DOCSLIB.ORG

Magnetic Monopoles and Dark Matter V

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Magnetic Monopoles and Dark Matter V ISSN 1063-7761, Journal of Experimental and Theoretical Physics, 2018, Vol. 127, No. 4, pp. 638–646. © Pleiades Publishing, Inc., 2018. Original Russian Text © V.V. Burdyuzha, 2018, published in Zhurnal Eksperimental’noi i Teoreticheskoi Fiziki, 2018, Vol. 154, No. 4, pp. 751–760. NUCLEI, PARTICLES, FIELDS, GRAVITATION, AND ASTROPHYSICS Magnetic Monopoles and Dark Matter V. V. Burdyuzha Astrospace Center, Lebedev Physical Institute, Russian Academy of Sciences, Profsoyuznaya ul. 84/32, Moscow, 117997 Russia e-mail: [email protected] Received October 8, 2017; in final form, May 29, 2018 Abstract—Schwinger’s idea about the magnetic world of the early Universe, in which magnetic charges (monopoles) and magnetic atoms (g+g–) could be formed, is developed. In the present-day Universe mag- netic charges with energies in the GeV range can be formed in the magnetospheres of young pulsars in super- strong magnetic fields. Spectroscopic features of magnetic atoms and possibilities for their observations are discussed. Relic magnetic atoms can contribute up to 18% to the dark matter density. The gamma-ray excess at our Galactic center could arise under two-photon annihilation of magnetic charges as a cooperative effect from neutron stars. A sharp physical difference of Schwinger’s magnetic world from Dirac’s present-day elec- tric world is pointed out. Artificial magnetic monopoles are also mentioned briefly. DOI: 10.1134/S1063776118100011 1. INTRODUCTION However, not all of the physicists “neglected” In electrodynamics the problem of magnetic magnetic charges, especially in the context of the early charges has not been completely clarified, although Universe. Furthermore, Sakharov [9] pointed out that the assertion that there are no free magnetic charges in black miniholes could evaporate heavy monopoles. nature has become fixed owing to Maxwell’s classical The inflationary cosmological model was developed equations. The problem has not become clearer even to avoid a great over-excess (up to 16 orders of magni- after the detection of structures similar to Dirac mag- tude) of high-energy GUT monopoles (GUT stands netic charges in laboratory conditions [1–3]. They for grand unified theory). Zel’dovich and Khlopov were called artificial magnetic monopoles. Therefore, [10] showed that the present-day concentration of the authors of [1–3] predict a revolution in physics. In relic monopoles with energies in the TeV range is contrast, in this paper we transfer some of the “revolu- extremely low (10–19 cm–3). Schwinger published the tionary ideas” to the cosmos. Magnetic atoms and review “A Magnetic Model of Matter” in UFN [11], even isolated magnetic charges that are “blown out”, thereby predicting the magnetic world of the early as electron and positrons, from young neutron stars Universe. In addition, an interesting remark was made can exist in cosmic conditions and, what is more, in [12]: “monopoles cannot play any role in the Stan- probably not all of the high-energy relic magnetic dard Model, and in its usual extensions, up to the atoms have decayed. Planck scale, on which they can lead to space discrete- Magnetic charges were first mentioned by Curie ness.” [4] more than 120 years ago. They were detected by the Here we want to draw attention to the possibility of Austrian physicist Ehrenhaft [5] and the Soviet physi- detecting monopoles with energies in the GeV range in cist Sizov [6]. However, nobody believed these scien- cosmic conditions and to enhance the role of high- tists, because in Maxwell’s equations divB = 0 and energy magnetic monopoles in the early Universe. Maxwell’s equations are “sacred”. Sizov in his time The main reason for our desire to revisit the leptogen- was not even certified as a scientist, because he was esis is a huge magnitude of magnetic forces. In the concerned with “rubbish”. Magnetic charges of high symmetric (Schwinger) case, the magnetic forces are energies 1015–1016 GeV were probably observed in stronger than the electric ones approximately by a fac- cosmic rays by Cabrera [7]. However, there were only tor of ~20000 (Section 3). The question about the two events in his experiment and, what is more, these influence of these forces on the generation of baryon were observed on Saint Valentine’s Day, which asymmetry of the Universe immediately arises here, caused distrust of the physical community. And, of because all of the known effects leading to CP-sym- course, the main argument for the impossibility to metry breaking are weak. observe isolated magnetic poles (monopoles) comes The detection of artificial magnetic charges in spin from the course of theoretical physics by Landau and ice as a result of geometrical (magnetic) frustration is Lifshitz [8]. actually a very interesting event emitting Dirac mono- 638 MAGNETIC MONOPOLES AND DARK MATTER 639 1 poles. The deconfinement of