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2006

Equations of motion approach to decoherence and current noise in ballistic interferometers coupled to a quantum bath

Equations of motion approach to decoherence and current noise in ballistic interferometers coupled to a quantum bath

Florian Marquardt

Physical Review B 74 (12) 125319 (2006) | Journal | PDF

We present a technique for treating many particles moving inside a ballistic interferometer, under the influence of a quantum-mechanical environment (phonons, photons, Nyquist noise, etc.). Our approach is based on solving the coupled Heisenberg equations of motion of the many-particle system and the bath, and it is inspired by the quantum Langevin method known for the Caldeira-Leggett model. As a first application, we treat a fermionic Mach-Zehnder interferometer. In particular, we discuss the dephasing rate and present full analytical expressions for the leading corrections to the current noise, brought about by the coupling to the quantum bath. In contrast to a single-particle model, both the Pauli principle as well as the contribution of hole-scattering processes become important, and are automatically taken into account in this method.

Correlation-induced resonances in transport through coupled quantum dots

Correlation-induced resonances in transport through coupled quantum dots

V Meden, F Marquardt

Physical Review Letters 96 (14) 146801 (2006) | Journal | PDF

We investigate the effect of local electron correlations on transport through parallel quantum dots. The linear conductance as a function of gate voltage is strongly affected by the interplay of the interaction U and quantum interference. We find a pair of novel correlation-induced resonances separated by an energy scale that depends exponentially on U. The effect is robust against a small detuning of the dot energy levels and occurs for arbitrary generic tunnel couplings. It should be observable in experiments on the basis of presently existing double-dot setups.

Dynamical multistability induced by radiation pressure in high-finesse micromechanical optical cavities

Dynamical multistability induced by radiation pressure in high-finesse micromechanical optical cavities

F Marquardt, JGE Harris, SM Girvin

Physical Review Letters 96 (10) 103901 (2006) | Journal | PDF

We analyze the nonlinear dynamics of a high-finesse optical cavity in which one mirror is mounted on a flexible mechanical element. We find that this system is governed by an array of dynamical attractors, which arise from phase locking between the mechanical oscillations of the mirror and the ringing of the light intensity in the cavity. We develop an analytical theory to map out the diagram of attractors in parameter space, derive the slow amplitude dynamics of the system, including thermal fluctuations, and suggest a scheme for exploiting the dynamical multistability in the measurement of small displacements.

Contact

Theory Division
Prof. Florian Marquardt

Max Planck Institute for the Science of Light
Staudtstr. 2
91058 Erlangen, Germany

For all general inquiries, please contact us at:

florian.marquardt@mpl.mpg.de
anna-gesine.murphy@mpl.mpg.de

Tel: +49 9131 7133 401
Fax: +49 9131 7133 409

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