**What's the big idea?**
The goal of the iDEA code is to improve the accuracy of approximations within fundamental theories of many-electron quantum mechanics. The iDEA code is a Python software suite (with Cython extensions) developed in Rex Godby's group at the University of York since 2010 in collaboration with others. It has a central role in a number of research projects related to many-electron quantum mechanics for electrons in matter.

**iDEA's main features:**
- Exact solution of the many-electron (time-dependent) SchrÃ¶dinger equation, including exact exchange and correlation
- Simplicity and exact solutions which approach the degree of exchange and correlation in realistic systems achieved using spinless electrons in one dimension
- An arbitrary external potential that may be time-dependent
- Optimisation methods to determine the exact (time-dependent) Kohn-Sham potential and energy components of (time-dependent) density functional theory
- Implementation of various approximate functionals (established and novel) for comparison
- Established and novel localisation measures
- Many-body perturbation theory

**The next step:**
Once more reliable approximations are devised, the next crucial step is for these new methods to be implemented into large-scale codes which model realistic systems in order to establish their accuracy. If these new methods prove to be improvements on existing methods, they can then be used to model a wider range of physical systems enhancing our knowledge of materials and chemicals.