Bulletin of the American Physical Society
42nd Annual Meeting of the APS Division of Atomic, Molecular and Optical Physics
Volume 56, Number 5
Monday–Friday, June 13–17, 2011; Atlanta, Georgia
Session J1: Interactions Between Hybrid Quantum Systems |
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Chair: Jake Taylor, JQI and NIST Room: A601 |
Wednesday, June 15, 2011 10:30AM - 10:42AM |
J1.00001: Sensitive position magnetometry and quantum state control in a hybrid BEC-membrane system Steven Steinke, Swati Singh, Mehmet Tasgin, Pierre Meystre, Keith Schwab, Mukund Vengalattore The dynamics of a spinor BEC coupled magnetically to a high-Q mechanical membrane are studied theoretically. In particular, we investigate the effects of using phase-contrast imaging to observe the spin of the BEC. In the case of highly dispersive measurements, the Larmor frequency of the BEC can be found to high precision, and the shift in this frequency provides useful information about the motion of the membrane. On the other hand, for projective spin measurements, a large back-action is induced in the membrane, allowing in some cases the production of non-classical states of motion. We investigate the possibilities for cooling and heating, the production of Fock and cat states, and probabilistic state control of the membrane in this latter case. [Preview Abstract] |
Wednesday, June 15, 2011 10:42AM - 10:54AM |
J1.00002: Detecting short-range forces with levitated laser-cooled microspheres Andrew Geraci, Scott Papp, John Kitching Optically levitated and cooled dielectric microspheres in ultra- high vacuum show great promise as resonant force detectors. By eliminating the need to tether the spheres to a solid substrate, excellent environmental decoupling is achieved, potentially leading to sub-attonewton sensitivity. Hence, they can be used to investigate Casimir forces or for testing non-Newtonian gravity [1]. We consider an experimental setup involving trapping a sub-wavelength silica microsphere in an optical cavity. The cavity is filled with two light fields to trap and cool the center of mass motion of the sphere, respectively. The sphere is trapped in an anti-node of the trapping light close to an end-mirror of the cavity. Casimir forces due to the end-mirror can be measured as a frequency shift of the oscillator, and non-Newtonian gravity-like forces can be measured by monitoring the displacement of the sphere as a mass is brought behind the cavity mirror. The technique we describe could potentially extend the search for non-Newtonian gravity by several orders of magnitude at the micrometer length scale.\\[4pt] [1] A.A.Geraci, S.B.Papp, and J.Kitching, Phys. Rev. Lett. 105, 101101 (2010). [Preview Abstract] |
Wednesday, June 15, 2011 10:54AM - 11:06AM |
J1.00003: An ab-initio model of anomalous heating in planar ion traps Arghavan Safavi-Naini, Peter Rabl, Philippe Weck, Hossein Sadeghpour Measurements of the electric field noise present in ion traps indicate that the noise-induced heating scales as the inverse fourth power of the distance from the trap electrodes to the ion and its spectral density scales with the inverse of frequency [1]. These measurements also suggest that some thermally activated random process is at work. In this work, we present an ab-initio model that accounts for the noise due to oscillating dipoles on the trap electrode surface. The dipoles are formed when atoms are adsorbed on the trap surface, whose interaction with the surface is described using DFT. The oscillations are both in the alignment of the dipoles as well as their size. Calculations for the spectral noise density, distance, frequency and temperature dependencies are presented.\\[4pt] [1] Q. A. Turchette et. al., Phys. Rev. A. \textbf{61}, 63418 (2000) [Preview Abstract] |
Wednesday, June 15, 2011 11:06AM - 11:18AM |
J1.00004: Cooling of a resonant circuit via laser cooled ions Nikos Daniilidis, Soenke Moeller, Boyan Tabakov, Aaron Bradley, Hartmut Haeffner We discuss our experimental progress towards coupling strings of trapped ions to an LC-resonator. The goal of our experiments is to cool the resonant mode of a superconducting high-quality resonant circuit to ultra-low temperatures. By continuously laser cooling a crystal of ions coupled to the circuit, energy is removed from the resonator. For quality factors on the order of 10$^5$, the time-scale of the environment-to-mode coupling, i.e. the time for the resonant mode of the LC-resonator to thermally equilibrate, can be on the order of a second. Thus, engineering an ion-resonator coupling of 10\,kHz results in a reduction of the resonant mode temperature by four orders of magnitude as compared to the ambient temperature of the resonator. The expected temperatures, below 1\,mK, approach the vibrational ground state of the oscillator mode. [Preview Abstract] |
Wednesday, June 15, 2011 11:18AM - 11:30AM |
J1.00005: A hybrid quantum system of ultracold atoms and trapped ions Carlo Sias, Lothar Ratschbacher, Christoph Zipkes, Michael Koehl In the last decades, trapped ions and ultracold atoms have emerged as exceptionally controllable experimental systems to investigate fundamental physics, ranging from quantum information science to simulations of condensed matter models. Even though they share some common grounds in experimental techniques, such as laser cooling, ion trapping and atom trapping have developed very much independently, and only little cross-pollination has been seen. In our experiment we study how cold atoms can be combined with single trapped ions to create a new hybrid quantum system with tailored properties. We have deterministically placed a single ion into an atomic Bose Einstein condensate and demonstrated independent control over the two components within the hybrid system. We have studied the fundamental interaction processes and observed sympathetic cooling of the single ion by the condensate. Additionally, we have characterized elastic and inelastic atom- ion collisions and measured the energy-dependent reaction rate constants. Our experiment paves the way for coupling atomic quantum many-body states to an independently controllable single-particle, giving access to a wealth of novel physics and to completely new detection and manipulation techniques. [Preview Abstract] |
