Home arrow Weekly Seminars
Weekly Seminars
Weekly Seminars for September 2017 Print E-mail
Friday September 8th, 2017 - 4:00pm
ICRANet Pescara (Meeting room, 1st Floor)
 
ICRANet Seminar
 
 
 
Speaker: Takahiro Hayashinaka

Institution: Research Center for the Early Universe (RESCEU), Department of Physics, Graduate School of Science, the University of Tokyo, Japan

Title: de Sitter QED and non-perturbative renormalization approach​
 
Abstract:  
This talk will be dedicated to show recent activities on the topic. In the first half of the talk, I explain how negative, i.e. unstable, electromagnetic responses have been revealed. Though this phenomenon was repeatedly reported by several groups recently [1], neither physical origin or intellectual interpretation of the phenomenon have been explicitly given up to the present. The rest of my talk involves this point. Inspired by a relevant negative response phenomenon in a specific ferroelectric matter [2], I recognized importance of spontaneous symmetry breaking and the effective action or potential of the system. A variation of renormalization group technique, which is called non-perturbative renormalization group (NPRG) [3], can be used for evaluation of the effective action. In this formalism, one introduces an IR cutoff scale. As a result, undesirable behavior of the IR modes in de Sitter spacetime can be virtually suppressed [4]. I will show how the electric field can change the shape of the scalar effective potential.


References:

[1] T. M. B. Frob, J. Garriga, S. Kanno, M. Sasaki, J. Soda, T. Tanaka, and A. Vilenkin, JCAP 2014 (2014) 04 009, R. G. Cai and S. P. Kim, JHEP 09 (2014) 072, T. Kobayashi and N. Afshordi, JHEP 2014 (2014) 10 1-36, C. Stahl, E. Strobel, and S. S. Xue, Phys. Rev. D 93 (Jan, 2016) 025004, E. Bavarsad, C. Stahl, and S. S. Xue, arXiv:1602.0655, C. Stahl and S. Xue Phys.Lett. B760 (2016) 288-292, T. Hayashinaka and J. Yokoyama, JCAP 1607 (2016) 07 012, T. Hayashinaka, T. Fujita and J. Yokoyama, JCAP 1607 (2016) 07 010

[2] G. Catalan et al., Nature matt. (2015) 14, 137, S. Kasamatsu et al., Adv. Mater. 2016, 28, 335-340

[3] Christof Wetterich. Phys. Lett., B301:90-94 (1993), M. Reuter and C. Wetterich. Nucl. Phys., B417:181-214 (1994)

[4] For recent application of NPRG in cosmology, see: Maxime Guilleux, Theses, Universite paris Diderot, September, 2016
 
*************************************************
ICRANet Secretariat
ICRANet
Piazza della Repubblica 10
65122 Pescara (PE)
Italy
tel.: +39 085 23054200
fax: +39 085 4219252
email: secretariat@icranet.org
 

 
<< Start < Prev 1 2 3 4 5 6 7 8 9 10 Next > End >>

Results 1 - 5 of 70
Organization
ICRANet Seats
Director and Staff
Personal Pages
Meetings
Upcoming Meetings
IYA 2009 Meetings
IYL 2015 Meetings
Marcel Grossmann
Galileo - Xu Guangqi
William Fairbank
Italian-Korean
Italian-Sino Meeting
ICRANet Workshops
Stueckelberg Meeting
C. Lattes Meeting
Sobral Meetings
Bego Rencontre
Urca Meetings
Zeldovich Meetings
Meetings in Armenia
Adriatic Meeting
ICRANet-Minsk workshop
Other Meetings
Erasmus Mundus Schools
Weekly Seminars
Yearly Scientific Meeting
Research
Research Groups
Visiting Scientists
Publications
Books
Proceedings
Articles Database
Visitors: 96451063