Quantum Computing
By: Sarvesh Patil
Tags: Quantum Computer, Quantum Computing, Future, Quantum, Computers

Transistors are combined to create Logic gates which do stuff like an AND gate giving output as 1(one) if both the inputs are 1(one) and a 0(zero) in all other cases. We can also add or subtract two numbers with the help of the logic gates. A group of logic gates breaks enormous tasks. Once we can add or subtract, it becomes eventually easy to do other calculations such as multiplication, division, and other operations.

CONFERENCE AT MIT

However, the tinier the things were getting, the more were the problems created by Quantum Physics. To overcome this problem, a meeting in the early ’80s commenced among the scientist at MIT, where the main motto was to find a solution for this, which 2 scientists of IBM lead, they are CHARLES BENNETT and ROLF LANDAUER. This was the first-ever presentation of the topic and is known as the origin of Quantum Information Science.

After this, the main question is where does quantum relate to electronics. Quantum Physics describes the behavior of an atom or fundamental particles, such as an electron or photons. Quantum Computer operates by controlling the behavior of these particles. But it completely differs in action with the regular computers. A LED light can never be said as a powerful version of a candle because it is a different technology. Same as a quantum computer is also a different & unique technology based on the concepts of quantum physics.

To give an example of how powerful a quantum computer is, imagine you are playing a game and against a normal computer, the computer can make moves just like a human player. Initially, there is a coin with heads on the top, the computer has an option whether to flip it or not, the computer’s move won’t be revealed. Next, it's your turn to do the same. Now, the computer doesn’t know whether we have flipped it or not, Now the computer has one last chance to flip the coin, and after that, if it turns out to be tails, we will win. And if it turns out to head, the computer will win.

COIN GAME

When this game was played with a normal computer the winning chances were almost 50% — 50%, or close to 50%.

RESULT WITH CLASSIC COMPUTER

But, when this game was played on Quantum computer, almost 97% times computer won the game and the rest of the 3% was some operational error in the computer.

RESULT WITH QUANTUM COMPUTER

So how did the Quantum Computer do that? To get known to it, Firstly, we would need to learn about Qubits (QUANTUM BITS). As in the normal world, we have bits. In quantum computing, we use qubits. Bits are either 1 or 0. But qubits are combinations or any number between a spectrum of 1 and 0. The difference is, they can be 0, 1, or both at the same time. This exploits a principle of quantum physics that is Superposition.

Qubits also use the same principle of superposition, which states that when a particle is in its waveform, it can be in N number of states at the same time. Only when the particle is evaluated, it shows a single state. The combination of these N states is its general state. It can be confusing, let’s analyze it with an example. Schrodinger’s cat experiment, where a cat was in a box with poisonous gases in it, the chances of the cat being alive or dead is 50%–50%. When we open the box we can see if the cat is dead or alive, but what before opening it? The principle of superposition says that before we open the box, the cat is alive and dead at the same time. Only when we open the box, we see the result. Using the same principle, a Qubit is 1 & 0 at the same time.

SUPERPOSITION

So when the game was played with a quantum computer. In quantum computer’s turn, it turned it into a combination of heads and tails, just like a fluid in which whether you flip it or not, there would exist a combination of 0 and 1. And in the final move, a quantum computer can unmix the mixture and perfectly recover the output it wants, which helps it to win almost all the time.

FUNCTIONING OF QUANTUM COMPUTER

As we saw, it is different from a Classical computer, a quantum computer would always need a classical computer by its side. The problem which we provide to the quantum computer is through a classical computer. In such cases, a quantum computer allows to simultaneously go through n number of probabilities. It allows you to calculate the 2^n number of combinations, where n is the number of Qubits. So if we create a quantum computer with 20 qubits. It will have 2²⁰, i.e. 1,048,576 configurations in one shot.

Many problems in the world, could not only be solved by a classical computer but also by a supercomputer. This happens because of its exponentially greater number. For example, if we try to find the factor of two prime numbers, it would take 28,000,000,000,000,000,000,000 years for current supercomputers to find it, but a quantum computer can compute this in 100 sec. This tells us about the power of a quantum computer.

Even though Quantum Computers are powerful enough to compute large computations, they cannot perform everyday activities like a normal computer. Quantum computers do not have memory or a processor. A conventional computer has a complex architecture which we miss in a quantum computer. They only have a group of Qubits that helps them to perform complex computations.

Let’s find some Facts about a Quantum Computer.

● To make a quantum computer work, the temperature, which we need is Absolute ZERO Temperature, which is about -273.15⁰C or 0 Kelvins.

● The way we send information to a Quantum Computer is, by sending a series of microwave pulses to a Quantum computer.

● Qiskit is the language generally used by programmers to program a Quantum computer.

● For making a Qubit, we require the electron from the outermost orbit of Phosphorus, which acts as a qubit.

● The storage of Information is exponentially denser in a quantum computer than that of a classic computer since a quantum computer is exponential in nature.

● There are 10³⁰⁰ molecules in the whole universe. So, we can represent each and every molecule in the universe in just 300 Qubit quantum computers.

Here are Some Quantum Computers :

IBMQ by IBM

The First is The IBMQ, which is a 16 Qubit quantum computer and is designed by IBM. This was the first-ever made Quantum Computer.

SYCAMORE by Google

The second is SYCAMORE which is The First 53 Qubit quantum computer. And is designed by Google.

In October 2019, Google made a big announcement that it has achieved quantum supremacy. This means defeating a supercomputer in a certain task very efficiently. And this may be the Future of Computing.