Advances in Physics These reviews are sometimes complemented by a "Perspectives" section which publishes shorter articles that may be controversial, with the intention of stimulating debate. The intended audience consists of physicists, materials scientists, and physical chemists working in universities, industry, and research institutes. Broad, interdisciplinary coverage includes topics ranging from condensed matter physics, statistical mechanics, quantum information, cold atoms, and soft matter physics to biophysics. The impact factor for "Advances in Physics" 18.062 in 2013, ranking it first in the discipline of condensed matter physics. This journal is indexed in the following databases: Advances in Physics Advances in Physics is a bimonthly
History of variational principles in physics History of variational principles in physics A variational principle in physics is an alternative method for determining the state or dynamics of a physical system, by identifying it as an extremum (minimum, maximum or saddle point) of a function or functional. This article describes the historical development of such principles. Variational principles are found among earlier ideas in surveying and optics. The rope stretchers of ancient Egypt stretched corded ropes between two points to measure the path which minimized the distance of separation, and Claudius Ptolemy, in his Geographia (Bk 1, Ch 2), emphasized that one must correct for "deviations