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BEGIN:VEVENT
DTSTAMP:20260814T215634Z
LAST-MODIFIED:20121116T203436Z
DTSTART:20121012T040000Z
DTEND:20121012T050000Z
UID:event1008@bu.edu
URL:http://physics.bu.edu/internal/events/show/1008
SUMMARY:From Effective Strings to the Simplest theory of Quantum Gravity an
	d Back
DESCRIPTION:Featuring Raphael Flauger\, IAS/NYU\n\nPart of the HET Seminar 
	Series.\n\nAbstract:\nString-like objects arise in many quantum field theor
	ies. Well known examples include flux tubes in QCD and cosmic strings. To a
	 first approximation\, their dynamics is governed by the Nambu-Goto action\
	, but for QCD flux tubes numerical calculations of the energy levels of the
	se objects have become so accurate that a systematic understanding of corre
	ctions to this simple description is desirable. In the first part of my tal
	k\, I discuss an effective field theory describing long relativistic string
	s. The construction parallels that of the chiral Lagrangian in that it is b
	ased on the pattern of symmetry breaking. To compare with previous works\, 
	I will present the results of the calculation of the S-matrix describing th
	e scattering of excitations on the string worldsheet. In the second part of
	 my talk\, I will discuss critical strings from the same point of view and 
	show that the worldsheet S-matrix in this case is non-trivial but can be ca
	lculated exactly. I will show that it encodes the familiar square-root form
	ula for the energy levels of the string\, the Hagedorn behavior of strings\
	, and argue that the theory on the string worldsheet behaves like a 1+1 dim
	ensional theory of quantum gravity rather than a field theory. In the last 
	part of the talk\, I will return to the task of computing of the energy lev
	els of flux-tubes using lessons learned from the second part and compare th
	e results to lattice data.
LOCATION:PRB 595\, 3 Cummington Mall\, 02215
STATUS:CONFIRMED
CLASS:PUBLIC
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