Quantum Yang–Mills Theory
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Defining Physics at Imaginary Time: Reflection Positivity for Certain
Defining physics at imaginary time: reflection positivity for certain Riemannian manifolds A thesis presented by Christian Coolidge Anderson [email protected] (978) 204-7656 to the Department of Mathematics in partial fulfillment of the requirements for an honors degree. Advised by Professor Arthur Jaffe. Harvard University Cambridge, Massachusetts March 2013 Contents 1 Introduction 1 2 Axiomatic quantum field theory 2 3 Definition of reflection positivity 4 4 Reflection positivity on a Riemannian manifold M 7 4.1 Function space E over M ..................... 7 4.2 Reflection on M .......................... 10 4.3 Reflection positive inner product on E+ ⊂ E . 11 5 The Osterwalder-Schrader construction 12 5.1 Quantization of operators . 13 5.2 Examples of quantizable operators . 14 5.3 Quantization domains . 16 5.4 The Hamiltonian . 17 6 Reflection positivity on the level of group representations 17 6.1 Weakened quantization condition . 18 6.2 Symmetric local semigroups . 19 6.3 A unitary representation for Glor . 20 7 Construction of reflection positive measures 22 7.1 Nuclear spaces . 23 7.2 Construction of nuclear space over M . 24 7.3 Gaussian measures . 27 7.4 Construction of Gaussian measure . 28 7.5 OS axioms for the Gaussian measure . 30 8 Reflection positivity for the Laplacian covariance 31 9 Reflection positivity for the Dirac covariance 34 9.1 Introduction to the Dirac operator . 35 9.2 Proof of reflection positivity . 38 10 Conclusion 40 11 Appendix A: Cited theorems 40 12 Acknowledgments 41 1 Introduction Two concepts dominate contemporary physics: relativity and quantum me- chanics. They unite to describe the physics of interacting particles, which live in relativistic spacetime while exhibiting quantum behavior. -
Mathematisches Forschungsinstitut Oberwolfach Reflection Positivity
Mathematisches Forschungsinstitut Oberwolfach Report No. 55/2017 DOI: 10.4171/OWR/2017/55 Reflection Positivity Organised by Arthur Jaffe, Harvard Karl-Hermann Neeb, Erlangen Gestur Olafsson, Baton Rouge Benjamin Schlein, Z¨urich 26 November – 2 December 2017 Abstract. The main theme of the workshop was reflection positivity and its occurences in various areas of mathematics and physics, such as Representa- tion Theory, Quantum Field Theory, Noncommutative Geometry, Dynamical Systems, Analysis and Statistical Mechanics. Accordingly, the program was intrinsically interdisciplinary and included talks covering different aspects of reflection positivity. Mathematics Subject Classification (2010): 17B10, 22E65, 22E70, 81T08. Introduction by the Organisers The workshop on Reflection Positivity was organized by Arthur Jaffe (Cambridge, MA), Karl-Hermann Neeb (Erlangen), Gestur Olafsson´ (Baton Rouge) and Ben- jamin Schlein (Z¨urich) during the week November 27 to December 1, 2017. The meeting was attended by 53 participants from all over the world. It was organized around 24 lectures each of 50 minutes duration representing major recent advances or introducing to a specific aspect or application of reflection positivity. The meeting was exciting and highly successful. The quality of the lectures was outstanding. The exceptional atmosphere of the Oberwolfach Institute provided the optimal environment for bringing people from different areas together and to create an atmosphere of scientific interaction and cross-fertilization. In particular, people from different subcommunities exchanged ideas and this lead to new col- laborations that will probably stimulate progress in unexpected directions. 3264 Oberwolfach Report 55/2017 Reflection positivity (RP) emerged in the early 1970s in the work of Osterwalder and Schrader as one of their axioms for constructive quantum field theory ensuring the equivalence of their euclidean setup with Wightman fields. -
Partial Differential Equations
