How Does Heisenberg's Matrix Mechanics Relate to Dirac's Notation?

  • Context: Undergrad 
  • Thread starter Thread starter Sophrosyne
  • Start date Start date
  • Tags Tags
    Matrix Mechanics
Click For Summary
SUMMARY

Heisenberg's matrix mechanics serves as a foundational formulation of quantum mechanics, particularly influencing Dirac's notation. The relationship between the two is established through Max Born's matrix formulation, which provides a clear mathematical framework for quantum observables. Key concepts include the use of Hermitian operators and orthonormal bases, where the eigenvalues correspond to observable outcomes. Understanding these principles requires a solid grasp of the underlying mathematics, as highlighted in the provided resources.

PREREQUISITES
  • Understanding of quantum mechanics principles
  • Familiarity with Hermitian operators
  • Knowledge of orthonormal bases in linear algebra
  • Basic proficiency in matrix algebra
NEXT STEPS
  • Study the mathematical foundations of quantum mechanics, focusing on matrix mechanics
  • Learn about Hermitian operators and their role in quantum observables
  • Explore Dirac's notation and its applications in quantum theory
  • Review Gleason's theorem and its implications for quantum mechanics
USEFUL FOR

Students of physics, quantum mechanics enthusiasts, and researchers looking to deepen their understanding of the mathematical frameworks underlying quantum theories.

Sophrosyne
Messages
128
Reaction score
21
I have been trying to read about Heisenberg's matrix mechanics on my own, and I am getting hopelessly lost. I understand it has something to do with anharmonic oscillators. I am no physicist, so please take it easy with the explanations.
Also, I read somewhere that these, along with Max Born's formulation of them into Matrix form, which were the inspiration for Dirac's notation later. Is there a relationship between the two?
 
Physics news on Phys.org
  • Like
Likes   Reactions: bhobba
Sophrosyne said:
Also, I read somewhere that these, along with Max Born's formulation of them into Matrix form, which were the inspiration for Dirac's notation later. Is there a relationship between the two?

Of course.

And its easy in the Dirac notation, but without the math forget it.

The fundamental thing is given an orthonormal basis |bi> Σ|bi><bi| = 1.

Now one of the foundational axioms of QM is given any observable you can find a Hermitian operator O whose eigenvalues yi are the possible outcomes of the observation. Now associated with any eigenvalue yi is an eigenvector |bi> and it turns out they form an orthonormal basis (there are a few subtleties - but that is pretty much it). Just as an aside its really the only axiom - but that is a whole new thread where the beautiful Gleason's theorem is discussed.

So here is what happens. You simply insert Σ|bi><bi| = 1 twice - O = Σ|bi><bi| O Σ|bj><bj| = ΣΣ|bi><bi|O|bj><bj| = ΣΣ<bi|O|bj>|bi><bj|. <bi|O|bj> is called the matrix representation of O and it turns out for eigenvectors is diagonal.

If the above is gobbly-gook then I am sorry - there is no out - you must learn the math:
http://quantum.phys.cmu.edu/CQT/chaps/cqt03.pdf

Thanks
Bill
 

Similar threads

  • · Replies 12 ·
Replies
12
Views
2K
  • · Replies 41 ·
2
Replies
41
Views
10K
  • · Replies 230 ·
8
Replies
230
Views
20K
  • · Replies 10 ·
Replies
10
Views
3K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 22 ·
Replies
22
Views
3K
  • · Replies 17 ·
Replies
17
Views
3K
  • · Replies 31 ·
2
Replies
31
Views
5K
Replies
3
Views
2K
  • · Replies 376 ·
13
Replies
376
Views
23K