Eigenvalues Definition and 820 Threads

  1. J

    Normalize both ψ1 and ψ2 and then find the energy eigenvalues of each

    Hi there this is my first post here, I am having some trouble with a homework question in quantum. I need to normalize both ψ1 and ψ2 and then find the energy eigenvalues of each. The given Hamiltonian is H0 = (1 2 ) (2 -1) And ψ1 = (...
  2. S

    About an equation with eigenvalues

    Let's say I have the equation p(t)f''(t)=Kf(t) with p(t) a known periodical function, K an unknown constant and f(t) the unknown function. This is an eigenvalues problem that once solved gives a set of K={k1, k2,...} eigenvalues. I get these eigenvalues and they coincide with the ones...
  3. L

    Computer Vision, Corners and Eigenvalues

    This question is about the use of eigenvalues in a specific application. The subject is Computer Vision and the topic is the Harris Corner detection method. The attached file is PDF document of slides that show the math in a bit more detail. In the slides, a corner is located by looking at...
  4. C

    Relationship between determinant and eigenvalues?

    Homework Statement Find the eigenvalues of B = [5 2 0 2], [3 2 1 0], [3 1 -2 4], [2 4 -1 2]. Compute the sum and product of eigenvalues and compare it with the trace and determinant of the matrix. Homework Equations The Attempt at a Solution I get the characteristic polynomial...
  5. P

    What do the directions of eigenvalues represent?

    Background: I'm having trouble using principal component analysis to try and align two data sets. I have two sets of 3D point data, and I can use PCA to get principal axes of the two sets of data. I do this by finding the eigenvectors of the covariance matrix for each set of data. This gives...
  6. C

    Can You Simplify Finding Eigenvalues of an n x n Matrix?

    Just wondering is there a way to get the characteristic equation of an n by n matrix without going through tedious calculations of solving multiple determinants of matrices?
  7. E

    The lowest energy eigenvalues

    Homework Statement compute and plot the 10 lowest energy eigenvalues of a particleinan infinity deep spherically symmetric square well? Homework Equations The Attempt at a Solution
  8. E

    Plot a several energy eigenvalues of a partical

    Hi How can i compute(or obtain from mathmatical tables) and plot a several energy eigenvalues of a particle in an infinity deep ,spherically and symmetric square well?
  9. N

    Linear Systems of ODE's: Eigenvalues and Stability

    Homework Statement Hi all. I am given by following linear system: \begin{array}{l} \dot x = dx/dt = ax \\ \dot y = dy/dt = - y \\ \end{array} The eigenvalue of the matrix of this system determines the stability of the fixpoint (0,0): A=\left( {\begin{array}{*{20}c} a & 0 \\...
  10. J

    Eigenvalues - real and imaginary

    Am I understanding this right? Let's say I have a 15x15 matrix called Z. Then the matrix of eigenvalues calculated from Z, called D, can have two forms - either diagonal or block diagonal. If the matrix D comes out with values only on the diagonal, then there are only real values. But...
  11. S

    Are Eigenvalues and Eigenvectors Correctly Understood in Matrix Operations?

    Homework Statement I am studying about eigenvalues and norms. I was wondering whether the way I understand them is correct. Homework Equations The Attempt at a Solution The eigenvalue of a matrix those that satisfy Ax = \lambda x, where A is a matrix, x is an eigenvector, \lambda...
  12. F

    Hermitian Operators and Eigenvalues

    Homework Statement C is an operator that changes a function to its complex conjugate a) Determine whether C is hermitian or not b) Find the eigenvalues of C c) Determine if eigenfunctions form a complete set and have orthogonality. d) Why is the expected value of a squared hermitian...
  13. R

    Problems related to eigenfunctions and eigenvalues

    can somebody help me with the solution of the following problems? Ques. Find the eigenfunctions and eigenvalues for the operators 1. sin d/d psi 2. cos(i d/d psi) 3. exp(i a d/d psi) 4. (d)square/d (x)square+z/x * d/dx
  14. J

    Connection between isolated eigenvalues and normalizable eigenstates

    It seems to be true, that if some eigenvalue of a Hamilton's operator is an isolated eigenvalue (part of discrete spectrum, not of continuous spectrum), then the corresponding eigenstate is normalizable, and on the other hand, if some eigenvalue of a Hamilton's operator is not isolated, then the...
  15. E

