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The Hopf Fibration and Encoding Torus Knots in Light Fields

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UNLV Theses, Dissertations, Professional Papers, and Capstones May 2016 The Hopf Fibration and Encoding Torus Knots in Light Fields John Vincent Waite University of Nevada, Las Vegas Follow this and additional works at: https://digitalscholarship.unlv.edu/thesesdissertations Part of the Physics Commons Repository Citation Waite, John Vincent, "The Hopf Fibration and Encoding Torus Knots in Light Fields" (2016). UNLV Theses, Dissertations, Professional Papers, and Capstones. 2756. http://dx.doi.org/10.34917/9112204 This Thesis is protected by copyright and/or related rights. It has been brought to you by Digital Scholarship@UNLV with permission from the rights-holder(s). You are free to use this Thesis in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s) directly, unless additional rights are indicated by a Creative Commons license in the record and/ or on the work itself. This Thesis has been accepted for inclusion in UNLV Theses, Dissertations, Professional Papers, and Capstones by an authorized administrator of Digital Scholarship@UNLV. For more information, please contact [email protected]. THE HOPF FIBRATION AND ENCODING TORUS KNOTS IN LIGHT FIELDS By John Waite Bachelor of Science - Mathematics University of Maryland, College Park 2010 A thesis submitted in partial fulfillment of the requirements for the Master of Science - Physics Department of Physics and Astronomy College of Sciences The Graduate College University of Nevada, Las Vegas May 2016 Thesis Approval The Graduate College The University of Nevada, Las Vegas April 8, 2016 This thesis prepared by John Waite entitled The Hopf Fibration and Encoding Torus Knots in Light Fields is approved in partial fulfillment of the requirements for the degree of Master of Science – Physics Department of Physics and Astronomy Bernard Zygelman, Ph.D. Kathryn Hausbeck Korgan, Ph.D. Examination Committee Chair Graduate College Interim Dean Michael Pravica, Ph.D. Examination Committee Member Stephen Lepp, Ph.D. Examination Committee Member Dieudonne D. Phanord, Ph.D. Graduate College Faculty Representative ii Abstract The first sections of this thesis explore a construction of electromagnetic fields first proposed by Bateman [2] and recently rediscovered [8] and expanded upon. With this powerful and elegant tool, I show that it is possible to construct families of EM fields that have a common topological structure that is preserved throughout time. This topological structure, known as the Hopf fibration, has been found to manifest itself in many areas of physics. Due to its utility, I have made a detailed study of it. The final section of this thesis develops an algorithm to parameterize a closed, bounded, and oriented surface that has as its boundary atorusknot.Thesetypesofsurfaces,knownasSeifertsurfaces[17],containinformation about the energy structure of the EM fields developed in the earlier sections of this thesis and may also lead to detection protocols for such fields. Because these surfaces are closed, bounded and oriented then Stokes’ theorem should be valid. A verification of this proposition is included. iii Acknowledgements I would like to thank my advisor, Dr. Bernard Zygelman, for the guidance and direction he provided me throughout the entire process of producing this thesis, and also for supplying me with the ideas in the first place. I would also like to acknowledge the other members of my committee, Drs. Lepp, Pravica, and Phanord, for their patience with me during the weeks leading to my defense. Finally, I would like to thank my wife, Kelly, for the sacrifices she was required to make in my behalf for the past two years. iv Dedication This thesis is dedicated to my dear wife Kelly. Without your support this project would never have started in the first place. v Table of Contents Abstract iii Acknowledgements iv Dedication v Table of Contents vi List of Figures viii 1 Introduction 1 2 Bateman’s Construction 3 2.1 Motivation . 3 2.2 Derivation . 3 2.3 Remarks . 9 3 Elliptically Polarized Plane Wave 10 3.1 Parameters . 10 3.2 Verifications . 11 3.3 Remarks . 12 4 The Torus 13 5 The Hopfion Solution 15 5.1 Introduction . 15 5.2 TheHopfFibration................................ 16 5.3 Parameters . 20 5.4 Verifications . 27 5.5 Remarks . 28 vi 6 Generalized Solutions on Torus Knots 29 6.1 Parameters . 29 6.2 Remarks . 31 7 Seifert Surfaces 32 7.1 ‘Top’and‘Bottom’Surfaces . 33 7.2 Twisted Bands . 37 7.3 Verification of Stokes’ Theorem . 40 8 Conclusions 45 Appendix A Parameterizing a Seifert Surface of the Trefoil Knot 46 Appendix B Verification of Stokes’ Theorem 50 Appendix C Visualizations of the Hopf Fibration 56 References 59 Curriculum Vitae 61 vii List of Figures 1The2-torusandtheplanearetopologicallyequivalent.............13 2 Nestedtori..................................... 