1. Identity And Individuality In Quantum Theory Identity and Individuality in quantum theory. What are the metaphysical implications of quantum physics? Auyang, SY, 1995, How is Quantum Field Theory Possible? http://plato.stanford.edu/entries/qt-idind/

version history HOW TO CITE THIS ENTRY Stanford Encyclopedia of Philosophy A B C D ... Z This document uses XHTML-1/Unicode to format the display. Older browsers and/or operating systems may not display the formatting correctly. last substantive content change FEB Identity and Individuality in Quantum Theory What are the metaphysical implications of quantum physics? One way of approaching this question is to consider the impact of the theory on our understanding of objects as individuals with well defined identity conditions. One view is that quantum theory implies that the fundamental particles of physics cannot be regarded as individual objects in this sense. Such a view has motivated the development of non-standard formal systems which are appropriate for representing such non-individual objects. However, it has also been argued that quantum physics is in fact compatible with a metaphysics of individual objects. Nevertheless, such objects are indistinguishable in a sense which leads to the violation of Leibniz's famous Principle of the Identity of Indiscernibles. Finally, this underdetermination of the metaphysics of individuality by the physics has important implications for the realism-antirealism debate. 1. Introduction

2. Many-Worlds Quantum Theory ManyWorldsquantum theory. What Does Many-Worlds Mean? Born Rule. Experimental Support for Many-Worlds. GRW Dynamical Collapse. Gray's History Selection Machine. Cosmology. Quantum Computing. Worlds http://www.innerx.net/personal/tsmith/ManyWorlds.html

Tony Smith's Home Page Many-Worlds Quantum Theory What Does Many-Worlds Mean? ... Sum-Over-Histories and the MacroSpace of the Many-Worlds Many-Worlds Physics was proposed by Hugh Everett Here and here are two web pages with a Many-Worlds FAQ and here is a Many-Worlds web page ManyWorlds may be representable by Density Matrices , by Bernoulli Shifts , and by Surreal Numbers What Does Many-Worlds Mean? According to John Cramer 's Alternate View 48 at every occasion where a quantum event has more than one outcome (e.g., when an electron may strike one atom or another), the universe splits . We have one universe where the electron hits atom A, another where it hits atom B, and so on for all of the possible outcomes. Similarly, if a light photon might be transmitted or reflected, if a radioactive atom might decay or not, the universe splits into alternative worlds, with one new universe for each and every potential outcome. This is the Many Worlds (MW) interpretation. From the MW viewpoint, the universe is like a tree that branches and re-branches into myriads of new sub-branches with every passing picosecond . And each of these new branch universes has a slightly different sub-atomic "history". Because an observer happens to have followed one particular path through the diverging branches of this Universe-Tree, he never perceives the splitting. Instead he interprets the resolution of the myriad of possibilities into one particular outcome as a Copenhagen-style collapse. But the observer plays no active role in the splitting. Events at the quantum level, of course, must lead to consequences in the every-day world. There should be a MW universe in which every physically possible event has happened. There should be MW universes where the dinosaurs dominate the planet ... Even as you read this sentence your universe may be fragmenting into a number of branches too large to count. ...

3. Measurement In Quantum Theory last substantive content change OCT 29 1999. Measurement in quantum theory. quantum theory of measurement and ergodicity requirements . Nuclear Physics. http://plato.stanford.edu/entries/qt-measurement/

version history HOW TO CITE THIS ENTRY Stanford Encyclopedia of Philosophy A B C D ... Z This document uses XHTML-1/Unicode to format the display. Older browsers and/or operating systems may not display the formatting correctly. last substantive content change OCT Measurement in Quantum Theory The dynamics and the postulate of collapse are flatly in contradiction with one another ... the postulate of collapse seems to be right about what happens when we make measurements, and the dynamics seems to be bizarrely wrong about what happens when we make measurements, and yet the dynamics seems to be right about what happens whenever we aren't making measurements. (Albert 1992, 79) This has come to be known as "the measurement problem" and in what follows, we study the details and examine some of the implications of this problem. The measurement problem is not just an interpretational problem internal to QM. It raises broader issues as well, such more general philosophical debates between, on the one hand, Cartesian and Lockean accounts of observation as the creation of "inner reflections" and, on the other, neo-Kantean conceptions of observation as a quasi-externalized physiological process. In this article I trace the history of these debates, and indicate some of the interpretative strategies that they stimulated. The Birth of the Measurement Problem The End of Copenhagen Monocracy Cats in Singlets The World of Many Interpretations ... Related Entries The Birth of the Measurement Problem The measurement problem in QM (Quantum Mechanics) grew out of early debates over Niels Bohr's "Copenhagen interpretation". Bohr maintained that the physical properties of quantum systems depend in a fundamental way upon experimental conditions, including conditions of measurement. This doctrine appeared explicitly in Bohr's 1935 reply to Einstein, Podolski, and Rosen: "The procedure of measurement has an essential influence on the conditions on which the very definition of the physical quantities in question rests" (Bohr 1935, 1025; see too Bohr 1929). To be specific, Bohr endorsed the following principle:

