# 6: Three-Dimensional Quantum Mechanics


In this chapter, we shall extend our previous one-dimensional formulation of non-relativistic quantum mechanics to produce a fully three-dimensional theory.

• 6.1: Fundamental Concepts
We have seen that in one dimension the instantaneous state of a single non-relativistic particle is fully specified by a complex wavefunction, $$\psi(x,t)$$.
• 6.2: Particle in Box
Consider a particle of mass $$m$$ trapped inside a cubic box of dimension $$a$$.
• 6.3: Degenerate Electron Gases
• 6.4: White Dwarf Stars
A main-sequence hydrogen-burning star, such as the Sun, is maintained in equilibrium via the balance of the gravitational attraction ending to make it collapse, and the thermal pressure tending to make it expand.
• 6.5: Exercises
