Correlation functions and quantized noise in mesoscopic systems

Le‐Man Kuang, Yiwen Wang, Mo‐Lin Ge

Dynamic evolution of a mesoscopic Josephson junction (MJJ) interacting with quantized electromagnetic fields (QEMF) is investigated. It is shown that the current-voltage steps of the MJJ can reflect quantum coherences of the external QEMF; these characteristics may be used to distinguish different types of quantum electromagnetic fields. It is found that supercurrent fluctuations exhibit periodic oscillations in the time evolution. Supercurrent correlation functions are also studied in some detail. It is shown that the thermal noise in the external electromagnetic field seriously affects the second-order correlation function of the supercurrent. \textcopyright{} 1996 The American Physical Society.

Hilda A. Cerdeira, F. Guinea López, U. Weiss

Xavier Oriols

The experimental current measured in mesoscopic systems fluctuates around average values as a consequence of the wave‐particle nature of electrons. An alternative quantum noise approach, based on Bohm trajectories, is presented. This formalism directly deals with the wave and particle nature of electrons and provides an intuitive framework to study quantum noise. The approach allows the direct consideration of coulomb correlation among electrons. In fact, most of the numerical techniques used in classical Monte Carlo simulations of electron devices can be directly adapted to our approach. Simulated noise results for interacting electrons tunnelling through double barriers are presented in agreement with experimental results. The present approach opens a new path for studying electron transport and quantum noise in mesoscopic systems.

Y. Yamamoto, Ataç İmamoğlu

Basic Concepts. Canonical Quantization. Quantum States of the Electromagnetic Fields. Coherence of the Electromagnetic Fields. Quantum States of Atoms. Interaction between Atoms and Fields. Mathematical Methods for System-Reservoir Interaction. Stochastic Wavefunction Methods. Quantum Nondemolition Measurements. Semiconductor Bloch Equations. Excitons and Polaritons. Coulomb Blockade and Squeezing. Current Noise in Mesoscopic and Macroscopic Conductors. Nonequilibrium Green's Function Formalism. Quantum Statistical Properties of a Laser. Index.

Neill Lambert