Foray into the world of Quantum Computing 

We are living in a world where “experience” is counted as the new currency. One of the fore-bearers of this experience comes from data insights. Data, which is now termed as the new “fuel” coupled with Insights, both reactive and predictive, “AI”, which is now termed as the new “Electricity”. 

Only a small portion of the world know that it is going to be hit in the next couple of years, with a new form of “force”, a force which would defy all common sense , a force which was so aptly described by one of the best physicist of our times, Richard Feynman

“If you think you understand quantum mechanics, you don't!!

When I was a kid in the university, it was widely believed that 1% of the world understands Einstein’s theory of general relativity but I can safely say today, no one understands Quantum Mechanics to its core and this non understandable, yet fully functional, fully true with all its theories is going to knock the software world with a force greater than the force of electricity described above. Yes, my friends, some of you would have guessed it right, it is Quantum Computing

In order to understand Quantum Computing , I would urge the reader to keep his/her common sense on for the first half of this paper and then slowly remove it on my request to understand the dynamic world you are about to enter. It is only when “Monkey Logic” is removed, that you begin to appreciate the vastness of quantum world that exists dormant in the sub-atomic particles.

Common Sense

Common sense tells us that we use “encryption” to ensure that the data we send across the wire is protected and preserved. The most common encryption algorithm used today is the 2048 bits based “RSA” algorithm. RSA algorithm develops itself from an algorithm called as the Shor’s Algorithm and Shor’s algorithm was based on a very simple principle of prime numbers

Take two prime numbers and multiply them. The resulting key becomes the public key and one of the multiplied keys can become the private key with an individual. Now, from the brute force theory, if we have the public key, it is very easy to get the colluding primes to find the private key for encryption, except that the colluding primes are so big (2048 bits) that it would take your normal PC some 48 quadrillion years to break this. The world’s largest and fastest super computer would also take about 2 billion years to break this, so essentially we are safe.

Even if Moore’s law holds (which I suspect would not), we would still enhance the speed and processing of the computer to a level where a computer would take 4 quadrillion years and a supercomputer about 20 million years so we are safe with RSA…Wrong!!

A fundamental shift, which I described as the Force coming in our lives, would disrupt this factor with the ability to break RSA in less than 100 seconds. If I was say Quantum Computing would essentially change the way computers program by making them massively parallel, it would be the end of this paper, unless I know the reader wishes to know a lot more nuances.

A Little History

It is essential to understand a little bit about the history of what triggered this Force in nature and you can blame it all on “Light”, yes “Light, which is both “Weird” and “Awesome” 

By the turn of the 19th century, Light was considered to be a wave. It was proven by the famous Thomas Young’s experiment of double slits. Young took a light beam and directed it to double slit, as shown below. Light coming out of the slit was measured by a light detector, a plate at the end of the double slits. What Young observed were patterns of dark and light interspersed at the back. We all know this from our classical wave theory as a phenomenon called “interference” .We also know this from our practical life, when we throw a stone at a still pond and the patterns we observe. The patterns that exhibit interference, ensuring that water essentially dissipates in a wave like pattern.

Well, this experiment essentially proved that light was a wave and it exhibited the usual wave like characteristics of “crests” and “troughs” when two or more waves collided which essentially caused the dark and light bands at the back of the double slits

Come 1900s, scientists observed another phenomenon, which was to become the precursor of yet another mystery in science. Scientists observed that when light was shined on a metal it emitted electrons. (Well no guesses here because a metal is made up of electrons and hence electrons help conduct electricity. It is for this reason that metals are good conductors of electricity).

 However, it was observed that only some kinds of light emitted electrons within some metals. The first thought was that since light is a wave and a wave has energy, it would take wave with an appropriate energy to dispel electrons. What this meant was whether the light source was far away or closer to the metal in question, it would enable the metal to release electrons. Well!! Surprise!! Surprise!!! Nothing of this sort happened. It did not matter, how far or close the light source was, all it mattered was, what the wavelength of the light was. 

It took no other than the brilliant young physicist Albert Einstein in 1905 to prove that light it its wake carried discrete packets of energy, called photons which dispelled electrons when they had the requisite energy. Photons carried these discrete packets of energy which were named “Quanta”. 

