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Topic: Monopole problem

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Flatness problem

Topological

Big Bang

	Before the Big Bang?
		The cosmic microwave background is the cooled remains of the radiation from the radiation-dominated phase of the Big Bang.
		In particle theory, a magnetic monopole arises from a topological glitch in the vacuum configuration of gauge fields in a Grand Unified Theory or other gauge unification scenario.
		According to that logic, there should be at least one magnetic monopole per horizon volume as it was when the symmetry breaking took place.
	www.superstringtheory.com /cosmo/cosmo4a.html (794 words)

	Magnetic monopole - Wikipedia, the free encyclopedia
		In physics, a magnetic monopole is a hypothetical particle that may be loosely described as a magnet with only one pole" (see electromagnetic theory for more on magnetic poles).
		A hypothetical isolated magnetic pole is called a magnetic monopole; it has been theorized that such things might exist in the form of tiny particles similar to electrons or protons, forming from topological defects in a similar manner to cosmic strings, but no such particles have ever been found.
		Non-inflationary Big Bang cosmology suggests that monopoles should be plentiful, and the failure to find magnetic monopoles is one of the main problems that led to the creation of cosmic inflation theory.
	en.wikipedia.org /wiki/Magnetic_monopole (834 words)

	Do we live in a magnetic monopole? - 12 November 1994 - New Scientist
		Monopoles are hypothetical particles which carry a north or south magnetic pole.
		Paradoxically, one of the reasons why theorists invented the idea of inflation was to get rid of magnetic monopoles, which are predicted by many of the grand unified theories that attempt to bring together three of the four basic forces of physics.
		Standard models of inflation solve the "monopole problem" by arguing that the seed from which our entire visible Universe grew was a quantum fluctuation so small that it contained only one monopole.
	www.newscientist.com /article/mg14419512.600-do-we-live-in-a-magnetic-monopole.html (441 words)

	Magnetic monopoles as engines for cosmological inflation
		New inflation had some problems of its own, chief among them the fact that the inflation process was extremely difficult to initiate.
		Previous theoretical studies of monopoles have all considered them to be point-like objects that were too small to be affected by inflation.
		If the initial inflationary region is visualized as a bubble, then each monopole creates a new bubble extending from the original and, in the process, creates new monopole pairs which begin creating other new bubbles, and so on for eternity.
	www.stanford.edu /dept/news/pr/94/940517Arc4260.html (891 words)

	Before the Big Bang?
		If this phase occurred before the radiation-dominated era, then the Universe could evolve to be extraordinarily flat when the radiation-dominated era began, so extraordinarily flat that the lumpy evolution of the radiation- and matter-dominated periods would be consistent with the high degree of remaining flatness that is observed today.
		The inflationary model also solves the magnetic monopole problem, because in the particle physics that underlies the inflationary idea, there would only be one magnetic monopole per vacuum energy bubble.
		There is also another attempt to solve the problems of Big Bang cosmology using a scalar field that never goes through an inflationary period at all, but evolves so slowly so that we observe it as being constant during our own era.
	www.superstringtheory.com /cosmo/cosmo41.html (1062 words)

	horizon problem concept from the Astronomy knowledge base (Site not responding. Last check: 2007-10-10)
		However, at the time of emission, when the universe was about 1 million years old, those regions were separated by roughly 100 million light years, much exceeding the distance light or heat could have traveled since the big bang.
		The problem is seen most clearly in the cosmic background radiation, which is believed to have been released at about 300000 years after the big bang, and has been observed to have the same temperature in all directions to an accuracy of one part in 100,000.
		Calculations in the traditional big bang theory show that the sources of the background radiation arriving today from two opposite directions in the sky were separated from each other, at 300000 years after the big bang, by about 100 horizon distances.
	www.csi.uottawa.ca:4321 /astronomy/horizonproblem.html (380 words)

	Four Cosmological Problems
		Actually, the magnetic monopole issue may not be a problem because the lack of observation of proton decay disfavors grand unified gauge theories and string theory provides a unification mechanism not requiring a unifying gauge group.
		It is straightforward to see why inflation solves the magnetic monopole problem if these particles are generated before inflation.
		The small-scale inhomogeneity problem is solved because the minute fluctuations that exist in the original causally connected volume are stretched out over a wide range of distance scales.
	www.jupiterscientific.org /sciinfo/cosmology/fourproblems.html (812 words)

	27
		A problem, however, is that we can show (from topology of the forces' symmetry groups) that in the breaking of a grand unified theory to asymmetric strong and electroweak interactions, monopoles must form, where the ground state winds spherically.
		Yet cosmology disallows the presence of these monopoles: their energy density would drive the expansion of the universe too fast, so that a universe with the parameters we observe today would be too young (that is, observed objects would be older than the inferred age of the universe).
		Particle physics' prediction of relic monopoles whose high density was ruled out by cosmology was called the ``monopole problem''.
	www.emory.edu /PHYSICS/Faculty/Benson/380-04/notes/27/27.html (965 words)

