Overview: Unsolved problems of noise and fluctuations

Abstract

Noise and fluctuations are at the seat of all physical phenomena. It is well known that, in linear systems, noise plays a destructive role. However, an emerging paradigm for nonlinear systems is that noise can play a constructive role-in some cases information transfer can be optimized at nonzero noise levels. Another use of noise is that its measured characteristics can tell us useful information about the system itself. Problems associated with fluctuations have been studied since 1826 and this Focus Issue brings together a collection of articles that highlight some of the emerging hot unsolved noise problems to point the way for future research. © 2001 American Institute of Physics. ͓DOI: 10.1063/1.1398543͔The study of fluctuations crosses many discipline boundaries as ''noise'' is a ubiquitous phenomenon. Noise is traditionally thought of as an unwanted effect that degrades the performance of a system. However, the emerging paradigm now recognizes that noise can play both a destructive or constructive role, depending on the circumstances. Thus there is now an intense interest in noise in many biological, physical, and other systems. The collection of papers in this Focus Issue examines open problems and debates surrounding the role of noise in both chaotic and nonchaotic systems. In this Overview we introduce the concepts of stochastic resonance, Brownian ratchets, 1Õf noise and vacuum fluctuations, and some problems surrounding them.

Randomized switching in the two-envelope problem

“…Both games of chance and games of strategy are currently finding increasing applications in physics (Abbott 2001;Abbott et al 2002) and econophysics (Johnson et al 2003).…”

A Review of Parrondo's Paradox

“…[12,[16][17][18][19][20]. However, Parrondo's games have gained particular attention because: (i) they are the first game-theoretic realization of such processes, (ii) in their original form, they can be directly mapped onto the workings of a flashing Brownian ratchet and (iii) the effect is strikingly counterintuitive and relatively simple to analyze.…”

Universal inverse power-law distribution for temperature and rainfall in the UK region

“…Noise and fluctuations are ubiquitous to all physical phenomena and is a multidisciplinary field of study (Abbott 2001). The roots of noise research trace back to the Scottish botanist Robert Brown who observed fluctuating pollen on the surface of a film of water in 1822.…”

“…The roots of noise research trace back to the Scottish botanist Robert Brown who observed fluctuating pollen on the surface of a film of water in 1822. The first unsolved noise problem was to find out the origin of Brownian motion (Abbott 2001).…”