1. Excitonic BEC in in Quantum Hall Bilayers Ramin Abolfath NRCC Anton Burkov UCSB Jim Eisenstein Cal Tech. Steve Girvin Yale Yogesh Joglekar LANL Jairo Sinova Texas A&M Ady Stern Weizmann Leo Radzihovsky UC Alvaro Nunez UTA Enrico Rossi UTA Giovanni Vignale UMC University of Texas at Austin May 2005

2. Reference Eisenstein and AHM Nature 432, 691 (2004)

3. Josephson Qubit Devoret Walraff & Martinis cond-mat/0411 Non-linear Non-Dissipative

4. Landau Liftshitz Gilbert

5. Excitons – Elementary Excitations of Intrinsic Semiconductors e - h h e Valence Band Conduction Band

6. Excitonic BEC and Superfluidity?

7. Electron-Hole Pairs (n’,n)=( ,  ) =Ferromagnetism (n’,n)=(c,v) = Excitonic BECs (n’,n)=(TopLayer,BottomLayer) Order Parameter Counterflow Superfluidity

8. Ga As Si AlGaAs GaAs 100 A AlGaAs Double Quantum Well - Quantum Wells

9. Ga As ultra high vacuum heated cells high quality GaAs substrate Al Molecular Beam Epitaxy Pfeiffer - Bell Labs Shayegan – Princeton

10. Electrons and Holes in the QH Regime Add magnetic field Particle-hole transformation Assemble Bilayer

11. I I e - voltmeter 0 0

12. Electron-hole Pair Current

13. Superflow in Electron-Electron Bilayers Kellogg and Eisenstein cond-mat/0401521 Hall Angle Not Large σ xx  1000 e 2 /h

14. Interlayer Voltage 0 Tunneling rate 0 Josephson-like Currents

15. Josephson Effect J.J. Dynamics eV = 0 Δ sin(φ) = I bias Correct Explanation? 0

16. Collective Dynamics & Dissipation Ferromagnets vs. Josephson Junctions vs. Bilayers J.J. Dynamics Thin Film Ferromagnet Dynamics

17. Joglekar TDHFA+SCBA  α φ >> α N Joglekar & AHM PRB (2002)

18. Thin Film Ferromagnets Buhrman & Ralph, MSU, NIST, Orsay Thin Film Ferromagnet Dynamics Spin Transfer

19. Transport Orbitals eV Condensate Orbitals K = X l 2 Coherent Edge Transport E mpl  10 -6 eV Δ QP  10 -3 eV G  e 2 /h Δ t  10 -9 eV V *  10 -6 Volts

20. Excitonic Bose Einstein Condensation in Quantum Hall Bilayers ! Macroscopic Quantum Coherence properties different from both JJ’s and thin film magnets