effective magnetic International Space Station, but this question requires charges in a crystal lattice (to be more precise, the an additional study. Magnetic charges (monopoles) 1 deconfinement of zero-dimension point topological and atoms consisting of them should be included in defects) arises at temperatures close to absolute zero. the composition of dark matter. Our explanation of the Note that the spectrum of topological defects in spin gamma-ray excess at the Galactic center in the energy 2 systems includes vortices, solitonic vortices, skyrmi- range 1–3 GeV is the combined effect from the anni- 3 ons, monopoles, and knots [13]. The new term “mag- hilation of produced magnetic charges in the magne- netricity” (by analogy with electricity) and even such a tospheres of a large number of young neutron stars— term as “magnetolyte” (by analogy with electrolyte) pulsars (this hypothesis will be discussed in Section 5). were introduced for the emerged current of magnetic Here we will focus our attention on magnetic charges. These experiments and magnetic frustration monopoles with energies in the GeV range. Mono- physics are described in detail in [13–17]. poles of very high energies (1015–1016 GeV), of course, In other words, for the appearance of a current of will be investigated also, but more briefly. Their detec- such magnetic charges the topological order in crystals tion is envisaged in the Dubna experiment on Lake is violated due to magnetic frustration [17]. As Bram- Baikal [23, 24] and in many other experiments world- well [16], one of the ideologists of spin ice, mono- wide. Sullivan and Fryberger [25] consider the execu- 3 3 poles, and magnetricity, said, “magnetricity is a cur- tion of an experiment in Japan by the BELLE II Col- rent of thermally excited defects in spin ice”. Possibly, laboration at the KEK facility aimed at searching for it should be added to this definition that it is necessary magnetic monopoles with a mass of 4–5 GeV/c2 for to take into account the spin correlations. The study of the natural, in their opinion, case where the electric magnetic systems in low-temperature physics includes and magnetic charges are equal to each other, i.e., several physical concepts: spin ice, magnetic mono- e = g. poles, anomalous Kondo and Hall effects [18]. In the opinion of Zvyagin [18], we already observe a new physics in frustrated magnets and it is probably hard 3. PHYSICAL SUBSTANTIATION not to agree with this. OF THE PRESENCE OF MAGNETIC CHARGES 2. MAGNETIC CHARGES, Formally, Maxwell’s classical equations do not THEIR ENERGIES, AND THEIR SEARCH suggest a complete symmetry of electric and magnetic processes and these equations yield correct results, Magnetic monopoles have been and are being although the presence of magnetic charges (g) can searched for in various energy ranges from 1016 GeV to explain the electric charge quantization. An important a few GeV or even lower and, of course, their search is dependence was derived in his time by Dirac [26]: conducted by various methods. At the Large Hadron eg Collider this is the MoEDAL experiment. A brief the- ==±±±k ,k 0,1,2,3,... (1) ory of leptonic magnetic monopoles is presented in c 2 [19, 20] and it was shown that a light magnetic mono- (k is the monopole quantum number). This classical pole could be included in a consistent way in the Stan- definition of k differs from its quantum definition dard Model through the extension of the leptonic sec- given in the review [11]. In his time Dirac accepted the tor, i.e., a magnetic analog of the Standard Model has challenge of Curie [4] and suggested the existence of been created. Leptonic magnetic monopoles can be an elementary magnetic charge. The relation between focused. A special accelerator is being built in France the charges g = 68.5e follows from the condition (1) at for this purpose [19]. Note that the observation of a k = 1, i.e., the magnetic charge is very large and this is moving magnetic monopole with charge g = 137e and its main peculiarity. Furthermore, we know well that a mass larger than 100 proton masses was announced 2 the fine-structure constant αe = e /c = 1/137 charac- in [21]. It should also be noted that many papers, terizes the force of attraction (or repulsion) between which make no sense to cite here, were devoted to α 2 closing the subject of the existence of magnetic two electric charges. Accordingly, g = g /c = 34.25 charges (monopoles). will characterize the force of attraction (or repulsion) between two magnetic charges. The ratio of these two Our interest in magnetic charges is associated with constants is the realization of a GeV monopolium (g+g–) atomic system in cosmic conditions, by analogy with positro- gc2 / + – = 4692.25. nium (e e ) [22], in which some transitions can be ec2 / observed in the gamma-ray range before annihilation, α ≫ as, incidentally, in positronium, but in the case of pos- Since g 1, accurate quantum-mechanical calcula- itronium this is the millimeter and radio bands.
