scholarly journals Interplay between strong and weak measurement: comparison of three experimental approaches to weak value estimation

2020 ◽  
Vol 22 (6) ◽  
pp. 065202
Author(s):  
Jan Roik ◽  
Karel Lemr ◽  
Antonín Černoch ◽  
Karol Bartkiewicz
Keyword(s):  
Weak Measurement ◽  
Weak Value ◽  
Value Estimation ◽  
Experimental Approaches

scholarly journals Weak-value amplification: state of play

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
George C. Knee ◽  
Joshua Combes ◽  
Christopher Ferrie ◽  
Erik M. Gauger
Keyword(s):  
Quantum Theory ◽  
Signal Amplification ◽  
Weak Measurement ◽  
Experimental Results ◽  
Weak Values ◽  
Theoretical Studies ◽  
Weak Value ◽  
Metrological Performance ◽  
Weak Value Amplification ◽  
Theory And Experiment

AbstractWeak values arise in quantum theory when the result of a weak measurement is conditioned on a subsequent strong measurement. The majority of the trials are discarded, leaving only very few successful events. Intriguingly those can display a substantial signal amplification. This raises the question of whether weak values carry potential to improve the performance of quantum sensors, and indeed a number of impressive experimental results suggested this may be the case. By contrast, recent theoretical studies have found the opposite: using weak-values to obtain an amplification generally worsens metrological performance. This survey summarises the implications of those studies, which call for a reappraisal of weak values’ utility and for further work to reconcile theory and experiment.

Detecting momentum weak value: Shack–Hartmann versus weak measurement wavefront sensor

2021 ◽  
Author(s):  
Yi Zheng ◽  
Mu Yang ◽  
Zheng-Hao Liu ◽  
Jin-Shi Xu ◽  
Chuanfeng Li ◽  
...  
Keyword(s):  
Weak Measurement ◽  
Wavefront Sensor ◽  
Weak Value

scholarly journals Anomalous Weak Values Without Post-Selection

Quantum ◽  
2019 ◽  
Vol 3 ◽  
pp. 194 ◽  
Author(s):  
Alastair A. Abbott ◽  
Ralph Silva ◽  
Julian Wechs ◽  
Nicolas Brunner ◽  
Cyril Branciard
Keyword(s):  
Quantum System ◽  
Weak Measurement ◽  
Weak Values ◽  
Weak Measurements ◽  
Weak Value ◽  
Average Value ◽  
Causal Structures

A weak measurement performed on a pre- and post-selected quantum system can result in an average value that lies outside of the observable's spectrum. This effect, usually referred to as an ``anomalous weak value'', is generally believed to be possible only when a non-trivial post-selection is performed, i.e., when only a particular subset of the data is considered. Here we show, however, that this is not the case in general: in scenarios in which several weak measurements are sequentially performed, an anomalous weak value can be obtained without post-selection, i.e., without discarding any data. We discuss several questions that this raises about the subtle relation between weak values and pointer positions for sequential weak measurements. Finally, we consider some implications of our results for the problem of distinguishing different causal structures.

Interference-based weak-value amplification effects in post-selected weak measurement

Laser Physics ◽  
2021 ◽  
Vol 31 (9) ◽  
pp. 095201
Author(s):  
Yurong Liu ◽  
Zhaoxue Li ◽  
Yucheng Ye ◽  
Junhao Ye ◽  
Zhiyou Zhang
Keyword(s):  
Weak Measurement ◽  
Weak Value ◽  
Weak Value Amplification

Weak Measurements in Nano-optics

2020 ◽  
Vol 5 (3) ◽  
pp. 191-213
Author(s):  
Niladri Modak ◽  
Ankit K. Singh ◽  
Shyamal Guchhait ◽  
Athira BS ◽  
Mandira Pal ◽  
...  
Keyword(s):  
High Precision ◽  
Spectral Response ◽  
Weak Measurement ◽  
Optical Systems ◽  
Physical Parameters ◽  
Weak Measurements ◽  
Temporal Shift ◽  
Measuring Device ◽  
Weak Value ◽  
Weak Value Amplification

Background: Weak measurement involves weak coupling between the system and the measuring device (pointer) enables large amplification and high precision measurement of small physical parameters. The outcome of this special measurement procedure involving nearly mutually orthogonal pre- and post-selection of states in such weakly interacting systems leads to weak value that can become exceedingly large and lie outside the eigenvalue spectrum of the measured observable. This unprecedented ability of weak value amplification of small physical parameters has been successfully exploited for various metrological applications in the optical domain and beyond. Even though it is a quantum mechanical concept, it can be understood using the classical electromagnetic theory of light and thus can be realized in classical optics. Objective: Here, we briefly review the basic concepts of weak measurement and weak value amplification, provide illustrative examples of its implementation in various optical domains. The applications involve measuring ultra-sensitive beam deflections, high precision measurements of angular rotation, phase shift, temporal shift, frequency shift and so forth, and expand this extraordinary concept in the domain of nano-optics and plasmonics. Methods: In order to perform weak value amplification, we have used Gaussian beam and spectral response as the pointer subsequently. The polarization state associated with the pointer is used as pre and post-selection device. Results: We reveal the weak value amplification of sub-wavelength optical effects namely the Goos-Hänchen shift and the spin hall shift. Further, we demonstrate weak measurements using spectral line shape of resonance as a natural pointer, enabling weak value amplification beyond the conventional limit, demonstrating natural weak value amplification in plasmonic Fano resonances and so forth. The discussed concepts could have useful implications in various nano-optical systems to amplify tiny signals or effects. Conclusion: The emerging prospects of weak value amplification towards the development of novel optical weak measurement devices for metrological applications are extensively discussed.

