What are quanta?
Our world is made up of quanta. Quanta are elementary particles that obey their own laws and physical principles that seem to defy common sense. However, the first research findings are already being translated into industrial applications. Photonics is the best example in this context. The science of light paves the way for quantum technologies in many ways.
What are quanta?
Put simply, a quantum is a smallest possible unit that cannot be split any further. For a long time, scientists thought that the atom was the smallest indivisible unit. However, today we know that even the atom is made up of smaller building blocks called protons, neutrons and electrons. These building blocks are referred to as quanta and obey the laws of quantum mechanics.
What is superposition?
Superposition is a fundamental principle of quantum mechanics that states that quantum particles can exist in multiple states simultaneously, whereas conventional particles can only be in a single fixed state.
In order to better understand this phenomenon, the physicist Erwin Schrödinger developed a thought experiment called Schrödinger’s Cat where a cat is put in a box with a vial of poison. The chance of the vial breaking and the poison killing the cat is 50% at any time. We can only say with certainty whether the cat in the box is dead or alive if we open the box and look inside. Until that moment, the cat essentially exists in both states simultaneously. Or rather, the chance of it being dead or alive is exactly the same. This state is called superposition. Once we look into the box, the state in which the cat is both dead and alive at the same time collapses because the cat can only be dead or alive. It cannot be both at the same time.
Similarly, a quantum particle can only be in a state of superposition until we observe or measure it. Once we measure it, it takes on a single state. This fundamental concept is at the basis of many applications of quantum technologies, including quantum computing and quantum communication.
What is entanglement?
The phenomenon of quantum entanglement plays as equally important a role in quantum technology as superposition. Entanglement describes a state in which two or more particles are connected so deeply that the state of one particle correlates perfectly with the state of another, irrespective of the distance between them. The principle of entanglement is at the heart of many applications in quantum communication.
Why does photonics play such a key role in quantum technology?
Photons are a type of quanta or rather, the smallest known quanta of light or indivisible energy packets of electromagnetic radiation. Photonics is the science that deals with photons and translates research on photons into technical applications. Laser technology is one such example. Lasers emit photons in the form of a coherent beam of light – a photonic technology that is based on the principles of quantum mechanics.
We need the knowledge and technologies of photonics for many quantum applications. Photonics is therefore a field of central importance for the development of quantum technologies in many respects. For example, some quantum computers use photons instead of ordinary bits. One advantage of photonic qubits over other types of qubits, or quantum bits, is their limited environmental interaction which means that they are more resilient to external disturbances. Photonics therefore offers an interesting approach for creating robust platforms for processing quantum information.
In 2022, the BMBF decided to pool two closely related research fields under the term quantum systems – photonics and quantum technologies. The BMBF has since provided funding for projects in these two areas via a dedicated research programme entitled “Quantensysteme – Spitzentechnologie entwickeln. Zukunft gestalten.” (Quantum systems – Developing cutting-edge technologies. Shaping the future.).
The development of quantum technologies
We already use quantum-based technologies in our everyday lives, whether it’s microchips, lasers or magnetic resonance imaging (MRI), to name just a few. These technologies are based on the fundamental principles of quantum mechanics. However, they are not quantum technologies as such as they do not require control over individual quanta. For example, the exact state of an individual photon doesn’t matter in laser technology. Instead, lasers depend on enough photons taking the same state at the same time in order to generate a laser beam.
In contrast, the new generation of quantum technologies require us to control individual quantum particles. This ability to control quantum mechanical principles such as entanglement and superposition makes entirely new technologies possible. It enables the development of precision measurement devices, a considerable increase in the security of data communication and significantly more powerful computers.
Quantum technologies in Germany
Quantum research currently focuses on five fields:
- quantum computers,
- quantum simulation,
- quantum communication,
- quantum measurements and
- basic technologies for quantum systems.
Research also focuses on developing strategies for providing as many people as possible with low-threshold knowledge about quantum technologies.
Quantum computing
Based on the laws of quantum mechanics, quantum computers have the potential to solve complex, computationally intensive tasks much faster than classical computers.
