scholarly journals Dynamic synthesis of Heisenberg-limited spin squeezing

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Long-Gang Huang ◽  
Feng Chen ◽  
Xinwei Li ◽  
Yaohua Li ◽  
Rong Lü ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Interaction Strength ◽  
Spin Squeezing ◽  
Interaction Coefficient ◽  
Measurement Precision ◽  
Precision Measurements ◽  
Quantum Metrology ◽  
Experimental Realization ◽  
Dynamic Synthesis ◽  
Measurement Signal

AbstractSpin squeezing is a key resource in quantum metrology, allowing improvements of measurement signal-to-noise ratio. Its generation is a challenging task because the experimental realization of the required squeezing interaction remains difficult. Here, we propose a generic scheme to synthesize spin squeezing in non-squeezing systems. By using periodical rotation pulses, the original non-squeezing interaction can be transformed into squeezing interaction, with significantly enhanced interaction strength. The sign of the interaction coefficient is also flippable, facilitating time-reversal readout protocol for nonlinear interferometers. The generated spin squeezing is capable of achieving the Heisenberg limit with measurement precision ∝ 1/N for N particles and its robustness to noises of pulse areas and separations has been verified as well. This work offers a path to extending the scope of Heisenberg-limited quantum precision measurements in non-squeezing systems.

Fluorescence Information Processing Based on Wavelet De-Noising

2015 ◽  
Vol 734 ◽  
pp. 56-63
Author(s):  
Yong Xin Shao ◽  
Xiao Ping Yang ◽  
Zhi Yong Wang ◽  
Ya Juan Yang
Keyword(s):  
Information Processing ◽  
Fluorescence Lifetime ◽  
Temperature Sensor ◽  
Signal To Noise Ratio ◽  
Measurement Precision ◽  
Measurement Reliability ◽  
Signal To Noise ◽  
Noise Interference ◽  
System Noise ◽  
Interference Measurement

<p>In this paper ,the method of the fluorescence lifetime (FL) in fluorescence optical fiber temperature sensor is used to measure the temperature. During the fluorescence information processing , because of existence of the system noise interference, measurement reliability of fluorescence lifetime has been greatly affected, thereby reducing the temperature measurement precision. This paper presents an improved wavelet threshold de-noising method to signal processing, which improves the signal-to-noise ratio and increases the measurement of fluorescence lifetime precision, reduce the error of temperature measurements at the same time. The experimental results demonstrate that this method is effective.</p>

Non-Markovian Dynamics of Spin Squeezing Under Detuning Modulation

2017 ◽  
Vol 24 (01) ◽  
pp. 1750003
Author(s):  
Xing Xiao ◽  
Jia-Ju Wu ◽  
Wo-Jun Zhong ◽  
Yan-Ling Li
Keyword(s):  
Sudden Death ◽  
Open Systems ◽  
Spin Squeezing ◽  
Zero Temperature ◽  
Quantum Metrology ◽  
Markovian Dynamics ◽  
Long Time ◽  
Markovian Regime

The dynamics of spin squeezing of an ensemble of N separate spin-1/2 particles, each coupled to a zero-temperature non-Markovian reservoir have been investigated. We show that the initial spin squeezing could be prolonged for a long time by utilizing detuning modification. We further explore that the spin squeezing sudden death (SSSD) could be circumvented with the increasing of detuning. By comparison with the results in Markovian regime with detuning and those in non-Markovian regime without detuning, we conclude that the disappearance of SSSD and the robust preservation of spin squeezing should be attributed to the combination of detuning and non-Markovian effect. The present results may be of direct importance for quantum metrology in open systems.

A Test to Measure Subjective and Objective Speech Intelligibility

2002 ◽  
Vol 13 (01) ◽  
pp. 038-049 ◽  
Author(s):  
Gabrielle H. Saunders ◽  
Kathleen M. Cienkowski
Keyword(s):  
Speech Intelligibility ◽  
Signal To Noise Ratio ◽  
Hearing Aid ◽  
Clinical Tool ◽  
Signal To Noise ◽  
Speech Reception ◽  
Measurement Signal ◽  
Perceptual Performance ◽  
Noise Ratio ◽  
Performance Discrepancy

Measurement of hearing aid outcome is particularly difficult because there are numerous dimensions to consider (e.g., performance, satisfaction, benefit). Often there are discrepancies between scores in these dimensions. It is difficult to reconcile these discrepancies because the materials and formats used to measure each dimension are so very different. We report data obtained with an outcome measure that examines both objective and subjective dimensions with the same test format and materials and gives results in the same unit of measurement (signal-to-noise ratio). Two variables are measured: a “performance” speech reception threshold and a “perceptual” speech reception threshold. The signal-to-noise ratio difference between these is computed to determine the perceptual-performance discrepancy (PPDIS). The results showed that, on average, 48 percent of the variance in subjective ratings of a hearing aid could be explained by a combination of the performance speech reception threshold and the PPDIS. These findings suggest that the measure is potentially a valuable clinical tool.

