Quantum computing is changing how machines are used to solve problems. Read on to discover what quantum computing is, how it works and the key concepts at the heart of it. We’ll also explore how quantum computing could reshape the field of computer science.
By Grant Longstaff. Published 21 January 2025.
What is quantum computing?
Quantum computing is an emerging area of computer science which utilises the principles of quantum mechanics to solve problems. The power and ability of quantum computers is vastly superior to even the most powerful traditional computers.
The devices we use daily, such as our laptops and smartphones, use “bits”. Bits are a simple unit of information and have a value of either 0 or 1. However, quantum computers use “quantum bits”, known as qubits. Qubits can exist in multiple states at once and means a quantum computer can perform calculations incredibly quickly. Much faster than the household devices we use.
This means a quantum computer could solve the most complex and intricate problems. What could take a classic computer decades to calculate, could be solved by a quantum computer in a matter of minutes.
The link between quantum computing and computer science is increasingly important. While quantum computing is rooted in quantum physics, it’s computer scientists who turn quantum theory into usable systems.
Applications of quantum computing
Quantum computers won’t replace our computers anytime soon. They’re designed to tackle very specific problems that are currently impractical or impossible to solve using conventional machines.
Cybersecurity
Many of today’s encryption systems rely on mathematical problems that are extremely hard for classical computers to solve. Quantum algorithms could break these systems much faster. This will have huge implications on areas including data protection, cybersecurity, financial systems, regulatory frameworks and even national security.
Healthcare
Quantum computers could be used in the pharmaceutical field as they’re able to simulate molecular interactions far more accurately than classical computers. This could help when it comes to developing new drugs and medical treatment.
Artificial Intelligence
Quantum computing has the potential to improve optimisation problems and speed up machine learning training processes, especially in instances involving huge datasets.
And more…
While large-scale quantum computers are still in development they could also help with everything from risk analysis and manufacturing processes to infrastructure and network improvement and supply chain optimisation.
Key principles of quantum computing
There are a number of core concepts at the heart of quantum mechanics you’ll need to grasp in order to understand how quantum computers work. Whilst they’re complex ideas, we’ve tried to break them down as simply as possible below.
Superposition
Above we discussed bits and their value of either 0 or 1. Qubits can be 0 and 1 at the same time. This is known as superposition and means a quantum computer can process many possible solutions simultaneously, massively increasing its potential.
Entanglement
Entanglement occurs when qubits become linked. This means the state of one qubit instantly affects the state of another, no matter how far apart they are. Entanglement allows quantum computers to perform coordinated tasks across qubits, making calculations more efficient and powerful.
Interference
Quantum algorithms are carefully designed to use interference to increase the probability of measuring the right answer at the end of a computation.
Decoherence
Decoherence occurs when qubits interact with their environment such as heat, radiation or noise. This causes them to lose their quantum state and act like classical bits. Preventing decoherence is one of the biggest technical challenges in building reliable quantum computers.
Components of quantum computing
As discussed, quantum computers differ from classic computers in a number of ways and require different hardware as a result. Some of the key components of quantum computing include:
Qubits
Qubits can be created using different physical technologies, such as superconducting circuits, trapped ions, photons or silicon-based systems. Each approach has advantages and disadvantages in terms of scalability, stability and error rates.
Quantum gates
Quantum gates manipulate qubits using precise electromagnetic pulses or laser signals. These gates form the building blocks of quantum algorithms.
Cryogenic systems
Quantum computers must operate at temperatures close to absolute zero to reduce noise and prevent decoherence.
Control electronics
Classical computers are still required to control quantum operations, send instructions and interpret results.
Quantum error correction
Because qubits are fragile, quantum error correction is essential. This involves encoding information across multiple qubits to find and correct errors without destroying the quantum state.
If you’re studying computer science and are new to the concept of quantum computing it can feel a little overwhelming. That said, by understanding the fundamentals you’ll build a foundation on which to shape your knowledge and understand the potential impact of quantum computing.
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