Bulletin of the American Physical Society
APS April Meeting 2016
Volume 61, Number 6
Saturday–Tuesday, April 16–19, 2016; Salt Lake City, Utah
Session B11: Precision Measurements and Fundamental Symmetries |
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Sponsoring Units: GPMFC Room: 250C |
Saturday, April 16, 2016 10:45AM - 10:57AM |
B11.00001: Updated measurement of the permanent electric dipole moment (EDM) of $^{199}$Hg Brent Graner, Yi Chen, Eric Lindahl, Blayne Heckel A permanent electric dipole moment (EDM) in an atom or particle would prove that time reversal symmetry is broken. In addition, an atomic EDM may provide evidence of new physics or CP symmetry violation in the strong sector. We have recently completed an improved measurement of the EDM of $^{199}$Hg utilizing a set of vapor cells containing isotopically-enriched $^{199}$Hg optically pumped and probed with UV laser light. I will discuss the most recent iteration of the experiment, and present unblinded results. [Preview Abstract] |
Saturday, April 16, 2016 10:57AM - 11:09AM |
B11.00002: Systematic errors in the measurement of the permanent electric dipole moment (EDM) of the $^{199}$Hg atom Yi Chen, Brent Graner, Eric Lindahl, Blayne Heckel This talk provides a discussion of the systematic errors that were encountered in the $^{199}$Hg experiment described earlier in this session. The dominant systematic error, unseen in previous $^{199}$Hg EDM experiments, arose from small motions of the Hg vapor cells due to forces exerted by the applied electric field. Methods used to understand this effect, as well as the anticipated sources of systematic errors such as leakage currents, parameter correlations, and E$^2$ and $\mathbf{v}\times\mathbf{E}/c$ effects, will be presented. The total systematic error was found to be 72\% as large as the statistical error of the EDM measurement. [Preview Abstract] |
Saturday, April 16, 2016 11:09AM - 11:21AM |
B11.00003: Measuring the Muon g-2 Magnetic Storage Field Via Proton Nuclear Magnetic Resonance Matthias Smith The Muon {\$}g-2{\$} experiment at Fermilab aims to measure the muon anomalous magnetic moment, {\$}a\textunderscore $\backslash $mu{\$}, to a precision of 140 ppb, using a technique that determines the muon spin precession frequency in the highly uniform magnetic field of a storage ring. Both precession frequency and field determination contribute equally to the final systematic uncertainty. The magnetic field is determined from the measurement of free induction decay (FID) signals provided by a matrix of custom proton nuclear magnetic resonance (pNMR) probes. FID simulations show that we can achieve the required precision for extraction of field values compared to systematic contributions. The recently powered muon storage ring is providing data to evaluate the pNMR measurement results. We will describe the performance to date of this system. [Preview Abstract] |
Saturday, April 16, 2016 11:21AM - 11:33AM |
B11.00004: Development of a tilt-free seismometer Katherine Dooley Seismometers play an integral role in the seismic isolation of gravitational wave detectors. They are used as sensors of ground and isolation table translation to provide feedback and feedforward control to quiet the motion of the interferometer mirrors. The problem is that the seismometers cannot distinguish between translation and tilt. This limits the extent of potential longitudinal control of the mirrors at frequencies where ground tilt dominates (below about 100 mHz), thus increasing the root-mean-square mirror motion. This reduces the detector up-time and induces excess technical noise in other interferometer control systems that affect the sensitivity to gravitational waves. We present the motivation, design and early results of a prototype low-noise seismometer that mechanically filters ground tilt to reduce the tilt-horizontal coupling. Such a tilt-free seismometer may be implemented in the future as an upgrade to the Advanced LIGO detectors. [Preview Abstract] |
Saturday, April 16, 2016 11:33AM - 11:45AM |
B11.00005: Improving active seismic isolation in aLIGO using a ground rotation sensor Krishna Venkateswara, Charles Hagedorn, Michael Ross, Jens Gundlach The active seismic isolation in Advanced LIGO achieves a factor of $10-10^4$ isolation from ground displacement in the frequency range from 0.1-10 Hz enabling stable low noise interferometer operation. It uses seismometers on the ground and the optics platform in feedback loops to reduce the transmission of ground motion to the platform. However, due to the inability of a seismometer to distinguish between horizontal acceleration and rotation (coupling through gravity), wind-induced tilt limits the performance of the active isolation in the 10-500 mHz frequency range, thereby reducing the duty-cycle of the detectors. We describe a ground rotation sensor, consisting of a low frequency beam-balance and an autocollimator readout with better than 0.4 nrad/rt(Hz) sensitivity above 10 mHz, which can be used to subtract tilt-noise from a horizontal seismometer, thus improving the active seismic isolation system. [Preview Abstract] |
