What is Quantum Computing and How it works?

 

Quantum computers are much more powerful than supercomputers. Large tech companies like IBM, Google, and Rigetti use them. Quantum computer ‘Sycamore’ was achieved by Google in 2019 with its Quantum Supremacy. Sycamore claims to perform calculations in 200 seconds which is usually done by supercomputers in 10,000 years. It is a 54-qubit computer. Special conditions with temperature as low as zero are required to keep such computers. 

Quantum Physics

Quantum computing falls under Quantum Physics. Superposition and Qubits (Quantum Bits) are the two components where Quantum computing’s heart and soul resides. What are these? Take an example of a coin and spin it in the air. The outcome of the coin on reaching the ground can either be head or tail. This cannot be exactly said until it touches the ground. However, when the coin is in the air it is head and tail both at the same time (Qubit). This condition can be called Superposition.

How it works

Bits are combinations of 0’s and 1’s (negative or positive states). On the contrary, Qubits have both at the same time. Qubits pass the “Grover Operator” at the end. This Grover Operator washes away all the possibilities, except one. Therefore, only one single positive outcome remains from a large set of combinations.

It is very important to understand how this exactly works. Two explanations will help to give an accurate picture. 

Explanation 1: In Quantum Mechanics, the following is as explained by Scott Aaronson, a Quantum scientist from the University of Texas, Austin.

Amplitude:

- An amplitude of negative and positive state

- These could be considered as 0 and 1

- Amplitudes that lead to wrong answers should cancel out each other

- Amplitude with the right answer remains

Superconductivity is what Quantum computers function on. Size of the chip is the same as the size of a normal computer chip with small coils of wire on the chip visible with naked eyes. Two different kinds of Quantum states of current flows through these coils, either corresponding or superposition to 0 and 1. An entangled state is generated when these coils interact with each other. This is an important state in Quantum computing. The Qubit interactions are programable. This allows to send electrical signals to qubits and also tweak them as required. With temperature almost zero, the chip is then put inside the refrigerator. This is how superconductivity occurs.

Explanation 2: This 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 only one can be used. If 4 qubits are kept in position, it can all the 16 combinations at once. This grows with every extra qubit. Hence, 20 qubits can store a million values parallelly.

A normal logic gate, to produce a definite output uses a simple set of inputs. A quantum gate to produce another set of superpositions as its out manipulates an input of superpositions and rotates probabilities.

Grover Operator: Grover algorithm works because of these quantum particles being entangled. Since one entangled qubit can vouch for the partners, it iterates until it finds the solution with higher degrees of confidence.

Quantum computing hasn’t been in real-life situations. Assuming they are efficient and ready to be used. We can make use of it in the following ways:

- Self-driven cars to pick up the pace by calculating the road outcomes

- If AI can construct a circuit board after having tried everything in the design architecture, this could result in promising AI-related applications.

The above article has been taken from GAVS Technology, who provide Digital Transformation Services and Solutions and, Cybersecurity and Compliance Services in USA.