- For example, parcel delivery services could use quantum computing to optimize their route planning. This would maximize the efficiency of parcel delivery as quantum computers would be able to take many additional factors into consideration. They could calculate whether or not it would make sense to reroute in order to avoid traffic jams, road works or traffic lights – and if so, propose a better route.
- Quantum computing could be used to plan the cutting of small parts from large metal sheets in order to minimize waste. This nesting process reduces costs and lowers prices.
How do quantum computers work?
Classical computers use bits that can exist in two states, either 1 or 0. Quantum computers, in turn, use qubits (quantum bits) that can exist in multiple states simultaneously due to the phenomena of quantum mechanics, i.e. superposition and entanglement. Quantum computers are therefore able to carry out vast numbers of calculations in parallel, instead of tackling them successively as classical computers do.
Quantum simulation
Quantum simulation uses a quantum system to simulate another quantum system. Quantum simulations are experiments in which researchers attempt to accurately mimic the behaviour of tiny particles. This can help us to develop new materials or better understand processes at the atomic level.
Quantum simulation is helpful, for example, in developing enhanced batteries that last longer and can be recharged faster. Researchers can also use quantum simulation to develop effective medicines with fewer side effects. In addition, quantum simulation helps us gain a better understanding of environmental influences.
Quantum communication
The primary goal of quantum communication is to ensure the secure transmission of data, particularly with regard to sensitive information, for example in finance, health care, research and government. In these areas, large amounts of confidential data that must be protected against unauthorized access are processed and shared every day.
To ensure their secure transmission, quantum communication makes use of the fact that quantum states cannot be copied. Sensitive information is secured with the help of an encryption key made of qubits. Anyone wanting to intercept the communication would have to measure the qubits. This measuring process, however, changes the state of the qubits, resulting in a changed key that would immediately be noticed and reveal eavesdropping. In this way, quantum communication is excellent for the detection of hacking.
Quantum measurements
Quantum systems make it possible to take measurements with an unprecedented level of precision. Researchers are already working on potentially groundbreaking quantum sensing and metrology technologies, for example to detect natural resources or unexploded bombs faster, to enhance cancer detection and imaging, or to measure neural signals precisely enough to control prostheses. Quantum-based measuring technology is considered the most advanced quantum technology.
Basic technologies for quantum systems
Basic technologies are the prerequisite for putting quantum technologies into practice. This includes basic physical research but also the development of technological devices. Any quantum technology is limited in its current applications by the equipment available, particularly in terms of size and reliability. That’s why an important step towards applying quantum technologies is to make the transition from sensitive lab set‑ups to robust devices that operate safely and can be manufactured economically. Photonics can play a particularly important role in this context.
Science communication
The success of new technologies depends on the people who will use them. We must therefore ensure that the general public can understand and experience quantum technologies first-hand. This is particularly challenging because many quantum mechanical phenomena are hard to grasp and seem paradoxical at first. If you want to learn more about the basics of quantum mechanics, you can read our quantum crash course or watch the videos on the Doktor Whatson science channel.
The Federal Ministry of Education and Research (BMBF) is the lead ministry in charge of organizing the Federal Government’s research policy strategy for quantum technologies.
In addition, the BMBF has launched a quantum research funding programme entitled Quantensysteme – Spitzentechnologie entwickeln. Zukunft gestalten. (Quantum systems – Developing cutting-edge technologies. Shaping the future.) to provide a long-term research policy framework that supports research projects and other initiatives in applied photonics and quantum technologies. Find more information on funding opportunities and projects at www.quantentechnologien.de.
Fostering young talent in quantum technologies – the BMBF’s Quantum Future programme
The Quantum Future programme shines a spotlight on achievements and future developments in quantum technology.
The programme aims to attract young talent, provide information about career opportunities in academia and industry, and provide young people with hands-on experiences and access to national and international networks to help them launch their careers.
Get in touch
Can we help? Whether you want to know more about funding opportunities or other BMBF initiatives in the area of quantum technologies – send us an email at redaktion[at]quantentechnologien.de.
Editorial deadline for this text: 01.11.2024