CALENDAR OF AMS MEETINGS THIS CALENDAR lists all meetings which have been approved by the Council pnor to the date this issue of the Nouces was sent to press. The summer and annual meetings are joint meetings of the Mathematical Association of America and the Ameri· can Mathematical Society. The meeting dates which fall rather far in the future are subject to change; this is particularly true of meetings to which no numbers have yet been assigned. Programs of the meetings will appear in the issues indicated below. First and second announcements of the meetings will have appeared in earlier issues. ABSTRACTS OF PAPERS presented at a meeting of the Society are published in the journal Abstracts of papers presented to the American Mathematical Society in the issue corresponding to that of the Notices which contains the program of the meet ing. Abstracts should be submitted on special forms which are available in many departments of mathematics and from the office of the Society in Providence. Abstracts of papers to be presented at the meeting must be received at the headquarters of the Society in Providence, Rhode Island, on or before the deadline given below for the meeting. Note that the deadline for ab stracts submitted for consideration for presentation at special sessions is usually three weeks earlier than that specified below. For additional information consult the meeting announcement and the list of organizers of special sessions. MEETING ABSTRACT NUMBER DATE PLACE DEADLINE ISSUE 778 June 20-21, 1980 Ellensburg, Washington APRIL 21 June 1980 779 August 18-22, 1980 Ann Arbor, Michigan JUNE 3 August 1980 (84th Summer Meeting) October 17-18, 1980 Storrs, Connecticut October 31-November 1, 1980 Kenosha, Wisconsin January 7-11, 1981 San Francisco, California (87th Annual Meeting) January 13-17, 1982 Cincinnati, Ohio (88th Annual Meeting) Notices DEADLINES ISSUE NEWS ADVERTISING June 1980 April 18 April 29 August 1980 June 3 June 18 Deadlines for announcements intended for the Special Meetings section are the same as for News. -
6. L CPT Reversal
6. CPT reversal l Précis. On the representation view, there may be weak and strong arrows of time. A weak arrow exists. A strong arrow might too, but not in current physics due to CPT symmetry. There are many ways to reverse time besides the time reversal operator T. Writing P for spatial reflection or ‘parity’, and C for matter-antimatter exchange or ‘charge conjugation’, we find that PT, CT, and CPT are all time reversing transformations, when they exist. More generally, for any non-time-reversing (unitary) transformation U, we find that UT is time reversing. Are any of these transformations relevant for the arrow of time? Feynman (1949) captured many of our imaginations with the proposal that to understand the direction of time, we must actually consider the exchange of matter and antimatter as well.1 Writing about it years later, he said: “A backwards-moving electron when viewed with time moving forwards appears the same as an ordinary electron, except it’s attracted to normal electrons — we say it has positive charge. For this reason it’s called a ‘positron’. The positron is a sister to the electron, and it is an example of an ‘anti-particle’. This phenomenon is quite general. Every particle in Nature has an amplitude to move backwards in time, and therefore has an anti-particle.”(Feynman 1985, p.98) Philosophers Arntzenius and Greaves (2009, p.584) have defended Feynman’s proposal, 1In his Nobel prize speech, Feynman (1972, pg.163) attributes this idea to Wheeler in the development of their absorber theory (Wheeler and Feynman 1945). -
Spontaneous Symmetry Breaking in Particle Physics: a Case of Cross Fertilization
SPONTANEOUS SYMMETRY BREAKING IN PARTICLE PHYSICS: A CASE OF CROSS FERTILIZATION Nobel Lecture, December 8, 2008 by Yoichiro Nambu*1 Department of Physics, Enrico Fermi Institute, University of Chicago, 5720 Ellis Avenue, Chicago, USA. I will begin with a short story about my background. I studied physics at the University of Tokyo. I was attracted to particle physics because of three famous names, Nishina, Tomonaga and Yukawa, who were the founders of particle physics in Japan. But these people were at different institutions than mine. On the other hand, condensed matter physics was pretty good at Tokyo. I got into particle physics only when I came back to Tokyo after the war. In hindsight, though, I must say that my early exposure to condensed matter physics has been quite beneficial to me. Particle physics is an outgrowth of nuclear physics, which began in the early 1930s with the discovery of the neutron by Chadwick, the invention of the