Dr. Kirill Fedorov

Courses and Dates

Offered Bachelor’s or Master’s Theses Topics

Observation of quantum switching in driven-dissipative superconducting oscillators

Classical nonlinear systems are known to exhibit metastable behaviour, where spontaneous transitions may take place. These transitions are often associated with spontaneous symmetry breaking and can be viewed as classical phase transitions. However, recent developments in quantum theory of driven-dissipative nonlinear resonators reveal that the underlying switching processes may be of purely quantum nature. This can be experimentally observed during the transient dynamics in nonlinear superconducting resonators. An immediate goal of this master project is to experimentally study switching dynamics in driven Josephson parametric amplifiers (JPAs) and observe quantum features, such as vacuum squeezing and Wigner function negativity, in the associated transient resonator states. The far-reaching goals of this research are related to fundamental investigation of quantum phase transitions in novel driven-dissipative superconducting systems, such as quantum metamaterials. In the framework of this project, the student will experimentally employ existing JPA devices as both the driven-dissipative system and quantum preamplifiers. The latter will be the key for efficient observation and quantum tomography of the transient JPA dynamics. More specifically, the tasks of the master student will consist of the FPGA programming, construction of an experimental set-up in a dilution refrigerator, cryogenic microwave measurements, and data analysis in collaboration with external theory partners. This project will be an important integral part of our various activities on quantum microwave communication, where JPAs are employed as the key building blocks. These activities are supported within the framework of the MCQST cluster, QMiCS project (EU Quantum Flagship), QuaMToMe project (BMBF, "Grand Challenge der Quantenkommunikation"), and will also have a significant overlap with the QuaRaTe project (BMBF) on quantum sensing.

suitable as

• Master’s Thesis Quantum Science & Technology

Supervisor: Rudolf Gross

Observation of quantum switching in driven-dissipative superconducting oscillators

Classical nonlinear systems are known to exhibit metastable behaviour, where spontaneous transitions may take place. These transitions are often associated with spontaneous symmetry breaking and can be viewed as classical phase transitions. However, recent developments in quantum theory of driven-dissipative nonlinear resonators reveal that the underlying switching processes may be of purely quantum nature. This can be experimentally observed during the transient dynamics in nonlinear superconducting resonators. An immediate goal of this master project is to experimentally study switching dynamics in driven Josephson parametric amplifiers (JPAs) and observe quantum features, such as vacuum squeezing and Wigner function negativity, in the associated transient resonator states. The far-reaching goals of this research are related to fundamental investigation of quantum phase transitions in novel driven-dissipative superconducting systems, such as quantum metamaterials. In the framework of this project, the student will experimentally employ existing JPA devices as both the driven-dissipative system and quantum preamplifiers. The latter will be the key for efficient observation and quantum tomography of the transient JPA dynamics. More specifically, the tasks of the master student will consist of the FPGA programming, construction of an experimental set-up in a dilution refrigerator, cryogenic microwave measurements, and data analysis in collaboration with external theory partners. This project will be an important integral part of our various activities on quantum microwave communication, where JPAs are employed as the key building blocks. These activities are supported within the framework of the MCQST cluster, QMiCS project (EU Quantum Flagship), QuaMToMe project (BMBF, "Grand Challenge der Quantenkommunikation"), and will also have a significant overlap with the QuaRaTe project (BMBF) on quantum sensing.

suitable as

• Master’s Thesis Applied and Engineering Physics

Supervisor: Rudolf Gross