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Topic: Renormalizable

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	Why strings?
		But the integrals go to infinity very slowly, like the logarithm of momentum, and it turns out that in this case, the theory can be renormalized so that the infinities can be absorbed into a redefinition of a small number of parameters in the theory, such as the mass and charge of the electron.
		Quantum electrodynamics was a renormalizable theory, and by the 19402, this was regarded as a solved relativistic quantum theory.
		But in 1971, a new type of quantum field theory came on the scene that explained the weak nuclear force by uniting it with electromagnetism into electroweak theory, and it was shown to be renormalizable.
	superstringtheory.com /basics/basic3a.html (959 words)

	Re: What QFTs are renormalizable?
		It's got to be a >polynomial, and for tabulation in each term: > > d's count as 1 > psi's, psi*'s count as 3/2 > bosons count as 1 > >and it's all got to add up to 4, the coefficient of the monomial >take up the slack.
		Yes, yes, of course that is the conventional wisdom, and, at least to some extent is proven to be true.
		However, where this all started was a reference to a paper which claimed that, contrary to CW, that the standard model is not actually renormalizable.
	www.lns.cornell.edu /spr/2002-06/msg0042444.html (267 words)

	Ouadratic-like maps
		A polynomial is renormalizable if restriction of some of its iterate gives a polinomial-like map of the same or lower degree.
		is renormalizable and all these renormalizations are hybrid equivalent to itself.
		is renormalizable, z = 0 is fixed after two iterations of the renormalized map.
	www.ibiblio.org /e-notes/MSet/Fagella2.htm (271 words)

	1.2 Identifying where the problems lie
		, 18], and it was recognized early on that general relativity is not renormalizable.
		As usually stated, the difficulty with non-renormalizable theories is that they are not predictive, since the obtention of well-defined predictions potentially requires an infinite number of divergent renormalizations.
		It is not the main point of the present review to recap the techniques used when quantizing the gravitational field, nor to describe in detail its renormalizability.
	www.univie.ac.at /EMIS/journals/LRG/Articles/lrr-2004-5/articlesu2.html (537 words)

	The Reference Frame: Lorentz violation and deformed special relativity
		If you only allow theories that are renormalizable perturbations of a relativistic theory, you obtain different results.
		Coleman and Glashow have shown that there are 46 CPT-even gauge-invariant renormalizable perturbations of the Standard Model that preserve the rotational symmetry in a preferred reference frame.
		The number 46 only counts the deformations that are renormalizable - relevant or marginal - according to the relativistic counting of dimensions of the operators.
	motls.blogspot.com /2006/12/lorentz-violation-and-deformed-special.html (2836 words)

	Rabbits show
		is renormalizable (see the right picture below) and z = 0 is its superattracting fixed point, therefore the biggest central red bulb is homeomorphic to J(0) (i.e.
		is renormalizable (see the picture to the left).
		is renormalizable too (see below) and z = 0 is its superattracting fixed point, therefore the red bulb in the center of J(c4) is a homeomorphic copy of J(0).
	www.ibiblio.org /e-notes/MSet/Quadrat.htm (155 words)

	Daniel Smania
		We also prove that renormalizations of infinitely renormalizable multimodal maps with same bounded combinatorial type are exponentially close.
		We prove the so-called complex bounds for multimodal, infinitely renormalizable analytic maps with bounded combinatorics: deep renormalizations have polynomial-like extensions with definite modulus.
		The complex bounds are the first step to extending the renormalization theory of unimodal maps to multimodal maps.
	www.math.sunysb.edu /~smania/index.html (492 words)

	Renormalization (Site not responding. Last check: 2007-10-08)
		The theory is then said to be renormalizable.
		A theory may be "crossing over" from one fixed point to another, as the length scale changes.
		In this case the cutoff cannot be buried, and the theory is not renormalizable.
	web.mit.edu /people/kerson/renormal.htm (267 words)

	renormalizability
		I assume you've looked at my webpage on renormalization, and you're reading this because you want to see how to actually tell if a given quantum field theory is renormalizable.
		On the other hand, theories that fail to be superficially renormalizable can sometimes be saved by subtler considerations, usually involving symmetry.
		Nonetheless checking superficial renormalizability is a pretty way to start checking if your quantum field theory is really renormalizable.
	math.ucr.edu /home/baez/renormalizability.html (1755 words)

	Homepage of Lucas Platter
		In contrast to conventional field theories as for example quantum electrodynamics, effective field theories (EFT) abandon the goal of describing the world with a finite set of renormalizable interactions.
		Instead, EFT's use a physical system's separation of scales, to describe its dynamics to a given accuracy with a finite set of renormalizable and nonrenormalizable interactions.
		In fact, one can consider all "old-fashioned" field theories as a special case of effective theories in which renormalizable interactions were so far sufficient to describe experimental results.
	www.phy.ohiou.edu /~lplatter (98 words)