4. QTP The quantum theory Project was founded in 1960 by Professor Per Olov Löwdin as a group of faculty is Samuel B. Trickey. quantum theory Project (QTP) is part of the http://www.qtp.ufl.edu/

5. New Scientist | Guide To The Quantum World This was Richard Feynman, speaking about quantum theory. It pays to take his warning seriously and familiar you'll come unstuck with quantum theory. Normal rules just don't apply http://www.newscientist.com/hottopics/quantum

"Do not take the lecture too seriously . . . just relax and enjoy it. I am going to tell you what nature behaves like. If you will simply admit that maybe she does behave like this, you will find her a delightful, entrancing thing. Do not keep saying to yourself "But how can it be like that?" because you will get...into a blind alley from which nobody has yet escaped. Nobody knows how it can be like that." This was Richard Feynman, speaking about quantum theory. It pays to take his warning seriously. By the time you finish this section of the site, you will understand the most extraordinary implications of a truly extraordinary theory. But if you try to picture it in familiar ways you will come hopelessly unstuck. The quantum world really is different, and the only way to come to grips with it is to suspend disbelief. So open your mind and become a genius in your own lunchtime Subscribe to New Scientist ADVERTISEMENTS DigitalCamera-HQ.com Digital Camera Digital Cameras Digital Camera Review ... Holiday Reviews FlightComparison.co.uk - Unbiased Cheap Flight comparison from the UK to all destinations.

6. General Chemistry Online: Companion Notes: The Quantum Theory The quantum theory. Electrons in atoms. The periodic table. Home Companion Notes. Print Comment Contact. Learning objectives. Relate wavelength, frequency, and velocity of waves. real analogy http://antoine.frostburg.edu/chem/senese/101/quantum/index.shtml

Home Common Compounds Exam Guide FAQ ... Glossary Companion Notes Just Ask Antoine! Resources Slide Index Toolbox ... Gases The quantum theory Electrons in atoms The periodic table Home Companion Notes ... Learning Objectives A checklist of concepts to learn and skills to master in this section. Lecture Notes Links Internet sites and paper references for further exploration. Frequently Asked Questions Find an answer, or ask a question Glossary Terms and definitions from the glossary are marked with an asterisk ( Learning objectives Relate wavelength frequency , and velocity of waves. Explain how electromagnetic radiation is produced by an oscillating charge. Explain how electromagnetic radiation carries energy from a transmitter to a receiver. Describe the collapsing atom paradox. List wave behaviors, and distinguish them from particle behaviors. Cite experimental evidence that implies that electromagnetic radiation can display both wave and particle behaviors. Cite experimental evidence that implies that electrons display both wave and particle behaviors. Connect particle and wave properties of matter using de Broglie's hypothesis.

7. Physics 219 Course Information of classical complexity theory, quantum complexity, efficient quantum algorithms, quantum errorcorrecting to this material are quantum theory Concepts and Methods by Asher http://www.theory.caltech.edu/people/preskill/ph229

Course Information for Physics 219/Computer Science 219 Quantum Computation (Formerly Physics 229) John Preskill Go to the home page of Ph219/CS219 for 2004 Contents Course Description Class Meetings Instructors Course Requirements ... Other Useful Links Go directly to course outline, references, lecture notes, or homework Course Description The theory of quantum information and quantum computation. Overview of classical information theory, compression of quantum information, transmission of quantum information through noisy channels, quantum entanglement, quantum cryptography. Overview of classical complexity theory, quantum complexity, efficient quantum algorithms, quantum error-correcting codes, fault-tolerant quantum computation, physical implementations of quantum computation. Class Meetings Mondays and Wednesdays and to 2:30 in 269 Lauritsen , first, second, and third terms. The first class meeting is on Monday, September 25, 2000 Instructors John Preskill Lauritsen Laboratory Telephone: 626-395-6691 email: preskill@theory.caltech.edu

