Department of Physics,
Faculty of Science and Technology, Keio University

3-14-1, Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan
TEL 045-563-1141 / FAX 045-566-1672

Quantum Physics in Mesoscopic Systems

About this lecture

Recent microfabrication techniques on semiconductors have enabled fabrication of systems on the submicron or nano scale whose dimensions are intermediate between microscopic and macroscopic, or mesoscopic. In mesoscopic systems, quantum-mechanical properties of electrons are observed in the electric transport, which have attracted a lot of interest from the application side to single-electron devices, quantum computers, etc. This course covers the fundamental properties of mesoscopic systems and introduces current topics listed below.

Contents

1. Introduction
• Two-dimensional electron gas
• Ballistic and diffusive regimes
• Magnetoresistance and Shubnikov-de Haas oscillations
• Einstein's relation
2. Interference effects of electrons in mesoscopic systems
• Microfabrication on semiconductors
• Landauer formula and conductance quantization
• Aharonov-Bohm(AB) effect, AAS effect and Anderson localization
• Persistent current
• Universal conductance fluctuation
3. Coulomb blockade in quantum dots
• Charging effect at small tunnel junctions
• Orthodox theory for single-electron transistors
• Artificial atoms: Semiconductor quantum dots
• single-electron turnstile and photon-assisted tunneling
4. Towards quantum computing devices
• Coupled quantum dot (1) charge qubit
• Coupled quantum dot (2) two spin-qubits
• Superconducting quantum dots
• Control of qubits

References

• Y. Imry, "Introduction to Mesoscopic Physics," (Oxford University Press, 1997).
• S. Datta, "ElectronicTransport in Mesoscopic Systems" (Cambridge University Press, 1995).
• Other books will be introduced in the lectures.

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