PT Journal
AU Fadel, M
   Yadin, B
   Mao, YP
   Byrnes, T
   Gessner, M
TI Multiparameter quantum metrology and mode entanglement with spatially split nonclassical spin ensembles
SO New Journal of Physics
JI New J. Phys.
PY 2023
BP 073006
EP 25pp
VL 25
IS 7
DI 10.1088/1367-2630/ace1a0
LA English
DE quantum metrology; Bose-Einstein condensates; spin-squeezing; Fisher information matrix; mode and particle entanglement
AB We identify the multiparameter sensitivity of entangled spin states, such as spin-squeezed and Dicke states that are spatially distributed into several addressable spatial modes. Analytical expressions for the spin-squeezing matrix of families of states that are accessible by current atomic experiments reveal the quantum gain in multiparameter metrology, as well as the optimal strategies to maximize the sensitivity gain for the estimation of any linear combination of parameters. We further study the mode entanglement of these states by deriving a witness for genuine k-partite mode entanglement from the spin-squeezing matrix. Our results highlight the advantage of mode entanglement for distributed sensing, and outline optimal protocols for multiparameter estimation with nonclassical spatially-distributed spin ensembles. We illustrate our findings with the design of a protocol for gradient sensing with a Bose-Einstein condensate in an entangled spin state in two modes.
ER