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Second Physics Conference May, 2007 A confined N – dimensional harmonic oscillator. Sami M. Al – Jaber Department of physics An- Najah National University, Nablus , Palestine. Abstract.

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### Second Physics ConferenceMay, 2007A confined N – dimensional harmonic oscillator

Sami M. Al – Jaber

Department of physics

An- Najah National University,

Nablus , Palestine

• We compute the energy eigenvalues for the N- dimensional harmonic oscillator confined in an impenetrable spherical cavity. The results show their dependence on the size of the cavity and the space dimension N. The obtained results are compared with those for the free N- dimensional harmonic oscillator, and as a result, the notion of fractional dimensions is pointed out. Finally, we examine the correlation between eigenenergies for confined oscillators in different dimensions.

2- The N- dimensional harmonic oscillator

• The radial part solution, , satisfies

### lettingR (r)=u (r) / r(N-1)/2

and Looking for solutions of the

### We get

And thus

1F1(a,b,z)=

• Where,

• The value of λ is

• We consider the case a = -1and

Table 1: onea = -1 and

Table 2: The case onea = -1 and

For onea = -2, 1F1(a,b,z) has two roots. and

• For the ground state we have

and b =N /2, and thus

• The two roots z1 and z2 yield two radii for the

cavity , S1 and S2, which correspond to the states = ( 4 ,0) and ( 4 , 2) for the

free harmonic oscillator

Table 3: onea = -2 and

General Case one

• = even integer implies even or odd.

The n = even case yields mod 4,

a = negative integer, and this

energy corresponds to the states for the free harmonic oscillator with whose number is n /2.

n= odd case yields one mod 4, a = negative half – integer, and the energy corresponds to the states

for the free harmonic oscillator with

whose number is (n+1)/2.

n = odd integer : using

n =half odd integer. This energy could be written in two ways:

The first: which is the same

as that of the states of the free harmonic oscillator in (N-1) dimensions. The values of are given by

The second one: which is the same as that of the states

of the free harmonic oscillator in(N+1) dimensions. The values of are given by

For computational purposes, we choose onec=1 and

and it is just the energy of the

state ( 0 ,0) or ( 1 , 1) for the free harmonic

oscillator in ( N+1) or ( N-1) dimensions respectively,

c=half odd integer: For example if c= , then the energy of the confined oscillator becomes

This energy could be written as

which is just the ground – state energy of the state (n' , ) (0 ,0 ) for the free harmonic oscillator in the fractional dimension

if we let with n being odd, then the energy of the confined harmonic oscillator becomes

This energy could be written as

which is exactly the energy of the state (n' , )=

for the free harmonic oscillator in the fractional dimension

Letting the value of, for a given at which 1F1 has its zero at

We numerically compute E10, E21, and E32 for two cavities.

Table 7:Results for oscillatorE10 & E20 for S=4A0.

It is observed that oscillatorE10 corresponds to the state (n , ) = (0 , 0) for the free N –dimensional harmonic oscillator.E20 corresponds to the state ( 2, 0) with energy

• One also observes that the effect of the boundary is relatively larger on the energy levelE20 compared to its effect onE10.

• Mapping of energy eigenvalues

For example, the energies for in dimension N =5 are identical to the three- dimensional solutions for the case

For oscillatorN = odd and angular momentum the energies correspond to solutions for the roots of 1F1

• These correspond exactly to those either for dimension (N-2) and angular momentum

or they correspond to the three dimensional case with

• For N = even and angular momentum the energies correspond to those in dimension (N-2) with angular momentum or they correspond to those for two- dimensional case (N=2) with

Conclusion oscillator

• The energy eigenfunctions were computed numerically using mathematica.

• We pointed out the connection between solutions for the confined oscillator and the free one.

• The effect of the boundaries and the dimension N were discussed.

• The notion of fractional dimensions was explored.

• Mapping between energy eigenvalues in different dimensions was examined.