Universal Constants, Standard Models and Fundamental Metrology
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Glossary Physics (I-Introduction)
1 Glossary Physics (I-introduction) - Efficiency: The percent of the work put into a machine that is converted into useful work output; = work done / energy used [-]. = eta In machines: The work output of any machine cannot exceed the work input (<=100%); in an ideal machine, where no energy is transformed into heat: work(input) = work(output), =100%. Energy: The property of a system that enables it to do work. Conservation o. E.: Energy cannot be created or destroyed; it may be transformed from one form into another, but the total amount of energy never changes. Equilibrium: The state of an object when not acted upon by a net force or net torque; an object in equilibrium may be at rest or moving at uniform velocity - not accelerating. Mechanical E.: The state of an object or system of objects for which any impressed forces cancels to zero and no acceleration occurs. Dynamic E.: Object is moving without experiencing acceleration. Static E.: Object is at rest.F Force: The influence that can cause an object to be accelerated or retarded; is always in the direction of the net force, hence a vector quantity; the four elementary forces are: Electromagnetic F.: Is an attraction or repulsion G, gravit. const.6.672E-11[Nm2/kg2] between electric charges: d, distance [m] 2 2 2 2 F = 1/(40) (q1q2/d ) [(CC/m )(Nm /C )] = [N] m,M, mass [kg] Gravitational F.: Is a mutual attraction between all masses: q, charge [As] [C] 2 2 2 2 F = GmM/d [Nm /kg kg 1/m ] = [N] 0, dielectric constant Strong F.: (nuclear force) Acts within the nuclei of atoms: 8.854E-12 [C2/Nm2] [F/m] 2 2 2 2 2 F = 1/(40) (e /d ) [(CC/m )(Nm /C )] = [N] , 3.14 [-] Weak F.: Manifests itself in special reactions among elementary e, 1.60210 E-19 [As] [C] particles, such as the reaction that occur in radioactive decay. -
An Atomic Physics Perspective on the New Kilogram Defined by Planck's Constant
An atomic physics perspective on the new kilogram defined by Planck’s constant (Wolfgang Ketterle and Alan O. Jamison, MIT) (Manuscript submitted to Physics Today) On May 20, the kilogram will no longer be defined by the artefact in Paris, but through the definition1 of Planck’s constant h=6.626 070 15*10-34 kg m2/s. This is the result of advances in metrology: The best two measurements of h, the Watt balance and the silicon spheres, have now reached an accuracy similar to the mass drift of the ur-kilogram in Paris over 130 years. At this point, the General Conference on Weights and Measures decided to use the precisely measured numerical value of h as the definition of h, which then defines the unit of the kilogram. But how can we now explain in simple terms what exactly one kilogram is? How do fixed numerical values of h, the speed of light c and the Cs hyperfine frequency νCs define the kilogram? In this article we give a simple conceptual picture of the new kilogram and relate it to the practical realizations of the kilogram. A similar change occurred in 1983 for the definition of the meter when the speed of light was defined to be 299 792 458 m/s. Since the second was the time required for 9 192 631 770 oscillations of hyperfine radiation from a cesium atom, defining the speed of light defined the meter as the distance travelled by light in 1/9192631770 of a second, or equivalently, as 9192631770/299792458 times the wavelength of the cesium hyperfine radiation. -
Non-Einsteinian Interpretations of the Photoelectric Effect
NON-EINSTEINIAN INTERPRETATIONS ------ROGER H. STUEWER------ serveq spectral distribution for black-body radiation, and it led inexorably ~o _the ~latantl~ f::se conclusion that the total radiant energy in a cavity is mfimte. (This ultra-violet catastrophe," as Ehrenfest later termed it, was point~d out independently and virtually simultaneously, though not Non-Einsteinian Interpretations of the as emphatically, by Lord Rayleigh.2) Photoelectric Effect Einstein developed his positive argument in two stages. First, he derived an expression for the entropy of black-body radiation in the Wien's law spectral region (the high-frequency, low-temperature region) and used this expression to evaluate the difference in entropy associated with a chan.ge in volume v - Vo of the radiation, at constant energy. Secondly, he Few, if any, ideas in the history of recent physics were greeted with ~o~s1dere? the case of n particles freely and independently moving around skepticism as universal and prolonged as was Einstein's light quantum ms1d: a given v~lume Vo _and determined the change in entropy of the sys hypothesis.1 The period of transition between rejection and acceptance tem if all n particles accidentally found themselves in a given subvolume spanned almost two decades and would undoubtedly have been longer if v ~ta r~ndomly chosen instant of time. To evaluate this change in entropy, Arthur Compton's experiments had been less striking. Why was Einstein's Emstem used the statistical version of the second law of thermodynamics hypothesis not accepted much earlier? Was there no experimental evi in _c?njunction with his own strongly physical interpretation of the prob dence that suggested, even demanded, Einstein's hypothesis? If so, why ~b1ht~. -
Chapter 1 Introduction and Overview
Chapter 1 Introduction and Overview Particle physics is the most fundamental science there is. It is the study of the ultimate constituents of matter (the elementray particles) and of how these particles interact with one another (the fundamental forces). The primary aim of this module is to introduce you to what people mean when they refer to the Standard Model of Particle Physics To do this we need to describe the very small (via quantum mechanics) and the very fast since when elementary particles move, they travel at or close to the speed of light (via special relativity). These requirements demand we work in the language of Quantum Field Theory(QFT). QFT as a subject is a huge (and rather advanced) subject in its own right but thankfully we will be able to use a prescriptive (and rather simple) approach to the QFT which is embodied in the Feynman Rules - for those who want to go further into the theoretical structure of the Standard Model see module PX430 - Gauge Theories of Particle Physics. It is a remarkable fact that, theoretically, the fundamental interactions derive from an invariance of the QFT with respect to certain internal symmetry transformations known as local gauge transformations. The resulting dynamical theories of electromagnetism, the weak interaction and the strong interaction and known respectively as Quantum Elec- trodynamics(QED), the electroweak (or Glashow-Weinberg-Salam) theory and Quantum Chromodynamics(QCD). It is this collection of local gauge theories which have become known as the Standard Model(SM). N.B. Gravity plays a negligible role in Particle Physics and a workable quantum theory of gravity does not exist. -
1. Physical Constants 1 1
1. Physical constants 1 1. PHYSICAL CONSTANTS Table 1.1. Reviewed 1998 by B.N. Taylor (NIST). Based mainly on the “1986 Adjustment of the Fundamental Physical Constants” by E.R. Cohen and B.N. Taylor, Rev. Mod. Phys. 59, 1121 (1987). The last group of constants (beginning with the Fermi coupling constant) comes from the Particle Data Group. The figures in parentheses after the values give the 1-standard- deviation uncertainties in the last digits; the corresponding uncertainties in parts per million (ppm) are given in the last column. This set of constants (aside from the last group) is recommended for international use by CODATA (the Committee on Data for Science and Technology). Since the 1986 adjustment, new experiments have yielded improved values for a number of constants, including the Rydberg constant R∞, the Planck constant h, the fine- structure constant α, and the molar gas constant R,and hence also for constants directly derived from these, such as the Boltzmann constant k and Stefan-Boltzmann constant σ. The new results and their impact on the 1986 recommended values are discussed extensively in “Recommended Values of the Fundamental Physical Constants: A Status Report,” B.N. Taylor and E.R. Cohen, J. Res. Natl. Inst. Stand. Technol. 95, 497 (1990); see also E.R. Cohen and B.N. Taylor, “The Fundamental Physical Constants,” Phys. Today, August 1997 Part 2, BG7. In general, the new results give uncertainties for the affected constants that are 5 to 7 times smaller than the 1986 uncertainties, but the changes in the values themselves are smaller than twice the 1986 uncertainties. -
Determination of Planck's Constant Using the Photoelectric Effect
