Figure 5
From: On the survival of the quantum depletion of a condensate after release from a magnetic trap
Sketch of the experimental sequence. A BEC is released from a harmonic trap (a) and expands during freefall before being split into a superposition of the \(m_J\in \{-1,0,1\}\) states (b) by an RF chirp. A magnetic field gradient separates the clouds (c) ensuring that only the magnetically insentitive \(m_J=0\) cloud lands on the detector (d), from which the momentum information is reconstructed. Due to the finite detector radius, the collection region in momentum-space is restricted to two vertically-oriented spherical segments (shaded region) whose boundary subtends an angle \({\phi _c}=\pi /3\) with the horizontal (x, y) plane. The quantum depletion lies in the dilute tails at large momentum \(\gtrsim 6\mu {{\text {m}}}^{-1}\) (see Fig. 1).
