Quantum Technologies

Definition

Basic kinds

• Quantum computers: Computing devices using quantum bits (qubits) that can represent multiple states simultaneously, enabling parallel information processing on an unprecedented scale.
• Quantum cryptography: Information security technologies based on the principle of quantum entanglement and the Heisenberg uncertainty principle, preventing data capture if not detected by the sender and receiver.
• Quantum sensors: Precision measurement devices that use quantum phenomena, such as interference and superposition, to detect very weak signals or changes in the environment with high accuracy.

Main roles

• Medicine: Precision quantum sensors can be used for medical imaging at the molecular level, allowing early detection of diseases such as cancer. Quantum technologies are also used in drug research and genomics (the science of analysing and mapping the genome of organisms).
• Telecommunications: Quantum cryptography enables secure communications that are resistant to data capture attempts, which is crucial in defense and for financial institutions.
• Research: Quantum computers make it possible to solve problems that were previously impossible to handle on classical supercomputers, which can accelerate scientific development in fields such as quantum chemistry, materials physics, and astrophysical simulations.
• Finance: quantum applications are used in financial modelling, portfolio optimisation, risk management and fraud detection.

Basic elements

• Qubit: A basic unit of information in quantum computers, whose state, unlike classical bits, can be 0, 1, and a superposition of both states simultaneously.
• Quantum entanglement: A phenomenon in which two particles remain connected in such a way that the state of one immediately affects the state of the other, regardless of the distance.
• Quantum interference: A phenomenon used for precision measurements in quantum sensing technology, where quantum waves can amplify or attenuate measurement results.

Mechanism of action

• Superposition: In classical computing systems, a bit can represent a value of 0 or 1. In quantum computers, thanks to the phenomenon of superposition, a qubit can be simultaneously in states 0 and 1 or any combination of the two states. This means that quantum computers can process huge amounts of data in parallel, making them extremely efficient in solving complex problems, such as optimisation, molecular simulations, and multidimensional data analysis. In practice, superposition allows quantum computers to perform multiple calculations at the same time, greatly speeding up complex tasks.
• Quantum entanglement: Quantum entanglement is a phenomenon in which two particles that are entangled remain inseparable, regardless of the distance between them. A change in the state of one particle immediately affects the state of the other, even if they are hundreds of kilometres apart. This phenomenon is the basis of quantum cryptography, where quantum entanglement is used to transmit information securely as any attempt to capture data automatically changes the state of entanglement, which is immediately detected. Entanglement also makes it possible to create highly efficient quantum networks that can transmit data faster and more securely than traditional networks.
• Quantum tunnelling: Quantum tunnelling is a phenomenon that allows quantum particles to tunnel through energy barriers that would be impassable in the classical world. This phenomenon is used in a variety of devices, such as quantum sensors, which are capable of detecting extremely weak signals or changes in the environment. Tunnelling is also used in advanced quantum transistors that can operate at the atomic level, enabling miniaturisation and increased performance of electronic devices.
• Quantum interference: In quantum sensing technology, quantum interference plays a key role in obtaining precise results. It involves the superposition of quantum waves, which can amplify or attenuate signals depending on their phase. As a result, quantum sensors are able to detect even the slightest changes in the environment, making them indispensable in medicine (e.g. precision medical imaging), geophysics (e.g. detection of anomalies in the gravitational field), and even military navigation systems. Quantum interference enables extremely high measurement accuracy, which is unattainable with traditional technologies.
• Quantum parallel computing: In classical computers, calculations are performed sequentially, one after the other. In quantum computers, thanks to superposition and entanglement, many operations can be performed simultaneously. As a result, quantum algorithms, such as Shor’s algorithm (for decomposing numbers into prime factors) and Grover’s algorithm (for searching unstructured databases), offer much better results than their classical counterparts. This paves the way for solving problems that were previously considered unsolvable in a reasonable time, such as molecular modeling in quantum chemistry, logistic optimisation, and simulations of financial systems.
• Quantum signal amplification: In quantum sensing, phenomena such as superposition and entanglement allow measurement signals to be amplified, improving detection accuracy, even at the atomic level. Quantum signal amplification makes it possible to detect minimal fluctuations in magnetic or electric fields, which could be used in biomedical research, space radiation detection, or navigation systems.