Jay M. Brown

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We performed a search for neutron spin coupling to a Lorentz- and CPT-violating background field using a magnetometer with overlapping ensembles of K and ³He atoms. The comagnetometer is mounted on a rotary platform for frequent reversal of its orientation. We measure sidereal oscillations in the signal to search for anomalous spin coupling of extra-solar(More)
A magnetometer using spin-polarized K and 3He atoms occupying the same volume is used to search for anomalous nuclear spin-dependent forces generated by a separate 3He spin source. We measure changes in the 3He spin precession frequency with a resolution of 18 pHz and constrain anomalous spin forces between neutrons to be less than 2x10(-8) of their(More)
With the goal to study the physical and chemical evolution of ices in solar-mass systems, a spectral survey is conducted of a sample of 41 low luminosity YSOs (L ∼ 0.1 − 10 L ⊙) using 5–38 µm Spitzer Space Telescope and 3–4 µm ground-based spectra. The sample is complemented with previously published Spitzer spectra of background stars and with ISO spectra(More)
We develop a new comagnetometer using (21)Ne atoms with nuclear spin I=3/2 and Rb atoms polarized by spin exchange with K atoms to search for tensor interactions that violate local Lorentz invariance. We frequently reverse the orientation of the experiment and search for signals at the first and second harmonics of the sidereal frequency. We constrain 4 of(More)
We describe a multidisciplinary effort for creating interactive 3D graphical modules for visualizing optical phenomena. These modules are designed for use in an upper-level undergraduate physics course. The modules are developed in Open Inventor, which allows them to run under both Unix and Windows. The work is significant in that it applies contemporary(More)
Mid-infrared spectrophotometric observations have revealed a small sub-class of circumstellar disks with spectral energy distributions (SEDs) suggestive of large inner gaps with low dust content. However, such data provide only an indirect and model-dependent method of finding central holes. Imaging of pro-toplanetry disks provides an independent check of(More)
Mid-infrared spectrophotometric observations have revealed a small sub-class of circumstellar disks with spectral energy distributions (SEDs) suggestive of large inner gaps with low dust content. However, such data provide only an indirect and model dependent method of finding central holes. We present here the direct characterization of a 40 AU radius(More)