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Anharmonic oscillators, such as the pendulum, are widely used for precision measurement and to model nonlinear phenomena. Fluctuations-such as thermal or quantum mechanical noise-can excite random motion in the oscillator, ultimately imposing a bound on measurement sensitivity. In systems where equilibrium is established with the environment, noise-induced broadening scales with the intensity of fluctuations. But how does noise affect an out-of-equilibrium oscillator where the motion is varied faster than energy is exchanged with the environment? We create such a scenario by applying fast, frequency-chirped voltage pulses to a nonlinear superconducting resonator where the ring-down time is longer than the pulse duration. Under these conditions, the circuit oscillates with either small or large amplitude depending on whether the drive voltage is below or above a critical value. This phenomenon, known as autoresonance, is significant in planetary dynamics and plasmas, enables the excitation of particles in cyclotron accelerators and may even be used to detect the state of a quantum two-level system. Our results show that the amplitude of fluctuations determines the initial conditions of such a non-equilibrium oscillator and does not affect its time evolution. [ABSTRACT FROM AUTHOR]

Human exposure to man-made radiation sources is largely due to diagnostic X-ray examinations, and the overall effect depends on the frequency and close of every single procedure. This paper deals with the evaluation of the frequencies of different types of examinations. As the method of investigation in the former German Democratic Republic (GDR) the consumption of X-ray films combined with the statistical registration of all examinations in 3 of 15 districts of the GDR was used for the basic estimation. In former West Germany (FRG) we used data from the cost-covering institutions and from the diagnosis and therapy index of a commercial data bank. As a result in the GDR we discovered, for 17 million people. 13 million examinations, plus .5 million photofluorographs of the lung and 2.5 million dental films. In the FRG the frequency was, for 65 million people, almost 99 million examinations, including 17.5 million dental films. The most frequent X-ray examinations in both parts of the country involve the skeletal system, followed by examinations of the lung. In Germany the examination frequency is high despite the rather broad use of alternative diagnostic methods. A more strictly controlled indication could reduce the number of examinations without loss in quality. [ABSTRACT FROM AUTHOR]

In the continuous pursuit of enhancing the sensitivity of nanophotonic biosensors by leveraging phase phenomena, a recent development involved the engineering of an atomically thin Ge 2 Sb 2 Te 5 layer on a silver nanofilm to generate large Goos-Hänchen-shifts associated with phase singularities. The resulting detection limit reached ~7 × 10 -7 RIU., (© 2024. The Author(s).)

Research toward photonic biosensors for point-of-care applications and personalized medicine is driven by the need for high-sensitivity, low-cost, and reliable technology. Among the most sensitive modalities, interferometry offers particularly high performance, but typically lacks the required operational simplicity and robustness. Here, we introduce a common-path interferometric sensor based on guided-mode resonances to combine high performance with inherent stability. The sensor exploits the simultaneous excitation of two orthogonally polarized modes, and detects the relative phase change caused by biomolecular binding on the sensor surface. The wide dynamic range of the sensor, which is essential for fabrication and angle tolerance, as well as versatility, is controlled by integrating multiple, tuned structures in the field of view. This approach circumvents the trade-off between sensitivity and dynamic range, typical of other phase-sensitive modalities, without increasing complexity. Our sensor enables the challenging label-free detection of procalcitonin, a small protein (13 kDa) and biomarker for infection, at the clinically relevant concentration of 1 pg mL -1 , with a signal-to-noise ratio of 35. This result indicates the utility for an exemplary application in antibiotic guidance, and opens possibilities for detecting further clinically or environmentally relevant small molecules with an intrinsically simple and robust sensing modality., Competing Interests: Conflict of interestThe authors declare that they have no conflict of interest., (© The Author(s) 2020.)