[seminar] Posdsjetnik na sutrašnji seminar na IF-u srijeda, 06.11.2019. u 15:00h - dr. Anže Lošdorfer Božić

[Damir Dominko]

****

*Institut za fiziku, Bijenička cesta 46,*

*predavaonica u zgradi Mladen Paić*

**srijeda, 06.11.2019. u 15:00 sati*
*
**
*Hyperuniformity and classification of order on the sphere*
*Dr. Anže Lošdorfer Božić*
*Institut Jožef Stefan, Ljubljana, Slovenija*
Understanding how particles are arranged on the surface of a sphere is 
not only central to numerous physical, biological, soft matter, and 
materials systems but also finds applications in computational problems, 
approximation theory, and analysis of geophysical and meteorological 
measurements. Objects that lie on a sphere experience constraints that 
are not present in Euclidean space and that influence both how the 
particles can be arranged as well as their statistical properties. These 
constraints, coupled with the curved geometry, require a careful 
extension of quantities used for the analysis of particle distributions 
in Euclidean space to distributions confined to the surface of a sphere. 
I will introduce a framework designed to analyze and classify structural 
order and disorder in particle distributions constrained to the sphere. 
The classification is based on the concept of hyperuniformity, which was 
first introduced 15 years ago and since then studied extensively in 
Euclidean space, yet has only very recently been considered also for 
spherical surfaces. It employs a generalization of the structure factor 
on the sphere, related to the power spectrum of the corresponding 
multipole expansion of particle density distribution. The spherical 
structure factor is shown to couple with cap number variance, a measure 
of density variations at different scales, allowing us to analytically 
derive different forms of the variance pertaining to different types of 
distributions. Based on these forms, we construct a classification of 
hyperuniformity for scale-free particle distributions on the sphere and 
show how it can be extended to include other distribution types as well. 
I will demonstrate that hyperuniformity on the sphere can be defined 
either through a vanishing spherical structure factor at low multipole 
numbers or through a scaling of the cap number variance—in both cases 
extending the Euclidean definition, while at the same time pointing out 
crucial differences. The presented work provides a comprehensive tool 
for detecting global, long-range order on spheres and for the analysis 
of spherical computational meshes, biological and synthetic spherical 
assemblies, and ordering phase transitions in spherically distributed 
particles.

******Voditelji seminara IF-a: Ivan Balog <mailto:balog at ifs.hr> i Damir 
Dominko <mailto:ddominko at ifs.hr>**

-- 
Remember, remember the 6th of November

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.phy.pmf.unizg.hr/pipermail/seminar/attachments/20191105/1680f434/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: jkjcgogbogfcofam.png
Type: image/png
Size: 25435 bytes
Desc: not available
URL: <http://www.phy.pmf.unizg.hr/pipermail/seminar/attachments/20191105/1680f434/attachment-0001.png>
-------------- next part --------------
BEGIN:VCALENDAR
PRODID:-//Google Inc//Google Calendar 70.9054//EN
VERSION:2.0
CALSCALE:GREGORIAN
METHOD:PUBLISH
X-WR-TIMEZONE:Europe/Zagreb
BEGIN:VEVENT
DTSTART:20191108T140000Z
DTEND:20191108T150000Z
DESCRIPTION:
LOCATION:
SEQUENCE:0
STATUS:CONFIRMED
SUMMARY:Seminar na IF-u srijeda, 06.11.2019. u 15:00h - dr. Anže Lošdorfer Božić
TRANSP:OPAQUE
END:VEVENT
END:VCALENDAR