SLIDE 1 Pauli-Heisenberg Oscillations in Electron Quantum Transport
UPoN 2015 Karl Thibault1
In collaboration with : Julien Gabelli2, Christian Lupien1, Bertrand Reulet1
1- Université de Sherbrooke Sherbrooke, Québec, Canada 2 - Université de Paris-Sud Orsay, France July 17th 2015
1 1
SLIDE 2 Outline
- Motivation
- Method
- Sample and Experimental set-up
- Results
- Interpretation
- Conclusion
SLIDE 3 Motivation
Theory of quantum transport predicts that electrons are emitted regularly each 1.
- 1. Lesovik, G. B. & Levitov, L. S. Noise in an ac biased junction : Nonstationary Aharonov-Bohm
- effect. Phys. Rev. Lett. 72, 538–541 (1994).
SLIDE 4
Method
Goal : Measure the current-current correlator in the time domain and show that . Method : Measure the noise spectral density vs frequency with a very large bandwidth.
SLIDE 5
Tunnel junction
SLIDE 6 Tunnel junction
Normal-metal – Isolator – Normal-metal
- Classical regime : current is a succession of
uncorrelated random impulses current follows a Poisson distribution shot noise : S =
- Quantum regime : Correlations appear
SLIDE 7
SLIDE 8
Experimental set-up
Tunnel junction
SLIDE 9
Noise temperature
Bruit à l’équilibre (Johnson In general, we express the spectral density of current-current fluctuations as a noise temperature :
SLIDE 10 Thermal noise : V=0
Vacuum noise
SLIDE 11
SLIDE 12
Vacuum noise
SLIDE 13 Shot Noise
Vacuum noise
SLIDE 14
SLIDE 15
Time-domain : Equilibrium (V=0)
Fourier Transform Diverges!
SLIDE 16
Time-domain : Shot noise (V≠0)
Fourier Transform
Since the quantum part diverges, we need to substract it :
SLIDE 17 Fourier Transform Shot noise (V≠0)
Thermal decay caused by temperature
SLIDE 18
Oscillations in aaa.
SLIDE 19
Interpretation using Pauli and Heisenberg principles
SLIDE 20 Conclusion
- We have measured the current-current correlator in
time domain and shown that it
- scillates with a period .
Future Work
- Measuring in a device where the are
- ther intrinsic time scales (like a diffusive wire, where
- - is important).
- Measure this correlator in the non-stationnary regime.
SLIDE 21
Thank you!
Questions?
SLIDE 22
Calibration
What we actually measure is : Gain of the system , Amplifier Noise Problem : Method : classical limit/Schottky formula
SLIDE 23
Spectral density before calibration
SLIDE 24
Calibration – Gain of the measurement system
SLIDE 25
Calibration – Noise temperature of the measurement system
