Quantum Mechanics
Lesson 2 of 4 11 min +120 XP

The Schrödinger Equation

The master equation of quantum states.

What you'll learn

  • State what the Schrödinger equation governs
  • Identify the Hamiltonian's role
  • Explain stationary states
The rulebook for the blur

If a quantum particle is a spreading, sloshing wave of possibility, something has to say how it sloshes over time. The Schrödinger equation is that rulebook — the equation that predicts how the wavefunction evolves from one moment to the next.

How a quantum state evolves

The time-dependent Schrödinger equation, iℏ ∂ψ/∂t = Ĥψ, governs how a wavefunction changes in time. Ĥ is the Hamiltonian operator — it encodes the system's total energy (kinetic + potential).

Stationary states

Solving Ĥψ = Eψ gives energy eigenstates with definite energy E. Their probability density |ψ|² doesn't change in time — hence 'stationary'.

Lab · Read the equation
  1. Identify the operator acting on ψ on the right side.
  2. Note what E represents in Ĥψ = Eψ.
  3. Recall what stays constant for an eigenstate.

What you should see: Ĥ is the energy operator; E is the state's definite energy; |ψ|² is constant in time for an eigenstate.

Knowledge Check

+30 XP / correct

1. In Ĥψ = Eψ, the operator Ĥ represents the system's…

2. A stationary state is one whose ___ does not change in time.