BEFORE THE BANG

Generating Ekpyrotic Curvature Perturbations Before the Big Bang

We analyze a general mechanism for producing a nearly scale-invariant spectrum of cosmological curvature perturbations during a contracting phase preceding a big bang, that can be entirely described using 4d effective field theory. The mechanism, based on first producing entropic perturbations and then converting them to curvature perturbations, can be naturally incorporated in cyclic and ekpyr...

9 Quantum kinetic equation before and after Big Bang

The energy dissipation in a gas of structured objects, e.g. molecules, is considered in density matrix formalism. It is shown that the macroscopic irreversibility of the kinetic processes can be considered as a consequence of the microscopic operator ordering. Our approach is free of any special assumptions on the space-time geometry, except for the general causality assumptions, so it can be a...

The Bang-Bang Funnel Controller (long version)

A bang-bang controller is proposed which is able to ensure reference signal tracking with prespecified time-varying error bounds (the funnel) for nonlinear systems with relative degree one or two. For the design of the controller only the knowledge of the relative degree is needed. The controller is guaranteed to work when certain feasibility assumptions are fulfilled, which are explicitly give...

The Big Bang is bang on.

Modeling of Jitter Characteristics for the Second Order Bang-Bang CDR

Bang-Bang clock and data recovery (BBCDR) circuits are hard nonlinear systems due to the nonlinearity introduced by the binary phase detector (BPD). The specification of the CDR frequency response is determined by jitter tolerance and jitter transfer. In this paper, jitter transfer and jitter tolerance of the second-order BBCDR are characterized by formulating the time domain waveforms. As a re...