    Diagonalizable Matrices & Eigenvalues

    Hello, Is it sufficient to determine that a nXn matrix is not diagonalizable by showing that the number of its distinct eigenvalues is less than n? Thanks for your time.
  16. F

    Why Is (A-3I)^2 Used Instead of (A-3I)^3 in Finding Eigenvectors?

    my question is take A= {(5,0,-1),(2,3,-1),(4,0,1)} find all eigenvalues and eigenvectors by using the characteristic equation i get -(lamda-3)3 however its the next bit i don't understand, in the answers (A-3I)(x,y,z)=(0,0,0) is used which I'm perfectly ok with and then (A-3I)2 is used and...
  17. F

    Solving Eigenvalues of Hessian Matrix

    g(x,y) = x^3 - 3x^2 + 5xy -7y^2 Hessian Matrix = 6x-6******5 5********-7 Now I have to find the eigenvalues of this matrix, so I end up with the equation (where a = lambda) (6x - 6 - a)(-7 - a) - 25 = 0 Multiplying out I get: a^2 - 6xa + 13a - 42x + 17 = 0 How am I supposed to solve...
  18. 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
  19. J

    Is There an Easier Way to Find the Signs of Eigenvalues for Sparse Matrices?

    Homework Statement Hey guys, for my linear algebra class I need to find the signs of the eigenvalues (I just need to know how many are positive and how many are negative) of an nxn matrix with zeros everywhere except for the two diagonals directly above and directly below the main diagonal...
  20. S

    What are the eigenvalues of a non-Hermitian operator?

    Hi, everyone! While I was studying for my midterm, I encountered this question. ------ Consider the hermitian operator H that has the property that H4 = 1 What are the eigenvalues of the operator H? What are the eigenvalues if H is not restricted to being Hermitian? ------ What I am...
  21. S

    Help finding the eigenvalues of this

    Homework Statement alright, so i have a question which asks me to find the eigenvalues of a 3x3 square matrix A. after working on it for a long time, i can't figure it out, i know the process of it and i can do 2x2 matrices easily, i cannot figure this one out though. here is the matrix A; 2...
  22. M

    How Do Eigenstates and Eigenvalues Relate to Quantum Observables?

    Homework Statement I have the hamiltonian : H=C(|2><1|+|1><2|) where : C=costant |1> and |2> are eigenstates of an osservable A. what are the eigenstate and eigenvalues of the hamiltonian? what is the probability that the system is in the state |2>? The Attempt at a Solution...
  23. N

    How can get the eigenvalues of the two spin entangle

    there is a equation for two spins in entangled Hamiltonian: H=J(\vec{\sigma}^1\cdot\vec{\sigma}^2+\vec{\sigma}^2\cdot\vec{\sigma}^1)+B(\vec{\sigma}^1_z+\vec{\sigma}^2_z) where \vec{\sigma}^i=(\sigma^i_x,\sigma^i_y,\sigma^i_z) are the pauli matrics for the ith (i=1,2) spin. J is the exchange...
  24. L

    Strange question regarding eigenvectors / eigenvalues

    Homework Statement Suppose that the 2x2 matrix A has eigenvalues lambda = 1,3 with corresponding eigenvectors [2,-1]^T and [3,2]^T. Find a formula for the entries of A^n for any integer n. And then, find A and A^-1 from your formula. Homework Equations Ax = lambda X (P^-1)AP = D A =...
  25. S

    Matrix with repeated eigenvalues

    The question is asking for what values of x will the matrix have at least one repeated eigenvalue (algebraic multiplicity of 2 or greater). The matrix is | 3 0 0 | | 0 x 2 | So naturally a normal attempt to find the eigenvalue in a question with only intergers | 0 2 x | I would continue...
  26. M

    Proving Hermitian if it has real eigenvalues

    If you had an operator A-hat whose eigenvectors form a complete basis for the Hilbert space has only real eigenvalue how would you prove that is was Hermitian?
  27. M

