Bulletin of the American Physical Society
2013 Joint Meeting of the APS Division of Atomic, Molecular & Optical Physics and the CAP Division of Atomic, Molecular & Optical Physics, Canada
Volume 58, Number 6
Monday–Friday, June 3–7, 2013; Quebec City, Canada
Session P4: Precision Measurements using Atom Interferometry |
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Chair: Harold Metcalf, State University of New York - Stony Brook Room: 204 |
Thursday, June 6, 2013 2:00PM - 2:12PM |
P4.00001: Quantum Test of the Equivalence Principle: The STE-Quest Mission Naceur Gaaloul, Ernst Rasel STE-QUEST aims for a test of General Relativity through testing the Universality of Free Fall with a dual species atom interferometer on a satellite. This test is based on measuring the differential acceleration of two test bodies assumed to be zero by Einstein's Equivalence Principle (EP). The Eotvos ratio derived from the differential signal will be determined with an accuracy of parts in 1e-15 beyond state-of-the art precision of 1e-13 established by lunar laser ranging and torsion balances. Quantum degenerated ensembles of $^{87}$Rb and $^{85}$Rb will act as test bodies in the dual species interferometer and would show the first quantum test of the EP. Due to the weightlessness conditions in space these test masses will be simultaneously prepared and interrogated with a free evolution time of 10 s. Within a single cycle of 20 s a shot noise limited sensitivity to accelerations of 3e-12 m/s$^{2}$ is anticipated. The simultaneous interferometry is carried out in a double diffraction Mach-Zehnder geometry. Challenges in this mission lie both in suppressing noise and bias terms as well as in the accommodation to the limited resources of a satellite. In this talk the measurement principle will presented, an overview of the preliminary payload design will be given, and the estimated error budget will be discussed. STE-QUEST is a proposal for an M3 mission in the frame of the Cosmic Vision program of ESA. [Preview Abstract] |
Thursday, June 6, 2013 2:12PM - 2:24PM |
P4.00002: Towards a test of Einstein's equivalence principle using a Rb-K atom interferometer Dennis Schlippert, Jonas Hartwig, Ulrich Velte, Henning Albers, Jonas Matthias, Wolfgang Ertmer, Ernst Rasel We report on our work directed towards a dual species matter-wave interferometer for performing a differential measurement of the acceleration of free falling $^{87}$Rb and $^{39}$K atoms with the aim to test the universality of free fall and hence Einstein's equivalence principle. According to the minimal Standard Model Extension such a test is very sensitive to composition based equivalence principle violating effects and complementary to classical tests. Simultaneous dual species operation guarantees high common noise suppression. We will show the environmental noise limited performance of the single species rubidium gravimeter ($7.84\cdot10^{-6}$ m/s$^2/\sqrt{\textrm Hz}$ and $3.86\cdot10^{-8}$ m/s$^2$ @ 49152 s) in comparison to a classical accelerometer and the implementation progress of the potassium gravimeter. [Preview Abstract] |
Thursday, June 6, 2013 2:24PM - 2:36PM |
P4.00003: MAQRO - Testing the foundations of quantum physics in space Rainer Kaltenbaek, Gerald Hechenblaikner, Nikolai Kiesel, Ulrich Johann, Markus Aspelmeyer One of the central objectives of modern physics is to investigate the relation between quantum physics and gravity. Several space missions that will look for deviations from general relativity (violations of the equivalence principle) are currently being planned or are already scheduled to be launched in the near future, e.g., Microscope and STE-Quest. In a complementary approach, we propose a medium-sized mission, MAQRO, to test for deviations from quantum theory. The main scientific experiment of this proposed mission is DECIDE, which is a matter-wave experiment with massive objects. DECIDE would test the predictions of quantum theory in a parameter regime several orders of magnitude beyond what is testable in ground-based experiments today. In that regime, several extensions to quantum theory predict deviations from standard quantum theory (possibly due to quantum gravity) to become observable. Here, we will present the motivation for performing such experiments in space, as well as the technical requirements that have to be met to realize such an experiment. [Preview Abstract] |
Thursday, June 6, 2013 2:36PM - 2:48PM |
P4.00004: Exotic Dirac Wavepackets Accumulating Aharonov-Bohm-type Phase in Free Space Ido Kaminer, Jonathan Nemirovsky, Mikael Rechtsman, Rivka Bekenstein, Mordechai Segev Following the seminal 1958 paper by Aharonov-Bohm (AB), it is expected that two parts of the wavefunction of an electron can accumulate phase difference even when they are confined to a region in space with zero EM field. The AB effect was groundbreaking: the EM vector potential is a physical quantity affecting the outcome of experiments directly, not only through the fields extracted from it. But is the EM potential a real necessity for an AB-type effect? Can such effect exist in a potential-free system such as \textbf{free-space}? Here, we find self-accelerating solutions of the potential-free Dirac equation, for massive/massless fermions/bosons. These exotic Dirac particles mimic the dynamics of a free-charge moving under a ``virtual'' EM field. They accelerate even though no field is acting on them (and no charge is defined): the entire dynamics is a direct result of the initial conditions. We show that such particles display an \textbf{effective AB effect} that can be explained by a ``virtual'' potential that ``causes'' the exact same acceleration. We prove that one can create all effects induced by EM fields by only controlling the initial conditions of a wave pattern. Altogether, measurements taken along the trajectory cannot distinguish between a real force and this virtual force: self-induced by the wavepacket itself. The measurable effects of this virtual force are real by all measurable quantities. These phenomena can be observed in various settings: e.g., optical waves in hyperbolic metamaterials, and matter waves in honeycomb interference structures. [Preview Abstract] |
Thursday, June 6, 2013 2:48PM - 3:00PM |
P4.00005: High Data Rate, Six Axis Atom Interferometer for Dynamic Environments Akash Rakholia, Grant Biedermann, Hayden McGuinness Atom interferometers have the potential to be exceptional broadband inertial sensors. However, typically such systems are designed for laboratory environments in pursuit of maximum sensitivity, and thus are bulky, fragile, and are only able to operate at the few Hertz rate. Recently we demonstrated an atom interferometer accelerometer operating between 50 Hz and 300 Hz which had a compact and robust form-factor and exhibited sensitivities suitable for inertial navigation in dynamic environments. We have expanded on this high data-rate model and produced a six-axis design based on the concept of an exchange MOT system. This device is capable of simultaneous acceleration and rotation measurements at rates of up to 80 Hz, with sensitivities at the level of $\mathrm{\mu g / \sqrt{Hz}}$ and $\mathrm{\mu rad / s / \sqrt{Hz}}$, with further gains in operation rate and sensitivity expected. This approach suggests an attractive alternative to currently available commercial technologies for inertial navigation. [Preview Abstract] |
Thursday, June 6, 2013 3:00PM - 3:12PM |
P4.00006: Novel cooling and matter wave beam splitters of lithium for atom interferometry Paul Hamilton, Geena Kim, Biswaroop Mukherjee, Trinity Pradhananga, Daniel Tiarks, Chenghui Yu, Holger M\"{u}ller The cooling of lithium to near recoil-limited temperatures is a step towards our goal of a dual species $^{6,7}$Li interferometer for testing Einstein's equivalence principle. We first discuss our demonstration of a novel cooling method for lithium combining Sisyphus cooling and adiabatic expansion. Lithium's unresolved hyperfine structure was thought to make it impossible to reach sub-Doppler temperatures via the optical molasses typically used for other alkali atoms. We achieve cooling of a substantial fraction ($30-50\%$) of our $^{7}$Li atoms to $<3$ times the recoil velocity. Our scheme requires only a single cooling laser with modest power ($<100$ mW) and detuning (1-5 GHz) and should be applicable to all alkali atoms. Next we report on our efforts to demonstrate the first ultracold lithium atom interferometer. While lithium's light mass increases its sensitivity to possible violations of the equivalence principle [1], its large velocity, even near the recoil temperature, and lack of a simple cycling transition for fluorescence detection make interferometry challenging. We discuss our recent investigation of novel beam splitters to increase the sensitivity of a typical Raman interferometer.\\[4pt] [1] M. Hohensee et al., J. Mod. Optics {\bf 58}, 2021 (2011). [Preview Abstract] |
Thursday, June 6, 2013 3:12PM - 3:24PM |
