1. Low Noise Single Electron Source Jin Zhang, Yury Sherkunov, Nicholas d’Ambrumenil, Boris Muzykantskii University of Warwick, U.K. Conference on Computational Physics 2009, Kaohsiung, 16 th, Dec.

2. Single Electron Excitation Arbitrary Pulse:

3. Single Electron Excitation Minimal Excitation States (MES): Ivanov Lee Levitov, Phys. Rev. B 56, 6839 Keeling Klich Levitov, Phys. Rev. Lett. 97, 116403

4. Noise Characterization Partition Noise: Thermal Noise: Equilibrium Noise (T=0): DD 0 t D

5. Noise Minimization Minimized by setting 0 D t for abrupt opening at GHz 0 t D D Low temperature -- mK High frequency -- GHz

6. Suppression of the Equilibrium Noise 1. Single Lorentzian pulse to the barrier 2. Double Lorentzian pulses to the barrier When 0.8

7. Low Noise Single Electron Source Total noise from single electron emission: JZ YS NdA BM Phys. Rev. B 80, 245308 Phys. Rev. B 80, 041313 (R) Probability Distribution: High yield single electron emission Suppressed multiple electron emission

8. Conclusion Suppressing the quantum equilibrium noise at low temperature by tuning the tunneling barrier (QPC) transparency Low noise on-demand single electron source at low temperature Many thanks for your attention!

9. Single Electron Source Fève et.al, Science 316,1169 Averaged over millions of events Too Noisy Working Condition: GHz, mK Keeling et.al, PRL 101, 196404 Minimize the Noise?

10. Optimal Electronic Entangler Apply Single Lorentzian pulse to the barrier “useful”, Not “useful” No excessive not “useful” noise at all 50% Entanglement efficiency, Theoretical maximum

11. Theory of Full Counting Statistics (I) Characteristic Function Current, Noise, etc... Understood with density matrix of outgoing states:

12. Theory of Full Counting Statistics (II) Abanov et.al 2008

13. Non Optimal Pulses For finite cut-off, additional noises are induced

14. Noise Characterization D Shot Noise: Equilibrium Noise: