Semiconductor Quantum Devices

• Fundamentals
• Historical motivation, scientific & technological context.
• Material systems (silicon-based, III-V, diamond, 2D-materials and silicon-carbide).
• Tailoring electronic properties by nano-patterning & interactions.
• Nano-analytical and spectroscopic methods to characterize quantum systems.
• Quantum emitters: self-assembled quantum dots + defects in crystalline solids.
• Quantum Electronic Devices
• High mobility materials for quantum electronics.
• Trapping single electrons and spins.
• Quantum transport in semiconductor nanomaterials
• Integer and fractional quantum Hall effects
• Using topological excitations in semiconductors as qubits
• Quantum Photonic Technologies
• Photonic modes in waveguides, directional couplers and cavities.
• Light-matter interactions in semiconductors.
• Generating single and entangled photons on demand.
• Simulation and computation using photons
• Quantum limited detectors based on semi-(super)conductors
• Quantum Fluids of Light
• Semiconductor microcavity designs (planar, tunable, plasmonic and hybrid).
• Microcavity polaritons.
• Bose-Einstein condensation of MC-Polaritons (coherent and incoherent pumping).
• Superfluid hydrodynamics of the photon fluid.
• Strongly correlated photons.

After participation in the Module the student is able to:

1. Understand the rationale for building semiconductor-based quantum electronic and photonic devices and combining them into quantum circuits.
2. Understand how semiconductor nanostructures can be used to generate, manipulate and detect quantum light.
3. Explain key-aspects of coherent light-matter interactions at the quantum limit, in the isolated and dissipative regime.
4. Describe key quantum photonic technologies including quantum cryptography, photonic quantum simulation and linear-optics-quantum-communication.
5. Explain how microcavity polaritons can undergo Bose-Einstein condensation and describe their non-linear quantum properties.
6. Make the device concepts related to interacting fluids-of-light comprehensible.

No prerequisites beyond the requirements for the Master’s program in Quantum Science and Technology.

The module consists of a lecture series (4 SWS), comprising two lecture sessions per week.

Quantitative concepts and analysis will be presented at the blackboard or via iPad+beamer. The latter will be used to discuss the implementation of experimental set-ups. These presentations will be complemented by videos, QuTiP simulations and practical experiments.

Combined Power Point and blackboard/iPad presentation, videos, simulations and experiments.

• Mark Fox - Quantum Optics: An introduction (Oxford University Press 2006)
• M.A. Nielsen and I.L. Chuang - Quantum Computation and Quantum Information (Cambridge University Press)
• Peter Michler - Quantum Dots for Quantum Information Technologies - (Springer, 2017).

There will be a written exam of 60 minutes duration. Therein the achievement of the competencies given in section learning outcome is tested exemplarily at least to the given cognition level using comprehension questions and sample problems.

For example an assignment in the exam might be:

• Summarise the requirements of quantum states in a semiconductor that allow them to be used as a qubit ?
• Explain two coherent control methods used to manipulate spin qubits in semiconductors.
• Describe the process of coherent light-matter interaction in the rotating-wave approximation.
• Describe how interactions can be generated between single photons in a semiconductor?
• Explain the fundamental principles of quantum cryptography using single photons and continuous optical fields?
• How to detect if Bose-Einstein condensation has occurred in a microcavity?

In the exam the following learning aids are permitted: Hand-written sheet with formulas + concepts, double-sided

Participation in the exercise classes is strongly recommended since the exercises prepare for the problems of the exam and rehearse the specific competencies.