cyclotron by Lawrence, and the ‘invention’ of meson theory by Yukawa [1]. The appearance of an ever increasing array of new particles in the sub- sequent decades and advances in quantum field theory gradually led to our understanding of the basic laws of nature, culminating in the present stan- dard model. When we faced those new particles, our first attempts were to make sense out of them by finding some regularities in their properties. Researchers in- voked the symmetry principle to classify them. A symmetry in physics leads to a conservation law. Some conservation laws are exact, like energy and electric charge, but these attempts were based on approximate similarities of masses and interactions. -
Phase with No Mass Gap in Non-Perturbatively Gauge-Fixed
Phase with no mass gap in non-perturbatively gauge-fixed Yang{Mills theory Maarten Goltermanay and Yigal Shamirb aInstitut de F´ısica d'Altes Energies, Universitat Aut`onomade Barcelona, E-08193 Bellaterra, Barcelona, Spain bSchool of Physics and Astronomy Raymond and Beverly Sackler Faculty of Exact Sciences Tel-Aviv University, Ramat Aviv, 69978 ISRAEL ABSTRACT An equivariantly gauge-fixed non-abelian gauge theory is a theory in which a coset of the gauge group, not containing the maximal abelian sub- group, is gauge fixed. Such theories are non-perturbatively well-defined. In a finite volume, the equivariant BRST symmetry guarantees that ex- pectation values of gauge-invariant operators are equal to their values in the unfixed theory. However, turning on a small breaking of this sym- metry, and turning it off after the thermodynamic limit has been taken, can in principle reveal new phases. In this paper we use a combination of strong-coupling and mean-field techniques to study an SU(2) Yang{Mills theory equivariantly gauge fixed to a U(1) subgroup. We find evidence for the existence of a new phase in which two of the gluons becomes mas- sive while the third one stays massless, resembling the broken phase of an SU(2) theory with an adjoint Higgs field. The difference is that here this phase occurs in an asymptotically-free theory. yPermanent address: Department of Physics and Astronomy, San Francisco State University, San Francisco, CA 94132, USA 1 1. Introduction Intro Some years ago, we proposed a new approach to discretizing non-abelian chiral gauge theories, in order to make them accessible to the methods of lattice gauge theory [1]. -
8 Non-Abelian Gauge Theory: Perturbative Quantization
8 Non-Abelian Gauge Theory: Perturbative Quantization We’re now ready to consider the quantum theory of Yang–Mills. In the first few sec- tions, we’ll treat the path integral formally as an integral over infinite dimensional spaces, without worrying about imposing a regularization. We’ll turn to questions about using renormalization to make sense of these formal integrals in section 8.3. To specify Yang–Mills theory, we had to pick a principal G bundle P M together ! with a connection on P . So our first thought might be to try to define the Yang–Mills r partition function as ? SYM[ ]/~ Z [(M,g), g ] = A e− r (8.1) YM YM D ZA where 1 SYM[ ]= tr(F F ) (8.2) r −2g2 r ^⇤ r YM ZM as before, and is the space of all connections on P . A To understand what this integral might mean, first note that, given any two connections and , the 1-parameter family r r0 ⌧ = ⌧ +(1 ⌧) 0 (8.3) r r − r is also a connection for all ⌧ [0, 1]. For example, you can check that the rhs has the 2 behaviour expected of a connection under any gauge transformation. Thus we can find a 1 path in between any two connections. Since 0 ⌦M (g), we conclude that is an A r r2 1 A infinite dimensional affine space whose tangent space at any point is ⌦M (g), the infinite dimensional space of all g–valued covectors on M. In fact, it’s easy to write down a flat (L2-)metric on using the metric on M: A 2 1 µ⌫ a a d ds = tr(δA δA)= g δAµ δA⌫ pg d x. -
Arthur Strong Wightman (1922–2013)
