What is Quantum Computing?

Quantum computing harnesses the principles of quantum mechanics to process information. Unlike classical computers that use bits (0s and 1s) to represent data, quantum computers use qubits. Qubits can represent both 0 and 1 simultaneously, thanks to a property called SuperPosition.

Simple Analogy

Think of a classical computer as a very fast librarian who can only read one book at a time. A quantum computer, on the other hand, is like a super-librarian who can read millions of books at once and find connections between them instantly.

Classical vs Quantum Computing

Classical Computing

- Used by common, multipurpose computers and devices.

- Stores information in bits with discrete states, 0 or 1.

- Processes data logically and sequentially.

Quantum Computing

- Used by specialised and experimental quantum mechanics-based hardware.

- Stores information in qubits as 0, 1, or a superposition of both.

- Processes data with quantum logic in parallel instances, relying on interference.

Understanding Quantum computing Principles

As mentioned earlier Quantum computing leverages the principles of quantum mechanics to perform computations far beyond the capabilities of classical computers. Let us see some key principles to understand:

1. Superposition: Classical bits are limited to being either 0 or 1. In contrast, quantum bits (qubits) can exist in multiple states at the same time. This unique property enables quantum computers to handle a large amount of information simultaneously. Think of a classical bit as a switch that can only be ON (1) or OFF (0). A qubit, however, is more like a dimmer switch that can be off, on, or in any state in between.

2. Entanglement: This phenomenon occurs when qubits become interconnected, so the state of one qubit directly influences the state of another, regardless of the distance between them. This interconnection can be harnessed to perform complex computations more efficiently. Take two separate light switches they operate independently in classical computing, however in quantum computing, imagine these two switches linked together in a way that changing state of one switch instantly changes the state of other. This illustrates how entangled qubits work together.

3. Decoherence: Quantum states are delicate and can be easily disrupted by their environment, causing them to lose their quantum properties. Managing decoherence is one of the significant challenges in building practical quantum computers. Decoherence is the process in which quantum particles and systems can decay, collapse, or change, converting into single states measurable by classical physics. Classical bits are stable and not easily disrupted by their environment. Quantum states are fragile and can be easily disturbed by external factors, leading to decoherence. This is like trying to keep a soap bubble intact in a windy environment.

4. Interference: Quantum algorithms use interference to amplify the probabilities of correct answers and cancel out the wrong ones. This helps in solving certain problems much faster than classical algorithms. Classical algorithms process data in a straightforward, step-by-step manner. For example, sorting a list of numbers by comparing each pair of numbers. Quantum algorithms use interference to amplify the probabilities of correct answers and cancel out incorrect ones. This is like using waves to enhance certain paths and diminish others, leading to faster problem-solving.

These principles enable quantum computers to tackle complex problems more efficiently than classical computers, especially in fields like cryptography, optimisation, and material science.

Real-World Scenarios

1. Medicine:

- Drug Discovery: Quantum computers can simulate molecular structures and interactions much faster than classical computers, speeding up the discovery of new medicines and treatments.

2. Cryptography:

- Security: Quantum computers can break many of the encryption methods currently used to secure data. However, they can also create new, more secure encryption methods.