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oai:odr.chalmers.se:20.500.12380/1597582026-02-27T10:05:36ZPhysicsChemistryMathscom_20.500.12380_19com_20.500.12380_1col_20.500.12380_50

Sathyamoorthy, Sankar Raman Chalmers tekniska högskola / Institutionen för mikroteknologi och nanovetenskap Chalmers University of Technology / Department of Microtechnology and Nanoscience 2019-07-03T12:51:02Z 2019-07-03T12:51:02Z 2012 https://hdl.handle.net/20.500.12380/159758 Typical photon counters involve absorption of photons to generate electric signals, thus basically destroying the information carried by the photon. This is all the more disastrous if the photon is used as a quantum information carrier, such as a part of an entangled pair. Quantum non-demolition (QND) measurements are de- signed to overcome this limitation. Such a non-destructive photon detection would play a key role in quantum networks where photons can be used as “flying” qubits. In this thesis, using circuit QED we investigate if QND detection of a prop- agating microwave photon is possible. The system considered consists of a three level artificial atom (transmon) interacting with signal and probe fields. The fields are in the microwave regime with their frequencies on par with the energy levels of the transmon. The interaction of these two fields with the artificial atom, imparts a phase change on the probe field via the cross-Kerr effect. By measuring this phase change, we indirectly infer the presence of the signal. In this thesis, we investigate if it is possible to achieve a single photon detection, at first using a single transmon and then using multiple transmons. We find that, while single photon detection is not possible with a single transmon, it is indeed possible with multiple transmons under certain conditions. We also find that with multiple transmons, we can have a large phase change in the probe, which might be desirable in other applications. eng Technical report MC2 - Department of Microtechnology and Nanoscience, Chalmers University of Technology PhysicsChemistryMaths Grundläggande vetenskaper Informations- och kommunikationsteknik Nanovetenskap och nanoteknik Atomfysik Mesoskopisk fysik Basic Sciences Information & Communication Technology Nanoscience & Nanotechnology Atomic physics Mesoscopic physics Quantum non-demolition detection of propagating microwave photons Examensarbete för masterexamen Master Thesis H open.access