Load more

Recommended publications
  • Magnetic Monopole Searches See the Related Review(S): Magnetic Monopoles
    Citation: P.A. Zyla et al. (Particle Data Group), Prog. Theor. Exp. Phys. 2020, 083C01 (2020) Magnetic Monopole Searches See the related review(s): Magnetic Monopoles Monopole Production Cross Section — Accelerator Searches X-SECT MASS CHG ENERGY (cm2) (GeV) (g) (GeV) BEAM DOCUMENT ID TECN <2.5E−37 200–6000 1 13000 pp 1 ACHARYA 17 INDU <2E−37 200–6000 2 13000 pp 1 ACHARYA 17 INDU <4E−37 200–5000 3 13000 pp 1 ACHARYA 17 INDU <1.5E−36 400–4000 4 13000 pp 1 ACHARYA 17 INDU <7E−36 1000–3000 5 13000 pp 1 ACHARYA 17 INDU <5E−40 200–2500 0.5–2.0 8000 pp 2 AAD 16AB ATLS <2E−37 100–3500 1 8000 pp 3 ACHARYA 16 INDU <2E−37 100–3500 2 8000 pp 3 ACHARYA 16 INDU <6E−37 500–3000 3 8000 pp 3 ACHARYA 16 INDU <7E−36 1000–2000 4 8000 pp 3 ACHARYA 16 INDU <1.6E−38 200–1200 1 7000 pp 4 AAD 12CS ATLS <5E−38 45–102 1 206 e+ e− 5 ABBIENDI 08 OPAL <0.2E−36 200–700 1 1960 p p 6 ABULENCIA 06K CNTR < 2.E−36 1 300 e+ p 7,8 AKTAS 05A INDU < 0.2 E−36 2 300 e+ p 7,8 AKTAS 05A INDU < 0.09E−36 3 300 e+ p 7,8 AKTAS 05A INDU < 0.05E−36 ≥ 6 300 e+ p 7,8 AKTAS 05A INDU < 2.E−36 1 300 e+ p 7,9 AKTAS 05A INDU < 0.2E−36 2 300 e+ p 7,9 AKTAS 05A INDU < 0.07E−36 3 300 e+ p 7,9 AKTAS 05A INDU < 0.06E−36 ≥ 6 300 e+ p 7,9 AKTAS 05A INDU < 0.6E−36 >265 1 1800 p p 10 KALBFLEISCH 04 INDU < 0.2E−36 >355 2 1800 p p 10 KALBFLEISCH 04 INDU < 0.07E−36 >410 3 1800 p p 10 KALBFLEISCH 04 INDU < 0.2E−36 >375 6 1800 p p 10 KALBFLEISCH 04 INDU < 0.7E−36 >295 1 1800 p p 11,12 KALBFLEISCH 00 INDU < 7.8E−36 >260 2 1800 p p 11,12 KALBFLEISCH 00 INDU < 2.3E−36 >325 3 1800 p p 11,13 KALBFLEISCH 00 INDU < 0.11E−36 >420 6 1800 p p 11,13 KALBFLEISCH 00 INDU <0.65E−33 <3.3 ≥ 2 11A 197Au 14,15 HE 97 <1.90E−33 <8.1 ≥ 2 160A 208Pb 14,15 HE 97 <3.E−37 <45.0 1.0 88–94 e+ e− PINFOLD 93 PLAS <3.E−37 <41.6 2.0 88–94 e+ e− PINFOLD 93 PLAS <7.E−35 <44.9 0.2–1.0 89–93 e+ e− KINOSHITA 92 PLAS <2.E−34 <850 ≥ 0.5 1800 p p BERTANI 90 PLAS <1.2E−33 <800 ≥ 1 1800 p p PRICE 90 PLAS <1.E−37 <29 1 50–61 e+ e− KINOSHITA 89 PLAS <1.E−37 <18 2 50–61 e+ e− KINOSHITA 89 PLAS <1.E−38 <17 <1 35 e+ e− BRAUNSCH..
