Many-body k-local ground states as probes for unitary quantum metrology 

 Many-body k-local ground states as probes for unitary quantum metrology 

Seminar author:Guillem Müller-Rigat

Event date and time:02/18/2026 02:30:pm

Event location:GIQ Seminar rool

Event contact:

Multipartite quantum states saturating the Heisenberg limit of sensitivity typically require full-body correlators to be prepared. On the other hand, experimentally practical Hamiltonians often involve few-body correlators only. Here, we study the metrological performances under this constraint, using tools derived from the quantum Fisher information. Our work applies to any encoding generator, also including a dependence on the parameter. We find that typical random symmetric ground states of k-body permutation-invariant Hamiltonians exhibit Heisenberg scaling. Finally, we establish a tradeoff between the Hamiltonian’s gap, which quantifies preparation hardness, and the quantum Fisher information of the corresponding ground state.