P4.00007: Large momentum transfer atom interferometer for a matter-wave clock and measurement of fundamental constants Pei-Chen Kuan, Shau-Yu Lan, Brian Estey, Damon English, Justin Brown, Michael Hohensee, Holger M\"{u}ller Light-pulse atom interferometers have been used as quantum inertial sensors and for precision tests of fundamental laws of physics. We present the first clock referenced the mass of a single particle, based on combining a Ramsey-Bord\'{e} interferometrer with an optical frequency comb, demonstrating the fundamental connection between time and mass. The rest mass of a particle defines its Compton frequency, $mc^{2}/ \hbar$ through relativity and quantum mechanics, and thereby sets a fundamental timescale. Our clock stabilizes a 10MHz radio-frequency signal to a certain fraction of the Cs Compton frequency. Future work could result in an elementary-particle (electron) or even antimatter (positron) clock, opening up new ways to test CPT symmetry and the equivalence principle. I will also report our progress towards a new determination of fine structure constant using large momentum transfer atom interferometers. We reduced the leading systematic effect by a factor of 3 and added Raman sideband cooling. This increases the overall signal about tenfold, suppresses the thermal expansion of the atom cloud and increases contrast. [Preview Abstract] |
Thursday, June 6, 2013 3:24PM - 3:36PM |
P4.00008: Progress Towards a Cavity Based Atom Interferometer Inertial Sensor Justin Brown, Brian Estey, Paul Hamilton, Holger M\"{u}ller Inertial sensing relies on absolute measurements of acceleration and rotation to determine one's location independent of external references (e.g. GPS). While atom interferometers have been able to achieve unparalleled sensitivity to inertial effects, they are typically bulky and require long interrogation times, making them unsuitable for real world applications. High order Bragg diffraction allows for increased atom interferometer sensitivity, which would allow for more compact setups, but the momentum transfer is limited by laser power and beam quality. Utilizing an optical cavity to circumvent these problems and enhance the momentum transfer of Bragg beamsplitters, we expect to achieve the sensitivity required for practical inertial sensing (acceleration noise of 10 ng/Hz$^{1/2}$ and rotation noise of 100 nrad/s/Hz$^{1/2}$) in an interaction region of a few cm. We report on our progress in developing this new interferometer using cold Cs atoms and discuss its prospects for exploring large momentum transfer up to 100~$\hbar k$ in a single Bragg diffraction process. In addition we discuss how we can utilize the cavity to create accelerometers and gyroscopes with very accurate scale factors. [Preview Abstract] |
Thursday, June 6, 2013 3:36PM - 3:48PM |
P4.00009: Quantum-limited measurement of magnetic-field gradient with entangled atoms Ho Tsang Ng Probing the magnetic field is important in different areas of science. Recently, ultracold atoms have been used for detecting magnetic field due to negligible Doppler broadening and long coherence times. In this talk, I will discuss a method to detect the microwave magnetic-field gradient by using a pair of entangled two-component Bose-Einstein condensates [1]. We consider the two spatially separated condensates to be coupled to the two different magnetic fields. The magnetic-field gradient can be determined by measuring the variances of population differences and relative phases between the two-component condensates in two wells. The precision of measurement can reach the Heisenberg limit. The effects of one-body, two-body atom losses and atom-atom interactions on the detection will be discussed.\\[4pt] [1] H. T. Ng, arXiv:1301.3242. [Preview Abstract] |
Thursday, June 6, 2013 3:48PM - 4:00PM |
P4.00010: High-Precision Measurements with a Yb Bose-Einstein Condensate Interferometer Alan Jamison, Ben Plotkin-Swing, Subhadeep Gupta We report high-precision results from a matter-wave interferometer using a Yb Bose-Einstein condensate (BEC) as a source. This contrast interferometer measures h/m, where h is Planck's constant and m is the mass of a ytterbium atom, which is used to determine the fine structure constant. In addition to a high-precision measurement of h/m, we report ongoing work for measuring and controlling the effects of atomic interactions on the results. Interaction effects have limited the accuracy of previous BEC interferometers. With our current level of control we achieve the highest accuracy to date with a BEC matter-wave interferometer. [Preview Abstract] |
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