    [Show full text]
  • The Moedal Experiment at the LHC. Searching Beyond the Standard
    126 EPJ Web of Conferences , 02024 (2016) DOI: 10.1051/epjconf/201612602024 ICNFP 2015 The MoEDAL experiment at the LHC Searching beyond the standard model James L. Pinfold (for the MoEDAL Collaboration)1,a 1 University of Alberta, Physics Department, Edmonton, Alberta T6G 0V1, Canada Abstract. MoEDAL is a pioneering experiment designed to search for highly ionizing avatars of new physics such as magnetic monopoles or massive (pseudo-)stable charged particles. Its groundbreaking physics program defines a number of scenarios that yield potentially revolutionary insights into such foundational questions as: are there extra dimensions or new symmetries; what is the mechanism for the generation of mass; does magnetic charge exist; what is the nature of dark matter; and, how did the big-bang develop. MoEDAL’s purpose is to meet such far-reaching challenges at the frontier of the field. The innovative MoEDAL detector employs unconventional methodologies tuned to the prospect of discovery physics. The largely passive MoEDAL detector, deployed at Point 8 on the LHC ring, has a dual nature. First, it acts like a giant camera, comprised of nuclear track detectors - analyzed offline by ultra fast scanning microscopes - sensitive only to new physics. Second, it is uniquely able to trap the particle messengers of physics beyond the Standard Model for further study. MoEDAL’s radiation environment is monitored by a state-of-the-art real-time TimePix pixel detector array. A new MoEDAL sub-detector to extend MoEDAL’s reach to millicharged, minimally ionizing, particles (MMIPs) is under study Finally we shall describe the next step for MoEDAL called Cosmic MoEDAL, where we define a very large high altitude array to take the search for highly ionizing avatars of new physics to higher masses that are available from the cosmos.
    [Show full text]
  • Accelerator Search of the Magnetic Monopo
    Accelerator Based Magnetic Monopole Search Experiments (Overview) Vasily Dzhordzhadze, Praveen Chaudhari∗, Peter Cameron, Nicholas D’Imperio, Veljko Radeka, Pavel Rehak, Margareta Rehak, Sergio Rescia, Yannis Semertzidis, John Sondericker, and Peter Thieberger. Brookhaven National Laboratory ABSTRACT We present an overview of accelerator-based searches for magnetic monopoles and we show why such searches are important for modern particle physics. Possible properties of monopoles are reviewed as well as experimental methods used in the search for them at accelerators. Two types of experimental methods, direct and indirect are discussed. Finally, we describe proposed magnetic monopole search experiments at RHIC and LHC. Content 1. Magnetic Monopole characteristics 2. Experimental techniques 3. Monopole Search experiments 4. Magnetic Monopoles in virtual processes 5. Future experiments 6. Summary 1. Magnetic Monopole characteristics The magnetic monopole puzzle remains one of the fundamental and unsolved problems in physics. This problem has a along history. The military engineer Pierre de Maricourt [1] in1269 was breaking magnets, trying to separate their poles. P. Curie assumed the existence of single magnetic poles [2]. A real breakthrough happened after P. Dirac’s approach to the solution of the electron charge quantization problem [3]. Before Dirac, J. Maxwell postulated his fundamental laws of electrodynamics [4], which represent a complete description of all known classical electromagnetic phenomena. Together with the Lorenz force law and the Newton equations of motion, they describe all the classical dynamics of interacting charged particles and electromagnetic fields. In analogy to electrostatics one can add a magnetic charge, by introducing a magnetic charge density, thus magnetic fields are no longer due solely to the motion of an electric charge and in Maxwell equation a magnetic current will appear in analogy to the electric current.
