The potential of quantum technology i enormous with applications spanning across healthcare, mobility, sensing, defence and military, aviation, computing, communications, technology, and so on. These and many more are industries that could be revolutionised by quantum technology once it achieves widespread adoption.

However, there are many hindrances to the commercialisation of quantum technology today and without those challenges resolved, quantum technology may not live up to its true potential as the next frontier of industrialisation. This is why a lot of companies are working hard to see that these problems are tackled and applied in new product releases.

The Major Problems with Quantum Computing

1. Quantum decoherence

Quantum decoherence occurs when a particle or wave interacts with its internal and external environment and falls out of phase between different quantum states. This means that the particle loses alignment either with itself or with its external environment. In quantum computing, this is a major challenge as it leads to partial or total information loss. It also leas to high errors in computations as the system is not able to accurately finish computations when there is decoherence.

2. Error Correction

Error correction algorithms are put in place to identify and fix errors in quantum computers due to the high amount of ‘noise’ that is generated during computations. The typical experience is that the more ‘noise’ in a quantum system, the more qubits are required to run the algorithms needed for error correction. 

Today, error correction is still a work in progress for many quantum computing companies as they are yet to meet the requirements to completely eliminate ‘noise’ or reduce it to an insignificant value.

3. Scalability

System scalability in quantum computing is achieved when there is a balance in the integration of data processing, error correction, and control on a quantum processor. The challenge with this today is that due to the fact that error correction is a priority, more physical qubits and programmed into logical qubits making the whole system cumbersome. 

This defeats the idea of creating a simple quantum system that can be used anywhere in the world. This remains a major challenge to solve if quantum computing will be really useful in our world

4. Complex Hardware

The nature of the hardware that make-up a quantum computer can get really complex easily. There are various factors at play that determine the types of hardware that can be used to solve certain problems. For example, in orer to achieve reasonable computation speed and hgh fidelity (which is the performance level of quantum computers), qubits are typically added in a netowork so that a complex computation. 

The reason for this is that, qubits maintain coherence for a very short time before generating ‘noise’ thereby leading to errors. So, to achieve coherence, many qubits have to be stringed together. If you then want to solve multiple problems consistently, what amount of hardware will be needed? This is still a big challenge for the industry.

5. Qubits Longevity

In the earlier section, we talked about the fact that qubits maintain coherence for a short period (nanoseconds to milliseconds) and since information in quantum computing cannot be copied, the qubits used become obsolete in the process. There have been researches on how to increase the lifespan of a qubit and progress have been made in that regard but the commercial value is yet to be seen.

6. Quantum-Classical communication

Preserving quantum state integrity over long distances, scaling the technology for broad adoption, and creating interoperable standards between quantum and classical communication systems is also a big challenge in the adoption of quantum computing at scale.

7. High Costs

Quantum computing systems are highly expensive to build and maintain. They require large amounts of capital to build and one quantum computer can cost up to $1M. Single qubits according to quantum explainer costs between $1,000 - $2,000 while cooling systems can cost up to $500,000. The software is also a big cost center as algorithms cost between $200,000 - $500,000. This is different from platforms that charge separately. This cost is a big problem that may stop the advancement of quantum computing as it is not sustainable.