(a)The quantum Hall effects occur when a two-dimensional electron gas is placed in a magnetic field, B (yellow arrow). (b)The electrons (red dots) can be mathematically transformed into composite fermions, which consist of an electron plus two magnetic flux quanta that point in the opposite direction to B. (c)In the "mean field approximation" these flux quanta are replaced by a uniform magnetic field of magnitude B_1/2. The net magnetic field that each composite fermion experiences is now B=B-B_1/2. The behavior of composite fermions in a field B can be related to the behavior of electrons in stronger field, B. (d)The behavior of the longitudinal resistivity, _xx, near B_1/2, where the composite fermions behave as charged fermions in a relatively weak magnetic field.
Moty Heiblum, Ady Stern, "Fractional quantum Hall effects", Physics World, pp. 37-43 (March 2000).

 Research Interests:

• Composite fermion theory of the fractional quantum Hall effect
• Double layer electronic systems: inter layer correlations and Coulomb drag
• Mesoscopic physics, particularly quantum dots
• Geometric phases in condensed matter physics

 Selected Publications:

1. Oscillating sign of drag in high Landau levels.
   Felix von Oppen, Steven H. Simon, Ady Stern, Phys. Rev. Lett.  8710: 6803 (2001).

2. Coulomb drag between a metal and a Wigner crystal.
   V. Braude, A. Stern, Phys Rev. B  6411 (11): 5431 (2001).

3. Mesoscopic fluctuations of the Coulomb drag at $\nu$=1/2.
   B. N. Narozhny, I. L. Aleiner, Ady Stern, Phys. Rev. Lett.  86: 3610-3613 (2001).

4. Spin orbit effects in a GaAs quantum dot in a parallel magnetic field.
   B.I. Halperin, Ady Stern, Y. Oreg, J.H. Cremers, J. Folk, C.M. Marcus (Harvard, Weizmann), Phys. Rev. Lett.  86 (10): 21062109 (2001).

5. Theory of interlayer tunneling in bi-layer quantum Hall ferromagnets
   Ady Stern (Weizmann Institute), S.M. Girvin (Indiana University), A.H. MacDonald (Indiana University), Ning Ma (Indiana University), Phys Rev. Lett.  86 (9): 1829-1832 (2001).

6. The Evolution of Quasiparticle Charge in the Fractional Quantum Hall Regime
   T. G. Griffiths, E. Comforti, M. Heiblum, Ady Stern, V. Umansky, Phys. Rev. Lett.  85 (18): 3918-3921 (2000).

7. Striped quantum Hall phases.
   Felix von Oppen, Bertrand I. Halperin, Ady Stern, Advances in Quantum Many-Body Theory, vol. 3, ed. R.F. Bishop, N.R. Walet, and Y. Xian (World Scientific 2000).

8. Coulomb Drag between Quantum Wires.
   Rochus Klesse, Ady Stern, Phys. Rev. B  62 (24): 16912-16925 (2000).

9. Conductivity tensor of striped quantum Hall phases.
   Felix von Oppen (Cologne), Bertrand I. Halperin (Harvard), Ady Stern (Weizmann), Phys. Rev. Lett.  84 (13): 2937-2940 (2000).

10. Dissipationless transport in low density bilayer systems. Ady Stern, S. Das Sarma, Matthew P. A. Fisher, S. M. Girvin, Phys. Rev. Lett.  84 (1): 139-142 (2000). [abstract]  [postscript]
11. On the Relation between Interband Scattering and the "Metallic Phase" of Two Dimensional Holes in GaAs/AlGaAs. Yuval Yaish, Oleg Prus, Evgeny Buchstab, Gidi Ben Yoseph, Uri Sivan, Ady Stern, Phys. Rev. Lett.  84 (21): 4954-4957 (2000). [abstract]  [postscript]
12. The half-filled Landau level - composite fermions and dipoles. Felix von Oppen, Bertrand I. Halperin, Steven H. Simon, Ady Stern, [abstract]  [postscript]
13. The Different Effect of Electron-Electron Interaction on the Spectrum of Atoms and Quantum Dots. Kinneret Keren, Ady Stern, Uri Sivan, European Physics Journal B  18: 311 (2000). [abstract]  [postscript]
14. The half-filled Landau level as a Fermi liquid of dipolar quasiparticles. Felix von Oppen, Bertrand I. Halperin, Steven H. Simon, Ady Stern, Phys. Rev. B  59 (19): 12547-12567 (1999). [abstract]  [postscript]
15. Coulomb drag at \nu = 1/2: Composite fermion pairing fluctuations. Iddo Ussishkin and Ady Stern, Physical Review Letters  81 (18): 3932-3935 (1998). [abstract]  [postscript]
16. Quantum limitations on superluminal propagation. Yakir Aharonov, Benni Reznik and Ady Stern, Physical Review Letters  81 (11): 2190-2193 (1998). [abstract]  [postscript]
17. Compressibility of a quantum Hall system at $\nu = 1/2$. Bertrand I. Halperin and Ady Stern, Physical Review Letters   80: 5457 (1998). [abstract]  [postscript]
18. Composite Fermions in Modulated Structures: Transport and Surface Acoustic Waves. Felix von Oppen, Ady Stern and Bertrand I. Halperin, Physical Review Letters  80: 4494 (1998). [abstract]  [postscript]
19. Coulomb drag in the quantum Hall nu = 1/2 state: Role of disorder. Ady Stern and Iddo Ussishkin. Physica E   1: 176 (1997). [abstract]  [postscript]
20. Coulomb drag in compressible quantum Hall states. Iddo Ussishkin and Ady Stern. Phys. Rev. B  56: 4013 (1997) . [abstract]  [postscript]
21. Polymer Winding Numbers and Quantum Mechanics. David R. Nelson and Ady Stern, [abstract]  [postscript]
22. Current noise, electron-electron interactions, and quantum interference. Felix von Oppen and Ady Stern. Phys. Rev. Lett.  79: 1114 (1997). [abstract]  [postscript]
23. Composite Fermions with Orbital Magnetization. Steven H. Simon, Ady Stern and Bertrand I. Halperin. Phys. Rev. B  54: R11114, (1996). [abstract]  [postscript]
24. The Physical Significance of Singularities in the Chern--Simons Fermi Liquid Description of a Partially Filled Landau Level. Ady Stern and Bertrand I. Halperin. Surface Science  361: 42 (1996). [abstract]  [postscript]
25. Singularities in the Fermi liquid description of a partially filled Landau level and the energy gaps of fractional quantum Hall states. Ady Stern and Bertrand I. Halperin. Physical Review B  52: 5890 (1995). [abstract]  [postscript]
26. Quantum Hall Fluid of Vortices in a Two Dimensional Array of Josephson Junctions. Ady Stern. Phys. Rev. B  50: 10092 (1994). [abstract]  [postscript]

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