Precision measurements with ultracold atoms

The Quantum Metrology Group is working with precision measurements with ultracold atoms that uses quantum physics to make precise measurements by means of quantum optics. The ultra-precise quantum optical measurements range from precision measurements of the physical structure of atomic nuclei to research on ultra-precise atomic clocks, which can be used for navigation and space missions.

The group works with experimental setups in the laboratory, where the atoms are trapped in a magnetic field, where they are held by precise beams of laser light and are cooled down to near absolute zero, minus 273 degrees Celsius. They use different atoms for the experiments, for example, strontium, magnesium or ytterbium, which all have two electrons in the outer shell, which gives them particular quantum mechanical properties.

These quantum mechanical properties are used for research on an ultra-precise atomic clock. An atomic clock is comprised of atoms, here strontium, which are captured and manipulated using laser light. An atom consists of a nucleus and some electrons that move in clearly defined orbits around the nucleus and you can get the electron to jump back and forth in a well defined way between these orbits using focused laser light. It is this that forms the pendulum in the atomic clock.

The result is an atomic clock that is now so precise that it only loses one second every 300 million years, but physicists are working to make it even more precise and this has great potential. Looking towards the Earth, you will be able to measure the tiny movements of continental drift and this could perhaps give geophysicists a new tool to predict earthquakes. Looking towards space, you could use atomic clocks for space-based optical interferometry, which can be used to search for gravitational waves or planets orbiting other stars than the Sun.