Universal Sound Absorption in Amorphous Solids: A Theory of Elastically Coupled Generic Blocks

Glasses are known to exhibit quantitative universalities at low temperatures, the most striking of which is the ultrasonic attenuation coefficient 1/Q. In this work we develop a theory of coupled generic blocks with a certain randomness property to show that universality emerges essentially due to the interactions between elastic blocks, regardless of their microscopic nature.Comment: (Revised) 16 pages, 2 figures. To appear in Journal of Non-Crystalline Solid

When Models Interact with their Subjects: The Dynamics of Model Aware Systems

A scientific model need not be a passive and static descriptor of its subject. If the subject is affected by the model, the model must be updated to explain its affected subject. In this study, two models regarding the dynamics of model aware systems are presented. The first explores the behavior of "prediction seeking" (PSP) and "prediction avoiding" (PAP) populations under the influence of a model that describes them. The second explores the publishing behavior of a group of experimentalists coupled to a model by means of confirmation bias. It is found that model aware systems can exhibit convergent random or oscillatory behavior and display universal 1/f noise. A numerical simulation of the physical experimentalists is compared with actual publications of neutron life time and {\Lambda} mass measurements and is in good quantitative agreement.Comment: Accepted for publication in PLoS-ON

Universal sound attenuation in amorphous solids at low-temperatures

Disordered solids are known to exhibit quantitative universalities at low temperatures, the most striking of which is the ultrasonic attenuation coefficient 1/Q(??). The established theory of tunneling two state systems (TTLS) in its original form (i.e. without extra fitting functions and parameters) is unable to explain this universality. While the TTLS model can be modified, particularly by including long range phonon induced interactions to explain the universal value of 1/Q, (a) it is not clear that the essential features of the original model that has been successful in explaining the experimental data is preserved, and (b) even if it is, it is not clear that the postulates of the original model remain necessary. The purpose of this study is to derive the universal acoustic absorption and related quantities observed in disordered solids by starting from a many-body quantum theory of unspecified amorphous blocks that mutually interact through the strain field. Based on very generic assumptions and having no adjustable fitting parameters, the frequency and initial state averaged macroscopic attenuation of a group of interacting disordered blocks is calculated in the low temperature regime (T<<??) by a novel "trace method???, which then is iterated up-to experimental length scales through a real space renormalization group approach. Then using a heuristic second-order perturbation argument, the frequency dependence of 1/Q(??) is found, and combined with the previous result to yield the observed universal values in the MHz-Ghz range of frequencies. It is concluded that the TTLS postulates are not necessary in order to explain, at least the thermal conductivity, velocity shift and sound attenuation of disordered media in the low temperature regime

Spatial Self-Organization Resolves Conflicts Between Individuality and Collective Migration

Files containing data for each figure of the paper in MATLAB .fig file format from which the data points can be extracted. <br