  Quantum metrology is the use of genuinely quantum properties such as
entanglement as a resource to outperform classical sensing strategies.
Typically, entanglement is created by implementing gate operations or inducing
many-body interactions. However, existing sensing schemes with these approaches
require accurate control of the probe system such as switching on and off the
interaction among qubits, which can be challenging for practical applications.
Here, we propose an entanglement-enhanced sensing scheme with an always-on
nearest-neighbor interaction between qubits. We adopt the transverse field
Ising chain as the probe system, making use of the so-called quantum domino
dynamics for the generation of the entangled states. In addition to the
advantage that our scheme can be implemented without controlling the
interactions, it only requires initialization of the system, projective
measurements on a single qubit, and control of the uniform magnetic fields. We
can achieve an improved sensitivity beyond the standard quantum limit even
under the effect of realistic decoherence.