Full-Isolation Load Equivalent and Parameter Measurement Instrument Development

2012 ◽  
Vol 229-231 ◽  
pp. 1226-1229
Author(s):  
Jiang Yang ◽  
Jun Liu ◽  
Zhou Chan He
Keyword(s):  
Instrument Development ◽  
Measurement Instrument ◽  
Data Access ◽  
Measurement Precision ◽  
Parameter Measurement ◽  
Graphical Display ◽  
State Test ◽  
Measurement Signal ◽  
Ethernet Network ◽  
Isolation Test

The measurement instrument of Full-Isolation load equivalent and parameter measurement is developed. The composing framework and operating principle are presented. The implement techniques of full-isolation test access are introduced. The load equivalent and parameter measurement instrument is made up general portable computer and test box, which accomplishes the functions of load equivalent, signal test, measurement signal graphical display and the instrument test-self. The isolation test access is consisting of analog signal test access, on-off state test access, 1553B signal test access and Ethernet network data access. By experiment the instrument functions is fulfilled and meet measurement precision.

scholarly journals Influence of Pumping Regime on Temperature Resolution in Nanothermometry

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1782
Author(s):  
Jonas Thiem ◽  
Axel Ruehl ◽  
Detlev Ristau
Keyword(s):  
High Precision ◽  
Lower Energy ◽  
Material Selection ◽  
Signal To Noise Ratio ◽  
Energy Levels ◽  
Precision Measurements ◽  
Temperature Resolution ◽  
Excitation Scheme ◽  
State Regime ◽  
Continuous Excitation

In recent years, optical nanothermometers have seen huge improvements in terms of precision as well as versatility, and several research efforts have been directed at adapting novel active materials or further optimizing the temperature sensitivity. The signal-to-noise ratio of the emission lines is commonly seen as the only limitation regarding high precision measurements. The role of re-absorption caused by a population of lower energy levels, however, has so far been neglected as a potential bottleneck for both high resolution and material selection. In this work, we conduct a study of the time dependent evolution of population densities in different luminescence nanothermometer classes under the commonly used pulsed excitation scheme. It is shown that the population of lower energy levels varies when the pump source fluctuates in terms of power and pulse duration. This leads to a significant degradation in temperature resolution, with limiting values of 0.5 K for common systems. Our study on the error margin indicates that either short pulsed or continuous excitation should be preferred for high precision measurements. Additionally, we derive conversion factors, enabling the re-calibration of currently available intensity ratio measurements to the steady state regime, thus facilitating the transition from pulse regimes to continuous excitation.

scholarly journals Squeezing metrology: a unified framework

Quantum ◽  
2020 ◽  
Vol 4 ◽  
pp. 292
Author(s):  
Lorenzo Maccone ◽  
Alberto Riccardi
Keyword(s):  
Central Limit Theorem ◽  
Limit Theorem ◽  
General Theory ◽  
Spin Squeezing ◽  
Quantum Systems ◽  
Quantum Metrology ◽  
Unified Framework ◽  
The Central Limit Theorem ◽  
Arbitrary Quantum ◽  
Classical Strategy

Quantum metrology theory has up to now focused on the resolution gains obtainable thanks to the entanglement among N probes. Typically, a quadratic gain in resolution is achievable, going from the 1/N of the central limit theorem to the 1/N of the Heisenberg bound. Here we focus instead on quantum squeezing and provide a unified framework for metrology with squeezing, showing that, similarly, one can generally attain a quadratic gain when comparing the resolution achievable by a squeezed probe to the best N-probe classical strategy achievable with the same energy. Namely, here we give a quantification of the Heisenberg squeezing bound for arbitrary estimation strategies that employ squeezing. Our theory recovers known results (e.g. in quantum optics and spin squeezing), but it uses the general theory of squeezing and holds for arbitrary quantum systems.

scholarly journals Beating the classical precision limit with spin-1 Dicke states of more than 10,000 atoms

2018 ◽  
Vol 115 (25) ◽  
pp. 6381-6385 ◽  
Author(s):  
Yi-Quan Zou ◽  
Ling-Na Wu ◽  
Qi Liu ◽  
Xin-Yu Luo ◽  
Shuai-Feng Guo ◽  
...  
Keyword(s):  
Laser Interferometer ◽  
Precision Measurements ◽  
Quantum Limit ◽  
Quantum Metrology ◽  
Standard Quantum ◽  
Standard Quantum Limit ◽  
Precision Limit ◽  
Individual Particles ◽  
Entangled Atoms ◽  
Dicke States

