Non-Gaussian entangled states and quantum metrology with ultracold atomic ensemble

Lü, Bo; Han, Chengyin; Zhuang, Min; Ke, Yongguan; Huang, Jiahao; Lee, Chaohong

doi:10.7498/aps.68.20190147

Cited by 9 publications

(4 citation statements)

References 82 publications

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“…It is shown that machine optimization provides a powerful tool for designing optimal quantum metrology protocols. It can also be widely used for improving the performances of the key stages of parameter estimation, such as efficient preparation of highly entangled states [64][65][66][67] and optimal control processes for parameter extraction [63,68,69]. resources and may not be stable depending on the properties of the objective function.…”

Section: Summary and Discussionmentioning

confidence: 99%

Machine optimized quantum metrology of concurrent entanglement generation and sensing

Huo

Zhuang

Huang

et al. 2022

Quantum Sci. Technol.

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Entanglement is one of the key ingredients for enhancing the measurement precision of quantum sensors. Generally, there is a trade-off between state preparation and sensing within a limited coherence time. To fully exploit temporal resources, concurrent entanglement generation and sensing with designed sequence of rotations are proposed. Based on twist-and-turn dynamics, modulated rotations along only one axis may be sufficient to drive the state to the optimal one for tiny estimated parameter. However, when the estimated parameter is not tiny, it may impact the evolved state and hence degrade the final measurement precision. Here, we introduce another modulated rotations along different axis and find out the optimal control sequences by means of machine optimization. The optimal measurement precision bounds become independent on the estimated parameter, which improves the dynamic range of the machine designed sensors. Particularly, by optimizing the interaction strength for different particle number and the time-modulated rotations along two different axes via machine optimization, the Heisenberg-limited precision scaling can be attained. Our work points out a way for designing optimized quantum-enhanced metrology protocols, which is promising for developing practical quantum sensors.

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Section: Summary and Discussionmentioning

confidence: 99%

Machine optimized quantum metrology of concurrent entanglement generation and sensing

Huo

Zhuang

Huang

et al. 2022

Quantum Sci. Technol.

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“…For an ensemble of N uncorrelated atoms, the measurement precision can only reach the standard quantum limit (SQL) [10], which is the basic statistical scaling of 1/ √ N . By employing atom-atom entanglement, entangled states such as spin squeezed state [11][12][13][14][15], Greenberger-Horne-Zeilinger (GHZ) and NOON states [5,6,16], twin-Fock states [17][18][19][20] and spin cat states [21,22] can beat the SQL or even approach the fundamental limit of quantum metrology, the Heisenberg limit (HL) [2,23] with a scaling of 1/N . Spin cat states are promising candidates for approaching the HL [24].…”

Section: Introductionmentioning

confidence: 99%

Efficient Generation of Spin Cat States

Huang,

Huo,

Zhuang

et al. 2022

Preprint

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Spin cat states are promising candidates for achieving Heisenberg-limited quantum metrology. It is suggested that spin cat states can be generated by adiabatic evolution. However, due to the limited coherence time, the adiabatic process may be too slow to be practical. To speed up the state generation, we propose to use machine optimization to generate desired spin cat states. Our proposed scheme relies only on experimentally demonstrated one-axis twisting interactions with piecewise time-modulation of rotations designed via machine optimization. The required evolution time is much shorter than the one with adiabatic evolution and it does not make large modification to the existing experimental setups. Our protocol with machine optimization is efficient and easy to be implemented in state-of-the-art experiments.

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“…However, the SQL can be surpassed by using specially manipulated particles with entanglement. Especially, by inputting the Greenberger-Horne-Zeilinger (GHZ) state into the interferometry, the measurement precision can be improved to the Heisenberg-limited scaling, i.e., ∝ 1/N [44][45][46][47][48][49][50]. Quantum-enhanced magnetometers have been proposed and realized in various systems, including nitrogen-vacancy defect centers [51][52][53], Bose-Einstein condensates [55][56][57][58][59][60][61][62][63], trapped ions [64,65], solid-state spin systems [66][67][68][69].…”

Section: Introductionmentioning

confidence: 99%

Simultaneous Measurement of dc and ac Magnetic Fields at the Heisenberg Limit

2020

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High-precision magnetic field measurement is an ubiquitous issue in physics and a critical task in metrology. Generally, magnetic field has DC and AC components and it is hard to extract both DC and AC components simultaneously. The conventional Ramsey interferometry can easily measure DC magnetic fields, while it becomes invalid for AC magnetic fields since the accumulated phases may average to zero. Here, we propose a scheme for simultaneous measurement of DC and AC magnetic fields by combining Ramsey interferometry and rapid periodic pulses. In our scheme, the interrogation stage is divided into two signal accumulation processes linked by a unitary operation. In the first process, only DC component contributes to the accumulated phase. In the second process, by applying multiple rapid periodic π pulses, only the AC component gives rise to the accumulated phase. By selecting suitable input state and the unitary operations in interrogation and readout stages, and the DC and AC components can be extracted by population measurements. In particular, if the input state is a GHZ state and two interaction-based operations are applied during the interferometry, the measurement precisions of DC and AC magnetic fields can approach the Heisenberg limit simultaneously. Our scheme provides a feasible way to achieve Heisenberglimited simultaneous measurement of DC and AC fields. J m=−J C m J 2 J [(−1) m + 1]|J, m − 1 √ 2 [cos(B 1 JT 1 ) sin(B 2 JT 2 /π) + i sin(B 1 JT 1 ) cos(B 2 JT 2 /π)] J m=−J C m J 2 J [(−1) m − 1]|J, m = 1 √ 2 {cos(B 1 JT 1 )[cos(B 2 JT 2 /π) − sin(B 2 JT 2 /π)] − i sin(B 1 JT 1 )[cos(B 2 JT 2 /π) + sin(B 2 JT 2 /π)]} J m=−J C m J 2 J (−1) m |J, m + 1 √ 2 {cos(B 1 JT 1 )[cos(B 2 JT 2 /π) + sin(B 2 JT 2 /π)] + i sin(B 1 JT 1 )[cos(B 2 JT 2 /π) − sin(B 2 JT 2 /π)]} J m=−J C m J 2 J |J, m .

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Non-Gaussian entangled states and quantum metrology with ultracold atomic ensemble

Cited by 9 publications

References 82 publications

Machine optimized quantum metrology of concurrent entanglement generation and sensing

Machine optimized quantum metrology of concurrent entanglement generation and sensing

Efficient Generation of Spin Cat States

Simultaneous Measurement of dc and ac Magnetic Fields at the Heisenberg Limit

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