Field theoretical models of nonsingular compact objects

doctoral thesis

• Title (croatian): Modeli nesingularnih kompaktnih objekata u teoriji polja
• Author: Anja Marunović; MBZ: 15238890128
• Mentor: Dubravko Horvat (mentor)
• Committee member: Nevenko Bilić (predsjednik povjerenstva)
• Committee member: Dubravko Horvat (član povjerenstva)
• Committee member: Vernesa Smolčić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Science; (Department of Physics); Zagreb
• Defense date and country: 2013-06-19, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Physics
• Universal decimal classification (UDC): 53 - Physics

Abstract

A method for testing linear stability of the anisotropic structures with the de Sitter interior is proposed. It was shown that from a lagrangian, field-theoretic description, one can obtain stable, compact astrophysical objects that at large distances behave as black hole mimickers but, unlike black holes, possess neither curvature singularities nor event horizons. Two models are presented: 1) lagrangian of the scalar field which is nonminimally coupled to gravity (the so called boson stars), and 2) lagrangian of the multi-component scalar field that generates a topologically stable global monopole (the so called D (defect) – stars). In the first model, a dark energy like stars are obtained, while in the second model an object with large compactness is obtained and as such represents a good black hole mimicker.

Abstract (croatian)

Predložena je metoda za testiranje linearne stabilnosti anizotropnih struktura s de Sitterovom jezgrom i primijenjena na gravastarske objekte. Pokazano je da se iz mikroskopskog pristupa, tj. unutar klasične teorije polja opisane lagran žijanom i (samo)interagirajućim poljima, mogu konstruirati stabilni, visoko kompaktni astrofizički objekti koji, za razliku od crnih rupa, ne posjeduju singularitet u središtu niti horizont dogadaja na Schwarzschildovom radijusu, a čiji je potpis vanjskom promatraču (u daljini) usporediv s potpisom crnih rupa. Predstavljena su dva modela: 1) lagranžijan skalarnog polja neminimalno vezanog na gravitaciju (tzv. bozonske zvijezde), te 2) lagranžijan više-komponentnog skalarnog polja koji generira topološki stabilan globalni monopol (tzv. D (defektne) - zvijezde). U prvom modelu su dobivene zvijezde slične zvijezdama tamne energije, a u drugom modelu su dobiveni objekti koji zbog jako visoke kompaktnosti predstavljaju dobru alternativu crnoj rupi.

• Keywords: gravastar; boson star; global monopole; nonminimal coupling; black hole mimicker
• Keywords (croatian): gravastar; bozonska zvijezda; globalni monopol; neminimalno vezanje; alternativa crnoj rupi
• Language: english
• URN:NBN: urn:nbn:hr:217:766282
• Study programme: Title: Physics; Study programme type: university; Study level: postgraduate; Academic / professional title: doktor/doktorica znanosti, područje prirodnih znanosti, polje fizika (doktor/doktorica znanosti, područje prirodnih znanosti, polje fizika)
• Type of resource: Text
• Extent: 111 str.
• File origin: Born digital
• Access conditions: Open access
• Created on: 2017-08-23 09:28:08