Multiparameter Gaussian quantum metrology

Nichols, Ralph C.; Liuzzo-Scorpo, Pietro; Knott, P. A.; Adesso, Gerardo

doi:10.1103/physreva.98.012114

Cited by 108 publications

(105 citation statements)

References 81 publications

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“…In the last few years, several theoretical investigations on multiparameter estimation have been reported [9,31,[34][35][36][37][38][39], while experimental tests are surprisingly few. These include the simultaneous estimation of phase and its diffusion noise [40][41][42], phase and quality of the probe state [43], the discrimination of an actual signal from parasitic interference [44], and quantum-enhanced tomography of an unknown unitary process by multiphoton states [21].…”

Section: Introductionmentioning

confidence: 99%

Experimental multiphase estimation on a chip

Polino¹,

Riva²,

Valeri³

et al. 2019

Optica

116

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Multiparameter estimation is a general problem that aims at measuring unknown physical quantities, obtaining high precision in the process. In this context, the adoption of quantum resources promises a substantial boost in the achievable performances with respect to the classical case. However, several open problems remain to be addressed in the multiparameter scenario. A crucial requirement is the identification of suitable platforms to develop and experimentally test novel efficient methodologies that can be employed in this general framework. We report the experimental implementation of a reconfigurable integrated multimode interferometer designed for the simultaneous estimation of two optical phases. We verify the high-fidelity operation of the implemented device, and demonstrate quantum-enhanced performances in two-phase estimation with respect to the best classical case, post-selected to the number of detected coincidences. This device can be employed to test general adaptive multiphase protocols due to its high reconfigurability level, and represents a powerful platform to investigate the multiparameter estimation scenario.

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Section: Introductionmentioning

confidence: 99%

Experimental multiphase estimation on a chip

Polino¹,

Riva²,

Valeri³

et al. 2019

Optica

116

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“…General multimode Gaussian unitary channels (Bogoliubov transformations) are considered with pure probe states not restricted to Gaussian states and the behavior of the QFI for large mean photon numbers is discussed [46]. A formula for the QFI matrix is derived for general multimode Gaussian states and multiparameter Gaussian quantum metrology is discussed [61,64].…”

Section: Introductionmentioning

confidence: 99%

Optimal Gaussian metrology for generic multimode interferometric circuit

et al. 2019

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Bounds on the ultimate precision attainable in the estimation of a parameter in Gaussian quantum metrology are obtained when the average number of bosonic probes is fixed. We identify the optimal input probe state among generic (mixed in general) Gaussian states with a fixed average number of probe photons for the estimation of a parameter contained in a generic multimode interferometric optical circuit, namely, a passive linear circuit preserving the total number of photons. The optimal Gaussian input state is essentially a single-mode squeezed vacuum, and the ultimate precision is achieved by a homodyne measurement on the single mode. We also reveal the best strategy for the estimation when we are given L identical target circuits and are allowed to apply passive linear controls in between with an arbitrary number of ancilla modes introduced.

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“…Several extensions of the ideas we have proposed here can be envisioned, most notably dropping the assumption of fast parameter encoding. This means that, instead of only delaying the demise of the QFI of an initial state, we should consider the situation where the parameter is encoded simultaneously to the open dynamics, e.g., by adding an Hamiltonian term in the Lindblad master equation or estimating parameters of the non-unitary part of the Gaussian dynamics, see, e.g., [83][84][85][86][87][88][89]. In such scenarios time-local control would be used to increase the rate at which information about the parameter is acquired during the dynamics.…”

Section: Conclusion and Remarksmentioning

confidence: 99%

Time-local optimal control for parameter estimation in the Gaussian regime

2020

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Information about a classical parameter encoded in a quantum state can only decrease if the state undergoes a non-unitary evolution, arising from the interaction with an environment. However, instantaneous control unitaries may be used to mitigate the decrease of information caused by an open dynamics. A possible, locally optimal (in time) choice for such controls is the one that maximises the time-derivative of the quantum Fisher information (QFI) associated with a parameter encoded in an initial state. In this study, we focus on a single bosonic mode subject to a Markovian, thermal master equation, and determine analytically the optimal time-local control of the QFI for its initial squeezing angle (optical phase) and strength. We show that a single initial control operation is already optimal for such cases and quantitatively investigate situations where the optimal control is applied after the open dynamical evolution has begun.

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Multiparameter Gaussian quantum metrology

Cited by 108 publications

References 81 publications

Experimental multiphase estimation on a chip

Experimental multiphase estimation on a chip

Optimal Gaussian metrology for generic multimode interferometric circuit

Time-local optimal control for parameter estimation in the Gaussian regime

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