# Available student project - Quantum tunnelling in many-body systems

## Research fields

- Theoretical Physics
- Quantum Science and Applications

## Project details

Quantum tunnelling allows a particle to cross a potential barrier even if it does not have anough energy to do so. This process, which is forbidden in classical mechanics, is well understood in the case of an elementary particle such as the electron. In particular, it is used in scanning tunnelling spectroscopy. However, the case of composite systems, such as molecules or atomic nuclei, is more complex. Indeed, the internal motion of the particles may induce quantum decoherence and dissipation. How these processes affect the tunnelling of a system is one of the key open questions in quantum physics. It would help to understand various processes such as fusion of atomic nuclei (see figure).

Various projects are proposed. Examples of projects based on both formal developments and numerical simulations include modelling tunnelling of:

- A particle in interaction with an environment, inducing decoherence and leading to a quantum-to-classical transition.
- A composite particle with an internal environment, such as the possibility for the system to vibrate while tunneling.
- A system of weakly interacting particles, such as a Bose-Einstein condensate (BEC).
- A system of strongly interacting particles, such as nucleons in a nucleus undergoing fusion or fission.

Another project, more formal, include the development of a mean-field theory in complex time following the Feynman-path integral formulation of quantum mechanics.

## Required background

A course on basic quantum mechanics (PHYS2013) is a pre- or co-requisite.

More advanced theoretical physics courses (PHYS3001 and PHYS3002) would be an advantage for more formal projects, but they are not compulsory.

## Project suitability

- 3rd year special project
- PhB (1st year)
- PhB (2nd or 3rd year)
- Honours project
- Phd or Masters
- Vacation scholar