    Find the eigenvalues and a basis of each eigenspace

    Homework Statement Matrix A is -4 4 4 -4 4 4 4 -4 -4 It has two real eigenvalues, one of multiplicity 1 and one of multiplicity 2. Find the eigenvalues and a basis of each eigenspace. The Attempt at a Solution I got the eigenvalues: the one of multiplicity 1 is -4 the one of multiplicity...
  28. J

    Orthogonality of eigenfunctions with continuous eigenvalues

    Homework Statement With knowledge of the orthogonality conditions for eigenfunctions with discrete eigenvalues, determine the orthonormal set for eigenfunctions with continuous eigenvalues. Use the definition of completeness to show that | a(k) |^2 = 1. 2. The attempt at a solution The first...
  29. S

    Comparing Eigenvalues for Sarah & Janie: Is It Compatible?

    Suppose for a given matrix A, Sarah finds the eigenvectors v1 = [1 3 4 5]' and v2 = [5 6 3 4]' form a base for eigenspace of labmda = 2. Now suppose Janie finds the eigenvectors v3 = [1 2 2 3]' and v4 = [7 8 7 6]' form a base for eigenspace of lambda = 4. Is Janie's solution compatible with...
  30. S

    Distinct Eigenvalues in matlab

    All I want to know is if a number and its negative appear as eigenvalues of a matrix, are they considered distinct? I have 4,1,-2,3 and -1 as eigenvalues of a particular matrix, but I can't get 5 linearly independent eigenvectors (to diagonalise the original matrix). I've plugged away and...
  31. K

    What Are the Eigenvalues and Degeneracies of a Coupled Ising Spin System?

    Homework Statement Consider two Ising spins coupled together −βH = h(σ1 + σ2) + Kσ1σ2, where σ1 and σ2 commute and each independently takes on the values ±1. What are the eigenvalues of this Hamiltonian? What are the degeneracies of the states? The Attempt at a Solution Four possible...
  32. W

    Orthogonal matrix and eigenvalues

    a) Let M be a 3 by 3 orthogonal matrix and let det(M)=1. Show that M has 1 as an eigenvalue. Hint: prove that det(M-I)=0. I think I'm supposed to begin from the fact that det(M)=1=det(I)=det(MTM) and from there reach det(M-I)=0 which of course would mean that there's an eigenvalue of 1 as...
  33. maverick280857

    Diagonalizing a square matrix with degenerate eigenvalues

    Hi This is more of a math question but in the context of Quantum Mechanics, hence I posted it here. Suppose I have a matrix A of order 3x3 with three eigenvalues: 0, 0, 5. I am supposed to find the diagonalizing matrix for A. I know that in general, if P denotes the matrix of eigenvectors of...
  34. F

    Iterated maps and eigenvalues and vectors

    Totaly stuck on this one can't even start to fathom an attempt. first part of the question is show that the eigenvalues of the matrix (2x2 left to right) 4,-1,-4,4 are sigma1=2 and sigma2 =2 and eigenvectors e1= (1,2)T and e2=(1,-2)T done this no problem but am writing this as the second part of...
  35. S

    Eigenvalues & eigenvectors of N x N matrix?

    How to get eigenvalues & eigenvectors of N x N matrix? Please can anyone help me out i have searched a lot but not able to find the solution. Regards
  36. J

    Eigenvalues of A: Same Eigenspaces for A^-1, Transpose, A^k

    Is this a correct realization? The eigenspaces corresponding to the eigenvalues of A are the same as the eigenspaces corresponding to the eigenvalues of A^-1, transpose of A, and A^k for any k > 1. It took me some time to realize this but the v's, when you manipulate these equations, don't...
  37. rocomath

    Understanding Eigenvalues: Question on Diagonalizability and Orthogonality

    I wasn't sure about this question on my exam. Let eigenvalues be 0, 1, -1 Is it true that a. Not Invertible b. Diagonalizable c. Orthogonal a. True, since the determinant is 0 b. I'm not sure, but I chose False b/c I had an eigenvalue of 0 c. True, ah not sure either LOL!
  38. rocomath

    What is the significance of Eigenvalues in a 2 by 2 matrix?

