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Quantum 101: What is Quantum Physics?

QNu Labs   |   Dec 20, 2023

Quantum physics is the most perplexing branch of physics. Also called particle physics, it explains the world of the smallest of the smallest–atoms and subatomic particles. 

Classical physics describes the macroscopic world we observe in our daily lives, but quantum physics delves into the microscopic realm revealing a bizarre and counterintuitive set of principles such as:


Superposition is one of the most iconic concepts in quantum physics. The principle says that the particles such as electrons can exist in multiple positions simultaneously. For example, imagine a coin tossed in the air—it is not in a definite state of heads or tails while in the air until it is observed. Similarly, sub-atomic particles in quantum superposition exist in all possible states until they are measured.

Wave-Particle Duality

Quantum physics challenges the conventional understanding of particles and waves. Traditionally, light and sound were associated with waves and particles with matter. However, quantum physics says that sub-atomic particles such as electrons, exhibit both particle-like and wave-like properties depending on the experimental conditions. 

This duality blurs the line between what is thought of as discrete particles and continuous waves. Everything appears like waves before it is observed and measured. 

Quantum Entanglement

Two or more connected particles are called ‘entangled’ if one particle instantly influences the state of the other, regardless of the distance between them. The distances can be as large as universes apart. Described by Einstein as “spooky action at a distance,” such mysterious connections are possible in the quantum realm. 

Implications of Quantum Physics

Quantum physics has far-reaching implications that challenge our intuitive understanding of reality. The age-old observations and conclusions from classical physics stand corrected by quantum physics. Some of the intriguing implications are:

Uncertainty Principle

As formulated by Werner Heisenberg, the uncertainty principle asserts that it is impossible to simultaneously know a particle’s exact position and momentum. This inherent uncertainty at the quantum level has profound consequences for our understanding of determinism and predictability.

Quantum Computing

Quantum computers leverage the principles of superposition and entanglement to perform complex calculations exponentially faster than classical computers. Such a computer has the potential to revolutionise the fields of encryption, optimisation, and simulation.

Quantum Cryptography

Scientists have achieved a breakthrough in cryptography by successfully using entangled particles for secure communication. Termed quantum cryptography, it promises unhackable communication channels. The reason: with quantum entanglement, any attempt to eavesdrop on one particle would disrupt the state of all entangled particles, alerting users to potential security breaches.

Quantum physics takes us on a wild journey into a world where the rules of classical physics break down, and reality becomes a blend of probabilities and uncertainties. While the principles of quantum physics may seem perplexing, their application holds the promise of transformative technologies that could reshape the landscape of computing, communication, and our understanding of the universe.

As we unravel the mysteries of the quantum realm, one thing remains certain: the more we learn, the more we realise how much there is still left to discover. 

Quantum physics challenges our fundamental assumptions about the nature of reality, inviting us to explore a universe that is, in many ways, stranger than we could ever have imagined.