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Nov
27
comment translation invariance of the Laughlin wave function
@Carlo Beenakker : What about Laughlins wavefunction on the sphere ? In this case Laughlins wavefunction is SU(2) invariant.
Sep
3
comment How to solve such an optimization problem
It's here (already cited in another comment): 130.44.194.100/mcom/2001-70-236/S0025-5718-00-01262-X/… . Since it contains a raw internet address it's not allowed to use this as a link in an answer.
Sep
2
revised How to solve such an optimization problem
Index Legendre polynomial K -1 instead of N - 1 .
Aug
31
answered How to solve such an optimization problem
Aug
24
comment How to solve such an optimization problem
Here a link to the paper of Fejer : math.technion.ac.il/hat/fpapers/fejerpisa.pdf
Aug
23
comment How to solve such an optimization problem
@peng : If the optimal values of $x_i$ take only K different values, then these values are the Fekete points, because then all non zero terms in the sum are maximized.
Aug
19
awarded  Yearling
Aug
1
comment Finite subgroups (lattices) in the large N limit of SU(N)
A larger finite subgroup than the Weyl-Heisenberg group is its normalizer, see e.g. arxiv.org/abs/1003.3591v2 .
Jul
2
awarded  Curious
Jun
12
comment Method to Generate Random Mutually Orthogonal Unitary Matrices
What exactly is the probability measure you want to simulate ?
Jun
11
comment Computing $\int_0^T e^{itA}Be^{-itA} dt$ without an infinite series
Why so complicated ? Simply diagonalize A, as mentioned by Christian Remling.
May
25
awarded  Editor
May
25
revised Is this functional maximized by SU(2) coherent states?
added 6 characters in body
May
25
asked Is this functional maximized by SU(2) coherent states?
May
22
comment eigenvalues of product of many symmetric positive definite matrices
if d is even then all eigenvalues might be negative : According to the theorem of Ballantine (projecteuclid.org/download/pdf_1/euclid.pjm/1102991595) we can write minus identity as a product of positive definite real matrices, since it has positive determinant.
May
22
comment eigenvalues of product of many symmetric positive definite matrices
Wurlitzer : to "negative definite" : Not true, e.g. for x = 2, there is 1 positive and 1 negative eigenvalue, so its neither positive nor negative definite.
May
20
comment Absolute value inequality for complex numbers
@Deane Yang : Doesn't work because for the 3 distinct third roots of unity also equality holds.
May
20
comment Absolute value inequality for complex numbers
If we choose the third roots of unity for a,b,c then equality holds.
May
18
comment Solvability of a Fredholm system in $L^2$
@fedja : So the answer is yes : all eigenfunctions with non zero eigenvalue of the integral operator restricted to the subspace of odd functions are solutions.
Apr
1
comment A.C. spectrum of the non additive perturbation BAB of a self-adjoint operator A where B is strictly positive
Is this related to anderson localisation ?