8. The Jade Hut Imagine a cross between economics and thermodynamics http://www.geocities.com/CollegePark/1003/

Welcome to The Jade Hut PES College of Engineering Mandya This page is dedicated to all our classmates with whom we spent the best and most colorful days of our lives and to all our beloved teachers who put up with us. The Colorful Class of 93! Vyshali B S Venkategowda Vandana Krishnan Usha Devi K Thomson B Sudharma Rao P Srinivas Gopalan Sanjay R Bhakta Sanjay Mahale Samartha Raghava N Rekha M A Ravi Kiran M V Ravindran H Ravindra Kumar C P Ramesh S Ramamurthy J Rakesh Saha Raghavendra G Premkumar L Prasad KSV Nayana D K Naveen S Natesh Nayak Nanda Kishore Mohan H Madhusudhan N R Madhusudan Hebbar Lokesh Kumar Latha K Kumar K V Krishna C S Kali Krishna Kavirajan R K Karthik S. Karthik B Gyaneshwaran Ganesh S Ganesh Krishnan Chetan Kumar M Chandrika G V Chandrashekar S Our respected teachers... This page will always be under construction... Write to the webmaster Subscribe to Enter your e-mail address: pesce_ec93 archive An e-group hosted by eGroups.com You are visitor number

9. Quantum Theory Without Observers Decoherent histories (DH) approach was initiated in 1984 http://www.math.rutgers.edu/~oldstein/papers/qts/qts.html

Next: Introduction Quantum Theory Without Observers Sheldon Goldstein Department of Mathematics, Rutgers University New Brunswick, NJ 08903, USA July 23, 1997 The concept of `measurement' becomes so fuzzy on reflection that it is quite surprising to have it appearing in physical theory at the most fundamental level. ... [D]oes not any analysis of measurement require concepts more fundamental than measurement? And should not the fundamental theory be about these more fundamental concepts? (Bell 1981 [ , page 117]) Introduction Decoherent Histories Spontaneous Localization Bohmian Mechanics ... About this document ... Shelly Goldstein Wed Aug 13 17:22:41 EDT 1997

10. Rudiments Of Quantum Theory Rudiments of quantum theory. quantum theory was not created out of the blue . For another decade, extensions to this quantum theory proved unsatisfying. http://www.chembio.uoguelph.ca/educmat/chm386/rudiment/rudiment.htm

Rudiments of Quantum Theory Quantum theory was not created "out of the blue". It's mathematical framework and ideas grow out of a long history of classical mechanics. A number of certain experiments around the turn of the century created the need to replace the classical theory of matter with a new quantum theory. The first attempt's (Bohr) had remarkable yet limited success. This became known as the Old Quantum Theory. Classical Tour Experimental Tour Quantum Tour Mathematical Basics ... Simple Quantum Models An important aspect of understanding of one's position is to appreciate where one came from. This is also true of modern science. Though admittedly more complex, it is possible to follow a thread through the last four centuries up to the birth of modern quantum mechanics. Rene Descartes is often credited as the Father of Modern Mathematics. While a mercenary soldier, he experienced a dream one night that triggered in his mind the idea of modern algebra. (Some nightmare!) It is helpful to follow a short tour from Descartes through to Newton, Bernoulli, Euler, Hamilton, Maxwell, Einstein, Schrodinger, Heisenberg, and Dirac. It is revealing to see how the mathematical ideas of one generation opened new avenues for the next.

11. To 100 Anniversary Of Quantum Theory To 100 anniversary of quantum theory Friden Korolkevich. The quantum theory is based on constant and quantum. But the essence of the constant is not clear. http://cust.idl.com.au/rubbo/quantum/

To 100 anniversary of Q uantum T heory Friden Korolkevich The quantum theory is based on constant and quantum But the essence of the constant is not clear. Planck called it the mysterious messenger from the real world[1] and de Broglie called it the mysterious costant[2]. What object of nature does it characterize? It is not clear. It is something like the Cheshire Cat’s smile in Lewis Carrol’s tale about Alice: there is a quantity of something, but this something is not yet or already seen. In 1951 Albert Einstein wrote to his friend Michael Besso that a conscious search for half a century had not brought him closer to answering the question: what are quanta of light? And it is still the same[3]. Consequently, the quantum theory is based on two famous but little understood categories, which are accepted without dispute. In 1911 Puancare described the Planck constant as small and unchangeable atoms of energy. Boltsman, Erenfest, Ioffe himself had the same thought. In 1924 Planck proposed we accept that the energy of the single oscillation of the light source be equal to one constant of the value Consequently, in its most general view and following principles of mechanics, the physical essence of light can be brought down to the notion of radiation energy.

