Focus on Mechanical Systems at the Quantum Limit

Abstract

The last five years have witnessed an amazing development in the field of nano- and micromechanics. What was widely considered fantasy ten years ago is about to become an experimental reality: the quantum regime of mechanical systems is within reach of current experiments.Two factors (among many) have contributed significantly to this situation. As part of the widespread effort into nanoscience and nanofabrication, it is now possible to produce high-quality nanomechanical and micromechanical resonators, spanning length scales of millimetres to nanometres, and frequencies from kilohertz to gigahertz. Researchers coupled these mechanical elements to high-sensitivity actuation and readout systems such as single-electron transistors, quantum dots, atomic point contacts, SQUID loops, high-finesse optical or microwave-cavities etc. Some of these ultra-sensitive readout schemes are in principle capable of detection at the quantum limit and a large part of the experimental effort is at present devoted to achieving this.On the other hand, the fact that the groups working in the field come from various different physics backgrounds—the authors of this editorial are a representative sample—has been a constant source of inspiration for helpful theoretical and experimental tools that have been adapted from other fields to the mechanical realm. To name just one example: ideas from quantum optics have led to the recent demonstration (both in theory and experiment) that coupling a mechanical resonator to a high-finesse optical cavity can be fully analogous to the well-known sideband-resolved laser cooling of ions and hence is capable in principle of cooling a mechanical mode into its quantum ground state. There is no doubt that such interdisciplinarity has been a crucial element for the development of the field. It is interesting to note that a very similar sociological phenomenon occurred earlier in the quantum information community, an area which is deeply enriched by the diverse backgrounds and approaches of the researchers.As diverse as the approaches are the manifold of goals and perspectives for operating mechanical systems close to or within the quantum regime. Already now, nanomechanical sensors achieve single-molecule mass detection and magnetic resonance force detection from single-electron spins although they are operated far from quantum. Quantum-limited mechanical devices promise a new technology with hitherto unachieved performance for high-resolution sensing. This is also of high relevance for macroscopic mechanical resonators used in gravitational wave detectors. Furthermore, the increasing capability to couple mechanical modes to individual quantum systems raises the interesting question of whether mechanics can serve as a quantum bus in hybrid implementations of quantum information processing. Finally, the possibility of generating quantum superposition states that involve displacements of a massive macroscopic object (such as the center of mass of a mechanical beam) provides a completely new parameter regime for testing quantum theory over the amazing range from nanomechanical objects of several picograms up to gram-scale mirrors used in gravitational wave interferometers. We are looking forward to these fascinating developments!This Focus Issue is intended to highlight the present status of the field and to provide both introduction and motivation for students and researchers who want to get familiar with this exciting area or even want to join it. It also complements the conference activities of our community during the last year, where a series of dedicated invited sessions at several international conferences (APS March Meeting 2008, CLEO/QELS 2008, OSA Frontiers in Optics 2008, PQE 2008/2009 etc) culminated in the first Gordon Conference on 'Mechanical Systems at the Quantum Limit'.Given the fast development of the field it was not surprising to see that during the collection of the following contributions new progress was reported almost on a monthly basis and new groups entered the field. We intend to keep submission to this Focus Issue open for some time and invite everyone to share their latest results with us.And finally, a note to our fellow colleagues: keep up the good work! We would like to call the next Focus Issue 'Mechanical Systems IN the Quantum Regime'. Focus on Mechanical Systems at the Quantum Limit ContentsPractical recipes for the model order reduction, dynamical simulation and compressive sampling of large-scale open quantum systems John A Sidles, Joseph L Garbini, Lee E Harrell, Alfred O Hero, Jonathan P Jacky, Joseph R Malcomb, Anthony G Norman and Austin M WilliamsonClassical to quantum transition of a driven nonlinear nanomechanical resonator Itamar Katz, Ron Lifshitz, Alex Retzker and Raphael StraubExperimental optomechanics with silicon micromirrors Olivier Arcizet, Chiara Molinelli, Tristan Briant, Pierre-François Cohadon, Antoine Heidmann, Jean-Marie Mackowski, Christophe Michel, Laurent Pinard, Olivier Français and Lionel RousseauNonlinear quantum metrology using coupled nanomechanical resonators M J Woolley, G J Milburn and Carlton M CavesAll mechanical mixing by means of orthogonally coupled cantilevers A Knoll, O Züger and U DuerigParametric coupling between macroscopic quantum resonators L Tian, M S Allman and R W SimmondsQuantum noise in a nanomechanical Duffing resonator E Babourina-Brooks, A Doherty and G J MilburnCreating and verifying a quantum superposition in a micro-optomechanical system Dustin Kleckner, Igor Pikovski, Evan Jeffrey, Luuk Ament, Eric Eliel, Jeroen van den Brink and Dirk BouwmeesterGround-state cooling of a nanomechanical resonator via a Cooper-pair box qubit Konstanze Jaehne, Klemens Hammerer and Margareta WallquistDissipation in circuit quantum electrodynamics: lasing and cooling of a low-frequency oscillator Julian Hauss, Arkady Fedorov, Stephan André, Valentina Brosco, Carsten Hutter, Robin Kothari, Sunil Yeshwanth, Alexander Shnirman and Gerd SchönRoute to ponderomotive entanglement of light via optically trapped mirrors Christopher Wipf, Thomas Corbitt, Yanbei Chen and Nergis MavalvalaNanomechanical-resonator-assisted induced transparency in a Cooper-pair box system Xiao-Zhong Yuan, Hsi-Sheng Goan, Chien-Hung Lin, Ka-Di Zhu and Yi-Wen JiangHigh-sensitivity monitoring of micromechanical vibration using optical whispering gallery mode resonators A Schliesser, G Anetsberger, R Rivière, O Arcizet and T J KippenbergOptomechanical to mechanical entanglement transformation Giovanni Vacanti, Mauro Paternostro, G Massimo Palma and Vlatko VedralThe optomechanical instability in the quantum regime Max Ludwig, Björn Kubala and Florian MarquardtQuantum limits of photothermal and radiation pressure cooling of a movable mirror M Pinard and A DantanMechanical feedback in the high-frequency limit R El Boubsi, O Usmani and Ya M BlanterBack-action evasion and squeezing of a mechanical resonator using a cavity detector A A Clerk, F Marquardt and K JacobsSimultaneous cooling and entanglement of mechanical modes of a micromirror in an optical cavity Claudiu Genes, David Vitali and Paolo TombesiDispersive optomechanics: a membrane inside a cavity A M Jayich, J C Sankey, B M Zwickl, C Yang, J D Thompson, S M Girvin, A A Clerk, F Marquardt and J G E HarrisCavity-assisted backaction cooling of mechanical resonators I Wilson-Rae, N Nooshi, J Dobrindt, T J Kippenberg and W ZwergerCavity cooling of a nanomechanical resonator by light scattering I Favero and K KarraiProbing the quantum coherence of a nanomechanical resonator using a superconducting qubit: II. Implementation M P Blencowe and A D ArmourProbing the quantum coherence of a nanomechanical resonator using a superconducting qubit: I. Echo scheme A D Armour and M P BlencoweNanoelectromechanics of suspended carbon nanotubes A K Hüttel, M Poot, B Witkamp and H S J van der ZantProspects for cooling nanomechanical motion by coupling to a superconducting microwave resonator J D Teufel, C A Regal and K W Lehnert