What is quantum computing?

In simple terms, quantum computing is a form of computing that harnesses the principles of quantum mechanics to process information. Unlike traditional computing, quantum computing does not use binary digits (either 0 or 1), or bits. Instead, quantum computing is based on qubits, which can represent much more information than bits can. Qubits can be both a 0 and a 1 simultaneously, which allows quantum computers to calculate larger datasets much faster than traditional computers.

Quantum computers can also explore several possible solutions at once. This gives them a distinct advantage in solving problems related to optimization, cryptography, machine learning and financial modeling. In addition, quantum computers have promising applications in chemistry and material science. For example, quantum computing can simulate how a chemical compound might react in various scenarios.

How does quantum computing work?

Quantum computing is based on the principles of superposition and entanglement. In quantum mechanics, superposition describes the ability of a system to remain in multiple states at the same time until it is measured. Measurement in this context refers to any interaction between qubits and an external system, such as a detector or sensor, that would cause the qubits to collapse from multiple states to a single state.

To understand the concept of superposition, it's useful to imagine a coin spinning on its edge. When a coin is spinning, it is said to be in a state of superposition, meaning it is not defined as either heads or tails. However, if the coin is bumped or disturbed in any way, it will stop spinning and will end up displaying either heads or tails. In this analogy, the coin would be the qubits and the measurement would be whatever caused the coin to stop spinning.

Qubits are sensitive to interference from their environment and are usually stored at very low temperatures in computing devices to protect them from influences such as temperature fluctuations, electromagnetic fields and other particles.

For its part, entanglement describes a deep connection between two qubits, where the state of one qubit is directly dependent on the other qubit, no matter the distance between the two.

There are two key properties of entanglement that all applications derived from it depend on. The first one, the Monogamy of Entanglement, states that entanglement between two qubits cannot be shared with a third. The second property of entanglement is called Maximal Coordination — it posits that the quantum state of a system is a combination of all the possible states that the system could be in, and that each state is measured by its probability.

Maximal Coordination is an important feature of quantum mechanics that sets it apart from classical physics, and is what allows quantum computer systems to exhibit superposition and entanglement.

What are the main uses of quantum computing?

Quantum computing can be used in a wide range of industries, including finance, pharmaceuticals and logistics. For example, quantum computers could optimize stock portfolios, develop new drugs more quickly or improve supply chain management.

Quantum computing has been applied to developing machine-learning algorithms as well, a realm that is still in relatively early stages of development and is brimming with potential for groundbreaking advancements.

Two quantum algorithms that have already contributed greatly to the field of machine learning are Grover’s Algorithm, which can yield unstructured search results faster and improve pattern recognition in machines; and the Quantum Fourier Transform algorithm, which has properties that make it instrumental for understanding temporal dynamics, giving it a distinct edge for applications such as market trend analysis, weather forecasting and language recognition.

Quantum computing, together with artificial intelligence, will undoubtedly catalyze the development of solutions to some of the world's most complex problems. However, like many emerging technologies, the unique properties that make quantum computing such a promising field also present challenges and risks.

Some experts have pointed out that quantum computers have the potential to break most encryption techniques that are currently used for cybersecurity. As quantum computers become more powerful, encryption techniques will need to be replaced with newer quantum-resistant alternatives. Staying one step ahead of the ever-evolving landscape of cybersecurity threats will be crucial.

In response to these threat to cybersecurity, the Biden administration signed the Quantum Computing and Cybersecurity Preparedness Act into law in 2022. It requires federal agencies to adopt adequate defenses against quantum-computing-enabled attacks and migrate systems to post-quantum cryptography.

How to invest in quantum computing companies

For those wondering how to invest in quantum computing, the major tech firms discussed below offer an entry point, as do venture capital funds invested in private quantum computing companies. Accredited investors can purchase pre-IPO shares in privately held companies via online investment platforms such as Hive and EquityZen.

Exchange-traded funds (ETFs) offer another avenue into this emerging tech sector. There is currently just one pure-play quantum computing ETF: Defiance Quantum ETF (NASDAQ:QTUM), which tracks companies developing and commercializing quantum computing applications and other advanced technologies. QTUM's great performance is indicated in its yearly returns, up 30.15 percent as of October 10, 2024. Its top holdings are Alibaba Group (NYSE:BABA) at a weight of 2.04 percent, Coherent (NYSE:COHR) at 2.02 percent and IBM at 1.97 percent.