Dr. Kirill Fedorov

Courses and Dates

Offered Bachelor’s or Master’s Theses Topics

Fabrication of low-loss Josephson parametric devices

Superconducting Josephson devices represent one of the leading hardware platforms of modern quantum information processing. In particular, these devices often employ nonlinear parametric effects for tunable coupling schemes or quantum-limited amplification. Such effects can be also used in a multitude of quantum communication & sensing protocols. In this context, a particular challenge arises due to the fundamental requirement for minimizing losses in superconducting systems in order to preserve the fragile quantum nature of related microwave states. To this end, one needs to develop advanced routines for fabrication of low-loss Josephson parametric amplifiers & parametric couplers by exploring various surface treatment approaches or studying novel superconducting materials. The low-loss Josephson devices are to be used in our ongoing experiments towards experimental investigation of particular novel concepts, such as the quantum radar or remote entanglement distribution protocols. This master thesis will involve designing superconducting parametric circuits, cleanroom fabrication, and characterization measurements of fabricated devices with an aim to employ these in microwave quantum communication & sensing experiments.

suitable as

• Master’s Thesis Quantum Science & Technology

Supervisor: Rudolf Gross

Fabrication of low-loss Josephson parametric devices

Superconducting Josephson devices represent one of the leading hardware platforms of modern quantum information processing. In particular, these devices often employ nonlinear parametric effects for tunable coupling schemes or quantum-limited amplification. Such effects can be also used in a multitude of quantum communication & sensing protocols. In this context, a particular challenge arises due to the fundamental requirement for minimizing losses in superconducting systems in order to preserve the fragile quantum nature of related microwave states. To this end, one needs to develop advanced routines for fabrication of low-loss Josephson parametric amplifiers & parametric couplers by exploring various surface treatment approaches or studying novel superconducting materials. The low-loss Josephson devices are to be used in our ongoing experiments towards experimental investigation of particular novel concepts, such as the quantum radar or remote entanglement distribution protocols. This master thesis will involve designing superconducting parametric circuits, cleanroom fabrication, and characterization measurements of fabricated devices with an aim to employ these in microwave quantum communication & sensing experiments.

suitable as

• Master’s Thesis Applied and Engineering Physics

Supervisor: Rudolf Gross

Fabrication of low-loss Josephson parametric devices

Superconducting Josephson devices represent one of the leading hardware platforms of modern quantum information processing. In particular, these devices often employ nonlinear parametric effects for tunable coupling schemes or quantum-limited amplification. Such effects can be also used in a multitude of quantum communication & sensing protocols. In this context, a particular challenge arises due to the fundamental requirement for minimizing losses in superconducting systems in order to preserve the fragile quantum nature of related microwave states. To this end, one needs to develop advanced routines for fabrication of low-loss Josephson parametric amplifiers & parametric couplers by exploring various surface treatment approaches or studying novel superconducting materials. The low-loss Josephson devices are to be used in our ongoing experiments towards experimental investigation of particular novel concepts, such as the quantum radar or remote entanglement distribution protocols. This master thesis will involve designing superconducting parametric circuits, cleanroom fabrication, and characterization measurements of fabricated devices with an aim to employ these in microwave quantum communication & sensing experiments.

suitable as

• Master’s Thesis Condensed Matter Physics

Supervisor: Rudolf Gross

Hybrid quantum teleportation

Microwave quantum communication is a novel field of science and technology, where one exploits quantum properties of propagating microwave signals to achieve quantum advantage in various communication scenarios. Here, a particularly important protocol is quantum teleportation, where one bypasses fundamental limitations on fidelity of transferred quantum states by exploiting shared entanglement. In this context, an open challenge is teleportation of the most exotic, non-Gaussian, quantum states, such as Fock or Schrödinger cat states, with the help of Gaussian entangled states. In theory, this problem can be addressed by using non-deterministic approaches or incorporating non-Gaussian operations in the teleportation protocol. This master thesis will focus on a theory analysis & numerical simulation of quantum microwave teleportation of non-Gaussian quantum states. Later stages of this master project may include experimental investigation of proof-of-principle hybrid quantum teleportation protocols based on superconducting quantum circuits in the cryogenic environment.

