Vignesh Ramamurthy

Vignesh Ramamurthy

In the MARVEL multiverse, Ant-Man has one of the coolest superpowers out there. He can shrink himself down as well as blow himself up to any size he desires! He was able to reduce to a subatomic size so that he could enter the Quantum Realm. Some fancy stuff indeed.

Likewise, there is Quantum computing. Quantum computers are more powerful than supercomputers and tech companies like Google, IBM, and Rigetti have them.

Google had achieved Quantum Supremacy with its Quantum computer ‘Sycamore’ in 2019. It claims to perform a calculation in 200 seconds which might take the world’s most powerful supercomputer 10,000 years. Sycamore is a 54-qubit computer. Such computers need to be kept under special conditions with temperature being close to absolute zero.

quantum computing

Quantum Physics

Quantum computing falls under a discipline called Quantum Physics. Quantum computing’s heart and soul resides in what we call as Qubits (Quantum bits) and Superposition. So, what are they?

Let’s take a simple example, imagine you have a coin and you spin it. One cannot know the outcome unless it falls flat on a surface. It can either be a head or a tail. However, while the coin is spinning you can say the coin’s state is both heads and tails at the same time (qubit). This state is called Superposition.

So, how do they work and what does it mean?

We know bits are a combination of 0s and 1s (negative or positive states). Qubits have both at the same time. These qubits, in the end, pass through something called “Grover Operator” which washes away all the possibilities, but one.

Hence, from an enormous set of combinations, a single positive outcome remains, just like how Doctor Strange did in the movie Infinity War. However, what is important is to understand how this technically works.

We shall see 2 explanations which I feel could give an accurate picture on the technical aspect of it.

In Quantum Mechanics, the following is as explained by Scott Aaronson, a Quantum scientist from the University of Texas, Austin.

Amplitude – an amplitude of a positive and a negative state. These could also be considered as an amplitude for being 0, and also an amplitude for being 1. The goal for an amplitude here is to make sure that amplitudes leading to wrong answers cancel each other out. Hence this way, amplitude with the right answer remains the only possible outcome.

Quantum computers function using a process called superconductivity. We have a chip the size of an ordinary computer chip. There are little coils of wire in the chip, nearly big enough to see with the naked eye. There are 2 different quantum states of current flowing through these coils, corresponding to 0 and 1, or the superpositions of them.

These coils interact with each other, nearby ones talk to each other and generate a state called an entangled state which is an essential state in Quantum computing. The way qubits interact are completely programmable, so we can send electrical signals to these qubits, and tweak them according to our requirements. This whole chip is placed in a refrigerator with a temperature close to absolute zero. This way superconductivity occurs which makes it to briefly behave as qubits.

Following is the explanation given according to ‘Kurzgesagt — In a Nutshell’, a YouTube channel.

We know a bit is either a 0 or 1. Now, 4 bits mean 0000 and so on. In a qubit, 4 classical bits can be in one of the 2^4 different configurations at once. That is 16 possible combinations out of which we can use just one. 4 qubits in position can be in all those 16 combinations at once.

This grows exponentially with each extra qubit. 20 qubits can hence store a million values in parallel. As seen, these entangled states interact with each other instantly. Hence while measuring one entangled qubit, we can directly deduce the property of its partners.

A normal logic gate gets a simple set of inputs and produces one definite output. A quantum gate manipulates an input of superpositions, rotates probabilities, and produces another set of superpositions as its output.

Hence a quantum computer sets up some qubits, applies quantum gates to entangle them, and manipulates probabilities. Now it finally measures the outcome, collapsing superpositions to an actual sequence of 0s and 1s. This is how we get the entire set of calculations performed at the same time.

What is a Grover Operator?

We now know that while taking one entangled qubit, it is possible to easily deduce properties for all the partners. Grover algorithm works because of these quantum particles being entangled. Since one entangled qubit is able to vouch for the partners, it iterates until it finds the solution with higher degrees of confidence.

What can they do?

As of now, quantum computing hasn’t been implemented in real-life situations just because the world right now doesn’t have such an infrastructure.

Assuming they are efficient and ready to be used. We can make use of it in the following ways: 1) Self-driving cars are picking up pace. Quantum computers can be used on these cars by calculating all possible outcomes on the road. Apart from sensors to reduce accidents, roads consist of traffic signals. A Quantum computer will be able to go through all the possibilities of how traffic signals

function, the time interval, traffic, everything, and feed these self-driving cars with the single best outcome accordingly. Hence, what would result is nothing but a seamless commute with no hassles whatsoever. It’ll be the future as we see in movies.

2) If AI is able to construct a circuit board after having tried everything in the design architecture, this could result in promising AI-related applications.

Disadvantages

RSA encryption is the one that underpins the entire internet. It could breach it and hackers might steal top confidential information related to Health, Defence, personal information, and other sensitive data. At the same time, it could be helpful to achieve the most secure encryption, by identifying the best one amongst every possible encryption. This can be made by finding out the most secure wall to break all the viruses that could infect the internet. If such security is made, it would take a completely new virus to break it. But the chances are very minuscule.

Quantum computing has its share of benefits. However, this would take years to be put to use. Infrastructure and the amount of investment to make is humongous. After all, it could only be used when there are very reliable real-time use cases. It needs to be tested for many things. There is no doubt that Quantum Computing will play a big role in the future. However, with more sophisticated technology, comes more complex problems. The world will take years to be prepared for it.

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About the Author –

Vignesh is part of the GAVel team at GAVS. He is deeply passionate about technology and is a movie buff.