Quantum computers could be disruptive and impact many industries. Researchers in the United Kingdom (UK) and the Netherlands explored two different quantum problems. They attempted to break the encryption of Bitcoin (a digital currency) and simulate the molecule responsible for biological nitrogen fixation.

The researchers present a tool they developed to determine the size of a quantum computer needed to solve such problems and how long it will take. AVS Quantum Science is available from AIP Publishing.

“The majority of work in this area focuses on one particular hardware platform, superconducting device platforms, like those IBM or Google are working towards,” stated Mark Webber of the University of Sussex. “Different hardware platforms will have different key specifications such as the speed of operations and quality of control on qubits (quantum bit).

For many of the most interesting quantum advantage applications, a quantum computer that has been corrected for errors will be required. Error correction allows for longer computations by correcting internal errors in the quantum computer. However, it will require more physical qubits.

It is possible to improve the energy-intensive process used to extract nitrogen from the atmosphere to produce ammonia for fertilizers. This would help address both the global food crisis and the climate crisis. Even the fastest supercomputers in the world are unable to reproduce important molecules. However, next-generation quantum computers will be able to.

Webber stated that the tool automates the calculation error-correction overheads as a function of key hardware specifications. We can make the quantum algorithm run more quickly by adding more physical qubits. To achieve the desired runtime, we add qubits to the physical hardware. This is critically dependent on the speed of operations at the physical hardware.

Most quantum computing hardware platforms are restricted because only qubits within proximity can interact with one another. Some platforms, such as certain trapped ion designs, allow the qubit’s physical movement rather than being locked in one place. This allows each qubit to interact directly with many other qubits.

Webber stated that they explored the best way to take advantage of the ability to connect distant qubits. The goal was to solve problems in less time and with fewer qubits. We must adapt the error-correction strategies to maximize the strengths of the hardware. This may enable us to solve extremely important problems with a smaller quantum computer than we previously thought.

Quantum computers can break many encryption algorithms more effectively than traditional computers. The majority of the world’s secure communications use RSA encryption. Bitcoin’s elliptic-curve digital signature technique and RSA encryption can be vulnerable to quantum computing attacks in the future. However, currently, no supercomputer can compromise security.

Researchers estimated how large a quantum computer would need to be to crack the encryption of Bitcoin within the very short time frame it would pose a threat — between the announcement and its integration into the blockchain. This window is likely shorter if the transaction fee is higher, but it could last minutes to hours.

Webber stated, ” State-of-the-art quantum computers only have 50-100 qubits today.” Webber stated that Bitcoin is safe from quantum attacks because it requires between 30 million and 300 million physical qubits. However, devices this large are usually considered possible. Future advancements could reduce the requirements.

“The Bitcoin network could perform a ‘hard-fork” onto a quantum secure encryption technique. However, this may cause network scaling problems due to increased memory requirements.

Researchers emphasize the rapid improvement in quantum algorithms and error-correction protocols.

Webber stated that four years ago, it was estimated that a trapped ion device would require a billion physical qubits to break RSA encryption. This required a device measuring 100-by-100 meters. This could be reduced to 2.5-by-22.5 square meters with the help of improvements all around.