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Spectral and Wavefunction Statistics (I). V.E.Kravtsov, Abdus Salam ICTP. Level Statistics of non-interacting electrons in quantum dots. Quantum dots and random matrices Level repulsion Introduction to Random Matrix Theory. Quantum dots and Quantum billiards. Integrable circular billiard.
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Spectral and Wavefunction Statistics (I) V.E.Kravtsov, Abdus Salam ICTP
Level Statistics of non-interacting electrons in quantum dots • Quantum dots and random matrices • Level repulsion • Introduction to Random Matrix Theory
Quantum dots and Quantum billiards Integrable circular billiard Chaotic billiard Simple statistics of wavefunctions in a chaotic billiard Random superposition of plane waves Wavefunction amplitude in a chaotic billiard
Random superposition of plane waves on an energy shell E=const Invariance under basis rotation Rotation of basis: Does not change statistics of wavefunction (basis invariance) CLT Large number of terms in the sum over k (large energy E) Gaussian statistics
Distribution of eigenvalues and eigenvectors Old variables: Hnm New variables: eigenvalues En, eigenvectors
Jacobian J and the effective level interaction Effective logarithmic interaction Double set for complex U (b=2)
Dyson symmetry classes b is a temperature of the effective plasma model b=2 for complex H b=1 for real H E
Level repulsion: a pedestrian derivation When two levels are much closer than the average spacing: 2X2 block:
The Wigner surmise Independently fluctuating energy levels Was expected for Coulomb blockade peaks of conductance in small quantum dots but was significantly modified by interaction effects. Observed for level statistics in microwave cavities. w b
Interaction effects Random interaction in chaotic dot is responsible for transformation of the Wigner surmise into a Gaussian distribution.