    Assuming 2 by 2. Ok, I'm asked to find the Eigenvalues. How do I know which should be lambda 1 and lambda 2? I can find the lambda's easily, but does it matter which is 1 or 2? It becomes important when I'm asked to diagonalize. A=S\Lambda S^{-1}
  39. A

    I don't get Eigenvalues or Eigenvectors

    I just finished Differential Equations, and I know how to find eigenvalues/eigenvectors, and I understand how to use them to solve a differential equation. But I don't really understand "what they are". How is a matrix with complex eigenvalues any different than a matrix with real...
  40. A

    Approximate Eigenvalues for [4 3] [3 5]

    [SOLVED] Approximate eigenvalues Homework Statement Use some QR method to approximate the eigenvalues of [4 3] [3 5] and compare with the actual values. The actual values are (9±√37)/2 Homework Equations A(0)=Q(0)R(0) A(1)=R(0)Q(0) A-α(0)I=Q(0)R(0) A(1)=R(0)Q(0) + α(0)I...
  41. A

    Positive Definite Matrices eigenvalues

    [SOLVED] Positive Definite Matrices a) If A is Symmetric show that A-λI is positive definite if and only if all eigenvalues of A are >λ, and A-λI is negative definite if and only if all eigenvalues of A are <λ. b) Use this result to show that all the eigenvalues of [ 5 2 -1 0] [ 2 5 0...
  42. A

    Can QR Method Accurately Approximate Eigenvalues? [SOLVED]

    [SOLVED] Approximate eigenvalues Use some QR method to approximate the eigenvalues of [4 3] [3 5] and compare with the actual values. The actual values are (9±√37)/2
  43. I

    Interpretation/significance of the eigenvalues for a system?

    Hi folks! I wasn't sure where to put this... so I put it here! I'm wondering if there is a physical interpretation/significance of the eigenvalues for a system? I've had people tell me things like "they're the basic solutions to the system" but I just don't quite see what they're saying...
  44. F

    Eigenvalues and diagonalizability

    This is a concept question.. I'm having trouble understanding why for an n x n matrix A, in order to have eigenvalues, it must have linearly dependent columns (so that a nontrivial solution exists), but for the same A, in order to be diagonalizable, the columns must be linearly INdependent...
  45. H

    Solving Repeated Eigenvalues - [2,2,1;1,3,1;1,2,2]

    Homework Statement Obtain the eigenvalues and corrosponding eigenvectors for the matrix: [2,2,1;1,3,1;1,2,2] Homework Equations The Attempt at a Solution I can solve for the eigenvalues, 5, 1, and 1 I can solve the eigenvalue 5 for the eigenvector B[1;1;1] Yet somehow, the...
  46. S

    What does multiplicity in eigenvalues mean?

    Can someone please explain multiplicity to me? I've been able to solve the problems involving it, but I'm not quite sure what it means in terms of the eigenvalue. Thanks.
  47. O

    MATLAB, eigenvalues and condition number of a symmetric square matrix

    2. Write a MATLAB® function to calculate the condition number of a symmetric square matrix of any size by means of Eigenvalues: § The power method should be used to calculate the Eigenvalues. § The script (function) should give an error message if the matrix is not...
  48. E

    What Are the Eigenvalues and Eigenfunctions of the Operators x d/dx and d/dx x?

    a) Consider the operator x d/dx(where 1st d/dx acts on the function, then x acts on the resulting function by simply multiplying by x )acting on the set of functions of a real variable x for x>0. What are the eigenvalues and the corresponding eigenfunctions of this operator? b) What about...
  49. E

    Are Sums and Differences of Eigenfunctions Also Eigenfunctions?

    a) Consider a linear operator L with 2 different eigenvalues a1 and a2, with their corresponding eigenfunction f1 and f2. Is f1 + f2 also an eigenfunction of L? If so, what eigenvalue of L does it correspond to? If not, why not? b) Answer the same question as in part (a) but for the...
  50. K

    Local Extrema, Hessian & Eigenvalues

    1) f(x,y,z)=x3-3x-y3+9y+z2 Find and classify all critical points. I am confused about the following: The Hessian matrix is diagonal with diagonal entries 6x, -6y, 2. Now, the diagonal entries of a diagonal matrix are the eigenvalues of the matrix. (this has to be true, it is already...
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