The pros and cons of quantum computing

Inside laboratories kept at very cold temperatures, scientists are building quantum computers – machines that could transform our world. Quantum computers don’t just represent the next step in computing; they’re an entirely new technological species.

Traditional computers use bits – simple on/off switches (0s and 1s) – to process information. Quantum computers use something radically different: qubits (quantum bits). The use of qubits is hard to explain, and to understand, but imagine flipping a coin. Will it be heads or tails?

In the quantum world, it’s both at the same time, a quality called “superposition”. This means quantum computers can explore multiple solutions simultaneously rather than checking them one by one. A quantum computer’s power doubles with each additional qubit, creating exponential growth inGoogle reached a significant milestone in quantum computing in 2019, when its 53-qubit Sycamore processor performed a specialised calculation in just 200 seconds, which Google initially claimed would have taken a traditional supercomputer about 10,000 years. IBM contested this claim, saying it could be done in days with the right approach. Either way, it demonstrated quantum computing’s potential.

IBM knows this. In 2022 it unveiled its 433-qubit Osprey processor, and its public roadmap targets a massive 4158-qubit system this year. To put this in perspective, a 4000+ qubit system would theoretically manage more calculations than there are atoms in the observable universe.

Microsoft has taken a different path in quantum computing, focusing on developing more stable “topological qubits” that could potentially solve quantum computing’s biggest challenge: maintaining fragile quantum states long enough to perform reliable everyday calculations. (Qubits are extremely sensitive to their environment, and small shifts can cause them to lose their quantum properties.)

Amazon, meanwhile, has focused on businesses and researchers who can’t build quantum hardware, launching Braket in 2020, a cloud service providing access to quantum computers through three quantum computing companies – D-Wave, IonQ, and Rigetti. This means research institutions in New Zealand can already run quantum experiments without multi-million dollar investments in hardware. 

Quantum computing is likely to solve problems that today’s most advanced supercomputers would need centuries to solve. Of course it also comes with considerable risks. Most obviously, what would be considered secure passwords could be easily cracked, which would affect many aspects of our lives – our bank accounts, our power grid, our water infrastructure and even many cars.

Most online transactions, banking systems, and sensitive communications are protected by encryption that works because certain mathematical problems take traditional computers too long to solve. A sufficiently powerful quantum computer running Shor’s algorithm (a quantum algorithm that efficiently factors large integers and solves discrete logarithm problems in polynomial time) could potentially break widely used cryptographic systems that classical computers would take impractical amounts of time to crack.

We need to start preparing for post-quantum cryptography, also known as quantum-proof, quantum-safe, quantum-resistant cryptography. This will be essential for New Zealand’s banks and financial institutions to protect digital transactions in a post-quantum world. The risks extend well beyond our financial sector. Critical infrastructure, government systems, and telecommunications all rely on encryption that could be vulnerable.

The Australian Strategic Policy Institute argues that countries in the Asia-Pacific region, including New Zealand, need to develop comprehensive quantum security strategies that address the threats but also the opportunities presented by quantum technologies.

Kiwis are already in the quantum game. Te Whai Ao – The Dodd-Walls Centre for Photonic and Quantum Technologies has earned international recognition for advanced research in quantum optics. Universities are developing post-quantum computing programs, which will help us develop quantum-ready workforces who can harness quantum computing’s transformative potential.

Quantum-enhanced weather modelling could extend reliable forecasts from the current week-long window to two weeks or more — giving farmers and crop producers crucial planning advantages. For a country where agriculture drives exports, such as New Zealand, this could mean billions in optimised production.

Our pharmaceutical researchers could leverage quantum simulations to develop new medications in a fraction of the time, modelling complex molecular interactions that would overwhelm today’s computers.

In finance, quantum algorithms could revolutionise portfolio optimisation and risk management. For materials science and manufacturing, quantum computers can model new compounds with specific properties, potentially developing better batteries, solar panels, and superconductors.

In mining, quantum algorithms could enhance resource exploration by processing vast geological datasets to identify mineral deposits with greater precision, while optimising extraction operations through improved scheduling algorithms. Transportation networks could benefit from quantum-solved routing problems, while energy grids could achieve superior real-time optimisation through quantum computing’s ability to process complex systems with numerous variables.

The global quantum computing market is projected to reach approximately US$42 billion by 2030, according to more conservative estimates. For New Zealand, early investment in quantum applications for agriculture, mining, and finance could deliver significant competitive advantages.

As quantum computing matures from research curiosity to a practical tool over the next decade, the world’s most complex challenges – from climate modelling to materials science to medical research – may find solutions in the quantum realm. The computational power of the near future offers remarkable possibilities – particularly for countries willing to invest in it today.

Just as the internet transformed our world in ways unimaginable to previous generations, quantum computing stands at the threshold of redefining what’s possible in human innovation.