We study cosmological perturbations in generalized Einstein scenarios and show the equivalence of inflationary observables both in the Jordan frame and the Einstein frame. In particular the consistency relation relating the tensor-to-scalar ratio with the spectral index of tensor perturbations coincides with the one in Einstein gravity, which leads to the same likelihood results in terms of inf...

We analyze the evolution of energy density fluctuations in cosmological scenarios with a mixture of cold dark matter and quintessence, in which the quintessence field is modeled by a constant equation of state. We obtain analytic expressions for the time evolution of the quintessence perturbations in models with light fields. The fluctuations behave analogously to a driven harmonic oscillator, ...

Two novel sources of variable frequency microwave energy with increased efficiency are described in this paper: a backward wave oscillator (BWO) with auto modulation of electron emission and a two-section BWO, which second section operates in the traveling wave tube (TWT) mode. In the first case, the BWO output is connected through a section of a slow-wave structure to the control electrode of ...

The frequencies of a cryogenic sapphire oscillator and a hydrogen maser are compared to set new constraints on a possible violation of Lorentz invariance. We give a detailed description of microwave resonators operating in Whispering Gallery modes and then apply it to derive explicit models for Lorentz violating effects in our experiment. Models are calculated in the theoretical framework of Ro...

This application note tracks the history of voltage-controlled oscillators (VCOs) since approximately 1910 and provides examples of VCO integration in RF ICs. It traces the technology, and discusses evolution of product performance and size. Future trends are projected. A similar version of this article appeared in the July 2002 issue of Microwaves & RF magazine.

The current state-of-the art of oscillator simulation techniques is presented. Candidate approaches for the next genertion of oscillator simulation techniques are reviewed. The method is presented which uses an efficient and robust convolution-based procedure to integrate frequency-domain modeling of a distributed linear network in transient simulation. The impulse response of the entire linear...

The behavior of arrays of coupled oscillators has been previously studied by computational solution of a set of nonlinear differential equations describing the time dependence of each oscillator in the presence of signals coupled from neighboring oscillators. The equations are sufficiently complicated in that intuitive understanding of the phenomena which arise is exceedingly difficult. We prop...

A new optical topology and signal readout strategy for a laser interferometer gravitational wave detector were proposed recently by Braginsky and Khalili. Their method is based on using a nonlinear medium inside a microwave oscillator to detect the gravitational-wave-induced spatial shift of the interferometer’s standing optical wave. This paper proposes a quantum nondemolition scheme that coul...

Optical frequency combs based on erbium-doped fiber lasers are attractive tools in precision metrology due to their inherent compactness and stability. Here we study a femtosecond Er:fiber comb that passively eliminates the carrier– envelope phase slip by difference frequency generation. Quantum statistics inside the all-fiber soliton oscillator governs its free-running performance. Active stab...

We present an optomechanical displacement transducer that relies on three cavity modes parametrically coupled to a mechanical oscillator and whose frequency spacing matches the mechanical resonance frequency. The additional resonances allow reaching the standard quantum limit at a substantially lower input power (compared to the case of a single cavity mode), as both sensitivity and quantum bac...