Wednesday, June 15, 2011 11:30AM - 11:42AM |
J1.00006: Atoms and photonic crystal cavities Michal Bajcsy, Andrei Faraon, Kelley Rivoire, Arka Majumdar, Jelena Vuckovic Atoms coupled to micro- or nano-scale optical resonators create a system interesting both for fundamental studies and practical applications. In particular, photonic crystal cavities fabricated in thin semiconductor membranes have extremely small optical mode volumes and are well suited for integration with optical waveguides and on-chip electronics. Here, we study how deposition of cesium atoms affects the properties of a photonic crystal cavity fabricated in gallium phosphide. Additionally, we introduce a proposal for a single photon switching scheme based on cesium atoms coupled to a photonic crystal cavity with a moderate Q-factor. [Preview Abstract] |
Wednesday, June 15, 2011 11:42AM - 11:54AM |
J1.00007: Superradiance of cold atoms coupled to a superconducting circuit Daniel Braun, Jonathan Hoffman, Eite Tiesinga We investigate superradiance of an ensemble of atoms coupled to an integrated superconducting LC-circuit. Particular attention is paid to the effect of inhomogeneous coupling constants. Combining perturbation theory in the inhomogeneity and numerical simulations we show that inhomogeneous coupling constants can significantly affect the superradiant relaxation process. Incomplete relaxation terminating in ``dark states'' can occur, from which the only escape is through individual spontaneous emission on a much longer time scale. The relaxation dynamics can be significantly accelerated or retarded, depending on the distribution of the coupling constants. On the technical side, we also generalize the previously known propagator of superradiance for identical couplings in the completely symmetric sector to the full exponentially large Hilbert space. [Preview Abstract] |
Wednesday, June 15, 2011 11:54AM - 12:06PM |
J1.00008: Negative Refraction in a Raman Chiral System Using Rare-earth Atoms Daniel Sikes, Deniz Yavuz We propose a new scheme to achieve negative refraction in an atomic system using laser-induced magnetoelectric cross-coupling. Our scheme uses a combination of one photon and far-off-resonant Raman transitions to coherently drive the electric and magnetic responses for a probe beam according to a chiral approach for negative refraction. The key idea of a chiral cross-coupling is that the medium's electric polarization is additionally coupled to the magnetic field of the wave and the medium's magnetization is coupled to the electric field. Under such conditions, a negative refractive index can be achieved with a fraction of the density required by non-cross-coupled systems. The energy level structure of this scheme has an advantage over other proposed schemes in that it does not require the existence of electric and magnetic dipole transitions at the same resonant frequency. By allowing a separation of electric and magnetic transition wavelengths we hope to apply this scheme toward realizable experiments with rare-earth atoms such as dysprosium. [Preview Abstract] |
Wednesday, June 15, 2011 12:06PM - 12:18PM |
J1.00009: Variations of Positive and Negative Dispersions in Both Highly and Weakly Absorptive Atomic Systems Tony Abi-Salloum, Scott Snell, Jon Davis, Frank Narducci Positive and negative dispersive media are essential in subluminal, superluminal and negative group velocity pulse propagation applications. Three-level atomic media at resonance, especially the Lambda configuration, are positively dispersive and transparent. In contrast, two-level atomic systems are negatively dispersive and opaque. In this work we study higher level atomic systems comprised of three fields coupled to three levels (double lambda) or four levels (N-Scheme). We explore the systems of interest for critical features such as negative dispersion and transparency, a combination that is needed in numerous applications, e.g. optical gyroscopes. We solve the time dependent equations perturbatively and compare them to well established behavior in three-level systems. Some of the results are analyzed in terms of resonances which control the different features of the observed dispersive and absorptive behaviors. [Preview Abstract] |
Wednesday, June 15, 2011 12:18PM - 12:30PM |
J1.00010: Remote Entanglement between a Single Atom and a Bose-Einstein Condensate Stefan Riedl, Matthias Lettner, Martin M{\"u}cke, Christoph Vo, Carolin Hahn, Simon Baur, J{\"o}rg Bochmann, Stephan Ritter, Stephan D{\"u}rr, Gerhard Rempe Entanglement between stationary systems at remote locations is a key resource for quantum networks. Here we report on an experiment where entanglement is established between a single atom inside a cavity and a Bose-Einstein condensate (BEC) located in two different laboratories. To achieve this, a single photon is generated from the atom-cavity system, such that the polarisation qubit of the photon is entangled with the atomic spin state. The photon is transported through a fibre to the BEC and converted into a collective excitation by a Raman process based on electromagnetically induced transparency. After a variable delay, the produced matter-matter entanglement is converted into photon-photon entanglement by creating two single photons, one from each atomic system. The observed overall fidelity of 95\% and the matter-matter entanglement lifetime of 100 $\mu$s demonstrates the excellent performance of this novel hybrid system. [Preview Abstract] |
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