Optimal quantum resource distribution in quantum dense metrology

Quantum entanglement can engineer the statical distribution of photons and then lead to the enhancement of measurement sensitivity. However, the generated entanglement couldn't be infinite. Quantum dense coding and metrology are proposed to equally divide quantum resource to two conjugate physical quantities for achieving the joint measurement of multiple observable. Here we present a variation of quantum dense metrology. We achieve the quantum enhancement at arbitrary quadrature through reasonably controlling the angle in phase-sensitive amplifiers to create what is called SU(1,1) interferometry.