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LT » Nano Theory » Current fluctuations

Current fluctuations

Current fluctuations can be regarded as unwanted noise or as a source of spectroscopic information on some given system. In equilibrium, the second-order correlator of these current fluctuations is given by the fluctuation-dissipation relation. Driven far from equilibrium, mesoscopic systems (systems with dimension smaller than the electron-phonon scattering length) contain additional noise, shot noise, which is essentially due to the fact that current is carried by discrete entities, electrons. Another interesting property about current fluctuations in mesoscopic systems is the fact that they are non-Gaussian. The statistics of these fluctuations is another relevant topic studied in the Nano theory group. In addition to studying shot noise and counting statistics in mesoscopic systems, we also concentrate on the microscopic theory of their measurement using other mesoscopic systems as spectrometers.

Our recent publications connected to the current fluctuations are (to get the papers, follow the links in the Publications page):

1. Ojanen, T., [Thesis] Quantum fluctuations and transport in mesoscopic physics, Low Temperature Laboratory (2007).
2. Peltonen, J.T., Timofeev, A.A., Meschke, M., Heikkilä, T.T., and Pekola, J.P., "Detecting non-Gaussian current fluctuations using a Josephson threshold detector". Physica E, 40, 111-122 (2007).
3. Stenberg, M.P., Virtanen, P., and Heikkilä, T.T., "Phase-dependent noise correlations in normal-superconducting structures". Physical Review B, 76, 144504/1-5 (2007).
4. Ojanen, T. and Heikkilä, T.T., "Photon heat transport in low-dimensional nanostructures". Physical Review B, 76, 073414/1-4 (2007).
5. Timofeev, A.V., Meschke, M., Peltonen, J.T., Heikkilä, T.T., and Pekola, J., "Wideband detection of the third moment of shot noise by a hysteretic Josepson junction". Physical Review Letters, 98, 207001/1-4 (2007).
6. Heikkilä, T.T. and Ojanen, T., "Quantum detectors for the third cumulant of current fluctuations". Physical Review B, 75, 035335/1-12 (2007).
7. Saira, O.-P., Bergholm, V., Ojanen, T., and Möttönen, "Equivalent qubit dynamics under classical and quantum noise". Physical Review A, 75, 012308/1-5 (2007).
8. Lindell, R.K., Sillanpää, M.A., Heikkilä, T.T., Delahaye, J., Sonin, E.B., and Hakonen, P.J., "Effect of non-Gaussian noise in small Josephson junction". AIP Conference Proceedings, 850, 1421-1422 (2006).
9. Virtanen, P. and Heikkilä, T.T., "Rectifying non-Gaussian noise with incoherent Cooper Pair tunneling". AIP Conference Proceedings, 850, 771-772 (2006).
10. Virtanen, P. and Heikkilä, T.T., "Circuit theory for noise in incoherent normal-superconductor structures". New Journal of Physics, 8, 1-9 (2006).
11. Ojanen, T. and Heikkilä, T.T., "Quantum transition induced by the third cumulant of current fluctuations". Physical Review B, 73, 020501/1-4 (2006).
12. Heikkilä, T.T., and Roschier, L., "Cyclostationary measurement of low-frequency odd moments of current fluctuations". Physical Review B, 71, 085316/1-11 (2005).
13. Heikkilä, T.T., Virtanen, P., Johansson, G., and Wilhelm, F.K., "Measuring non-Gaussian fluctuations through incoherent Cooper-pair current". Physical Review Letters, 93, 247005/1-4 (2004).
14. Lindell, R.K., Delahaye, J., Sillanpää, M.A., Heikkilä, T.T., Sonin, E.B., and Hakonen, P., "Observation of shot-noise-induced asymmetry in the Coulomb blockaded Josephson junction". Physical Review Letters, 93, 197002/1-4 (2004)
15. Roschier, L., Heikkilä, T., and Hakonen, P., "Cyclostationary shot noise in mesoscopic measurements". Journal of Applied Physics, 96, 5927 (2004).