Multiparameter quantum metrology and mode entanglement with spatially split nonclassical spin ensembles

Fadel, Matteo; Yadin, Benjamin; Mao, Yuping; Byrnes, Tim; Gessner, Manuel

doi:10.1088/1367-2630/ace1a0

Cited by 11 publications

(3 citation statements)

References 72 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Advantages of using pure, spatially split spin-squeezed atomic ensembles for magnetic gradiometry (estimation of the difference θ 1 − θ 2 ) beyond SQL were outlined in [20]. Generally, when using atom interferometers for distributed sensing (i.e., sensing a field at many different spatial points), there are two classes of quantum sensing strategies that can be used, which are straightforward generalizations of their single-parameter sensing counterparts [42].…”

Section: Gradiometry With Doubled Tf and Statesmentioning

confidence: 99%

See 1 more Smart Citation

Globally optimal interferometry with lossy twin Fock probes

Volkoff,

Ryu

2024

Front. Phys.

View full text Add to dashboard Cite

Parity or quadratic spin (e.g., Jz2) readouts of a Mach–Zehnder (MZ) interferometer probed with a twin Fock (TF) input state allow saturating the optimal sensitivity attainable among all mode-separable states with a fixed total number of particles but only when the interferometer phase θ is near zero. When more general Dicke state probes are used, the parity readout saturates the quantum Fisher information (QFI) at θ = 0, whereas better-than-standard quantum limit performance of the Jz2 readout is restricted to an o(N) occupation imbalance. We show that a method of moments readout of two quadratic spin observables Jz2 and J+2+J−2 is globally optimal for Dicke state probes; i.e., the error saturates the QFI for all θ. In the lossy setting, we derive the time-inhomogeneous Markov process describing the effect of particle loss on TF states, showing that the method of moments readout of four at-most-quadratic spin observables is sufficient for globally optimal estimation of θ when two or more particles are lost. The analysis culminates in a numerical calculation of the QFI matrix for distributed MZ interferometry on the four-mode state |N4,N4,N4,N4〉 and its lossy counterparts, showing that an advantage for the estimation of any linear function of the local MZ phases θ1 and θ2 (compared to independent probing of the MZ phases by two copies of |N4,N4〉) appears when more than one particle is lost.

show abstract

Section: Gradiometry With Doubled Tf and Statesmentioning

confidence: 99%

“…and O 2 = J y , allows saturating the QFI matrix for θ → (0, 0) [19]. Saturation of the QFI matrix can also be obtained using four operators which are at most quadratic in the spin operators [20].…”

Section: Introductionmentioning

confidence: 99%

Globally optimal interferometry with lossy twin Fock probes

Volkoff,

Ryu

2024

Front. Phys.

View full text Add to dashboard Cite

show abstract

“…In this sense, observing F Q > N is only a sufficient condition for entanglement. Extensions to the QFI in the form of a QFI matrix have also been proposed to the simultaneous estimation of multiple parameters and characterization of entanglement in multi-mode systems [151,152].…”

Section: Detecting Multipartite Correlations Useful For Quantum Metro...mentioning

confidence: 99%

Probing quantum correlations in many-body systems: a review of scalable methods

Frérot,

Fadel,

Lewenstein

2023

Rep. Prog. Phys.

Self Cite

View full text Add to dashboard Cite

We review methods that allow one to detect and characterize quantum correlations in many-body systems, with a special focus on approaches which are scalable. Namely, those applicable to systems with many degrees of freedom, without requiring a number of measurements or computational resources to analyze the data that scale exponentially with the system size. We begin with introducing the concepts of quantum entanglement, Einstein–Podolsky–Rosen steering, and Bell nonlocality in the bipartite scenario, to then present their multipartite generalization. We review recent progress on characterizing these quantum correlations from partial information on the system state, such as through data-driven methods or witnesses based on low-order moments of collective observables. We then review state-of-the-art experiments that demonstrate the preparation, manipulation and detection of highly-entangled many-body systems. For each platform (e.g. atoms, ions, photons, superconducting circuits) we illustrate the available toolbox for state preparation and measurement, emphasizing the challenges that each system poses. To conclude, we present a list of timely open problems in the field.

show abstract

Distributed quantum sensing with mode-entangled spin-squeezed atomic states

Malia

Martínez-Rincón

et al. 2022

Nature

View full text Add to dashboard Cite

In "Distributed quantum sensing with mode-entangled spin-squeezed atomic states" Nature (2022) [1], Malia et. al. claim to improve the precision of a network of clocks by using entanglement. In particular, by entangling a clock network with up to four nodes, a precision 11.6 dB better than the quantum projection noise limit (i.e. precision without any entanglement) is reported. These claims are incorrect, Malia et. al. do not achieve an improved precision with entanglement. Here we show their demonstration is more than two orders of magnitude worse than the quantum projection noise limit.The central message in "Distributed quantum sensing with mode-entangled spin-squeezed atomic states" Nature (2022) [1] is that by entangling atoms in an atomic clock network, a precision is demonstrated that is impossible to attain using the same number of atoms and time without entanglement. Should we accept this message? Putting aside the impressive technical achievements in the paper, we can objectively assess whether the experimental data are in agreement with the claim.The final two figures of the paper present the supporting data. In Fig. 3, ∆( θ) is plotted as a function of the number of clocks M, each with N = 45, 000 atoms, where the black line (1/ √ MN ) is supposed to denote a limit that cannot be surpassed without entanglementthe quantum projection noise limit (QPN). One point should be made clear, ∆( θ) > 1/ √ MN is very definitively not the limit without entanglement. To see this requires an explanation of what ∆( θ) is. Despite the authors calling ∆( θ) the 'measured sensitivity', it is not a sensitivity at all. θ is simply the difference in values between two measurements (for M = 1).

show abstract

Multiparameter quantum metrology and mode entanglement with spatially split nonclassical spin ensembles

Cited by 11 publications

References 72 publications

Globally optimal interferometry with lossy twin Fock probes

Globally optimal interferometry with lossy twin Fock probes

Probing quantum correlations in many-body systems: a review of scalable methods

Distributed quantum sensing with mode-entangled spin-squeezed atomic states

Contact Info

Product

Resources

About