Now showing items 1-20 of 21

• #### A 1.9 Earth Radius Rocky Planet and the Discovery of a Non-Transiting Planet in the Kepler-20 System ﻿

(American Astronomical Society, 2016)
Kepler-20 is a solar-type star (V = 12.5) hosting a compact system of five transiting planets, all packed within the orbital distance of Mercury in our own solar system. A transition from rocky to gaseous planets with a ...
• #### An astro-comb calibrated solar telescope to search for the radial velocity signature of Venus ﻿

(2016)
We recently demonstrated sub-m/s sensitivity in measuring the radial velocity (RV) between the Earth and Sun using a simple solar telescope feeding the HARPS-N spectrograph at the Italian National Telescope, which is ...
• #### Calibration of an Astrophysical Spectrograph Below 1 m/s Using a Laser Frequency Comb ﻿

(Optical Society of America, 2012)
We deployed two wavelength calibrators based on laser frequency combs (“astro-combs”) at an astronomical telescope. One astro- comb operated over a 100 nm band in the deep red (∼ 800 nm) and a second operated over a 20 nm ...
• #### Characterizing K2 Planet Discoveries: A Super-Earth Transiting the Bright K Dwarf Hip 116454 ﻿

(IOP Publishing, 2015)
We report the first planet discovery from the two-wheeled Kepler (K2) mission: HIP 116454 b. The host star HIP 116454 is a bright (V = 10.1, K = 8.0) K1 dwarf with high proper motion and a parallax-based distance of 55.2 ...
• #### Coherent-Population-Trapping Resonances with Linearly Polarized Light for All-Optical Miniature Atomic Clocks ﻿

(American Physical Society (APS), 2010)
We present a joint theoretical and experimental characterization of the coherent population trapping (CPT) resonance excited on the $D_1$ line of $^{87}Rb$ atoms by bichromatic linearly polarized laser light. We observe ...
• #### Conjugate Fabry–Perot Cavity Pair for Improved Astro-Comb Accuracy ﻿

(Optical Society of America, 2012)
We propose a new astro-comb mode-filtering scheme composed of two Fabry–Perot cavities (coined “conjugate Fabry–Perot cavity pair”). Simulations indicate that this new filtering scheme makes the accuracy of astro-comb ...
• #### An Earth-sized planet with an Earth-like density ﻿

(Springer Nature, 2013)
Recent analyses1–4 of data from the NASA Kepler spacecraft5 have established that planets with radii within 25 per cent of Earth’s (R⊕) are commonplace throughout the Galaxy, orbiting at least 16.5 per cent of Sun-like ...
• #### Electromagnetically induced transparency in paraffin-coated vapor cells ﻿

(American Physical Society (APS), 2011)
Antirelaxation coatings in atomic vapor cells allow ground-state coherent spin states to survive many collisions with the cell walls. This reduction in the ground-state decoherence rate gives rise to ultranarrow-bandwidth ...
• #### Electromagnetically Induced Transparency with Noisy Lasers ﻿

(American Physical Society, 2009)
We demonstrate and characterize two coherent phenomena that can mitigate the effects of laser phase noise for Electromagnetically Induced Transparency (EIT): a laser-power-broadening-resistant resonance in the transmitted ...
• #### HARPS-N Observes the Sun as a Star ﻿

(IOP Publishing, 2015)
Radial velocity (RV) perturbations induced by stellar surface inhomogeneities including spots, plages and granules currently limit the detection of Earth-twins using Doppler spectroscopy. Such stellar noise is poorly ...
• #### In-Situ Determination of Astro-Comb Calibrator Lines to Better Than 10 cm $s^{-1}$ ﻿

(Optical Society of America (OSA), 2010)
Improved wavelength calibrators for high-resolution astrophysical spectrographs will be essential for precision radial velocity (RV) detection of Earth-like exoplanets and direct observation of cosmological deceleration. ...
• #### The Kepler-10 planetary system revisited by HARPS-N: A hot rocky world and a solid Neptune-mass planet. ﻿

(IOP Publishing, 2014)
Kepler-10b was the first rocky planet detected by the Kepler satellite and confirmed with radial velocity follow-up observations from Keck-HIRES. The mass of the planet was measured with a precision of around 30%, which ...
• #### The Kepler-454 System: A Small, Not-rocky Inner Planet, a Jovian World, and a Distant Companion ﻿

(American Astronomical Society, 2016)
Kepler-454 (KOI-273) is a relatively bright (V = 11.69 mag), Sun-like star that hosts a transiting planet candidate in a 10.6 day orbit. From spectroscopy, we estimate the stellar temperature to be 5687 ± 50 K, its metallicity ...
• #### Limits on Isotropic Lorentz Violation in QED from Collider Physics ﻿

(American Institute of Physics, 2009)
We consider the possibility that Lorentz violation can generate differences between the limiting velocities of light and charged matter. Such effects would lead to efficient vacuum Cherenkov radiation or rapid photon decay. ...
• #### The Mass of Kepler-93b and the Composition of Terrestrial Planets ﻿

(IOP Publishing, 2015)
Kepler-93b is a 1.478 ± 0.019 R⊕ planet with a 4.7 day period around a bright (V = 10.2), astroseismically characterized host star with a mass of 0.911 ± 0.033 M and a radius of 0.919 ± 0.011 R. Based on 86 radial velocity ...
• #### ﻿Optimization of Filtering Schemes for Broadband Astro-Combs ﻿

(Optical Society of America, 2012)
To realize a broadband, large-line-spacing astro-comb, suitable for wavelength calibration of astrophysical spectrographs, from a narrowband, femtosecond laser frequency comb (“source-comb”), one must integrate the source-comb ...
• #### The Orbit and Mass of the Third Planet in the Kepler-56 System ﻿

(American Astronomical Society, 2016)
While the vast majority of multiple-planet systems have orbital angular momentum axes that align with the spin axis of their host star, Kepler-56 is an exception: its two transiting planets are coplanar yet misaligned by ...
• #### Particle-Accelerator Constraints on Isotropic Modifications of the Speed of Light ﻿

(American Physical Society, 2009)
The absence of vacuum Cherenkov radiation for 104.5 GeV electrons and positrons at LEP combined with the observed stability of 300 GeV photons at the Tevatron constrains deviations of the speed of light relative to the ...
• #### Slow light in paraffin-coated Rb vapour cells ﻿

(Informa UK Limited, 2006)
Preliminary results from an experimental study of slow light in anti-relaxation- coated Rb vapour cells are presented, and the construction and testing of such cells are described. The slow ground state decoherence rate ...
• #### Slow-light dynamics from electromagnetically-induced-transparency spectra ﻿

(American Physical Society (APS), 2009)
We show how slow-light pulse delays in realistic electromagnetically-induced-transparency (EIT) media can be determined directly from static transmission spectra. Using only the measured EIT linewidth and off-resonant ...