A quantum sensor: simultaneous precision gravimetry and magnetic   gradiometry with a Bose-Einstein condensate
  A Bose-Einstein condensate is used as an atomic source for a high precision sensor. A $5\times 10^6$ atom F=1 spinor condensate of $^{87}$Rb is released into free fall for up to $750$ms and probed with a Mach-Zehnder atom interferometer based on Bragg transitions. The Bragg interferometer simultaneously addresses the three magnetic states, $\left| m_f=1,0,-1 \right\rangle$, facilitating a simultaneous measurement of the acceleration due to gravity with an asymptotic precision of $2.1\times 10^{-9}$$\Delta$g/g and the magnetic field gradient to a precision $8$pT/m. 
Kyle S. Hardman, Patrick J. Everitt, Gordon D. McDonald, Perumbil   Manju, Paul B. Wigley, Mahasen A. Sooriyabadara, Carlos ...
physics.atom-ph