Learned Placebo Effects in the Immune System

2014 ◽  
Vol 222 (3) ◽  
pp. 148-153 ◽  
Author(s):  
Sabine Vits ◽  
Manfred Schedlowski
Keyword(s):  
Nervous System ◽  
Immune System ◽  
Associative Learning ◽  
Placebo Response ◽  
Immunosuppressive Drug ◽  
Immune Functions ◽  
Placebo Effects ◽  
New Therapeutic Approaches ◽  
Biological Variables ◽  
Experimental Approaches

Associative learning processes are one of the major neuropsychological mechanisms steering the placebo response in different physiological systems and end organ functions. Learned placebo effects on immune functions are based on the bidirectional communication between the central nervous system (CNS) and the peripheral immune system. Based on this “hardware,” experimental evidence in animals and humans showed that humoral and cellular immune functions can be affected by behavioral conditioning processes. We will first highlight and summarize data documenting the variety of experimental approaches conditioning protocols employed, affecting different immunological functions by associative learning. Taking a well-established paradigm employing a conditioned taste aversion model in rats with the immunosuppressive drug cyclosporine A (CsA) as an unconditioned stimulus (US) as an example, we will then summarize the efferent and afferent communication pathways as well as central processes activated during a learned immunosuppression. In addition, the potential clinical relevance of learned placebo effects on the outcome of immune-related diseases has been demonstrated in a number of different clinical conditions in rodents. More importantly, the learned immunosuppression is not restricted to experimental animals but can be also induced in humans. These data so far show that (i) behavioral conditioned immunosuppression is not limited to a single event but can be reproduced over time, (ii) immunosuppression cannot be induced by mere expectation, (iii) psychological and biological variables can be identified as predictors for this learned immunosuppression. Together with experimental approaches employing a placebo-controlled dose reduction these data provide a basis for new therapeutic approaches to the treatment of diseases where a suppression of immune functions is required via modulation of nervous system-immune system communication by learned placebo effects.

The Factors Influencing Tourist Visitations Number in Curug Silawe

2019 ◽  
Vol 2 (3) ◽  
pp. 553-561
Author(s):  
Novian Hangga Prakosa ◽  
Fafurida Fafurida
Keyword(s):  
Economic Value ◽  
Consumer Surplus ◽  
Sampling Technique ◽  
Travel Cost ◽  
Analysis Tool ◽  
Literature Study ◽  
Factors Influencing ◽  
Negative Effect ◽  
Value Estimation ◽  
Positive Effect

The purposes of this research are to identify the influence of travel cost, income, distance, access, facilities, natural beautiness, and age on the number of individual visits to Curug Silawe and to estimate the economic value of Curug Silawe through individual travel cost method. The population in this study are tourists that visited Curug Silawe with sample of 98 respondents taken by the quota accidental sampling technique. The data collection method used are literature study and questionnaire. The analysis tool used are OLS linear regression and economic value estimation. The results showed the variables that influence the number of individual visits to Curug Silawe are income, distance and age. Income and age has a positive effect. While distance has a negative effect. The economic value of Curug Silawe reached IDR 1,109,930,140.48 per year. This value is obtained from consumer surplus obtained per individual per year of IDR 308,656.88. Tujuan dari penelitian ini adalah untuk mengidentifikasi pengaruh biaya perjalanan, pendapatan, jarak, akses, fasilitas, keindahan alam, dan usia pada jumlah kunjungan individu ke Curug Silawe dan untuk memperkirakan nilai ekonomi Curug Silawe melalui metode biaya perjalanan individu . Populasi dalam penelitian ini adalah wisatawan yang berkunjung ke Curug Silawe dengan sampel 98 responden yang diambil dengan teknik quota accidental sampling. Metode pengumpulan data yang digunakan adalah studi literatur dan kuesioner. Alat analisis yang digunakan adalah regresi linear OLS dan estimasi nilai ekonomi. Hasil penelitian menunjukkan variabel yang mempengaruhi jumlah kunjungan individu ke Curug Silawe adalah pendapatan, jarak dan usia. Penghasilan dan usia memiliki efek positif. Sedangkan jarak memiliki efek negatif. Nilai ekonomi Curug Silawe mencapai Rp1.109.930.140,48 per tahun. Nilai ini diperoleh dari surplus konsumen yang diperoleh per individu per tahun sebesar Rp308.656,88.

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