# Lesson 1: What Is Quantum Computing?

H Hannan

## Introduction to Quantum Computing

Quantum computing represents one of the most exciting frontiers in technology today. We are witnessing steady progress toward fully functional quantum computers that leverage the bizarre nature of quantum physics to solve problems believed to be impossible for classical computers. This introduction will cover some quantum computing basics about how these quantum machines differ from traditional systems and offer a glimpse into their future capabilities.

## Quantum Bits vs Classical Bits

At the core of any computer are its basic units of information storage and processing. Classical computers encode information into binary bits existing in one of two states – a 0 or a 1. Quantum computers utilize quantum bits, or qubits, which harness quantum properties to exist in a superposition of both 0 and 1 simultaneously.

## Quantum Superposition and Entanglement

Superposition arises from the ability of quantum objects like electrons to act also as waves that can combine into a single system. This enables a qubit to exist in all 0 and 1 permutations simultaneously. Consider a traditional penny that, when flipped, can land on heads or tails. Now imagine if that penny could land on both heads AND tails at the same time whenever it’s flipped. That ability to encode multiple states is what superposition enables for quantum systems.

Entanglement leverages properties of superposition to correlate the states of distinct qubits, even when physically separated by large distances. This enables entangled qubits to act as a single system representing a far greater range of values than non-entangled qubits. As an example, imagine having a pair of dice where the outcome of one die instantly tells you the facing side of the other die, even if you look at them in different locations. That’s the type of correlation entanglement creates.

Both superposition and entanglement enable capabilities completely impossible in traditional computing systems. Superposition allows exponentially more information storage and processing, while entanglement permits distributed systems to act together as a single machine. Harnessing them is the key innovation that will unleash the potential of quantum computers.

## Potential Applications of Quantum Computing

Experts predict quantum computing will impact several industries and enable new breakthroughs not possible with classical systems. While today’s noisy intermediate-scale quantum (NISQ) machines have limited qubit counts and stability, steady improvements toward fault tolerance will unlock revolutionary use cases.

In cryptography, quantum computers pose risks to current standards like RSA and elliptic-curve cryptography in use today. The ability to quickly factor in extremely large numbers also provides opportunities to develop new quantum-resistant encryption methods. Early adopters in cryptography and cybersecurity have an incentive to monitor quantum progress closely.

Quantum’s parallel processing power provides up to quadratic improvements in machine learning algorithms. By speeding up training and enhancing models, quantum promises to advance artificial intelligence toward broader real-world applications. Self-driving cars, medical diagnosis, financial analysis, and other data-intensive AI systems stand to accelerate tremendously.

Quantum computers also promise optimization breakthroughs across transportation, logistics, financial modelling, and engineering disciplines. Airlines can schedule crews and routes more efficiently saving millions, while banks can better model risk and construct profitable portfolios faster than before. In engineering, quantum promises materials, energy, and drug discoveries thanks to precise quantum physics simulations unavailable to traditional machines.

We have only scratched the surface of the emerging quantum landscape. But this introduction outlines how quantum differs from classical systems and why its applications have such revolutionary potential. As quantum hardware and software continue maturing, we will cover additional developments in areas like algorithms, programming models, and early use cases. The quantum era is here – and an exciting computing future awaits.