In the future, quantum computers should be a solution if supercomputers fail due to the complexity of applications. The first technologies of quantum technology and quantum computers are already ready for use. However, they still fail when it comes to efficiency and scaling.
Current state of quantum technology
The foundations of quantum physics were established approximately 100 years ago. The first applications are now available. Quantum computers are already superior to supercomputers in some tasks.
Quantum information is transported from orbit and via glass cables using entangled photons. The first quantum networks, quantum sensors and quantum modems are already being tested.
University of Chicago researchers led by David Awschalom examined the maturity of six different quantum technologies and identified where challenges and hurdles exist. The basic physical concepts are already established.
In some areas there are the first practical applications of quantum technology. Physicist David Awschalom speaks of a phase of upheaval that is comparable to the early days of the transistor. Quantum technology could draw important lessons from computer history.
Comparison of quantum platforms
David Awschalom’s team examined six leading and sometimes competing quantum technologies. For the assessment, the researchers used technology reports, specialist publications and an AI-supported evaluation to assess the technology readiness level (TRL).
To assess TRL, NASA developed a nine-level scale in the 1980s:
- TRL 1-2 for theoretical development of the operating principle
- TRL 3-4 for initial laboratory tests
- TRL 6-7 for prototypes
- TRL 8-9 for successful use
The team examined qubits in the form of superconducting quantum dots and based on ion traps or neutral atoms. Quantum dots in semiconductors, defects in the diamond lattice or purely photonic quantum platforms were evaluated.
The researchers classified the maturity of the technologies into quantum computing, quantum sensors, quantum communication and quantum simulation.
Results of the investigations
Superconducting qubits with TRL 6-8 and ion traps with TRL 6-7 are the most advanced when used as quantum computers. Neutral atoms with TRL 6-8 and ion traps with TRL 6-7 lead the way in quantum simulation.
With TRL 8-9, photonic systems have a long lead in quantum communication. Quantum sensors based on spin defects in diamond are classified similarly by the researchers. Ion traps still come in at TRL 6-8 in this category.
Even if a quantum technology already has a high level of maturity, that does not mean that it has been fully researched and achieved its goal.
The researchers were only able to demonstrate the basic usability. To reach its full potential, it needs to be scaled.
Quantum technologies are not yet fully developed
Quantum technology in its current state is comparable to the computer age in the 1970s. At that time, semiconductor chips had a maturity level of 7-9, but they were hardly comparable to today’s integrated circuits. A high TRL value is an indication that a technology is worth further optimizing.
Today’s quantum computer prototypes can be used via a cloud and used for research and education. However, commercial use is not yet possible.
There are the first commercial applications for quantum communication. A quantum internet or real quantum cryptography still requires further development. In order for comprehensive quantum-based communication to be possible, quantum networks must be created that can connect significantly more powerful qubit arrays than today’s ones.
Scaling as a hurdle
In order for quantum technologies to be widely applicable, scaling is important. A quantum computer requires millions of qubits and a low error rate to enable everyday applications.
According to the researchers, there are problems with the cabling, energy requirements, materials and production methods as well as calibration and control. Despite new materials, cost-effective mass production must be developed based on common manufacturing methods. It is important to control errors and manipulations.
On most platforms, one to three channels per qubit are necessary for manipulating, controlling and reading signals. Each additional qubit requires additional wires. This is no longer practical when millions of qubits are used.
Multiplexing is an alternative. One line supplies multiple qubits. Another solution would be greater integration of the control electronics into the quantum arrays.
For quantum technologies, the energy requirement must also become more efficient. The quantum systems often have to be cooled to just above absolute zero. This is associated with high power consumption. However, powerful lasers are required for systems based on neutral atoms or ion traps. Size and power requirements become important factors.
Modular principle as a solution
Modularity could be a solution to the problems. According to the researchers, scaling could be divided into feasible pieces with a modular design of the systems. Cabling, power requirements, control hurdles and sizes would therefore be limited to the individual modules.
With parallel operation, several different quantum systems could be linked together. This would improve error control and efficiency. There are already initial attempts at modular quantum computing.
