Diagonalization Definition and 133 Threads

  1. A

    Simultaneous diagonalization and replacement of operators with eigenvalues ?

    Apparently, if I have a Hamiltonian that contains an operator, and that operator commutes with the Hamiltonian, not only can we "simultaneously diagonalize" the Hamiltonian and the operator, but I can go through the Hamiltonian and replace the operator with its eigenvalue everywhere I see it...
  2. K

    What are the criteria for determining if a matrix is diagonalizable?

    Homework Statement 1) Let's say I was trying to find the eigenvalues of a matrix and came up with the following characteristic polynomial: λ(λ-5)(λ+2) This would yield λ=0,5,-2 as eigenvalues. I'm kinda thrown off as to what the algebraic multiplicity of the eigenvalue 0 would be? I'm pretty...
  3. J

    Diagonalization 2: Explaining Theorem 2.5

    I am reading yet another theorem and was wondering If I could get more clarification on it. Theorem 5.2: Let A be in M_n_x_n(F). Then a scalar \lambda is an eigenvalue of A if and only if det(A - \lambdaI_n) = 0. Proof: A scalar \lambda is an eigenvalue of A if and only if there exists a...
  4. M

    Finding an Invertible Matrix for Matrix Diagonalization

    Homework Statement A = -10 6 3 -26 16 8 16 -10 -5 B = 0 -6 -16 0 17 45 0 -6 -16 (a) Show that 0, -1 and 2 are eigenvalues both of A and of B . (b) Find invertible matrices P and Q so that (P^-1)*(A)*(P) = (Q^-1)*(B)*(Q)= 0 0 0 0 -1 0 0 0 2 (c) Find an invertible...
  5. B

    Linear algebra diagonalization

    linear algebra diagonalization :( Homework Statement determine whether the given matrix is diagonalizable. where possible, find a matrix S such that S-1AS=Diag(λ1+λ2,...,λn) Homework Equations The Attempt at a Solution I was able to find the eigenvalues, which are λ=1,-4,4. This is given in...
  6. Deneb Cyg

    Square Matrix A that is not Diagonalizable but A^2 is Diagonalizable

    The question is "give an example of a square matrix A such that A^2 is diagonalizable but A is not." I know that if A^2 is diagonalizable, A^2 = P(D^2)P^-1. And if A is not diagonalizable, there is no invertible matrix P and diagonal matrix D such that A=PDP^-1. However I'm not sure how...
  7. C

    Why Do the Positions of C and C^-1 Switch in Matrix Diagonalization Definitions?

    Homework Statement My linear algebra textbook defines... similar matrices: A = C^-1BC diagonalized similar matrices: A = CDC^-1 A^n = C^-1*D^n*C Why do the C^-1 and C's get switched around between the definitions? Doesn't order of multiplication matter? Are these the correct...
  8. A

    Cantor diagonalization argument

    sorry for starting yet another one of these threads :p As far as I know, cantor's diagonal argument merely says- if you have a list of n real numbers, then you can always find a real number not belonging to the list. But this just means that you can't set up a 1-1 between the reals, and...
  9. J

    Bloch's theorem and diagonalization of translation operator

    I'm now interested in a Schrödinger's equation \Big(-\frac{\hbar^2}{2m}\partial_x^2 + V(x)\Big)\psi(x) = E\psi(x) where V does not contain infinities, and satisfies V(x+R)=V(x) with some R. I have almost already understood the Bloch's theorem! But I still have some little problems...
  10. S

    Quadratic forms, diagonalization

    Can a quadratic form always be diagonalised by a rotation?? Thx in advance
  11. J

    Matrix, eigenvalues and diagonalization

    Matrix A= 1 2 0 2 1 0 2 -1 3 i got eigenvalues k=3 k=-1 what do i do after that to prove it is not able to be diagonalized
  12. B

    What is wrong with this diagonalization problem.

    Homework Statement A is [4 0 1 2 3 2 1 0 4] Find an invertible P and a diagonal D so that D=P-1AP. I keep getting two linearly dependent eigenvalues which means it's not diagonal but this problem doesn't state "If it can't be done explain why" or anything like that. So I just...
  13. F

    Proving the Diagonalizability of a Real 2x2 Matrix Using Invertible Matrices

    Homework Statement Let A be a 2x2 real matrix which cannot be diagonalized by any matrix P (real or complex). Prove there is an invertible real 2x2 matrix P such that P^{-1}AP = \left( \begin{array}{cc} \lambda & 1 \\ 0 & \lambda \end{array} \right) I know how to diagonalize a matrix...
  14. J

    Linear Algebra: Diagonalization, Transpose, and Disctinct Eigenvectors.