12. Tour Quantum Mechanics Personalities quantum theory Comes of Age. With a body of convincing experimental evidence pointing to the significance and reality of Palnck s http://www.chembio.uoguelph.ca/educmat/chm386/rudiment/tourquan/tourquan.htm

Quantum Theory Comes of Age Niels Bohr - The Old Quantum Theory Louis de Broglie Wave Mechanics Werner Heisenberg ... Or you can escape from this tour Author: Dan Thomas email: Last Updated: Friday, July 5, 1996

13. Quantum Mechanics History The neutron was not discovered until 1932 so it is against this background that we trace the beginnings of quantum theory back to 1859. http://www-gap.dcs.st-and.ac.uk/~history/HistTopics/The_Quantum_age_begins.html

A history of Quantum Mechanics Mathematical Physics index History Topics Index It is hard to realise that the electron was only discovered a little over 100 years ago in 1897. That it was not expected is illustrated by a remark made by J J Thomson, the discoverer of the electron. He said I was told long afterwards by a distinguished physicist who had been present at my lecture that he thought I had been pulling their leg. The neutron was not discovered until 1932 so it is against this background that we trace the beginnings of quantum theory back to 1859. In 1859 Gustav Kirchhoff proved a theorem about blackbody radiation. A blackbody is an object that absorbs all the energy that falls upon it and, because it reflects no light, it would appear black to an observer. A blackbody is also a perfect emitter and Kirchhoff proved that the energy emitted E depends only on the temperature T and the frequency v of the emitted energy, i.e. E J T v He challenged physicists to find the function J In 1879 Josef Stefan proposed, on experimental grounds, that the total energy emitted by a hot body was proportional to the fourth power of the temperature. In the generality stated by Stefan this is false. The same conclusion was reached in 1884 by

14. Physics Essays Contents An overview of the classical and quantum theory related to solitons http://physics1.usc.edu/~vongehr/solitons_html/solitons.html

Click to download Solitons as .pdf file Linked to at: The Net Advance of Physics Altair 7 Communications Université Paris 7 Denis-Diderot

15. Bohr_Niels He talked of atomic stability and electrodynamic theory giving an account of the origins of quantum theory, the hydrogen spectrum, explaining the relationships http://www-gap.dcs.st-and.ac.uk/~history/Mathematicians/Bohr_Niels.html

Niels Henrik David Bohr Born: 7 Oct 1885 in Copenhagen, Denmark Died: 18 Nov 1962 in Copenhagen, Denmark Click the picture above to see ten larger pictures Show birthplace location Previous (Chronologically) Next Biographies Index Previous (Alphabetically) Next Main index Niels Bohr 's father was Christian Bohr and his mother was Ellen Adler. Christian Bohr was awarded a doctorate in physiology from the University of Copenhagen in 1880 and in 1881 he became a Privatdozent at the university. Late in the same year he married Ellen, who was the daughter of David Adler, a Jewish politician with a high standing in Danish political and commercial life. Christian and Ellen had three children. The eldest was Jenny born in 1883 in the mansion which David Adler had owned opposite Christiansborg Castle where the Danish Parliament sat. Ellen's mother had continued to live in this house after her husband David Adler died in 1878 and Ellen had gone back to her mother's home to have her child. Two years later Niels was born on his mother's 25 th birthday in the same stately home, Ellen again having returned to her mother's house for the birth of her child. The third child of the family, who went on to become a famous mathematician, was

16. Quantum Theory Tachyons and Time Travel. quantum theory. In this chapter we will explore the theory which is known as quantum mechanics. This theory has http://theory.uwinnipeg.ca/mod_tech/node143.html

Next: Early models of the Up: Physics 1501 - Modern Previous: Tachyons and Time Travel Quantum Theory In this chapter we will explore the theory which is known as quantum mechanics. This theory has some spectacular successes, among which is describing properties of atoms, but also presents us with some philosophical challenges regarding its interpretation. Early models of the atom Problems with early models Bohr model of the atom Bohr model ... modtech@theory.uwinnipeg.ca

17. The Search For A Quantum Field Theory Investigations undertaken to build a consistent quantum theory of fields http://www.cgoakley.demon.co.uk/qft/

