# Introduction of Quantum Computing

Computers are getting smaller and faster day by day because electronic components are getting smaller and smaller. But this process is about to meet its physical limit.

Quantum computing is an area of computing focused on developing computer technology based on the principles of quantum theory (which explains the behavior of energy and material on the atomic and subatomic levels). Computers used today can only encode information in bits that take the value of 1 or 0 — restricting their ability.

Quantum computing, on the other hand, uses quantum bits or qubits. It harnesses the unique ability of subatomic particles that allows them to exist in more than one state (i.e., a 1 and a 0 at the same time).

# KEY TAKEAWAYS

- Quantum computing is the study of how to use phenomena in quantum physics to create new ways of computing.
- Quantum computing is made up of qubits.
- Unlike a normal computer bit, which can be 0 or 1, a qubit can be either of those, or a superposition of both 0 and 1.
- The power of quantum computers grows exponentially with more qubits.
- This is unlike classical computers, where adding more transistors only adds power linearly.

# Quantum Computer vs. Classical Computer

**In classical computing,** bits have two possible states **either zero or one**. In quantum computing, a qubit (short for “quantum bit”) is a unit of quantum information — the quantum analogue to a classical bit. Qubits have special properties that help them solve complex problems much faster than classical bits. One of these properties is **superposition**, which states that instead of holding one binary value (“0” or “1”) like a classical bit, a qubit *can hold a combination of “0” and “1” simultaneously*. Qubits have two possible outcomes zero or one but those states are a superposition of zero and one. In the quantum world, qubits don’t have to be in one of those states. As soon as we measure its value it has to decide whether it is zero or one. This is called superposition. It is the ability of the quantum system to be in multiple states at the same time.

*Example there are 4 bytes. The combination of 4 bytes can represent 2⁴=16 values in total and one value a given instant. But in a combination of 4 qubits, all 16 combinations are possible at once*

Classical computing advances include adding memory to speed up computers. Meanwhile, quantum computers help solve more complicated problems. While quantum computers might not run Microsoft Word better or faster, they can run complex problems faster.

For example, Google’s quantum computer that’s in development could help with many processes, such as speed up machine-learning training or help create more energy-efficient batteries.2

Quantum computing has a number of other applications, including securely sharing information. Other methods include fighting cancer and various health concerns, such as cancer and developing new drugs. As well, quantum computers can help improve radars and their ability to detect such things as missiles and aircraft. Other areas include the environment and using quantum computing to keep the water clean with chemical sensors.

**What can quantum computers do?**

- Quantum computers can easily crack the encryption algorithms used today in very little time whereas it takes billions of years to best supercomputer available today. Even though quantum computers would be able to crack many of today’s encryption techniques, predictions are that they would create hack-proof replacements.
- Quantum computers are great for solving optimization problems.

## Quantum computer uses and application areas

A quantum computer cannot do everything faster than a classical computer, but there are a few areas where quantum computers have the potential to make a big impact.

Quantum simulation :- *Examples of quantum systems that we can model include photosynthesis, superconductivity and complex molecular formations.*

Cryptography :-

Optimisation :- *Optimisation is the process of finding the best solution to a problem given its desired outcome and constraints. By running quantum-inspired optimisation algorithms on classical computers, we can find solutions that were previously impossible. This helps us find better ways to manage complex systems such as traffic flows, airplane gate assignments, package deliveries and energy storage.*

Quantum machine learning :- *Machine learning on classical computers is revolutionising the world of science and business. However, training machine learning models comes with a high computational cost and that has hindered the scope and development of the field. To speed up progress in this area, we are exploring ways to devise and implement quantum software that enables faster machine learning.*

Search :- *A quantum algorithm developed in 1996 dramatically sped up the solution to unstructured data searches, running the search in fewer steps than any classical algorithm could.*

## How Do You Build a Quantum Computer?

Building a quantum computer takes a long time and is expensive. Google has been working on building a quantum computer for years and has spent billions of dollars. Google expects to have its quantum computer ready by 2029, although IBM hopes to have a 1,000-quibit quantum computer in place by 2023.

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