suitable as

• Master’s Thesis Applied and Engineering Physics

Supervisor: Rudolf Gross

Microwave cryptography with propagating quantum tokens

Quantum cryptography based on continuous-variables is a rapidly growing field of fundamental and applied research. It deals with various topics regarding fundamental limits on data communication & security. In particular, the microwave branch of quantum cryptography demonstrates a large potential for near term applications due to its natural frequency compatibility with the upcoming 5G and future 6G networks. In this context, we plan to investigate microwave photonic states, quantum tokens, which can be used for unconditionally secure storage and transfer of classical information. This security properties are provided by a peculiar combination of the quantum no-cloning theorem and vacuum squeezing phenomenon. The latter effect can be routinely achieved in the microwave regime with superconducting Josephson parametric amplifiers, which we plan to use for experimental generation & investigation of quantum token states. This master thesis will focus on developing numerical & experimental tools for the ongoing microwave quantum cryptography experiments. This includes programming various elements of FPGA data processing routines, performing cryogenic measurements with propagating microwaves, and analyzing measurement data for quantifying quantum correlations & unconditional security in propagating quantum token states.

suitable as

• Master’s Thesis Quantum Science & Technology

Supervisor: Rudolf Gross

Microwave cryptography with propagating quantum tokens

Quantum cryptography based on continuous-variables is a rapidly growing field of fundamental and applied research. It deals with various topics regarding fundamental limits on data communication & security. In particular, the microwave branch of quantum cryptography demonstrates a large potential for near term applications due to its natural frequency compatibility with the upcoming 5G and future 6G networks. In this context, we plan to investigate microwave photonic states, quantum tokens, which can be used for unconditionally secure storage and transfer of classical information. This security properties are provided by a peculiar combination of the quantum no-cloning theorem and vacuum squeezing phenomenon. The latter effect can be routinely achieved in the microwave regime with superconducting Josephson parametric amplifiers, which we plan to use for experimental generation & investigation of quantum token states. This master thesis will focus on developing numerical & experimental tools for the ongoing microwave quantum cryptography experiments. This includes programming various elements of FPGA data processing routines, performing cryogenic measurements with propagating microwaves, and analyzing measurement data for quantifying quantum correlations & unconditional security in propagating quantum token states.

suitable as

• Master’s Thesis Applied and Engineering Physics

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

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

Remote entanglement of superconducting qubits

Quantum computing represents a promising information processing paradigm exploiting quantum properties, such as superposition and entanglement. The latter entity is crucial for achieving quantum advantage in scalable quantum information processing with distributed quantum computers, including those built with superconducting qubits. Here, an important task is to study how quantum entanglement can be distributed between remote superconducting qubits. To this end, we plan to exploit propagating two-mode squeezed states as a carrier of quantum entanglement. We intend to analyze their interactions with remote superconducting quantum bits in theory & verify our findings in experiments. This master thesis will first focus on theory & numerical simulations of remote entanglement of superconducting qubits with propagating squeezed light. Later project stages may also include cryogenic experiments with superconducting transmon qubits & Josephson parametric amplifiers towards verifying novel concepts of remote entanglement.

suitable as

• Master’s Thesis Quantum Science & Technology

Supervisor: Rudolf Gross

Remote entanglement of superconducting qubits

Quantum computing represents a promising information processing paradigm exploiting quantum properties, such as superposition and entanglement. The latter entity is crucial for achieving quantum advantage in scalable quantum information processing with distributed quantum computers, including those built with superconducting qubits. Here, an important task is to study how quantum entanglement can be distributed between remote superconducting qubits. To this end, we plan to exploit propagating two-mode squeezed states as a carrier of quantum entanglement. We intend to analyze their interactions with remote superconducting quantum bits in theory & verify our findings in experiments. This master thesis will first focus on theory & numerical simulations of remote entanglement of superconducting qubits with propagating squeezed light. Later project stages may also include cryogenic experiments with superconducting transmon qubits & Josephson parametric amplifiers towards verifying novel concepts of remote entanglement.

suitable as

• Master’s Thesis Applied and Engineering Physics

Supervisor: Rudolf Gross