[Dr. Chris Oakley's home page] [More comments about academic research] The search for a quantum field theory "[Renormalization is] just a stop-gap procedure. There must be some fundamental change in our ideas, probably a change just as fundamental as the passage from Bohr's orbit theory to quantum mechanics. When you get a number turning out to be infinite which ought to be finite, you should admit that there is something wrong with your equations, and not hope that you can get a good theory just by doctoring up that number." Paul Adrian Maurice Dirac (in a 1970's radio interview) Quantum Field Theory purports to be the most fundamental of sciences in that it concerns the ultimate constituents of matter. The term "quantum field theory" is used interchangeably with "particle physics" and "high energy physics" on the grounds that the experimental support for this theory comes from expensive experiments involving high-energy beams of particles. Although such multi-billion-dollar experiments are needed to push the boundaries, the theories of course claim to be universal, and should apply equally to the familiar and everyday world. Current practitioners in the field will no doubt bemoan the fact that taxpayers of the world are increasingly less willing to find the money to pay for this esoteric study. Do they really care whether there are Higgs particles or heavier flavours of quarks? Probably not. Why not? Because it really makes no difference to their own lives. Their message is clear: study theology, philosophy or "useless" branches of science if you will, but if the cost is more than a few academic salaries, blackboards and chalk, then don't expect us to pay.

18. Quantum Mechanics History A history of Quantum Mechanics. Mathematical Physics index. History Topics Index. It is hard to realise that the electron was only discovered a little over 100 years ago in 1897. 1932 so it is against this background that we trace the beginnings of quantum theory back to 1859 work was not done with quantum theory in mind but, as so http://www-groups.dcs.st-and.ac.uk/~history/HistTopics/The_Quantum_age_begins.ht

A history of Quantum Mechanics Mathematical Physics index History Topics Index It is hard to realise that the electron was only discovered a little over 100 years ago in 1897. That it was not expected is illustrated by a remark made by J J Thomson, the discoverer of the electron. He said I was told long afterwards by a distinguished physicist who had been present at my lecture that he thought I had been pulling their leg. The neutron was not discovered until 1932 so it is against this background that we trace the beginnings of quantum theory back to 1859. In 1859 Gustav Kirchhoff proved a theorem about blackbody radiation. A blackbody is an object that absorbs all the energy that falls upon it and, because it reflects no light, it would appear black to an observer. A blackbody is also a perfect emitter and Kirchhoff proved that the energy emitted E depends only on the temperature T and the frequency v of the emitted energy, i.e. E J T v He challenged physicists to find the function J In 1879 Josef Stefan proposed, on experimental grounds, that the total energy emitted by a hot body was proportional to the fourth power of the temperature. In the generality stated by Stefan this is false. The same conclusion was reached in 1884 by

19. Twistor Web A new approach pioneered by Roger Penrose, starting with conformallyinvariant concepts, to the synthesis of quantum theory and relativity. Some papers on-lin. http://users.ox.ac.uk/~tweb/

20. Bohm Ford Nelson Prigogine Umezawa Quantum Theory And Bernoulli Schemes ZPF Quantum Fluctuations within the Electron Compton Radius Vortex can be described by the Hydrodynamical Formulation of Bohm quantum theory. http://www.innerx.net/personal/tsmith/mwbn.html

Tony's Home Are "Other" Quantum Theories Really Different from Many Worlds Bohm - Pilot Wave Sarfatti - Back-Reaction ... Prigogine - Nonequilibrium Thermodynamics What are the relationships among: Feynman Checkerboards; Ising Models; Cellular Automata, and Wei Qi David Bohm's Quantum Potential has Geometric Structure of MacroSpace on which Jack Sarfatti's Back-Reaction acts. Maxwell 's Equations imply Special Relativity. Quantum Mechanics describes the Hydrogen Atom. The 15-dimensional Conformal Group Spin(4,2) is the maximal symmetry group of both Maxwell's Equations and the Hydrogen Atom as well as, as shown in hep-th/9907009 by Liu, Ma, and Hou , the canonical Dirac Lagrangian for massive fermions The Conformal Group Spin(4,2) = SU(2,2) is used in the D4-D5-E6 physics model to describe Gravity and the Higgs Mechanism , and also shows relationships between Special Relativity and Quantum Theory. Barut and Raczka , in their book Theory of Group Representations and Applications (World 1986), describe the 15 Lie algebra basis elements of the Conformal Group Spin(4,2) = SU(2,2), which are 3 Spatial Rotations, 3 Lorentz Boosts, 4 Spacetime Translations, 1 Scale Transformation, and 4 Special Conformal Transformations. In Chapter 13 (particularly section 13.4) Barut and Raczka show that wave equations for massive particles are formally invariant under the Conformal Group if the mass is transformed by the 1 Scale Transformation and the 4 Special Conformal Transformations of the Conformal Group.

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