    [Show full text]
  • Magnetic Monopoles
    Magnetic Monopoles Since Maxwell discovered the unified theory, Maxwell equations, of electric and magnetic forces, people have studied its implications. Maxwell conjectured the electromagnetic wave in his equations to be the light, based on the speed of electromagnetic wave being close to the speed of light. Since Herz and Heaviside, independently, have written the current form of Maxwell’s equations, 1905 Poincare and Einstein independently found the Lorentz transformation which is the property of Maxwell equation. The study of cathode ray has led to the discovery of electrons. The electron orbits are bending around when a magnet was brought near it. By imagining the motion of electron near a tip of a very long solenoid, Poincare introduced a magnetic monopole around which the magnetic field comes out radially. B = gr/r3 1. Consider the motion of a charged particle with equation of motion, m d2r/dt2 = e v x B Find the conserved energy E and the explicit form of the conserved angular momentum J=mr x dr/dt+.… 2. Find the orbit of the charged particle. 3. Consider the motion of two magnetic monopoles appearing in the 4-dim field theory. Magnetic monopoles are characterized by their positions and internal phase angle. The Lagrangian for the relative position r and phase ψ is given as below. where ψ ~ ψ+2π and ∇xw(r)= -r/r3 , and r0 and a are constant positive parameters.. µ r r 1 1 a2 L = 1+ 0 r˙ 2 + r2 1+ 0 − (ψ˙ + w(r) r˙)2 + 0 2 r0 2 r r · 2µr0 1+ r Calling the conserved charge q under the shift symmetry of ψ and the conjugate momentum π of the coordinate r, find the expression for the conserved energy and angular momentum J.
    [Show full text]
  • 117. Magnetic Monopoles
    1 117. Magnetic Monopoles 117. Magnetic Monopoles Revised August 2019 by D. Milstead (Stockholm U.) and E.J. Weinberg (Columbia U.). 117.1 Theory of magnetic monopoles The symmetry between electric and magnetic fields in the source-free Maxwell’s equations naturally suggests that electric charges might have magnetic counterparts, known as magnetic monopoles. Although the greatest interest has been in the supermassive monopoles that are a firm prediction of all grand unified theories, one cannot exclude the possibility of lighter monopoles. In either case, the magnetic charge is constrained by a quantization condition first found by Dirac [1]. Consider a monopole with magnetic charge QM and a Coulomb magnetic field Q ˆr B = M . (117.1) 4π r2 Any vector potential A whose curl is equal to B must be singular along some line running from the origin to spatial infinity. This Dirac string singularity could potentially be detected through the extra phase that the wavefunction of a particle with electric charge QE would acquire if it moved along a loop encircling the string. For the string to be unobservable, this phase must be a multiple of 2π. Requiring that this be the case for any pair of electric and magnetic charges gives min min the condition that all charges be integer multiples of minimum charges QE and QM obeying min min QE QM = 2π . (117.2) (For monopoles which also carry an electric charge, called dyons [2], the quantization conditions on their electric charges can be modified. However, the constraints on magnetic charges, as well as those on all purely electric particles, will be unchanged.) Another way to understand this result is to note that the conserved orbital angular momentum of a point electric charge moving in the field of a magnetic monopole has an additional component, with L = mr × v − 4πQEQM ˆr (117.3) Requiring the radial component of L to be quantized in half-integer units yields Eq.