    Homework Statement Show that if an nxn matrix A has n linearly independent eigenvectors, then so does A^T The Attempt at a Solution Well, I understand the following: (1) A is diagonalizable. (2) A = PDP^-1, where P has columns of the independent eigenvectors (3) A is...
  15. J

    Regarding Diagonalization of Matrix by Spectral Theorem

    According to the spectral theorem for self-adjoint operators you can find a matrix P such that P^{-1}AP is diagonal, i.e. P^{T}AP (P can be shown to be orthogonal). I'm not sure what the result is if the same can be done for the following square (size n X n) and symmetric matrix of the form: A=...
  16. A

    Orthogonal Diagonalization of a Symmetric Matrix

    Homework Statement Orthogonally diagonalize the matrix: | 2 1 1| | 1 2 1| | 1 1 2| Homework Equations Since this only has...
  17. A

    Diagonalization, eigenvectors, eigenvalues

    [SOLVED] diagonalization, eigenvectors, eigenvalues Homework Statement Find a nonsingular matrix P such that (P^-1)*A*P is diagonal | 1 2 3 | | 0 1 0 | | 2 1 2 | Homework Equations I am at a loss on how to do this. I've tried finding the eigen values but its getting me...
  18. B

    Diagonalization & Eigen vectors proofs

    Homework Statement Question 1: A) Show that if A is diagonalizable then A^{T} is also diagonalizable. The Attempt at a Solution We know that A is diagonalizable if it's similar to a diagonal matrix. So A=PDP^{-1} A^{T}=(PDP^{-1})^{T} which gives A^{T}=(P^{-1})^{T}DP^{T} as...
  19. B

    Diagonalization and Matrix similarity

    Question1 : a) Show that if A is nonsingular and diagonalizable then A^-1 is diagonalizable b) Show that if A is diagonalizable then A^T is diagonalizable Question 2 Show that if A is similar to B and B similar to C, then A is similar to C.
  20. C

    How exactly does diagonalization work and how is it useful in qm?

    how exactly does it work and how is it useful in qm?
  21. N

    Diagonalization Algorithm for Large Matrices: Any Suggestions?

    Does anyone here know of any fast algorithms to diagonize large, symmetric matrices, that are mostly zeros? (by large I mean 300x300 up to several million by several million)
  22. E

    Diff equation by diagonalization

    Homework Statement solve initial value problem for the equation dx/dt = Ax where A = [1 -1] [0 1] x(0) = [1, 1]T x(t) = S*elambda*t*S -1*x(0) where S is diagonal matrix, lambda is eigenvalue; The Attempt at a Solution I tried to diagonalize it, but I get one eigenvalue =1 mult 2 and I don't...
  23. E

    Symmetric matrix and diagonalization

    This is a T/F question: all symmetric matrices are diagonalizable. I want to say no, but I do not know how exactly to show that... all I know is that to be diagonalizable, matrix should have enough eigenvectors, but does multiplicity of eigenvalues matter, i.e. can I say that if eignvalue...
  24. H

    Geometric and Physical Interpretation of Diagonalization

    I am a second year student in quantum mechanics. I heard in lecture that simultaneous diagonalization of matrices is important in quantum mechanics. I would like to know why is it significant when two matrices can be simultaneous diagonalized, and what is the geometric and physical...
  25. B

    Diagonalization of a matrix with repeated eigenvalues

    Hey guys, I know its possible to diagonalize a matrix that has repeated eigenvalues, but how is it done? Do you simply just have two identical eigenvectors?? Cheers Brent
  26. E

    Is the set of infinite strings of {a,b} countable?

    I am stumpt on this problem: Use Cantor's diagonalization method to show that the set of all infinite strings of the letters {a,b} is not countable: Can I have a hint? :redface:
  27. L

    Basic metric diagonalization questions

    I understand it is always possible to diagonalize a metric to the form diag[1,-1,\dots,-1] at any given point in spacetime because the metric is symmetric and we can always re-scale our eigenvectors. But is this achievable via a coordinate transformation? That is, would the basis...
  28. S

    What is Special Diagonalization?

    i need to know about specially diagonalization, is it orthogonal diagonalization or something different?
  29. B

    How Do You Simultaneously Diagonalize Two Commuting Hermitian Operators?

    I am having a hard with parts of this problem: Suppose V is a 3-dimensional complex inner-product space. Let B1 = {|v1>,|v2>,|v3>} be an orthonormal basis for V. Let H1 and H2 be self-adjoint operators represented in the basis B1 by the Hermitian matrices. I won't list them, but they...
  30. M

    How Do I Calculate the Inverse of Matrix P and Determine Eigenvectors?

    Could someone tell me how to get the P(inverse), P^-1. For example I read all the examples in my book and it has like given the matrix for P and then it finds the matrix for P(inverse)Vo , how do i find P^-1. Plz help me quickly. Ex. P= | 2 -1 | asdfasf| 3 as1 | and Vo=| 1 |...
  31. O

    A new point of view on Cantor's diagonalization arguments

    Hi, In this pdf (+ its links)http://www.geocities.com/complementarytheory/NewDiagonalView.pdf you can find a new point of view on Cantor's diagonalization arguments. I really want to send a BIG THANK YOU to Matt grime and Hurkyl for their hard time with me. Yours, Organic
  32. O

    Cantor's Diagonalization function on the combinations list

    PLEASE READ THIS POST UNTIL ITS LAST WORD, BEFORE YOU REPLY. THANK YOU. Let us check these lists. P(2) = {{},{0},{1},{0,1}} = 2^2 = 4 and also can be represented as: 00 01 10 11 P(3) = {{},{0},{1},{2},{0,1},{0,2},{1,2},{0,1,2}} = 2^3 = 8 and also can be represented...
  33. O

    A question on Cantor's second diagonalization argument

    Hi, Cantor used 2 diagonalization arguments. On the first argument he showed that |N|=|Q|. On the second argument he showed that |Q|<|R|. I have some question on the second argument. From Wikipedia, the free encyclopedia: http://en.wikipedia.org/wiki/Cantor's_diagonal_argument...
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