Obituary Arthur Strong Wightman (1922–2013) Arthur Wightman, a founding father of modern mathematical physics, passed away on January 13, 2013 at the age of 90. His own scientific work had an enormous impact in clar- ifying the compatibility of relativity with quantum theory in the framework of quantum field theory. But his stature and influence was linked with an enormous cadre of students, scientific collaborators, and friends whose careers shaped fields both in mathematics and theoretical physics. Princeton has a long tradition in mathematical physics, with university faculty from Sir James Jeans through H.P. Robertson, Hermann Weyl, John von Neumann, Eugene Wigner, and Valentine Bargmann, as well as a long history of close collaborations with colleagues at the Institute for Advanced Study. Princeton became a mecca for quantum field theorists as well as other mathematical physicists during the Wightman era. Ever since the advent of “axiomatic quantum field theory”, many researchers flocked to cross the threshold of his open office door—both in Palmer and later in Jadwin—for Arthur was renowned for his generosity in sharing ideas and research directions. In fact, some students wondered whether Arthur might be too generous with his time helping others, to the extent that it took time away from his own research. Arthur had voracious intellectual appetites and breadth of interests. Through his interactions with others and his guidance of students and postdocs, he had profound impact not only on axiomatic and constructive quantum field theory but on the de- velopment of the mathematical approaches to statistical mechanics, classical mechanics, dynamical systems, transport theory, non-relativistic quantum mechanics, scattering the- ory, perturbation of eigenvalues, perturbative renormalization theory, algebraic quantum field theory, representations of C⇤-algebras, classification of von Neumann algebras, and higher spin equations. -
1995 Steele Prizes
steele.qxp 4/27/98 3:29 PM Page 1288 1995 Steele Prizes Three Leroy P. Steele Prizes were presented at The text that follows contains, for each award, the awards banquet during the Summer Math- the committee’s citation, the recipient’s response fest in Burlington, Vermont, in early August. upon receiving the award, and a brief bio- These prizes were established in 1970 in honor graphical sketch of the recipient. of George David Birkhoff, William Fogg Osgood, and William Caspar Graustein Edward Nelson: 1995 Steele Prize for and are endowed under the Seminal Contribution to Research terms of a bequest from The 1995 Leroy P. Steele award for research of Leroy P. Steele. seminal importance goes to Professor Edward The Steele Prizes are Nelson of Princeton University for the following ...for a research awarded in three categories: two papers in mathematical physics character- for a research paper of fun- ized by leaders of the field as extremely innov- paper of damental and lasting impor- ative: tance, for expository writing, 1. “A quartic interaction in two dimensions” in fundamental and for cumulative influence Mathematical Theory of Elementary Particles, and lasting extending over a career, in- MIT Press, 1966, pages 69–73; cluding the education of doc- 2. “Construction of quantum fields from Markoff importance, toral students. The current fields” in Journal of Functional Analysis 12 award is $4,000 in each cate- (1973), 97–112. for expository gory. In these papers he showed for the first time The recipients of the 1995 how to use the powerful tools of probability writing, and for Steele Prizes are Edward Nel- theory to attack the hard analytic questions of son for seminal contribution constructive quantum field theory, controlling cumulative to research, Jean-Pierre Serre renormalizations with Lp estimates in the first influence for mathematical exposition, paper and, in the second, turning Euclidean and John T. -
Existence of Yang–Mills Theory with Vacuum Vector and Mass Gap
EJTP 5, No. 18 (2008) 33–38 Electronic Journal of Theoretical Physics Existence of Yang–Mills Theory with Vacuum Vector and Mass Gap Igor Hrnciˇ c´∗ Ludbreskaˇ 1b HR42000 Varazdinˇ , Croatia Received 7 June 2008, Accepted 20 June 2008, Published 30 June 2008 Abstract: This paper shows that quantum theory describing particles in finite expanding space–time exhibits natural ultra–violet and infra–red cutoffs as well as posesses a mass gap and a vacuum vector. Having ultra–violet and infra–red cutoffs, all renormalization issues disappear. This shows that Yang–Mills theory exists for any simple compact gauge group and has a mass gap and a vacuum vector. c Electronic Journal of Theoretical Physics. All rights reserved. Keywords: Finite Expanding Space–time; Yang–Mills fields; Renormalization; Regularization; Mass Gap; Vacuum Vector PACS (2006): 12.10.