    [Show full text]
  • Continuous Gravitational Waves and Magnetic Monopole Signatures from Single Neutron Stars
    PHYSICAL REVIEW D 101, 075028 (2020) Continuous gravitational waves and magnetic monopole signatures from single neutron stars † ‡ P. V. S. Pavan Chandra,1,* Mrunal Korwar,2, and Arun M. Thalapillil 1, 1Indian Institute of Science Education and Research, Homi Bhabha Road, Pashan, Pune 411008, India 2Department of Physics, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA (Received 2 December 2019; accepted 1 April 2020; published 15 April 2020) Future observations of continuous gravitational waves from single neutron stars, apart from their monumental astrophysical significance, could also shed light on fundamental physics and exotic particle states. One such avenue is based on the fact that magnetic fields cause deformations of a neutron star, which results in a magnetic-field-induced quadrupole ellipticity. If the magnetic and rotation axes are different, this quadrupole ellipticity may generate continuous gravitational waves which may last decades, and may be observable in current or future detectors. Light, milli-magnetic monopoles, if they exist, could be pair-produced nonperturbatively in the extreme magnetic fields of neutron stars, such as magnetars. This nonperturbative production furnishes a new, direct dissipative mechanism for the neutron star magnetic fields. Through their consequent effect on the magnetic-field-induced quadrupole ellipticity, they may then potentially leave imprints in the early stage continuous gravitational wave emissions. We speculate on this possibility in the present study, by considering some of the relevant physics and taking a very simplified toy model of a magnetar as the prototypical system. Preliminary indications are that new- born millisecond magnetars could be promising candidates to look for such imprints.
    [Show full text]
  • Measurement of Neutrino's Magnetic Monopole Charge, Vacuum Energy and Cause of Quantum Mechanical Uncertainty
    Measurement of Neutrino's Magnetic Monopole Charge, Vacuum Energy and Cause of Quantum Mechanical Uncertainty Eue Jin Jeong ( [email protected] ) Tachyonics Research Institute Dennis Edmondson Columbia College, Marysville, Washington Research Article Keywords: fundamental physics, elementary particle physics, electricity and magnetism, experimental physics Posted Date: October 9th, 2020 DOI: https://doi.org/10.21203/rs.3.rs-88897/v1 License: This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Measurement of Neutrino's Magnetic Monopole Charge, Vacuum Energy and Cause of Quantum Mechanical Uncertainty Abstract Charge conservation in the theory of elementary particle physics is one of the best- established principles in physics. As such, if there are magnetic monopoles in the universe, the magnetic charge will most likely be a conserved quantity like electric charges. If neutrinos are magnetic monopoles, as physicists have speculated the possibility, then neutrons must also have a magnetic monopole charge, and the Earth should show signs of having a magnetic monopole charge on a macroscopic scale. To test this hypothesis, experiments were performed to detect the magnetic monopole's effect near the equator by measuring the Earth's radial magnetic force using two balanced high strength neodymium rods magnets that successfully identified the magnetic monopole charge. From this observation, we conclude that at least the electron neutrino which is a byproduct of weak decay of the neutron must be magnetic monopole. We present mathematical expressions for the vacuum electric field based on the findings and discuss various physical consequences related to the symmetry in Maxwell's equations, the origin of quantum mechanical uncertainty, the medium for electromagnetic wave propagation in space, and the logistic distribution of the massive number of magnetic monopoles in the universe.
