Precision frequency measurements with interferometric weak values

We demonstrate an experiment which utilizes a Sagnac interferometer to measure a change in optical frequency of 129 kHz per root Hz with only 2 mW of continuous wave, single mode input power. We describe the measurement of a weak value and show how even higher frequency sensitivities may be obtained over a bandwidth of several nanometers. This technique has many possible applications, such as precision relative frequency measurements and laser locking without the use of atomic lines.Comment: 4 pages, 3 figures, published in PR

Ultrasensitive Beam Deflection Measurement via Interferometric Weak Value Amplification

We report on the use of an interferometric weak value technique to amplify very small transverse deflections of an optical beam. By entangling the beam's transverse degrees of freedom with the which-path states of a Sagnac interferometer, it is possible to realize an optical amplifier for polarization independent deflections. The theory for the interferometric weak value amplification method is presented along with the experimental results, which are in good agreement. Of particular interest, we measured the angular deflection of a mirror down to 560 femtoradians and the linear travel of a piezo actuator down to 20 femtometers

Optimizing the Signal to Noise Ratio of a Beam Deflection Measurement with Interferometric Weak Values

The amplification obtained using weak values is quantified through a detailed investigation of the signal to noise ratio for an optical beam deflection measurement. We show that for a given deflection, input power and beam radius, the use of interferometric weak values allows one to obtain the optimum signal to noise ratio using a coherent beam. This method has the advantage of reduced technical noise and allows for the use of detectors with a low saturation intensity. We report on an experiment which improves the signal to noise ratio for a beam deflection measurement by a factor of 54 when compared to a measurement using the same beam size and a quantum limited detector

Continuous phase amplification with a Sagnac interferometer

We describe a weak value inspired phase amplification technique in a Sagnac interferometer. We monitor the relative phase between two paths of a slightly misaligned interferometer by measuring the average position of a split-Gaussian mode in the dark port. Although we monitor only the dark port, we show that the signal varies linearly with phase and that we can obtain similar sensitivity to balanced homodyne detection. We derive the source of the amplification both with classical wave optics and as an inverse weak value.Comment: 5 pages, 4 figures, previously submitted for publicatio

NFAT5 genes are part of the osmotic regulatory system in Atlantic salmon (Salmo salar)

Acknowledgements This study was supported by a grant from the Biotechnology and Biological Sciences Research Council (BBSRC, BB/H008063/1), UK to DGH and SAM. Funding also came from Research Council Norway for project number 241016 for DGH and EJ. This work was carried out as part of a PhD thesis funded by the Marine Alliance of Science and Technology Scotland (MASTS).Peer reviewedPublisher PD

Interferometric weak value deflections: quantum and classical treatments

We derive the weak value deflection given in a paper by Dixon et al. (Phys. Rev. Lett. 102, 173601 (2009)) both quantum mechanically and classically. This paper is meant to cover some of the mathematical details omitted in that paper owing to space constraints

Conceptualizing Care Continua: Lessons from Hiv, Hepatitis C virus, Tuberculosis and implications for the Development of Improved Care and Prevention Continua

Background: To examine the application of continuum models to tuberculosis, HIV, and other conditions; to theorize the concept of continua; and to learn lessons that could inform the development of improved care and prevention continua as public health metrics. Methods: An analytic review of literature drawn from several fields of health care. Results: The continuum construct is now part of public health evaluation systems for HIV, and is increasingly used in public health and the medical literature. Issues with the comparability and optimal design of care continuum models have been raised, and their methodologic and theoretic underpinnings and scope of focus have been underaddressed. Review of relevant publications suggests that a key limitation of current models is their lack of measures reflecting incidence and mortality. Issues relating to continua data being longitudinal or cross-sectional, definition of numerators and denominators for each step, data sources, measures of timeliness of step completion, theoretic models to facilitate inferences of causes of care continuum gaps, how measures of prevention efforts, reinfection/relapses, and interactions of continua for co-occurring comorbidities should be reflected, and how analyses of differences in retention over time, across geographic regions, and in response to interventions should be conducted are critical to the development of sound care and prevention continuum models. Conclusion: Lessons learned from the application of continuum models to HIV and other conditions suggest that the application of well-formulated constructs of care and prevention continua, that depict, in well defined, standardized steps, incidence and mortality, along with degrees of and time to screening, engagement in care and prevention, treatment and treatment outcomes, including relapse or reinfection, may be vital tools in evaluating intervention and program outcomes, and in improving population health and population health metrics for a wide range conditions

Stochastic Simulation of Daily Rainfall

The design of many water resources projects requires knowledge of possible long-term rainfall patterns. In this project a stochastic model based on a first order Markov chain was developed to simulate daily rainfall at a point. The model is applicable to any point in Kentucky (and other areas with similar rainfall patterns). The model in its present form is useful in providing rainfall inputs into hydrologic models for designing water supply facilities and other water resources systems. The model uses historical rainfall data to estimate the Markov transitional probabilities. A separate matrix is estimated for each month of the year. In this report 7 X 7 transitional probability matrices were used. The model is capable of simulating a daily rainfall record of any length based on the estimated transitional probabilities and frequency distributions of rainfall amounts within each class interval. The simulated data has statistical properties similar to historical data

Situational Awareness and Public Wi-Fi Users\u27 Self-Protective Behaviors

Accessing public Wi-Fi networks can be as dangerous as it is convenient. People who access a public Wi-Fi network should engage in self-protective behaviors to keep their data safe from malicious actors on the same network as well as persons looking over their shoulder, literally and proverbially. Using two independent research designs, we examined under what circumstances were people more likely to access an unsecured Wi-Fi network and engage in risky behavior on these networks. Findings from the first study, based on survey data, reveal that people who are more situationally aware are less likely to access personal accounts on public Wi-Fi, and more likely to cover their screen to prevent others from viewing personal information. Additionally, findings show that people with higher computer proficiencies are less likely to engage with public Wi-Fi. For the second study, our research team designed and deployed honeypot Wi-Fi networks. We found that people are more likely to access these unsecured, rogue networks in establishments with fewer on-duty employees and that do not offer legitimate public Wi-Fi. Additionally, the number of on-duty employees is associated with an increase in physical security behaviors, such as concealing a screen. We conclude by discussing how these findings can aid in reducing susceptibility to online victimization

The Restrictive Deterrent Effect of Warning Messages Sent to Active Romance Fraudsters: An Experimental Approach

Victims of romance fraud experience both a financial and emotional burden. Although multiple studies have offered insight into the correlates of perpetration and victimization, no known study has examined if, and how, romance fraud can be curtailed. The current study uses a randomized experimental design to test the restrictive deterrent effect of warning messages sent to romance fraudsters via email. We find that active romance fraudsters who receive a deterrence message, instead of non-deterrence messages, respond at a lower rate; and, among those who respond, use fewer words and have a lower probability of seeking reply without denying wrongdoing. The results provide support for restrictive deterrence in cyberspace. Theoretical and policy implications are discussed