14 3TheRiemannSphere...............................19 4 ThefibersoftheHopfmaparelinkedcircles . 21 5Latitudesproducetori..............................21 6 TheHopffibration ................................ 22 7ThetorusT 2 with component circles shown . 33 8Deletingcrossings.................................33 9 Twodiscsinparallelplanes ........................... 34 10 Generalization of the top and bottom surfaces . 35 11 Parameterizing a disc . 36 12 Actualtopandbottomsurfaces . 37 13 The boundary of the band . 38 14 Twisted bands . 39 15 The finished Seifert surface for the trefoil knot . 39 16 Line elements for the contour integral . 41 17 Vectorsnormaltoasurface ........................... 42 18 Full surface with field . 44 viii 1 Introduction The study of knots has a rich history, dating back to the 1860’s when Lord Kelvin proposed his vortex atom hypothesis [18]. Although this hypothesis was eventually abandoned with the discovery of the atom about a decade later, the rigorous study of knots in a mathematical framework was well underway. Until recently, the study of knots was confined almost exclu- sively to the realm of pure mathematics. Knots, and their intrinsic topological properties, have again entered the domain of mainstream theoretical physics. The remarkable aspect of the solutions of Maxwell’s equations we will investigate are their stablity in time, and that they possess a topological invariant, in that the electric and magnetic field lines are linked for all time, and the Poynting field line structure is unchanged in time. This topological structure could be exploited in many applications. The study of topological invariants has recently gained ground in many branches of physics research. Notably, the advances made in the field of quantum computation and information have yielded promising results that utilize the topological nature of light and matter [4,10]. While much of this research is still confined to the realm of theoretical physics, it will not be long before these phenomenon may be realized in the laboratory. This recent activity has resulted in a large increase in the funding available for continued research and development. The solutions studied in this paper are confined to the realm of electromagnetic radiation, but it would not be prudent to limit the study of such solutions to light. There is no reason to assume that these types of solutions could not be applied to matter as well. The reason that such topological invariants are important to such branches of study such as quantum information lies in the stability and robustness of that topology. These types of invariants are nearly immune to noise and perturbations, making them ideal candidates for information storage and use as qubits, as they are essentially deaf to sources of decoherence. In Chapter 2, I will present the construction proposed by Bateman [2]. Chapter 3 will verify the validity of this construction on a familiar solution to Maxwell’s equations in free space. Chapters 4 and 5 provide some background on tori and a presentation of the structure 1 referred to as the Hopf fibration. Chapter 6 will examine the solutions proposed by Kedia et al. [8]. Finally, Chapter 7 will present an algorithm to parameterize Seifert surfaces and verify Stokes’ theorem on one such surface. 2 2 Bateman’s Construction 2.1 Motivation The usual solutions to Maxwell’s equations we encounter are plane waves. These solutions, while important and useful, are only a small subset of the total solutions that are allowed. Finding and developing solutions to the wave equation has been a part of physics education and continuing research for the past 150 years. The reason for this restricted subset of solu- tions arises from the methods used to solve the resulting wave equation. It is typical to use the method of separation of variables to find solutions. However, there is no fundamental reason for all solutions to be separable. With the advances made in technology, specifically in computation, we have been able to shed light on and further our understanding of these non-separable solutions. One of the basic principles that makes this field a nearly inex- haustible one is the fact that the superposition of solutions is also a solution. This principle of superposition, and accounting for various boundary conditions, is vital when we attempt to create new solutions from old ones. The following derivation explores another method to solving the wave equation. 2.2 Derivation The method outlined in the thesis uses the construction of an electromagnetic field proposed by Bateman [2] as early as 1915. This construction goes as follows.
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