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IPCMS - DMONS

PHYSIQUE MESOSCOPIQUE. IPCMS - DMONS. Rodolfo Jalabert Dietmar Weinmann. Post-docs: Jérôme Roccia (DMONS-DON) Guillaume Weick. Etudiants: Guido Intronati (Strasbourg – Buenos Aires) Wojciech Szewc. Domaines de recherche :.

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IPCMS - DMONS

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  1. PHYSIQUE MESOSCOPIQUE IPCMS - DMONS Rodolfo Jalabert Dietmar Weinmann Post-docs: Jérôme Roccia (DMONS-DON) Guillaume Weick Etudiants: Guido Intronati (Strasbourg – Buenos Aires) Wojciech Szewc

  2. Domaines de recherche : Conductance à travers de systèmes fortement corrélés Relaxation du spin Transport dépendant de spin Nanoparticules métalliques Electronique moléculaire (G.W.) Courants permanents et interactions (D.W.) Décohérence et dissipation (R.J.)

  3. Conductance à travers de systèmes fortement corrélés

  4. universality non-local effects interactions individual object nano size Quantum transport

  5. Landauer: conductance from scattering Two terminal conductance: - Separation of sample, leads and reservoirs - Mean field, quasi-particle scattering states at the Fermi energy - Equilibration in the reservoirs leads to dissipation - Contact resistance

  6. Conductance through an interacting region - Is the scattering approach still valid ? without inelastic process (zero temperature) embedding method - How do we calculate the transmission coefficient T ? persistent current for interacting region + leads Ground-state property!

  7. Numerical implementation

  8. Conductance through a correlated region g decreases with U g decreases with LS W = 0 Mott insulator g ≈ 1 for LS odd Perfect conductance only with adiabatic contacts

  9. Even-odd asymmetry and Coulomb blockade LSodd:Resonance NS NS +1 electrons in the interacting regionCoulomb blockade resonance (half filling) LS even: Transport involves charging energy U Interacting region is a barrier Observation of a parity oscillation in the conductance of atomic wires: R.H.M. Smit, et al, PRL ’03 Fabry-Perot interference in a nanotube electron waveguide Llang, et al, Nature ’01.

  10. Can we describe an interacting region by an effective one-particle scatterer? R = R+ + R- ohmic composition Quantum mechanics, non-locality S- S+ R ≠ R+ + R- S = S+ * S- Electron-electron interactions non local effect ! S ≠ S+ * S-

  11. Interaction-induced non-local effects universal correction!

  12. 0.7 anomaly M.A. Topinka et al, Nature, 2001 Conductance quantization in a point contact D.A. Wharam et al, J. Phys. C, 1988

  13. Nanoparticules métalliques

  14. MIE THEORY On the color of gold colloids - 1908 λ >> 2a in a metal: resonance pour surface plasmon

  15. Plasmon resonance in free clusters (visible) Bréchignac et al, PRL 1993 Photo-absorption cross section of 12C nucleus

  16. (ps) ps (eV) ps ps ps TIME RESOLVED EXPERIMENTS, POMP-PROBE Differential transmission correlated electrons collective modes nonthermal regime energy transfer to the matrix e-phonons scattering relaxation to the lattice cooling of the distribution e-e & e-surface scattering, thermal distribution Bigot et al., Chem. Phys., 2000

  17. COLLECTIVE AND RELATIVE COORDINATES relative coordinates:mean field center of mass: harmonic oscillator One-particle potential: uniform jellium background with a Coulomb tail plasmon coupling:dipole field

  18. Drude, τ‾1 confinement, a<τvF SIZE-OSCILLATIONS OF THE LINEWIDTH Kawabata & Kubo, 1966 Na Semiclassical approach Nonmonotonic behavior !! Time-Dependent Local Density Approximation

  19. PLASMON AS A COLLECTIVE EXCITATION RPA eigenenergies : restricted subspace additional subspace Plasmon= superposition of low-energy e-h coupled to high-energy e-h

  20. SPIN DIPOLE EXCITATION dipole absorption cross-section

  21. Décohérence et dissipation

  22. Spin echo (Hahn) H-H

  23. |yH(t) |yH0(t) - H H H0 H0 |yH0, -H (2t) H=H0+S environment Loschmidt echo (fidelity) in the presence of a weak coupling to the environment |yH0(t) |y0 |y0 M(t) = |y0| exp[+i(H0+S)t] exp[-iH0t] |y0|2 How does M(t) depend onH0,S, andt ?

  24. Time-reversal focusing C. Draeger, M. Fink, PRL 1997

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