	Amazon.com: Renormalizable: Books (Site not responding. Last check: 2007-10-08)
		On the mathematical structure of renormalizable field theories by Gyan Mohan (Unknown Binding - 1956)
		Scholes's and Merton's, reminded me of the complementary derivations of renormalizable quan- tum electrodynamics by Feynman and Schwinger in the late...
		This young boy was claiming that this theory was renormalizable!" Salam recalled, in a 1984 interview with Robert Crease and...
	www.amazon.com /s?ie=UTF8&keywords=Renormalizable&tag=httpexplaguid-20&index=books&link_code=qs&page=1 (888 words)

	Lorentz (Site not responding. Last check: 2007-10-08)
		Fermi's rule was like a perturbation formula, but it was strictly a phenomenological formula without a consistent field theory.
		Thanks to the works of Glashow, Salam, and Weinberg in the late 1969s, it became possible to construct a renormalizable field theory based on the Yang-Mill theory, spontaneous symmetry breaking, and Higg's mechanism.
		This renormalizable field theory requires placing electromagnetic and weak interactions into the same symmetry group.
	www2.physics.umd.edu /~yskim/maga/lorenuni.html (662 words)

	renormalisation, regularisation and number theory
		The requirement of renormalizability became a paradigm of quantum field theory, and it proved extremely fruitful.
		This renormalizability paradigm underwent a dramatic revision in the seventies as a result of Wilson's renormalization group theory.
		The concept of renormalizability thus acquires a new meaning: renormalizable theories, rather than being "fundamental" are merely those theories which survive the scaling down from the fundamental scale to the "laboratory scale.
	secamlocal.ex.ac.uk /~mwatkins/zeta/renormalisation.htm (5189 words)

	Renormalizable "non-renormalizable" theories
		You can prove, under very general conditions, that after dumping some arbitrary mix of bosons, scalar fields and fermions (subject to the power counting criteria), and imposing a suitable gauge principle, you automatically get Yang-Mills with a Higgs sector for the resulting Lagrangian.
		If the original theory was, in contract, NOT renormalizable, then the number of terms generated by the above process will be infinite and the resulting Lagrangian will be non-polynomial.
		What I'm guessing is that with a suitably formulated gauge invariance principle, you can actually constrain the forms of these terms (DESPITE there being an infinite number of them) so that the resulting Lagrangian resides in only a finitely-parametrized family of functions, possibly even unique.
	www.lns.cornell.edu /spr/2002-06/msg0042623.html (851 words)

	Duality symmetries in string theory
		For understanding the rest of this article it is not necessary to know the precise definition of a renormalizable local quantum field theory, but one should remember that these are special kind of theories, and not all quantum field theories fall into this category.
		In case of quantum field theories this would require that each of the two theories correspond to a renormalizable local quantum field theory (note 9), whereas in the case of string theory, this would require that each of the two theories is governed by simple interactions of the kind described in the previous article.
		Unlike a renormalizable quantum field theory or a string theory, one does not have a well-defined set of rules for computing this amplitude as a power series expansion in h.
	www.ias.ac.in /currsci/dec251999/articles20.htm (8398 words)

	renormalization
		If you want to see how to tell whether a given term in your Lagrangian is renormalizable or not, click here and I'll work you through an example called the "4-fermion interaction".
		Finally, for "renormalizable" theories, the physical coupling constants scale roughly like D to the zeroth power - i.e., they're roughly constant.
		For example, quantum electrodynamics is renormalizable, but it turns out to be nasty: at first the charge of the electron looks almost constant as we decrease D', but it actually grows - logarithmically at first, but then faster and faster.
	math.ucr.edu /home/baez/renormalization.html (4102 words)

	Citebase - Is the Standard Model Renormalizable?
		Authors: Cheng, Hung; Li, S. In this paper, we study the renormalizability of the Standard Model in the Landau gauge.
		On the basis of the Ward-Takahashi identities, we derive exact expressions for the physical masses of the W and Z as well as the renormalized coupling constants in the theory.
		Thus the quantum theory of the Standard Model with the divergent amplitudes obeying the Ward-Takahashi identities is not renormalizable.
	citebase.eprints.org /cgi-bin/citations?id=oai:arXiv.org:hep-th/9902212 (135 words)

	Renormalizable extra-dimensional models
		From the model-building point of view, such theories would be effectively perturbatively renormalizable in the normal way.
		A particularly attractive possibility is the construction of renormalizable extra-dimensional models of the weak interactions, which have the potential to address the full hierarchy problem.
		The simplest such gauge-Higgs unification model is however ruled out by a combination of theoretical and phenomenological constraints.
	stacks.iop.org /1126-6708/2005/i=01/a=002 (330 words)

