Online Test Banks
Score higher
See Online Test Banks
Learning anything is easy
Browse Online Courses
Mobile Apps
Learning on the go
Explore Mobile Apps
Dummies Store
Shop for books and more
Start Shopping

How to Use Ket Notation in Quantum Physics

In quantum physics, ket notation makes the math easier than it is in matrix form because you can take advantage of a few mathematical relationships. For example, here’s the so-called Schwarz inequality for state vectors:


This says that the square of the absolute value of the product of two state vectors,


is less than or equal to


This turns out to be the analog of the vector inequality:


So why is the Schwarz inequality so useful? It turns out that you can derive the Heisenberg uncertainty principle from it.

Other ket relationships can also simplify your calculations. For instance, two kets,


are said to be orthogonal if


And two kets are said to be orthonormal if they meet the following conditions:


This information is important for working with operators.

  • Add a Comment
  • Print
  • Share
blog comments powered by Disqus

Inside Sweepstakes

Win $500. Easy.