We study quantum-mechanical effects in mesoscopic structures, especially those related to structures formed from small superconducting structures. In these systems, one can fabricate devices that show characteristics of atoms but with properties that are fairly easy to tailor. Recently one has also been able to fabricate systems which mimic the atom-photon interactions - this is the field of circuit quantum electrodynamics. One aim with these systems is to build quantum bits, parts of a quantum computer. Our research in this field has concentrated mostly on measurements and their back-action on quantum systems, either using classical apparatus, or coupling the studied system to another mesoscopic system. Another field of study has been the study of the quantum effects in resonant structures.
Our recent publications connected to quantum engineering are (to get the papers, follow the links in the Publications page):
- Ojanen, T., [Thesis] Quantum fluctuations and transport in mesoscopic physics, Low Temperature Laboratory (2007).
- 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).
- Ojanen, T., Niskanen, A.O., Nakamura, Y., and Abdumalikov, A.A., "Global relaxation of superconducting qubits" Physical Review B, 76, 100505/1-4 (2007).
- Ojanen, T. and Heikkilä, T.T., "Photon heat transport in low-dimensional nanostructures" Physical Review B, 76, 073414/1-4 (2007).
- Ojanen, T. and Salo, J., "Possible scheme for on-chip element for squeezed microwave generation". Physical Review B, 75, 184508/1-6 (2007).
- Heikkilä, T.T. and Ojanen, T., "Quantum detectors for the third cumulant of current fluctuations". Physical Review B, 75, 035335/1-12 (2007).
- 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).
- 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).
- Virtanen, P. and Heikkilä, T.T., "Rectifying non-Gaussian noise with incoherent Cooper Pair tunneling". AIP Conference Proceedings, 850, 771-772 (2006).
- Ojanen, T. and Heikkilä, T.T., "Quantum transition induced by the third cumulant of current fluctuations". Physical Review B, 73, 020501/1-4 (2006).
- Lindell, R.K., Sillanpää, M.A., Heikkilä, T.T., Delahaye, J., Yamaguchi, T., Sonin, E.B., and Hakonen, P.J., "Small Josephson junction as detector of non-Gaussian noise". AIP Conference Proceedings, 800, 563-568 (2005).
- Ojanen, T., and Heikkilä, T., "State-dependent impedance of a strongly coupled oscillator - qubit system". Physical Review B, 72, 54502/1-8 (2005).
- 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).