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Physical Society ColloquiumInterview for Faculty PositionMesoscopic Detectors and the Quantum LimitAashish ClerkCornellAmong the many open issues related to solid state computation (and, more generally, the study of macroscopic quantum coherence) is the question of how one constructs an "ideal" quantum detector, that is a detector which reaches the quantum limit of measurement efficiency. In this talk I will discuss what it means to reach the quantum limit, why this is both interesting and desirable, and the symmetry properties required to have an arbitrary detector achieve this ideal limit. Interestingly, the resulting conditions are most naturally formulated in terms of information-theoretic ideas, suggesting a new way in which to look at mesoscopic systems. I will describe specific experiments investigating macroscopic quantum coherence (one involving a Josephson-junction qubit, the other a quantum point contact formed in a two-dimensional electron gas) in which these concerns are relevant, as well as related theoretical work we have undertaken.
Wednesday, February 12th 2003, 15:45
Ernest Rutherford Physics Building, R.E. Bell Conference Room (room 103) |