Technologies that rely on quantum phenomena are all around us. The first wave of quantum technologies gave us the transistor. These devices became the foundation of modern computers and digital communication. Other examples of technologies powered by quantum mechanics include:
... and many others! These technologies rely on quantum effects that need limited control. Quantum information technologies aim to fully control individual quantum systems. Achieving this control promises new capabilities for computation, digital communication, sensor technology, and other applications.
Magnetic resonance imaging (MRI) has revolutionized how we diagnose diseases, providing medical professionals with a non-invasive method to generate images inside human bodies. MRI machines work thanks to the quantum property of spin, which provides each atom with a predictable magnetic property. By exciting these magnets with radio-frequency light, we can make 3D maps of objects from the outside.
Modern medical MRIs have high enough resolution to image individual hairs. Physicists are developing a new MRI technique using defects in diamond as quantum processors that is thousands of times more precise — almost down to the size of an atom.
The laser, which stands for Light Amplification by Stimulated Emission of Radiation, is a quantum process that produces a highly focused beam of light. Lasers are only possible because of the quantized energy levels in atoms, which can be manipulated to emit more light when illuminated through a process called stimulated emission.
Lasers are used for optical disk storage (DVDs), surgery, fibre telecommunications and internet connections, playing with cats and many other applications. They’re also key in building other quantum technologies like atomic clocks.
Solar cells convert light into an electric current, a process known as the photovoltaic effect. This effect can only be explained if light comes in discrete packets (also called photons) – a cornerstone of quantum mechanics.
Electron microscopes are able to see some of the smallest details in the world by using electrons rather than light as a source of illumination. Because electrons have a wavelength up to 100,000 times shorter than that of visible light, electron microscopes have a much better resolution than traditional optical microscopes. Tunnelling electron microscopes are another type of microscope that uses quantum tunnelling to image surfaces of materials with atomic precision.
The Global Positioning System (GPS) uses very accurate atomic clocks for geolocation. Atomic clocks are better than any other clocks. They keep time by monitoring the microwave signal that electrons in atoms emit when they change energy levels. The best atomic clocks today are so precise that if we would have started two identical clocks 3 billion years ago, they would be off by less than one second today!