What Is Quantum Computing?

Key takeaways

• Quantum computing uses qubits, which can represent any combination of zero and one simultaneously, giving quantum computers greater processing power than classical computers.

• The key principles behind quantum mechanics are superposition, entanglement, interference, and decoherence.

• You can use quantum computing to help solve complex problems in areas such as artificial intelligence, medicine, and system optimization.

Learn how quantum computing works, how it differs from classical computing, and where it could have real-world applications. If you’re ready to build skills in artificial intelligence, consider enrolling in the IBM AI Developer Professional Certificate, where you can practice building generative AI-powered applications and gain skills in areas like responsive web design, software development, computer vision, and machine learning.

What is quantum computing?

Simply put, quantum computing builds on classical computing methods by leveraging the power of quantum mechanics, giving computers the ability to solve complex problems faster than before. Inspired by the quantum rules that shape the behavior of chemicals and molecules, scientists are researching how to simulate these principles with computers. From factoring large numbers at unprecedented speeds to analyzing sophisticated environmental data, quantum computing could address some of the world's most complex computational challenges. However, development efforts will need to continue for quantum computing to reach its full potential [1].

Why does quantum computing matter?

In recent years, tech companies such as Google and Microsoft have been making strides toward making quantum computing more mainstream, with the technology expected to make a significant impact in areas like artificial intelligence and machine learning, chemistry, and health care. Using features such as quantum parallelism, the ability to explore solutions to complex problems from multiple angles simultaneously, quantum computers are set to change what’s viewed as possible in computing [2].

How is quantum computing different from classical computing?

An important difference between quantum computing and classical computing lies in the number of solutions they can explore simultaneously. When classical computers operate, they have to perform a new calculation with each change to a variable. This means that when a classical computer is working to solve a problem, it explores one possibility at a time. In contrast, quantum computers can cover an exponentially larger number of possibilities simultaneously [3]. 

How does quantum computing work?

Quantum computing uses qubits, which can simultaneously act as both zero and one, allowing them to represent a multitude of possibilities at the same time. This gives quantum computers far more processing power compared to traditional computers. Akin to microchips in conventional computers, quantum chips provide the physical hardware for storing qubits.

From atoms to semiconductors, any particle or system that aligns with the rules of quantum physics can function as a qubit. Photons and trapped ion qubits are among the most widely used qubits. 

What are key principles of quantum mechanics?

Quantum computing gains its functionality by implementing several quantum mechanics principles, including superposition, entanglement, interference, and decoherence. Take a look at how each plays a contributing role in quantum computing [4]:

• Superposition: Qubits can represent combinations of zero and one, allowing a quantum computer to explore numerous outcomes at once.

• Entanglement: Connected qubits can share information, enabling coordinated calculations throughout a quantum system.

• Interference: Quantum algorithms manipulate probability patterns to amplify useful outcomes and reduce others.

• Decoherence: Environmental factors such as heat and radiation can disrupt quantum states and introduce computational challenges.

Putting it all together, quantum computing starts by arranging qubits so they can represent multiple possible states at once. A user-defined quantum circuit then entangles qubits and creates interference patterns. Note that the interference cancels out many possible outcomes while amplifying others. The “amplified” outcomes represent the final solutions of the computation.

What are real-life examples of quantum computing?

Although more work is necessary to get quantum computing to the point where it can start making real industry impacts, areas in which quantum computing is expected to provide significant value include artificial intelligence, medicine, and system optimization.

• Artificial intelligence: Quantum computing has the potential to change what’s possible with AI and machine learning by enhancing the efficiency of analyzing data sets, as well as introducing additional perspectives in comparison to traditional algorithmic analysis.

• Medicine: Drug discovery and medical treatment can benefit from quantum computing thanks to faster research and development and understanding of molecular interactions, while also lowering the costs for patients.

• System optimization: Complex systems across a wide range of industries, such as finance, supply chains, and manufacturing, can use quantum computing to reach new levels of problem-solving not currently achievable through today’s technology.

Read more: What Is Quantum AI?

What are the advantages and challenges of quantum computing?

Quantum computing stands out for its unmatched speed in solving complex problems. Thanks to quantum computers’ ability to process data using techniques otherwise inaccessible through classical computing, quantum computing can recognize patterns within data that would otherwise go unseen. 

Quantum computing still faces significant challenges, including decoherence, that hinder broader adoption. At the moment, quantum computers rely on specialized equipment, as they operate at low temperatures and require devices like dilution refrigerators to cool the machines. Additionally, quantum computing faces issues with qubit sensitivity and reliability, as errors are a frequent cause of concern.

What are the most recent advancements in quantum computing?

As things currently stand, quantum computing remains in the experimentation phase, as scientists are actively developing new solutions in key areas like scalability and error detection. Nonetheless, qubits are becoming increasingly stable, and concerns about loss mechanisms are being addressed, as quantum chip development moves the industry closer to scalable quantum computing.

After receiving an $8.6 billion valuation in 2024, the quantum computing industry is set to grow between 32 and 38 percent annually until 2030, supported by significant investments from governments and large corporations [5].

How do you learn quantum computing?

To learn quantum computing, you will need to focus on developing skills in mathematics, specifically calculus, trigonometry, probability, and linear algebra, in addition to programming proficiency in languages such as Python, Julia, and Q#, in order to develop computational algorithms and design quantum computing software programs. You should also gain an understanding of quantum mechanics principles, as well as research and problem-solving skills. 

Earning a relevant degree such as a bachelor’s degree in computer science, information technology, software engineering, physics, or mathematics, is a valuable first step toward learning quantum computing. Beyond your education, seeking out career opportunities with technology companies working on quantum computing can help you gain the experience you need to further grow in your field. 

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