Saturday, April 16, 2016 11:45AM - 11:57AM |
B11.00006: Cavity optomechanics with micromirrors: Progress towards the measurement of quantum radiation pressure noise and ponderomotive squeezing Jonathan Cripe, Robinjeet Singh, Thomas Corbitt Advanced LIGO is predicted to be limited by quantum noise at intermediate and high frequencies when it reaches design sensitivity. The quantum noise, including radiation pressure noise at intermediate frequencies, will need to be reduced in order to increase the sensitivity of future gravitational wave interferometers. We report recent progress towards measuring quantum radiation pressure noise in a cryogenic optomechanical cavity. The low noise microfabricated mechanical oscillator and cryogenic apparatus allow direct broadband thermal noise measurements which test thermal noise models and damping mechanisms. We also progress toward the measurement of the ponderomotive squeezing produced by the optomechanical cavity and the reduction of radiation pressure noise using squeezed light. These techniques may be applicable to an upgrade of Advanced LIGO or the next generation of gravitational wave detectors. [Preview Abstract] |
Saturday, April 16, 2016 11:57AM - 12:09PM |
B11.00007: Wavelength metrology with a color sensor integrated chip Jarom Jackson, Tyler Jones, Nils Otterstrom, James Archibald, Dallin Durfee We have developed a method of wavelength sensing using the TCS3414 from AMS, a color sensor developed for use in cell phones and consumer electronics. The sensor datasheet specifies 16 bits of precision and 200ppm/C° temperature dependence, which preliminary calculations showed might be sufficient for picometer level wavelength discrimination of narrow linewidth sources. We have successfully shown that this is possible by using internal etalon effects in addition to the filters’ wavelength responses, and recently published our findings in OpticsExpress. Our device demonstrates sub picometer precision over short time periods, with about 10pm drift over a one month period. This method requires no moving or delicate optics, and has the potential to produce inexpensive and mechanically robust devices. [Preview Abstract] |
Saturday, April 16, 2016 12:09PM - 12:21PM |
B11.00008: Scanning Frequncy Comb Microscopy; A New Tool With SUB-NM Resolution Mark Hagmann, Dmitry Yarotski The quasi-periodic excitation of a tunneling junction by a mode-locked ultrafast laser generates a regular sequence of femtosecond pulses of electrons at the pulse repetition rate f$_{\mathrm{R}}$ of the laser to be superimposed on the dc tunneling current. In the frequency domain this is equivalent to a microwave frequency comb (MFC) of harmonics at integer multiples of f$_{\mathrm{R}}$. Using a metal tip and sample in a scanning tunneling microscope and a mode-locked Ti:Sapphire laser with a f$_{\mathrm{R}}$ of 74.254 MHz, the 200$^{\mathrm{th}}$ harmonic at 14.85 GHz has a signal-to-noise ratio of 20 dB, and a linewidth \textless 1 Hz which sets the present state-of-the-art for narrow-linewidth in a microwave source. The decay in the amplitude of the harmonics with increasing frequency corresponds to a time constant of 320 ps which is attributed to 6.4 pF of shunting capacitance near the junction and the 50 $\Omega $ load of the spectrum analyzer. Spreading resistance in semiconductor samples causes the measured attenuation to be sensitive to the local concentration of the carriers. The laser photon energy must be less than the bandgap energy to prevent the creation of electron-hole pairs which would cause surge currents that interfere with the measurements. [Preview Abstract] |
Saturday, April 16, 2016 12:21PM - 12:33PM |
B11.00009: Progress Towards the Detection of Faraday Rotation on Spin Polarized $^{\mathrm{\mathbf{3}}}$\textbf{He} Josh Abney, Mark Broering, Wolfgang Korsch Off-resonance Faraday rotation can offer a new method to monitor the nuclear spin polarization of a dense $^{\mathrm{3}}$He target and gain access to new information about the magnetic polarizability of the $^{\mathrm{3}}$He nucleus. The interaction of the polarization state of light with the nuclear spin of the helium atom is very weak and has never been detected. A sensitive triple modulation technique has been developed which can detect the expected rotation angle on the order of 100 nrad. Once a Faraday rotation signal is observed, the next step is to separate the magnetic and electric contributions to the rotation by utilizing their different frequency dependencies. Recent studies involved optimizing several parameters which impact $^{\mathrm{3}}$He target polarization. Progress towards detecting nuclear spin optical rotation on $^{\mathrm{3}}$He will be reported. [Preview Abstract] |
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