A clock of atoms is spin-squeezed to a Wineland parameter .
PHYSICS · Multi-part · Fermi University Physics · Quantum Information & Technology · Physical realizations and quantum technologies · Physical realizations and quantum technologies
Quantum Information and Technology, Ch Quantum metrology and sensing
Problem
A clock of N=105 atoms is spin-squeezed to a Wineland parameter ξ2=0.05.
((a)) Find the one-shot phase uncertainty Δφ=ξ/N.
((b)) Find the factor by which this beats the standard quantum limit, 1/N.
((c)) Find the factor by which it still falls short of the Heisenberg limit, 1/N.
((d)) State whether the atoms are certified entangled by this value of ξ2, and why.
((e)) Find the ξ2 (and the equivalent figure in decibels, −10log10ξ2) that would be needed for a tenfold gain over the standard quantum limit.