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Exponentially Enhanced Quantum Metrology

S. M. Roy·Samuel L. Braunstein
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Abstract

We show that when a suitable entanglement generating unitary operator depending on a parameter is applied on N qubits in parallel, and an appropriate observable is measured, a precision of order 2 raised to the power (-N) in estimating the parameter may be achieved. This exponentially improves the precision achievable in classical and in quantum non-entangling parallel strategies. We propose a quantum-optics model of laser light interacting with an N-qubit system, say a polyatomic molecule, via a generalized Jaynes-Cummings interaction which, in principle, could achieve the exponentially enhanced precision.

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S. M. Roy, Samuel L. Braunstein. 2006-07-24. Exponentially Enhanced Quantum Metrology. https://doi.org/10.1103/physrevlett.100.220501

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