Recently, researchers have been able to get qubits to operate at 4K using FinFET technology. Why is getting qubits to operate at temperatures above 1K critical, what did the researchers do, and does it demonstrate that quantum computing will become an everyday technology?

Why temperature is critical in quantum computing

Despite the vast amount of development in quantum computing, its use in mainstream applications remains unseen. The challenges faced by quantum computing are not funding related as most of the largest tech companies in the world are trying to solve it; Google, Amazon, Intel, and IBM all have their eye on quantum computing.

What currently stops quantum computing from entering mainstream applications is the hardware needed to operate it. Quantum computing is nothing like traditional computing, which uses digital switches to represent 1’s and 0’s. Instead, quantum computing relies on the quantum nature of a particle such that its state is undefined until observed. Using extremely clever mathematics, quantum computers can be used to solve complex problems (such as searching algorithms) far faster than traditional computers.

But quantum states are extremely easy to upset (i.e. collapse their wavefunction), to the point where a simple thermal vibration can cause the quantum state of an electron to collapse into either up or down spin. Thus, the biggest challenge of quantum computers is to preserve the quantum state of a particle long enough that it can be used for processing data.

This is where the issue with quantum comes in; preserving this state requires extremely cold temperatures, all down to 1K and below. The equipment needed to do this is horrendously expensive, relying on liquid helium and complex cryogenic hardware, which cost millions of dollars. However, if the temperature of quantum computing can be raised to the tens of kelvin, then the cost of a quantum computer would fall from millions to tens of thousands as the equipment needed to create temperatures in the tens of kelvin is significantly cheaper.

Thus, quantum computing must solve its temperature issue if it is to become practical for commercial applications.

Researchers develop high-temperature quantum bits

Researchers have recently demonstrated quantum bits operating at much higher temperatures than standard 1K devices. For clarity, the term “hot” qubit is a relative term as a hot qubit is still unbelievably cold. In the case of what the researchers had achieved, their qubits were demonstrated to operate at 4K.

This ability to operate at 4K was achieved using FinFET technology, whereby charges in a FinFET transistor can be made to exhibit quantum properties, and the FinFET design help to insulate the quantum states from external interference. While both electrons and holes can be used to hold quantum data via spin, the researchers decided to use positive charge carriers (holes) to store spin. This means that the silicon crystal structure itself was being used as the quantum storage medium.

While 4K may seem extremely cold, it is very close to the boiling point of helium, meaning that future versions of the qubits may be able to operate purely on helium evaporation at standard atmospheric pressure. This would be significantly cheaper to operate than devices operating at sub 4K temperatures requiring special pumps and multiple evaporation stages.

Will quantum computing become an everyday technology?

It is shocking how many sites still spread misinformation about quantum computing, especially around its capabilities. Yes, quantum computing can outperform every computing system to date when it comes to specific algorithms that are optimised for quantum computers. This is especially true in maze finding algorithms and search indexers that look through vast quantities of data. However, quantum computers are significantly worse than traditional computing for everyday applications such as gaming and data processing that are geared towards sequential execution.

As such, quantum computers in the future will likely be used in conjunction with traditional processors that are used to handle quantum operations. If anything, they will most likely be used in encryption methods as quantum computers will make all current forms of encryption obsolete.

But the question is, “will quantum computers become an everyday technology”? This is extremely unlikely for the next few decades, and quantum services available to the masses will most likely be done over the cloud (similar to AWS).