	Open Questions: Beyond the Standard Model
		The problem is that we can observe portions of the universe, in opposite directions from each other, which could not have been in physical contact at a very early stage.
		Because monopoles are so massive, calculations of their expected rate of production in the early universe indicate that their mass should absolutely dominate everything else in the universe – causing it to collapse in as little as 1000 years.
		Note that this problem arises in the presence of two distinct features: (1) We are trying to formulate a grand unified theory which relates the electroweak and the strong force.
	www.openquestions.com /oq-ph009.htm (16519 words)

	MIT OpenCourseWare \| Physics \| 8.286 The Early Universe, Spring 2004 \| Syllabus
		Problem sets will be assigned about once every two weeks, depending on the length of the problem sets and on the pacing of the material being covered.
		I have allocated 25% of the grade to problem sets in order to encourage you to do them, and to make it easier for students who find it difficult to do well on tests.
		Solutions to many of the problems have been handed out in previous years, but I urge you for pedagogical reasons not to use these solutions - it is far better for you to figure out the answers, either on your own or with a group of friends.
	ocw.mit.edu /OcwWeb/Physics/8-286Spring-2004/Syllabus (950 words)

	Inflation for Beginners (Site not responding. Last check: 2007-10-10)
		The second puzzle is called the flatness problem This is the puzzle that the spacetime of the Universe is very nearly flat, which means that the Universe sits just on the dividing line between eternal expansion and eventual recollapse.
		Standard models of inflation solve the "monopole problem" by arguing that the seed from which our entire visible Universe grew was a quantum fluctuation so small that it only contained one monopole.
		Indeed, the biggest problem now is that the vocabulary of cosmology doesn't quite seem adequate to the task of describing all this activity.
	aether.lbl.gov /www/science/inflation-beginners.html (4780 words)

	Quantum Mechanics and the Multiverse II (Site not responding. Last check: 2007-10-10)
		Factorizing large numbers, such as a number with 125 digits, is an intractable problem, in the sense that the computing resources and time required are prohibitive.
		The problem becomes even more taxing in the multiverse concept since, as Tegmark points out, there are so many copies of “you” with identical past lives and memories that even if you had complete knowledge of the state of the entire multiverse, you simply could not compute your future.
		The problem becomes increasingly intractable from Level I, where it is treatable, to Level IV, where it is simply stupendous.
	www.geocities.com /tdl.geo/multi2.html (13619 words)

	Before the Big Bang?
		The experimental understanding of particle physics starts to poop out after the energy scale of electroweak unification, and theoretical physicists have to reach for models of particle physics beyond the Standard Model, to Grand Unified Theories, supersymmetry, string theory and quantum cosmology.
		The cosmic microwave background is the cooled remains of the radiation density from the radiation-dominated phase of the Big Bang.
		This is different from electric charge, where we can separate an arrangement of positive and negative electric charges so that only positive charge is in one collection and only negative charge is in another.
	www.superstringtheory.com /cosmo/cosmo4.html (728 words)

	ASTR 135 Course Notes
		Another way to look at the problem is to realize that at early times, the three possible fates for the universe resemble each other very closely, and in fact they all resemble the critical case.
		The matter/anti-matter problem is different from the monopole problem and is not discussed in this course.
		Another way to look at the flatness problem is to recall that, at early times, the universe will appear to be at or near the critical case.
	astro.wsu.edu /allen/courses/astr135/Notes/cosmology.html (2777 words)

	Alternate View Column AV-01
		Only if one monopole were to encounter another monopole of the opposite magnetic charge, north monopole meeting south monopole, could their burdens of magnetic flux be released so that the monopole pair could annihilate in a burst of energy and disappear.
		Thus the monopole is the analog of a chemical catalyst.
		The problem is that the needed amount of antimatter fuel would require a truly staggering investment, because the antimatter would have to be manufactured by earth-based or orbiting "antiproton factories" of monumental size.
	mist.npl.washington.edu /AV/altvw01.html (2793 words)

	problem Comparison Table (Site not responding. Last check: 2007-10-10)
		Cosmological puzzle associated with the fact that regions of the universe that are separated by vast distances nevertheless have nearly identical properties such as temperature.
		A problem, discovered by John Preskill in 1979, concerning the compatibility of grand unified theories with standard cosmology.
		Preskill showed that if standard cosmology were combined with grand unified theories, far too many magnetic monopoles would have been produced in the early universe.
	www.site.uottawa.ca:4321 /astronomy/problem_table.html (469 words)

	ess (Site not responding. Last check: 2007-10-10)
		He related the existence of monopoles to the phases of quantum waves and proposed that magnetic monopoles might exist with multiples of the magnetic unit charge.
		The necessity of magnetic monopoles in these theories was shown by the Dutch physicist G. t’Hooft and by the Russian physicist Alexander Polyakov.
		These monopoles can be regarded as relics of the early universe when temperature was high enough to produce them.
	www.physik.tu-dresden.de /~jseidel/es.html (956 words)

