2014

Focus on optomechanics

Focus on optomechanics

Ivan Favero, Florian Marquardt

New Journal of Physics 16 085006 (2014) | Journal | PDF

We provide a brief overview of the various topics addressed in this 'focus on' collection on optomechanics.

Cavity optomechanics

Cavity optomechanics

Markus Aspelmeyer, Tobias J. Kippenberg, Florian Marquardt

Reviews of Modern Physics 86 (4) 1391-1452 (2014) | Journal | PDF

The field of cavity optomechanics is reviewed. This field explores the interaction between electromagnetic radiation and nanomechanical or micromechanical motion. This review covers the basics of optical cavities and mechanical resonators, their mutual optomechanical interaction mediated by the radiation-pressure force, the large variety of experimental systems which exhibit this interaction, optical measurements of mechanical motion, dynamical backaction amplification and cooling, nonlinear dynamics, multimode optomechanics, and proposals for future cavity-quantum-optomechanics experiments. In addition, the perspectives for fundamental quantum physics and for possible applications of optomechanical devices are described.

Dissipative optomechanical squeezing of light

Dissipative optomechanical squeezing of light

Andreas Kronwald, Florian Marquardt, Aashish A. Clerk

New Journal of Physics 16 063058 (2014) | Journal | PDF

We discuss a simple yet surprisingly effective mechanism which allows the generation of squeezed output light from an optomechanical cavity. In contrast to the well known mechanism of 'ponderomotive squeezing', our scheme generates squeezed output light by explicitly using the dissipative nature of the mechanical resonator. We show that our scheme has many advantages over ponderomotive squeezing; in particular, it is far more effective in the good cavity limit commonly used in experiments. Furthermore, the squeezing generated in our approach can be directly used to enhance the intrinsic measurement sensitivity of the optomechanical cavity; one does not have to feed the squeezed light into a separate measurement device. As our scheme is very general, it could also e. g. be implemented using superconducting circuits.

Single-site-resolved measurement of the current statistics in optical
   lattices

Single-site-resolved measurement of the current statistics in optical lattices

Stefan Kessler, Florian Marquardt

Physical Review A 89 (6) 061601 (2014) | Journal | PDF

At present, great effort is spent on the experimental realization of gauge fields for quantum many-body systems in optical lattices. At the same time, the single-site-resolved detection of individual atoms has become a new powerful experimental tool. We discuss a protocol for the single-site-resolved measurement of the current statistics of quantum many-body systems, which makes use of a bichromatic optical superlattice and single-site detection. We illustrate the protocol by a numerical study of the current statistics for interacting bosons in one and two dimensions and discuss the role of the on-site interactions for the current pattern and the ground-state symmetry for small two-dimensional lattices with artificial magnetic fields.

Decoherence in a double-dot Aharonov-Bohm interferometer: Numerical
   renormalization group study

Decoherence in a double-dot Aharonov-Bohm interferometer: Numerical renormalization group study

Bjoern Kubala, David Roosen, Michael Sindel, Walter Hofstetter, Florian Marquardt

Physical Review B 90 (3) 035417 (2014) | Journal | PDF

Coherence in electronic interferometers is typically believed to be restored fully in the limit of small voltages, frequencies, and temperatures. However, it is crucial to check this essentially perturbative argument by nonperturbative methods. Here we use the numerical renormalization group to study ac transport and decoherence in an experimentally realizable model interferometer, a parallel double quantum dot coupled to a phonon mode. The model allows us to clearly distinguish renormalization effects from decoherence. We discuss finite-frequency transport and confirm the restoration of coherence in the dc limit.

Laser Theory for Optomechanics: Limit Cycles in the Quantum Regime

Laser Theory for Optomechanics: Limit Cycles in the Quantum Regime

Niels Loerch, Jiang Qian, Aashish Clerk, Florian Marquardt, Klemens Hammerer

Physical Review X 4 (1) 011015 (2014) | Journal | PDF

Optomechanical systems can exhibit self-sustained limit cycles where the quantum state of the mechanical resonator possesses nonclassical characteristics such as a strongly negative Wigner density, as was shown recently in a numerical study by Qian et al. [Phys. Rev. Lett. 109, 253601 (2012)]. Here, we derive a Fokker-Planck equation describing mechanical limit cycles in the quantum regime that correctly reproduces the numerically observed nonclassical features. The derivation starts from the standard optomechanical master equation and is based on techniques borrowed from the laser theory due to Haake and Lewenstein. We compare our analytical model with numerical solutions of the master equation based on Monte Carlo simulations and find very good agreement over a wide and so far unexplored regime of system parameters. As one main conclusion, we predict negative Wigner functions to be observable even for surprisingly classical parameters, i.e., outside the single-photon strong-coupling regime, for strong cavity drive and rather large limit-cycle amplitudes. The approach taken here provides a natural starting point for further studies of quantum effects in optomechanics.

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