Interferometry is a paradigm for most precision measurements. Using N uncorrelated particles, the achievable precision for a two-mode (two-path) interferometer is bounded by the standard quantum limit (SQL), 1/N, due to the discrete (quanta) nature of individual measurements. Despite being a challenging benchmark, the two-mode SQL has been approached in a number of systems, including the Laser Interferometer Gravitational-Wave Observatory and today’s best atomic clocks. For multimode interferometry, the SQL becomes 1/[(M−1)N] using M modes. Higher precision can also be achieved using entangled particles such that quantum noises from individual particles cancel out. In this work, we demonstrate an interferometric precision of 2.42−1.29+1.76 dB beyond the three-mode SQL, using balanced spin-1 (three-mode) Dicke states containing thousands of entangled atoms. The input quantum states are deterministically generated by controlled quantum phase transition and exhibit close to ideal quality. Our work shines light on the pursuit of quantum metrology beyond SQL.

scholarly journals Parallel Offset Crack Interactions in Rock under Unloading Conditions

2019 ◽  
Vol 2019 ◽  
pp. 1-18 ◽  
Author(s):  
Zihan Zhou ◽  
Zhonghui Chen
Keyword(s):  
Numerical Simulation ◽  
Theoretical Analysis ◽  
Inclination Angle ◽  
Shear Failure ◽  
Superposition Principle ◽  
Interaction Strength ◽  
Jointed Rock ◽  
Interaction Coefficient ◽  
Open Pit ◽  
Type I

Rock slopes contain numerous nonpenetrating intermittent joints which maintain stability under excavation disturbance. The tip interaction coefficient (IC) of parallel offset double cracks in a typical rock mass under unloading conditions was calculated in this study based on the superposition principle and fracture mechanics to determine the meso-influence law of intermittent joint interaction in the slope under the action of excavation. The influence of many factors on the said interaction was also analyzed theoretically. Lateral unloading tests were conducted on rock-like specimens with parallel offset cracks in addition to RFPA2D numerical simulation and theoretical analysis. The results show that a smaller length of rock bridge or staggered distance between the cracks results in more severe and sensitive interactions at the crack tip. The Type I interaction strength of the tip of the crack is not affected by the inclination angle of the crack, but shear failure gradually weakens as the angle changes. The shear failure of the tip of the crack is more sensitive to changes in the inclination angle when the cracks are closer to each other; the change is the most intense when α is about 60°. Lateral unloading test and RFPA2D numerical simulation results are in close agreement with the theoretical analysis, which validates the theoretical results. The current study shows the interaction of the parallel offset cracks in rock under unloading conditions and is conducive to the study of the meso-failure mechanism of the jointed rock slope in an open-pit mine under the action of excavation.

scholarly journals Shortcut-to-Adiabaticity-Like Techniques for Parameter Estimation in Quantum Metrology

Entropy ◽  
2020 ◽  
Vol 22 (11) ◽  
pp. 1251
Author(s):  
Marina Cabedo-Olaya ◽  
Juan Gonzalo Muga ◽  
Sofía Martínez-Garaot
Keyword(s):  
Parameter Estimation ◽  
Quantum Mechanics ◽  
Adaptive Control ◽  
Fisher Information ◽  
Upper Bound ◽  
Point Of View ◽  
Time Dependent ◽  
Precision Measurements ◽  
Quantum Metrology ◽  
Unitary Transformations

Quantum metrology makes use of quantum mechanics to improve precision measurements and measurement sensitivities. It is usually formulated for time-independent Hamiltonians, but time-dependent Hamiltonians may offer advantages, such as a T4 time dependence of the Fisher information which cannot be reached with a time-independent Hamiltonian. In Optimal adaptive control for quantum metrology with time-dependent Hamiltonians (Nature Communications 8, 2017), Shengshi Pang and Andrew N. Jordan put forward a Shortcut-to-adiabaticity (STA)-like method, specifically an approach formally similar to the “counterdiabatic approach”, adding a control term to the original Hamiltonian to reach the upper bound of the Fisher information. We revisit this work from the point of view of STA to set the relations and differences between STA-like methods in metrology and ordinary STA. This analysis paves the way for the application of other STA-like techniques in parameter estimation. In particular we explore the use of physical unitary transformations to propose alternative time-dependent Hamiltonians which may be easier to implement in the laboratory.

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