	MIT OpenCourseWare \| Physics \| 8.286 The Early Universe, Spring 2004 \| Syllabus
		Problem sets will be assigned about once every two weeks, depending on the length of the problem sets and on the pacing of the material being covered.
		I have allocated 25% of the grade to problem sets in order to encourage you to do them, and to make it easier for students who find it difficult to do well on tests.
		Solutions to many of the problems have been handed out in previous years, but I urge you for pedagogical reasons not to use these solutions - it is far better for you to figure out the answers, either on your own or with a group of friends.
	ocw.zju.edu.cn /OcwWeb/Physics/8-286Spring-2004/Syllabus/index.htm (950 words)

	Primordial black hole - Wikipedia, the free encyclopedia
		The evaporation of primordial fl holes has been suggested as one possible explanation for gamma ray bursts.
		Other problems for which primordial fl holes have been suggested as a solution include the dark matter problem, the cosmological domain wall problem
		Even if they do not solve these problems, the low number of primordial fl holes (they have never been detected) aids cosmologists by putting constraints on the spectrum of density fluctuations in the early universe.
	en.wikipedia.org /wiki/Primordial_black_hole (530 words)

	Inflation (Site not responding. Last check: 2007-10-10)
		His model was motivated by the monopole problem (the abundance of magnetic monopoles should be high in many GUT theories; however we do not observe any), which is explained as well by inflation.
		Preexisting magnetic monopoles or strings, and any topological defects (e.g domain walls between regions where the Higgs field chose an other symmetry axis) are diluted with astronomical value, and the visible universe will contain few if any of these objects.
		However, it is at present not known how to explain the shape of the potential of the Higgs field associated with the symmetry breaking that is needed to obtain a long enough period of inflation and the right amount of entropy generation and reheating at the end of the inflationary period.
	www.nikhef.nl /~henkjan/astro/node20.html (986 words)

	CERN Courier - DESY workshop combines gravi - IOP Publishing - article
		Inflation is a beautiful way to understand the cosmological flatness and horizon problems (see box overleaf) and apparently induces large-scale density fluctuations consistent with experimental observations.
		On the theoretical and conceptual level, the quest for a theory of quantum gravity is the most prominent and important problem facing theoretical physics.
		Despite its success, there are three problems with the Big Bang model which were hotly debated at the DESY theory workshop.
	www.cerncourier.com /main/article/42/3/17 (1851 words)

	Inflation
		If this phase occurred before the radiation-dominated era, then the Universe could evolve to be extraordinarily flat when the radiation-dominated era began, so extraordinarily flat that the lumpy evolution of the radiation- and matter-dominated periods would be consistent with the high degree of remaining flatness that is observed today.
		The inflationary model also solves the magnetic monopole problem, because in the particle physics that underlies the inflationary idea, there would only be one magnetic monopole per vacuum energy bubble.
		There is also another attempt to solve the problems of Big Bang cosmology using a scalar field that never goes through an inflationary period at all, but evolves so slowly so that we observe it as being constant during our own era.
	www.freeserbia.net /Editorial/Inflation.html (1214 words)

	altvw111
		The flatness problem is raised by the remarkable lack of curvature, either positive or negative, of the present universe.
		The inhomogeneity problem concerns the origins of the structure observed in the cosmic microwave background radiation and in the large-scale structure of the universe.
		The currently accepted solution for these problems, the "inflation scenario", assumes that in the very early stages of the Big Bang, for reasons not well understood, the universe expanded at an exponentially increasing rate, with the radius growing much faster than the speed of light.
	www.npl.washington.edu /AV/altvw111.html (1967 words)

	Before the Big Bang?
		In particle theory, a magnetic monopole arises from a topological glitch in the vacuum configuration of gauge fields in a Grand Unified Theory or other gauge unification scenario.
		A correlation length cannot be larger than causality would allow, therefore the correlation length for making magnetic monopoles must be at least as big as the horizon size determined by metric of the expanding Universe.
		According to that logic, there should be at least one magnetic monopole per horizon volume as it was when the symmetry breaking took place.
	superstringtheory.com /cosmo/cosmo4a.html (794 words)

	Science and Reason: The Big Bang
		There was one additional problem, and it arises from most theories of the GUT type that attempt to describe the unification of the strong and electroweak forces.
		The inspiration occurred to him that all three of the problems listed could be solved if the universe had undergone a dramatic bout of expansion, far in excess of the expansion that was a part of the big bang itself, just after the GUT phase transition (and presumably as some consequence of it).
		The monopole problem is solved, because all the monopoles that could have been created in the GUT era would have become so diluted that it would be extremely unlikely that even one of them could exist in the whole universe observable today.
	www.scienceandreason.net /oq/oq-co008.htm (20702 words)

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