- •General aspects
- •Introduction
- •Single particle
- •General aspects
- •Traps
- •Many particles
- •Basics of second quantization
- •Bosons
- •Fermions
- •Single particle operator
- •Two particle operator
- •Bosons
- •Free Bose gas
- •General properties
- •BEC in lower dimensions
- •Trapped Bose gas
- •Parabolic trap
- •Weakly interacting Bose gas
- •BEC in an isotr. harmonic trap at T=0
- •Comparison of terms in GP
- •Thomas-Fermi-Regime
- •Fermions
- •Free Fermions
- •General properties
- •Pressure of degenerated Fermi gas
- •Excitations of Fermions at T=0
- •Trapped non-interacting Fermi gas at T=0
- •Weakly interacting Fermi gas
- •Ground state
- •Decay of excitations
- •Landau-Fermi-Liquid
- •Zero Sound
- •Bardeen-Cooper-Shieffer-Theory
- •General treatment
- •BCS Hamiltonian
- •General energy-momentum relation
- •Calculation for section 3.3.1
- •Lifetime and Fermis Golden Rule
- •Bibliography
8 |
CHAPTER 1. GENERAL ASPECTS |
1.2Single particle
1.2.1 General aspects
The HAMILTONian is |
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~2 |
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4+U (~r) |
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(1.4) |
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H = |
2m |
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where U (~r) is the (Trap)potential. The solutions |
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jn : |
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(1.5) |
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Hjn = en jn |
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are orthogonal and the set of functions jn (~r) is complete |
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dr jn (r)jn0(r) = dnn0 |
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(1.6) |
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j (~r)j |
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0) = d(~r |
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~r 0): |
(1.7) |
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n |
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If the particle is free, i.e. U = 0 then n ! p and |
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jp = ei~p ~r |
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ep = |
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p2 |
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(1.8) |
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2m |
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1.2.2 Traps
General harmonic trap
U (~r) = |
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(wx2x2 + wy2y2 + wz2z2) |
with solutions |
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ynxnynz (~r) = jnx (x)jny (y)jnz (z): |
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For each space dimension the wave function is of the form |
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xi |
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jni (xi) = |
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e |
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Hni |
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xi |
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l0 |
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q2ni (ni)!ppl0 |
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l0 |
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q
Here Hn are the HERMITE polynomials and l0 = m~w .
(1.9)
(1.10)
(1.11)