

A130415


Coefficient table for polynomials related to the eigenfunctions of a certain Schroedinger problem (PoeschlTeller I).


1



1, 0, 1, 5, 0, 6, 0, 5, 0, 8, 35, 0, 112, 0, 80, 0, 7, 0, 28, 0, 24, 21, 0, 126, 0, 216, 0, 112, 0, 15, 0, 108, 0, 216, 0, 128, 165, 0, 1584, 0, 4752, 0, 5632, 0, 2304, 0, 55, 0, 616, 0, 2112, 0, 2816, 0, 1280, 143, 0, 2002, 0, 9152, 0, 18304, 0, 16640, 0, 5632, 0, 91, 0, 1456, 0, 7488
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OFFSET

0,4


COMMENTS

The eigenenergies are e_n = ((n+1)^21)/2, n=1,2,... and the normalized eigenfunctions (modulo phases) are Psi_n(q) which are for odd n: sqrt(1/(Pi*e_n))*((1+n*y^2)*U(n,y)/y  (n+1)*U(n1,y)) with y:=cos(q) and the Chebyshev polynomials U(n,y) (see A049310). For even n: sqrt(1/(Pi*e_n))*tan(q)*(n*U(n+1,y)+ (n+2)*U(n1,y))/2, with y:=cos(q).
The row polynomials P(n,y):=sum(a(n,m)*y^m,m=0..n1), n>=1, are related to the eigenfunctions as follows.
For odd n: P(n,y)= sqrt(Pi*e_n)*Psi_n(q)/(gcdrow(n)*y^2) with y=cos(q) and gcdrow(n) the greatest common divisor of the row coefficients factored out. It seems that gcdrow(2*k1)=2*A006519(2*k1), k=1,2,3,... (twice the highest power of 2 dividing n).
For even n: P(n,y)= sqrt(Pi*e_n)*Psi_n(q)/(8*gcdrow(n)*sin(q)*cos(q)) with y=cos(q) and the gcdrow(2*k) sequence is [1,1,2,2,1,1,4,4,1,1,2,2,1,1,8,8,1,1,2,2,1,1,...],k=1,2,... This looks like the doubled sequence A006519 (the first 100 terms have been checked).
The onedimensional, stationary Schroedinger equation with potential V(q) = (2/cos(q)^21)/ 2 where q < Pi/2 (socalled PoeschlTeller I potential) can be solved exactly, e.g., via supersymmetry adapted to quantum mechanics (and called D=1+0, N=2 supersymmetry). q:=Pi*x/L, L:=sqrt(m*w/hbar) with the coordinate x <= L/2 and m and w are the mass and the frequency of the underlying harmonic Bose oscillator. The reduced Planck constant is hbar = h/(2*Pi). The eigenenergies E_n and the potential are divided by hbar*w to become dimensionless e_n and V(q).


LINKS

Table of n, a(n) for n=0..71.
W. Lang, First 10 lines and more.


FORMULA

a(n,m) = [y^m] P(n,y), n=1,2,..., m=0,1,2,..., with the polynomials P(n,y) defined above for even and odd n in terms of Chebyshev polynomials and the eigenenergies e_n.


EXAMPLE

Ground state (n=1): e_1=3/2, Psi_1(q)= sqrt(2/(3*Pi))*((1+cos(q)^2)*2  2)= sqrt(2/(3*Pi))*2*cos(q)^2; gcdrow(1)=2, P(1,y)=sqrt(Pi*3/2)*(1/(2*y^2)*Psi_1(q=arccos(y)) =1.
First excited state (n=2): e_2=4, Psi_2(q)= sqrt(1/(4*Pi))*tan(q)*(2*U(3,cos(q))+4*U(1,cos(q)))/2 = (4/sqrt(Pi))*sin(q)*cos(q)^2; gcdrow(2)=1, P(2,y)= sqrt(Pi*4)*Psi_n(q=arccos(y))/(8*1*sqrt(1y^2)*y) =y.
Triangle begins:
[1];
[0,1];
[5,0,6];
[0,5,0,8];
[35,0,112,0,80];
[0,7,0,28,0,24];
...


CROSSREFS

Sequence in context: A137562 A021668 A004552 * A197029 A197030 A035550
Adjacent sequences: A130412 A130413 A130414 * A130416 A130417 A130418


KEYWORD

sign,tabl,easy


AUTHOR

Wolfdieter Lang, Jul 13 2007


STATUS

approved



