know if the cat was alive or dead until we opened the box, so that until the box was opened, the cat was both “dead or alive” or in superimposed state.
3. Quantum Entanglement:
Quantum Entanglement is when two particles become closely linked, and whatever happens to one immediately effects the other, regardless of where they are and how far apart they are.
Let’s say above two particles are closely linked, and one particle is at my home and the other one is at your home, so whenever the behaviour of one particle that is at my home changes which will immediately effect the state of the other particle which is at your home or vice versa.
Which means even if one particle is far away in another galaxy, then information from one particle will travel mysteriously to another particle far away in another galaxy affecting the state of that particle.
Hence it is also named as “Spooky action at a distance”.
4). Quantum Tunneling:
Quantum Tunneling is the quantum mechanical phenomenon where a subatomic particle disappears from one side of a potential barrier and appears on the other side without any current appearing inside the wall.
In modern computing transistors are used for transmitting information based on switching electrical signals as shown in the figure below.
As voltage is applied to transistors we can control or switch the electrical signals but in terms of smaller scale i.e. at quantum scale this role will not applicable, if you apply barrier (i.e. p-type base), electrons will not be stopped by this barrier even if you apply a stronger barrier, electrons will mysteriously appear on the next side.
So above are all kinds of characteristics of quantum mechanics which makes quantum computing very interesting to study and implement.
I will not be going deeper in above concepts in my future blogs of Quantum Computing series but I will show what all these have to do with Computers.
In my next blog in Quantum Computing Series, I will discuss the difference between Classical bit and Quantum Qubit.
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Suggestions are most welcome and do comment, if concepts I have mentioned need correction.
Thank you for reading.