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<TITLE>Seminar: Tomislav Prokopec (cetvrtak, 11.10., IRB, 14:00 sati c.t) </TITLE>
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<P DIR=LTR><SPAN LANG="en-gb"><FONT FACE="Times New Roman"></FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"> <FONT SIZE=2 FACE="Courier New">INSTITUT "Ruder Boskovic"</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New"></FONT> <FONT SIZE=2 FACE="Courier New">ZAVOD ZA TEORIJSKU FIZIKU</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New"></FONT> <FONT SIZE=2 FACE="Courier New">Bijenicka c. 54, Zagreb, Hrvats</FONT><FONT SIZE=2 FACE="Courier New">ka</FONT></SPAN></P>
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<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New"></FONT> <FONT SIZE=2 FACE="Courier New"> ----------------------------------------------------------------------</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New"> </FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New"></FONT> <FONT SIZE=2 FACE="Courier New"> SEMINAR TEORIJSKE FIZIKE</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New"></FONT> <FONT SIZE=2 FACE="Courier New"> (Zajednicki seminari Zavoda za fiziku PMF-a i</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New"></FONT> <FONT SIZE=2 FACE="Courier New"> Zavoda za teorijsku fiziku IRB-a)</FONT></SPAN></P>
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<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New"></FONT> <FONT SIZE=2 FACE="Courier New"> ----------------------------------------------------------------------</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New"></FONT> <FONT SIZE=2 FACE="Courier New"> </FONT></SPAN></P>
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<P DIR=LTR><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">Tomislav Prokopec</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"></SPAN></P>
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<P DIR=LTR><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">Utrecht University</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"></SPAN></P>
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<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New"> </FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">"</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">Symmetry breaking in de Sitter space</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">"</FONT></SPAN></P>
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<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New"></FONT> <FONT SIZE=2 FACE="Courier New"> Datum:</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"> <FONT SIZE=2 FACE="Courier New">11</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">.</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"> <FONT SIZE=2 FACE="Courier New">listopada</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New"></FONT> <FONT SIZE=2 FACE="Courier New">20</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">12</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">. (</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">cetvrtak</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">)</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New"></FONT> <FONT SIZE=2 FACE="Courier New"> Vrijeme: 1</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">4</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">:0</FONT><FONT SIZE=2 FACE="Courier New">0 sati c.t.</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New"></FONT> <FONT SIZE=2 FACE="Courier New"> Mjesto: IRB, predavaonica I krila</FONT></SPAN></P>
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<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New"></FONT> <FONT SIZE=2 FACE="Courier New"> Sazetak:</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New"> </FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New"></FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"> <FONT SIZE=2 FACE="Courier New">We consider an O(N) symmetric scalar</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"> <FONT SIZE=2 FACE="Courier New">fi</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">eld model in the mean</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"> <FONT SIZE=2 FACE="Courier New">fi</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">eld approximation a</FONT><FONT SIZE=2 FACE="Courier New">nd</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">show that the symmetry can be broken (down to O(N-1)) in de Sitter space. We</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"> <FONT SIZE=2 FACE="Courier New">fi</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">nd that</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">the phase transition is of a</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"> <FONT SIZE=2 FACE="Courier New">fi</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">rst order, and that its strength depends non-analytically on the</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">parameters of the model. We also show that the would-be Goldstone bosons</FONT><FONT SIZE=2 FACE="Courier New"> acquire a mass,</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">e</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">ff</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">ectively becoming pseudo-Goldstone bosons. Our results imply that topological defects</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">can form during in</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">fl</FONT></SPAN><SPAN LANG="en-gb"></SPAN><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New">ation.</FONT></SPAN></P>
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<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New"></FONT> <FONT SIZE=2 FACE="Courier New"> </FONT></SPAN></P>
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<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New"></FONT> <FONT SIZE=2 FACE="Courier New"> Voditeljica seminara:</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-gb"><FONT SIZE=2 FACE="Courier New"></FONT> <FONT SIZE=2 FACE="Courier New"> </FONT> <FONT SIZE=2 FACE="Courier New">Larisa Jonke (larisa at</FONT> <FONT SIZE=2 FACE="Courier New">irb.hr)</FONT></SPAN></P>
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