Quantum Computing

Quantum.

Have you ever heard about the term, “Quantum Physics”?

It’s a branch of physics that deals with quantum stuff, duh!

“Quantum means the minimal amount of physical entity”. See, there are two physics normal physics and quantum physics. When we scale to the sub-atomic level, the notions of normal physics do not apply.

You see, at sub-atomic level particles act as waves and waves act as particles. This is called the “Wave duality” behavior. The interesting thing here is no one could predict what nature it shows at what instance? It exhibits both properties simultaneously until you measure it - then it’ll read as one of it, crazy right!? It gets crazier, when unobserved, it’s not just one of both states, but an uncertain combination/proportion of both states. This phenomenon is called as Superposition.

There is a famous thought experiment by Scientist Erwin Schroedinger called “Schroedinger’s Cat”, that hypothesize that the cat is both alive and dead at the same time until inspected upon by external entity.

Quantum computers are here!

Quantum computers are here and they’re fast as hell. What does this have to do with you? What if I tell you, suddenly your passwords won’t be secure anymore. Quantum computers, in theory, can decrypt the most sophisticated software encryption technologies used today like RSA, SHA, etc. No matter, what your take is on the technology, this affects all the internet user.

Classical computers use circuits of transistors on a silicon chip, these transistors are used in logic gates like AND, OR, etc which in turn create small computing modules like a Sum Adder. Thing is, transistors are approaching the atom in size, and physically just can’t any smaller than this - that is without indulging in the quantum world.

What makes quantum computers so fast?

Classical computers work in bits

Classical computers work in bits - 0s and 1s - a proper arrangement of these bits defines some specific information. For example; a computer won’t understand the character ‘A’, it recognizes only 0s and 1s, so it saves ‘A’ as ‘0100 0001’ Given that it uses UTF-16 encoding but let’s not go there.

What if I asked you how is a bit itself is stored? It is not physically written as 1 or 0, right? Modern devices store a bit as a current pulse, or a direction of magnetization, one being 0 while the other 1.

Quantum computers work in qubits.

A qubit, at an instance, can be in any proportion of 0 and 1. Superposition.

Let me get things in proportion (excuse the pun), 4 bits [0001, 0010, etc] can represent a total 16 numbers, but at an instance be only one of the 16 numbers. 4 qubits, on the other hand, can be all the 16 numbers at once. Like the magnetization of a stored bit, a qubit exhibits properties as its magnetic spin and polarization. Unlike normal logical gates, this has quantum gates that take a superposition as input and output another superposition of qubits.

How pragmatic are these computers?

Quantum computers are not just fast, they are efficient searching beasts - a utility used in many computer fields. There are searching algorithms that exploit the superposition phenomenon and provide seemingly unnatural results. Take, Grover’s Algorithm for example, it’s an unstructured data searching algorithm. Say, you have four cards one of which is a Queen of hearts and the cards are shuffled. What is the worst case scenario, for getting the queen? Four (Complexity being O(n)). Grover’s algorithm gets it right on the first freaking try, every freaking time (See this IBM_Research video.) (Complexity: O(√n))

What first used to take 1,000,000 tries is reduced to 1,000 tries.

How long till it becomes commercial?

Well, the technology is still in its vacuum tubes phase, we certainly don’t see it hitting commercial markets anytime soon. IBM has made the quantum computers accessible to anyone from clouds though and people are already making prolific use, someone has written the first game on a quantum computer.

This is the dawn of a new era, we do not know how long until classical computers will become obsolete.

According to me, quantum computers are things straight out of science fiction. What do you think?