# Quantum Computing

### What is Quantum Computing?

Quantum computing is a field of computer science that uses quantum mechanics such as superposition to perform computations. These classical computers which perform quantum computation are known as quantum computers. Our traditional machines use bits to perform calculations while a quantum computer uses qubits to perform calculations.

We encounter the benefits of classical computing every day. Though there are limitations to our computers and there exist problems that our computers will never be able to solve. For enigmas above a specified extent and complexity, we don’t have sufficient computational strength on Earth to tackle them.

### Bits and Qubits (Quantum bit) in Quantum computing.

A standard bit that our systems use is represented by either 0 or 1. 0 means don’t let the signal pass, whereas one means let the signal pass. So there can be only one representation at a time.

On the other hand, quantum bits have the property of both 0 and 1 at the same time. There is a probability like 1 is 60%, and 0 is 40%, etc. What this provides us is more memory. There are some ways to create a qubit. we can use superconductivity to create and maintain a quantum state. We need to keep the superconducting qubits cool for a long period of time. Errors are introduced due to heat in the system that is the reason quantum computers operate at cooler temperatures close to zero, colder than even the vacuum of space.

The primary point to note here is that using 2 bits can be either 00, 01, 10, 11. But when we are working with the qubits, they will hold the properties of 00, 01, 10, 11 all at the same time.

We use majorly three properties of Quantum computing.

- Superposition
- Entanglement
- Interference

Let’s have a look at the above topics in detail.

**Superposition**

Suppose we take a coin and spin it, the state of the coin, while spinning is both heads and tails. This phenomenon is superposition. Superposition is the bit’s ability to be in both states 1 and 0 at the same time.

**Entanglement**

We use the word entangled in our everyday life. Entangled means that things are connected with each other and can be separated. In the quantum world when we entangle things it is really hard to separate them.

For example, you have two fair coins “A” and “B” and you spin them together. If the head appears on “A” theme the “B” will also be the same as “A” head. On the other hand, if tails appear on the “A” coin then “B” will also be tails. These two coins are entangled.

**Interference**

Interference is a phenomenon when two waves combine together to form a bigger or smaller wave. In quantum computers, interference is used to amplify the kind of signals toward the right answers and cancel the type of signals that are leading to the wrong answer.

### How quantum computing affect our lives?

**Artificial intelligence**

Artificial intelligence depends on algorithms that use a massive amount of data. It takes weeks to train a classifier using a classical computer. Quantum computers can help solve this problem in just a few hours.

**Security**

Quantum computers will change the whole cybersecurity world. Quantum computers can be used to create private keys for encrypting messages sent from one place to another. Hackers will never be able to crack the key because of the uncertainty present in quantum computing. Hackers have to break the laws of quantum physics to hack a key.

**Health and Medicine**

Quantum technology can also transform health care and medicine. The design and analysis of molecular drug development is a challenging problem today. It is a difficult problem because exactly describing and calculating all of the quantum properties of all the atoms in the molecule is a computationally difficult task even for supper computers. Quantum computers can perform better as it uses the same quantum properties as the molecule it is trying to simulate. With the help of quantum computers, we can treat diseases like Alzheimer’s.

**Teleportation of Information**

We send information from one place to another using some medium like cables, waves, etc. Quantum computers can be used to send information from one place to another without actually physically transmitting the information. This is possible because the fluid properties of quantum particles can get entangled across space and time is such that when you change something in one particle it will impact the other.

**Environmental Changes**

Environmental challenges today represent one of our most existential challenges yet. Nature is our most powerful quantum computer. At its core nature operates on a quantum scale and behaves according to the rules of quantum mechanics. We can feed the natural data into a quantum computer and get output about how to return or reduce environmental changes. Quantum computers can help us find the perfect material that we can use to capture carbon from the environment.

### Difficulties in the Implementation of Quantum Computers

Quantum computers are very very sensitive to perturbations, noise, and environmental effects. So any kind of noise or environmental factors can affect the dual nature of the qubits. The normal room temperature is 300 kelvin and a perfect quantum computer which keeps the superposition state needs 0 kelvin. So one thing should be clear that these Sci-fi computers are not going to be as normal as classical computers. IBM quantum computers operate at 0.015 Kelvin. Quantum computers are very fragile. Any kind of vibration impacts the atoms and causes decoherence.

### What does it take to create a fault-tolerant quantum system?

To enhance the computational ability of a quantum computer, developments are needed along two dimensions.

One is qubit count; the higher the number of qubits you have, the more states can in principle be manipulated and stored. The other is low error rates, which are needed to manipulate qubit states precisely and conduct sequential operations that give answers, not noise.

A helpful metric for understanding quantum capability is quantum volume. It includes the connection between number and quality of qubits, circuit connectivity, and error rates of operations. Developing systems with larger quantum volume will lead to discovering the first instances of applications where quantum computers can offer a computational advantage for solving real problems.