    [Show full text]
  • Searches for Magnetic Monopoles with Icecube
    EPJ Web of Conferences 168, 04010 (2018) https://doi.org/10.1051/epjconf/201816804010 Joint International Conference of ICGAC-XIII and IK-15 on Gravitation, Astrophysics and Cosmology Searches for magnetic monopoles with IceCube Anna Pollmann1, for the IceCube Collaboration 1Dept. of Physics, University of Wuppertal, 42119 Wuppertal, Germany Abstract. Particles that carry a magnetic monopole charge are proposed by various the- ories which go beyond the Standard Model of particle physics. The expected mass of magnetic monopoles varies depending on the theory describing its origin, generally the monopole mass far exceeds those which can be created at accelerators. Magnetic monopoles gain kinetic energy in large scale galactic magnetic fields and, depending on their mass, can obtain relativistic velocities. IceCube is a high energy neutrino detector using the clear ice at the South Pole as a detec- tion medium. As monopoles pass through this ice they produce optical light by a variety of mechanisms. With increasing velocity, they produce light by catalysis of baryon de- cay, luminescence in the ice associated with electronic excitations, indirect and direct Cherenkov light from the monopole track, and Cherenkov light from cascades induced by pair creation and photonuclear reactions. By searching for this light, current best lim- its for the monopole flux over a broad range of velocities was achieved using the IceCube detector. A review of these magnetic monopole searches is presented. 1 Introduction The existence of magnetic monopoles, particles carrying a single magnetic charge, is motivated by var- ious theories which extend the Standard Model of particles, such as Grand Unified Theories (GUTs), String theory, Kaluza-Klein, and M-Theory [1].
    [Show full text]
  • Magnetic Monopole Field Exposed by Electrons
    LETTERS PUBLISHED ONLINE: 1 DECEMBER 2013 | DOI: 10.1038/NPHYS2816 Magnetic monopole field exposed by electrons Armand Béché, Ruben Van Boxem, Gustaaf Van Tendeloo and Jo Verbeeck* The experimental search for magnetic monopole particles1–3 with m depending on the charge of the magnetic monopole and has, so far, been in vain. Nevertheless, these elusive particles φ being the azimuthal angle in the plane perpendicular to the of magnetic charge have fuelled a rich field of theoretical electron wave propagation. study4–10. Here, we created an approximation of a magnetic Approximating the magnetic monopole now by the end of a monopole in free space at the end of a long, nanoscopically magnetic needle leads to similar effects. Indeed, such a semi-infinite thin magnetic needle11. We experimentally demonstrate that cylinder of magnetic flux has been considered in earlier work on the interaction of this approximate magnetic monopole field magnetic monopoles but has remained a thought experiment so with a beam of electrons produces an electron vortex state, far22. From the description of the monopole field by a vector as theoretically predicted for a true magnetic monopole3,11–18. potential, a flux line, or `Dirac string' arises as a mathematical This fundamental quantum mechanical scattering experiment pathology that should be undetectable if a magnetic monopole is independent of the speed of the electrons and has was to be a true monopole, leading to the famous magnetic consequences for all situations where electrons meet such charge quantization1. monopole magnetic fields, as, for example, in solids. The set-up The magnetic vector potential A is a mathematical tool used not only shows an attractive way to produce electron vortex in quantum physics that has real, measurable effects12 that states but also provides a unique insight into monopole fields were experimentally demonstrated by electron diffraction18,23.
    [Show full text]
  • On the Existence of the Magnetic Monopole and the Non-Existence of the Higgs Particle
    DRAFT, May. 25, 2009 On the existence of the magnetic monopole and the non-existence of the Higgs particle Engel Roza1 Summary In this paper the existence of the Higgs field is taken as an undeniable starting point. However, the origin of the field is challenged. Rather than ascribing the origin of it to a yet undiscovered phan- tom particle, the origin is ascribed directly to electromagnetic energy, in particular as magnetic charge next to electric charge of elementary point-like particles. To this end two instruments are used. The first one is the transform of the Higgs field from a functional description into a spatial description, without changing the basic properties. The other instrument is the concept of the magnetic monopole, as introduced by Dirac. The two instruments appear to fit well together. The result of all of this is that electromagnetic energy on its own is the source of all mass. It implies that the search after the Higgs particle will remain fruitless. No other equations, apart from Max- well’s Equations and Dirac’s Equation are required to express the fundamentals of quantum waves and quantum fields, which makes the disputed Klein Gordon Equation obsolete. The the- ory reveals an algorithm to explain the ratios between the lepton masses. In that sense the theory shows a predictive element, while grosso modo, as shown, no derogation is done to the results and instruments of canonic theory. 1. Introduction Since the definition of its concept by Peter Higgs in 1964 a continuous search has been made after a particular massive elementary scalar particle, known as the Higgs boson [1].