-g; 12.15.-y; 03.70.+k; 11.10.-z; 03.65.-w 1. Introduction All the particle interactions – beside gravitational interactions – are today decribable by Standard model. Main theoretical tool for Standard model is Yang–Mills action. This action is able to describe all the possible particle interactions experimentally observed so far – including strong nuclear interactions. The bad part is that there are some issues regarding quantum theory in general. First issue is that any higher order correction in the perturbation calculations is singular – there are infra–red and ultra–violet catastrophes in calculations. Many mathe- matical methods have been devised over last half a century in order to cure singularities, but problem of renormalization still remains. Second issue is that in order to have confined particles, spectrum should exhibit a mass gap. -
Solutions in Constructive Field Theory
Solutions in Constructive Field Theory Leif Hancox-Li ∗ [email protected] June 7, 2016 Abstract Constructive field theory aims to rigorously construct concrete, non-trivial solutions to Lagrangians used in particle physics, where the solutions satisfy some relevant set of axioms. I examine the relationship of solutions in constructive field theory to both axiomatic and Lagrangian quantum field theory (QFT). I argue that Lagrangian QFT provides conditions for what counts as a successful constructive solution, and that it provides other information that guides constructive field theorists to solutions. Solutions matter because they describe the behavior of QFT systems, and thus what QFT says the world is like. Constructive field theory, in incorporating ingredients from both axiomatic and Lagrangian QFT, clarifies existing disputes about which parts of QFT are philosophically relevant and how rigor relates to these disputes. ∗I thank Bob Batterman and Michael Miller for comments and encouragement. Several anonymous referees also contribued valuable comments. Copyright Philosophy of Science 2016 Preprint (not copyedited or formatted) Please use DOI when citing or quoting 1 Introduction To date, philosophers of quantum field theory (QFT) have paid much attention to roughly two kinds of QFT: axiomatic approaches to algebraic QFT (Halvorson and Muger,¨ 2006), and Lagrangian-based QFT as used by particle physicists (Wallace, 2006). Comparatively less attention, however, has been paid to constructive QFT, an approach that aims to rigorously construct non-trivial solutions of QFT for Lagrangians and Hamiltonians that are important in particle physics, ensuring that such solutions satisfy certain axioms. In doing so, constructive QFT mediates between axiomatic approaches to QFT and physicists’ Lagrangian-based QFT. -
3. Interacting Fields
3. Interacting Fields The free field theories that we’ve discussed so far are very special: we can determine their spectrum, but nothing interesting then happens. They have particle excitations, but these particles don’t interact with each other. Here we’ll start to examine more complicated theories that include interaction terms. These will take the form of higher order terms in the Lagrangian. We’ll start by asking what kind of small perturbations we can add to the theory. For example, consider the Lagrangian for a real scalar field, 1 1 λ = @ @µφ m2φ2 n φn (3.1) L 2 µ − 2 − n! n 3 X≥ The coefficients λn are called coupling constants. What restrictions do we have on λn to ensure that the additional terms are small perturbations? You might think that we need simply make “λ 1”. But this isn’t quite right. To see why this is the case, let’s n ⌧ do some dimensional analysis. Firstly, note that the action has dimensions of angular momentum or, equivalently, the same dimensions as ~.Sincewe’veset~ =1,using the convention described in the introduction, we have [S] = 0. With S = d4x ,and L [d4x]= 4, the Lagrangian density must therefore have − R [ ]=4 (3.2) L What does this mean for the Lagrangian (3.1)? Since [@µ]=1,wecanreado↵the mass dimensions of all the factors to find, [φ]=1 , [m]=1 , [λ ]=4 n (3.3) n − So now we see why we can’t simply say we need λ 1, because this statement only n ⌧ makes sense for dimensionless quantities.