Einstein got his Noble prize in 1921 based on this theory. Yes, ladies and gentlemen, Einstein did not get his Noble prize for “theory of relativity” but for the light effect called as “photoelectric effect”

In comes another brilliant scientist, Louise De Broglie who shakes the scientific community with his suggestion that goes like this

“If Light is a wave that can behave as particles, can particles behave as waves too”

Louie De Broglie was ridiculed by his professors. They were confused whether this guy was a nut case or a genius. It took none other than Einstein to realize his genius. He was indeed right. In fact De Broglie went ahead to also duplicate the double slit experiment, but this time with electrons (as sub atomic particles)

The results were as De Broglie expected. When an electron beam was shined on a double slit used by Young, the effect seen at the Geiger counter at the plates was astonishingly the same as a wave. Electrons concentrated as particles with light and dark region. The wave and particle duality was confirmed. De Broglie even went ahead and calculated the wavelength of an electron to confirm his findings.

It was thus confirmed that light behaves as a particle and a wave and a duality law was established in nature. Edwin Schrodinger went ahead and even gave a wave function to each particle as below

This wave equation has a partial derivative and is the corner stone of all things in nature. The only component that comes out from this equation is the constant “h”. This constant is called as the Planck’s constant from the famous Max Planck .The significance of Planck's constant in this context is that radiation, such as light, is emitted, transmitted, and absorbed in discrete energy packets, or quanta, determined by the frequency of the radiation and the value of Planck's constant. Planck even had a number associated with this constant and that number is as follows

6.62607004 × 10-34 m2 kg / s

Yes, and the reason it is called a “constant:” is because it is a constant of nature. It is because of the Planck’s constant that quantum effects are only seen in subatomic particles. Had Planck’s constant been larger, we would have seen these effects in our classical world as well.

Schrodinger even devised a thought experiment including a cat. (No animal was harmed. It was a thought experiment only)

According to him, take a cat and put it in a box that is closed and has a radioactive material source. This radioactive material has a 50% decay rate. At a certain level, the material decays, clips the hammer and the hammer breaks the poison bottle. Is the cat dead or alive? Well unless the box is opened no one is sure whether the cat is dead or alive. Inside the box, the cat is in a state of quantum randomness which can have both probabilities and duality. Only when the box is opened and observed, can the observer know the classical state of the cat

History thus took us to a time, when wave and particle duality got created, a wave function for each particle was created and a constant driving this cause was established

Quantum Computing 

Let’s dive straight into it then. There is duality in nature to an extent that a particle exists as both wave and a particle but how does it affect computing would be the next big question. 

Silicon chips as we see it in computers today work on the principle of voltages. A +5 voltage (any positive) is deemed as “1” and a lack of voltage or “0” is considered to be a 0. This bits as we call it defines the entire logical structure and architecture of how computers compute today, but these are mathematical and classical jargons (Silicon chips being very real in the classical world we live in)

The Quantum world on the other hand is more probabilistic. As explained by Schrodinger’s thought experiment, a bit can be “0” or “1” at the same time. It is only when we observe the bit can the real nature be found out. In other words, a quantum system continues to be in a state of quantumness unless measured classically. It is only when a quantum system is measured, does it leave the quantum richness and collapses into a classical state.

This phenomenon described above gives the essence of speed. Where 1 bit in the classical world, allows a user to either use it as 0 or 1, a quantum bit (also referred to as Qubit) allows a superposition of both states at the same time unless measured so it allows 2 combinations. Let us increase the bits to 3 or n. A classical bit allows one out of the 2ⁿ combinations, a Qubit allows all the 2n combinations simultaneously which is a massively parallel approach to computing. Imagine a 32 qubit computer, where we can do 2³² parallel computations simultaneously to get an output. This number corresponds to the number of stars in our galaxy.

A qubit is referred to as |0> or a |1>, rather than just “0” or “1” . This is called a “Ket” notation. And these states are called Computational Basis States.

What is a Qubit? A qubit is just a vector is a complex vector space.

I would leave this paper at this point and go on and explain this in my papers later, Happy reading!!!

Image by Pete Linforth from Pixabay