    [Show full text]
  • The Search for Magnetic Monopoles Arttu Rajantie
    Physics Today The search for magnetic monopoles Arttu Rajantie Citation: Physics Today 69(10), 40 (2016); doi: 10.1063/PT.3.3328 View online: http://dx.doi.org/10.1063/PT.3.3328 View Table of Contents: http://scitation.aip.org/content/aip/magazine/physicstoday/69/10?ver=pdfcov Published by the AIP Publishing Reuse of AIP Publishing content is subject to the terms at: https://publishing.aip.org/authors/rights-and-permissions. Download to IP: 189.60.119.130 On: Mon, 17 Oct 2016 21:25:56 The search for MAGNETIC MONOPOLES Arttu Rajantie The discovery of the mysterious hypothetical particles would provide a tantalizing glimpse of new laws of nature beyond the standard model. HEIKKA VALJA/MoEDAL COLLABORATION Reuse of AIP Publishing content is subject to the terms at: https://publishing.aip.org/authors/rights-and-permissions. Download to IP: 189.60.119.130 On: Mon, 17 Oct 2016 21:25:56 Arttu Rajantie is a professor in the department of physics at Imperial College London and a member of the MoEDAL collaboration. lectricity and magnetism appear everywhere in the monopoles would attract each other and modern world and form the basis of most of our like monopoles would repel each other; their trajectories would bend in an elec- technology. Therefore, it would be natural to assume tric field, and so forth. Indeed, a hypo- that they are already fully understood and no longer thetical universe in which all electric pose unanswered fundamental physics questions. Indeed, charges were replaced by magnetic for most practical purposes they are perfectly well described by charges of the same strength would be completely indistinguishable from ours.
    [Show full text]
  • Emerging Magnetic Monopoles
    Emerging magnetic monopoles Petr Beneˇs IEAP CTU in Prague ATLAS CZ+SK 2019 Workshop Prague, June 24, 2019 Petr Beneˇs (IEAP CTU in Prague) Emerging magnetic monopoles Prague, June 24, 2019 1 / 32 Outline Descriptions of magnetic monopole within different physical paradigms: Classical physics −! Quantum mechanics −! Quantum field theory (Maxwell, Dirac, 't Hooft, Polyakov, Cho, Maison) Optionality/emergence of basic physical properties of magnetic monopole within different paradigms: Existence [sic] Mass Magnetic charge Petr Beneˇs (IEAP CTU in Prague) Emerging magnetic monopoles Prague, June 24, 2019 2 / 32 Magnetic monopole in classical physics Petr Beneˇs (IEAP CTU in Prague) Emerging magnetic monopoles Prague, June 24, 2019 3 / 32 ! Introducing the magnetic charge to the Maxwell's equations is nothing but trivial. Maxwell's equations Maxwell's equations: _ r · E = ρe r × B − E = je r · B = 0 −r × E − B_ = 0 Lorentz force: F = qe(E + v × B) Petr Beneˇs (IEAP CTU in Prague) Emerging magnetic monopoles Prague, June 24, 2019 4 / 32 Maxwell's equations Maxwell's equations: _ r · E = ρe r × B − E = je _ r · B = ρm −r × E − B = jm Lorentz force: F = qe(E + v × B)+ qm(B − v × E) ! Introducing the magnetic charge to the Maxwell's equations is nothing but trivial. Petr Beneˇs (IEAP CTU in Prague) Emerging magnetic monopoles Prague, June 24, 2019 4 / 32 Point-like magnetic charge (a.k.a. the magnetic monopole) Magnetic monopole (charge qm) is just a point-like magnetic charge density: The charge density 3 ρm = qmδ (r) B qm From the Maxwell's equations
    [Show full text]