Quantum and relativistic twin paradox
Suitable for: Students who have a basic knowledge of classical physics. Knowledge of quantum mechanics or relativity is not necessary. Familiarity with symbolic computation software (such as Mathematica, Maple) will be an asset.
Project description: In a classic twin paradox of relativity, two travellers embark simultaneously on two separate voyages, and when they meet again they discover that they have aged differently - depending on how much proper time elapsed along their respective paths. A single quantum traveller can embark on the two voyages, travelling along two paths in a quantum superposition. When the traveller's paths meet, he discovers that his age is ... You will learn the theoretician's answer in this project, but ultimately this has to be tested in experiments, for example, using atom interferometers.
In this project the student will compute proper times along trajectories accessible to an atomic quantum traveller in an atom fountain interferometer. The core idea behind an atomic fountain is simple: one shoots laser pulses to a cloud of atoms so that each has 50:50 chance to receive a laser-kick. This coherently splits the cloud into two - thus creating two paths in the interferometer. Similar shooting is repeated to make the paths meet again. The velocity of an atom which received a kick is determined by the momentum of light and atomic mass. Besides the kicks, the atoms are in free fall - this allows computing atomic trajectory, and the proper time along it. The project will, in particular, analyse how much proper time elapses along trajectories created by using different number of laser-kicks, and when using atoms of different mass. As a result of this project we will learn what combination of pulses creates the biggest difference in proper times elapsing along the paths in an atomic fountain, and is best for a future experiment. For a student familiar with quantum physics, there will be opportunity to additionally model the quantum traveller as well - by analysing additional effects arising when atom's energy is a superposition of two internal levels.
Expected outcomes: The applicant will gain knowledge and intuition about interplay between quantum mechanics and relativity, learning theoretical tools relevant for describing generic atom interference experiments. The applicant will have the opportunity to publish the results of the project in a peer-reviewed journal.
Project duration: 3 July - 11 August 2017 (6 weeks), 36hrs/week
Primary Supervisor: Dr Magdalena Zych Further information: Interested applicants please contact Dr Zych, email@example.com, about the project and prior to submitting an application.