Versatile Gaussian probes for squeezing estimation

Rigovacca, L.; Farace, Alessandro; Souza, Leonardo A. M.; Pasquale, Antonella De; Giovannetti, Vittorio; Adesso, Gerardo

doi:10.1103/physreva.95.052331

Cited by 13 publications

(16 citation statements)

References 54 publications

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“…The interplay between the average performance and the minimum one, which instead relies on discord, as well as a study of the role of entanglement, are detailed in (Farace et al, 2016). A similar study has been recently performed in continuous variable systems, in which the average quantum Fisher information for estimating the amount of squeezing applied to an input single-mode probe, without previous knowledge on the phase of the applied squeezing, was investigated with and without the use of a correlated ancilla (Rigovacca et al, 2017).…”

Section: H Average Precision In Black-box Settingsmentioning

confidence: 99%

Quantum-enhanced measurements without entanglement

et al. 2018

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Quantum-enhanced measurements exploit quantum mechanical effects for increasing the sensitivity of measurements of certain physical parameters and have great potential for both fundamental science and concrete applications. Most of the research has so far focused on using highly entangled states, which are, however, difficult to produce and to stabilize for a large number of constituents. In the following we review alternative mechanisms, notably the use of more general quantum correlations such as quantum discord, identical particles, or non-trivial Hamiltonians; the estimation of thermodynamical parameters or parameters characterizing non-equilibrium states; and the use of quantum phase transitions. We describe both theoretically achievable enhancements and enhanced sensitivities, not primarily based on entanglement, that have already been demonstrated experimentally, and indicate some possible future research directions. arXiv:1701.05152v2 [quant-ph]

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Section: H Average Precision In Black-box Settingsmentioning

confidence: 99%

Quantum-enhanced measurements without entanglement

et al. 2018

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“…We find that the information about a parameter encoded in the first moments is unaffected by the control strategies we consider, and thus we restrict to parameters encoded in the covariance matrix (CM), i.e., angle and strength of squeezing. Not surprisingly, the estimation of squeezing with Gaussian states has been considered by various authors [51][52][53][54][55][56][57]. Here, we find the optimal unitary controls to preserve the QFI associated with both the squeezing angle (i.e., an optical phase parameter) and the squeezing strength.…”

Section: Introductionmentioning

confidence: 77%

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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“…Due to the presence of quantum fluctuations, estimation precision using classical probe fields is limited to the standard quantum limit for optical measurements. In order to surpass this limit, quantum resource such as squeezed states [1][2][3] or entangled states [4][5][6][7][8][9][10][11][12][13][14][15][16][17] are required. A notable example is the use of quadrature squeezed states of light to enhance the detection of gravitational wave [18,19].…”

Section: Introductionmentioning

confidence: 99%

Accessible precisions for estimating two conjugate parameters using Gaussian probes

Assad,

Li,

Liu

et al. 2020

Preprint

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We analyse the precision limits for simultaneous estimation of a pair of conjugate parameters in a displacement channel using Gaussian probes. Having a set of squeezed states as an initial resource, we compute the Holevo Cramr-Rao bound to investigate the best achievable estimation precisions if only passive linear operations are allowed to be performed on the resource prior to probing the channel. The analysis reveals the optimal measurement scheme and allows us to quantify the best precision for one parameter when the precision of the second conjugate parameter is fixed. To estimate the conjugate parameter pair with equal precision, our analysis shows that the optimal probe is obtained by combining two squeezed states with orthogonal squeezing quadratures on a 50:50 beam splitter. If different importance are attached to each parameter, then the optimal mixing ratio is no longer 50:50. Instead it follows a simple function of the available squeezing and the relative importance between the two parameters.

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Versatile Gaussian probes for squeezing estimation

Cited by 13 publications

References 54 publications

Quantum-enhanced measurements without entanglement

Quantum-enhanced measurements without entanglement

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

Accessible precisions for estimating two conjugate parameters using Gaussian probes

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