Enhancement of frequency estimation by spatially correlated environments
In metrological tasks, employing entanglement can quantitatively improve the precision of parameter estimation. However, susceptibility of the entanglement to decoherence fades this capability in the realistic metrology and limits ultimate quantum improvement. One of the most destructive decoherence-type noise is uncorrelated Markovian noise which commutes with the parameter-encoding Hamiltonian and is modeled as a semigroup dynamics, for which the quantum improvement is constrained to a constant factor. It has been shown (Chin et al., 2012) that when the noisy time evolution is governed by a local and non-semigroup dynamics (e.g., induced by an uncorrelated non-Markovian dephasing), emerging the Zeno regime at short times can result in the Zeno scaling in the precision. Here, by considering the impact of the correlated noise in metrology, we show that spatially correlated environments which lead to a nonlocal and non-semigroup dynamics can improve the precision of a noisy frequency measurement beyond the Zeno scaling. In particular, it is demonstrated that one can find decoherence-free subspaces and subsequently achieve the Heisenberg precision scaling for an approximated dynamics induced by spatially correlated environments. - Highlights: • Here, the impact of correlated noise in metrology is studied. • We have focused on spatially correlated environments. • We show that such environments can result in precision beyond the Zeno scaling. • In particular, we find decoherence-free subspaces. • This leads to achieving the Heisenberg precision scaling.
- OSTI ID:
- 22701499
- Journal Information:
- Annals of Physics, Vol. 381; Other Information: Copyright (c) 2017 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0003-4916
- Country of Publication:
- United States
- Language:
- English
Similar Records
A Multi-Qubit Quantum Gate Using the Zeno Effect
Non-Markovian entanglement dynamics of noisy continuous-variable quantum channels