Fig. 1
From: Quantum-enhanced sensing using non-classical spin states of a highly magnetic atom
Experimental scheme and expected spin dynamics. a Experimental scheme. The spin J = 8 of Dy atoms is manipulated using an off-resonant laser field linearly polarized along x, leading to a non-linear coupling \(\hbar \omega \hat J_x^2\). The spin state is subsequently probed by imaging the atoms after a Stern–Gerlach separation of magnetic sublevels |m〉z, allowing to determine their individual populations. b Expected spin dynamics. The spin, initially prepared in |−J〉z (corresponding atom image in panel c for time t1), first collapses to a featureless state (time t2) on a fast timescale \(t_{\mathrm{c}} \ll 1/\omega\). We subsequently observe the formation of a superposition between states |−J〉z and |J〉z (time t3) and later of the polarized state |J〉z (time t4). Each image is the average of typically 10 resonant absorption images
