Implementacija rekurzivne metode za Greenove funkcije u paralelnom kvantnotransportnom simulatoru

master's thesis

• Title (english): Implementation of the recursive method for calculating Green's functions in the parallel quantum transport simulator
• Author: Tin Župančić
• Mentor: Mirko Poljak (mentor)
• Committee member: Mirko Poljak (predsjednik povjerenstva)
• Committee member: Vladimir Čeperić (član povjerenstva)
• Committee member: Tomislav Marković (član povjerenstva)
• Granter: University of Zagreb; Faculty of Electrical Engineering and Computing; Zagreb
• Defense date and country: 2022-07-07, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Computing

Abstract

NEGF formalizam moćan je teorijski okvir za računanje kvantnog transporta i analizu nanostruktura, ali uključuje resursno zahtjevan izračun inverza velikih matrica radi dobivanja retardirane Greenove funkcije. Rekurzivna metoda može se koristiti za izračun Greenove funkcije uz izvršenje znatno manjeg broja računskih operacija, bez izračuna punog inverza. Ovaj rad opisuje implementaciju rekurzivne metode u postojećem kvantnotransportnom simulatoru SPARQS. Performanse implementacije testirane su simulacijama bizmutenskih nanovrpci različitih dimenzija na klasteru za paralelno računanje. Izmjerena vremena izvršavanja za rekurzivnu metodu bila su značajno manja u svim testiranim slučajevima, s promatranim ubrzanjima na razini od nekoliko puta do nekoliko redova veličine boljim u usporedbi sa standardnom metodom.

Abstract (english)

NEGF formalism is a powerful framework for quantum transport and for the analysis of nanostructures, but requires a resource-consuming inversion calculation of large matrices to obtain the retarded Green’s functions. Recursive method can be employed to calculate the Green’s function with significantly less operations, evading the full matrix inversion. This paper describes the implementation of the method into an existing quantum transport simulator SPARQS. Performance of the implementation is tested on a parallel computing cluster by simulating bismuthene nanoribbons of various sizes. Observed execution times for the recursive method were lower in all cases, with execution acceleration ranging from several times to several orders of magnitude compared to the standard method.

• Keywords: kvantni transport; Greenova funkcija; NEGF; rekurzivna metoda za Greenove funkcije; simulacija; paralelno računanje; Intel MKL; MPI
• Keywords (english): quantum transport; Green’s function; NEGF; recursive Green’s function method; simulation; parallel computing; Intel MKL; MPI
• Language: croatian
• URN:NBN: urn:nbn:hr:168:618036
• Study programme: Title: Computing; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka računarstva (magistar/magistra inženjer/inženjerka računarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2023-01-13 16:33:34