	Quantum Field Theory
		A renormalizable theory is one in which the details of a deeper scale are not needed to describe the physics at the present scale, save for a few experimentally measurable parameters (see more in the section about "Renormalizable Theories").
		It has been shown subsequently by 't Hooft that the spontaneous symmetry breaking formulation remains renormalizable; the ultraviolet divergences encountered are no worse than those occurring in QED.
		In the Standard model the scalar field is identified as the Higgs field responsiable for the mass of fermions and gauge bosons.
	universe-review.ca /R15-12-QFT.htm (12639 words)

	week195
		In 4 dimensions, pure gravity without matter is renormalizable to 1 loop, but not 2.
		In 4 dimensions, pure gravity with non-supersymmetric matter is generically not renormalizable even to 1 loop.
		It is believed that most of these theories are not renormalizable to 3 loops, since a candidate divergent term is known.
	math.ucr.edu /home/baez/week195.html (5447 words)

	Citebase - Are Nonrenormalizable Gauge Theories Renormalizable?
		We raise the issue whether gauge theories, that are not renormalizable in the usual power-counting sense, are nevertheless renormalizable in the modern sense that all divergences can be cancelled by renormalization of the infinite number of terms in the bare action.
		We find that a theory is renormalizable in this sense if the em a priori constraints that we impose on the form of the bare action correspond to the cohomology of the BRST transformations generated by the action.
		Recent cohomology theorems of Barnich, Brandt, and Henneaux are used to show that conventionally nonrenormalizable theories of Yang-Mills fields (such as quantum chromodynamics with heavy quarks integrated out) and/or gravitation are renormalizable in the modern sense.
	citebase.eprints.org /cgi-bin/citations?id=oai:arXiv.org:hep-th/9510087 (179 words)

	Precision Electroweak Tests (Site not responding. Last check: 2007-10-08)
		The standard model is a mathematically consistent renormalizable field theory which predicts or is consistent with all known aspects of the elementary particles and their interactions over an enormous range of probes and scales.
		In particular, it is now clear that, with the possible exception of the Higgs sector, the standard electroweak model is the correct theory of nature to an excellent approximation down to a distance scale of
		Precision neutral current, charged current, and Z and W pole experiments have established or supported the framework of renormalizable field theory and of gauge theories; have established the
	dept.physics.upenn.edu /~pgl/precision/ew/ew.html (178 words)

	Interpretations of Quantum Mechanics and String Theories - Part 4
		Particle theories look totally disparate depending on the energies of the reactions they study.
		But, luckily, the reactions of massive particles are negligible in low energies - so renormalizable QFT (e.g., SM) is a fair approximation, althesame.
		At low energies, the combination of Special Relativity Theory (SRT) and any quantum theory is indistinguishable from a renormalizable QFT.
	samvak.tripod.com /string04.html (957 words)

	PhysOrgForum Science, Physics and Technology Discussion Forums -> Why gravity is incompatible with quantum theory?
		use quantum field theories that are renormalizable (especially
		Unfortunately, people can show that there are no renormalizable
		find in renormalizable quantum field theories, which is somewhat
	forum.physorg.com /index.php?showtopic=323 (1939 words)

	The Reference Frame: Objections to loop quantum gravity
		Many reasons are known why some classical theories do not have a quantum counterpart.
		General relativity is usually taken to be another example, because its quantum version is not renormalizable.
		It is known, therefore, that a classical theory is not always a good starting point for a quantum theory.
	motls.blogspot.com /2004/10/objections-to-loop-quantum-gravity.html (5507 words)

	Renormalization
		Thus one needs power counting to find out whether\nandgt; certain integrals are likely to converge.
		in higher dimensions and in\n\nandgt; field theory it is not really different.\nandgt;\nandgt; There is no shortcut to understanding the difference between\nandgt; renormalizable theories and those which are not.\n\nI\'m not hoping to get a shortcut.
		> renormalizable theories and those which are not.
	www.physicsforums.com /showthread.php?t=65552 (5223 words)

	What QFTs are renormalizable?
		I wonder if this classification is complete (includes all QFTs), or just conventional wisdom.
		Borel resummable theories, which probably can be rigorously defined.
		Next by thread: Re: What QFTs are renormalizable?
	www.lns.cornell.edu /spr/2002-06/msg0042316.html (154 words)

	D-Branes (Site not responding. Last check: 2007-10-08)
		D-branes had been studied for a number of years, but their significance was explained by Polchinski only recently[7]
		The importance of D-branes stems from the fact that they make it possible to study the excitations of the brane using the renormalizable 2D quantum field theory of the open string instead of the non-renormalizable world-volume theory of the D-brane itself.
		In this way it becomes possible to compute non-perturbative phenomena using perturbative methods.
	www.theory.caltech.edu /people/jhs/strings/str155.html (426 words)

	Feyn Calc--Computer Algebraic Calculation of Feynman Amplitudes -- from Mathematica Information Center
		We present the computer program FeynCalc for automatic algebraic calculation of Feynman amplitudes.
		The purpose of the package is to facilitate the process of calculating radiative creections in renormalizable gauge theories.
		We have use th eporgram to calculate tree level diagrams as well as 1- and 2- loop corrections in the Standard model.
	library.wolfram.com /infocenter/Articles/2033 (95 words)

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