Determination of Planck’s Constant Using the Photoelectric Effect Lulu Liu (Partner: Pablo Solis)∗ MIT Undergraduate (Dated: September 25, 2007) Together with my partner, Pablo Solis, we demonstrate the particle-like nature of light as charac- terized by photons with quantized and distinct energies each dependent only on its frequency (ν) and scaled by Planck’s constant (h). Using data obtained through the bombardment of an alkali metal surface (in our case, potassium) by light of varying frequencies, we calculate Planck’s constant, h to be 1.92 × 10−15 ± 1.08 × 10−15eV · s. 1. THEORY AND MOTIVATION This maximum kinetic energy can be determined by applying a retarding potential (Vr) across a vacuum gap It was discovered by Heinrich Hertz that light incident in a circuit with an amp meter. On one side of this gap upon a matter target caused the emission of electrons is the photoelectron emitter, a metal with work function from the target. The effect was termed the Hertz Effect W0. We let light of different frequencies strike this emit- (and later the Photoelectric Effect) and the electrons re- ter. When eVr = Kmax we will cease to see any current ferred to as photoelectrons. It was understood that the through the circuit. By finding this voltage we calculate electrons were able to absorb the energy of the incident the maximum kinetic energy of the electrons emitted as a light and escape from the coulomb potential that bound function of radiation frequency. This relationship (with it to the nucleus. some variation due to error) should model Equation 2 According to classical wave theory, the energy of a above. -
Pulsar,Pulsar Timing Array,And Gravitational Experiments
Pulsar,pulsar timing array,and gravitational experiments K. J. Lee ( 李柯伽 ) Kavli institute for astronomy and astrophysics, Peking university [email protected] 2019 Outline ● Pulsars ● Gravitational wave ● Gravitational wave detection using pulsar timing array Why we care about gravity theories? ● Two fundamental philosophical questions ● What is the space? ● What is the time? ● Gravity theory is about the fundamental understanding of the background, on which other physics happens, i.e. space and time ● Define the ultimate boundary of any civilization ● After GR, it is clear that the physical description and research of space time will be gravitational physics. ● But this idea can be traced back to nearly 300 years ago Parallel transport. Locally, the surface is flat, one can define the parallel transport. However after a global round trip, the direction will be different. b+db v b V' a a+da The mathematics describing the intrinsic curvature is the Riemannian tensor. Riemannian =0 <==> flat surface The energy density is just the curvature! Gravity theory is theory of space and time! Geometrical interpretation Transverse and traceless i.e. conserve spatial volume to the first order + x Generation of GW R In GW astronomy, we are detecting h~1/R. Increasing sensitivity by a a factor of 10, the number of source is 1000 times. For other detector, they depend on energy flux, which goes as 1/R^2, number of source increase as 100 times. Is GW real? ● Does GW carry energy? – Bondi 1950s ● Can we measure it? – Yes, we can find the gauge invariant form! GW detector ● Bar detector Laser interferometer as GW detector ● Interferometer has long history. -
Quantifying the Quantum Stephan Schlamminger Looks at the Origins of the Planck Constant and Its Current Role in Redefining the Kilogram
measure for measure Quantifying the quantum Stephan Schlamminger looks at the origins of the Planck constant and its current role in redefining the kilogram. child on a swing is an everyday mechanical constant (h) with high precision, measure a approximation of a macroscopic a macroscopic experiment is necessary, force — in A harmonic oscillator. The total energy because the unit of mass, the kilogram, can this case of such a system depends on its amplitude, only be accessed with high precision at the the weight while the frequency of oscillation is, at one-kilogram value through its definition of a mass least for small amplitudes, independent as the mass of the International Prototype m — as of the amplitude. So, it seems that the of the Kilogram (IPK). The IPK is the only the product energy of the system can be adjusted object on Earth whose mass we know for of a current continuously from zero upwards — that is, certain2 — all relative uncertainties increase and a voltage the child can swing at any amplitude. This from thereon. divided by a velocity, is not the case, however, for a microscopic The revised SI, likely to come into mg = UI/v (with g the oscillator, the physics of which is described effect in 2019, is based on fixed numerical Earth’s gravitational by the laws of quantum mechanics. A values, without uncertainties, of seven acceleration). quantum-mechanical swing can change defining constants, three of which are Meanwhile, the its energy only in steps of hν, the product already fixed in the present SI; the four discoveries of the Josephson of the Planck constant and the oscillation additional ones are the elementary and quantum Hall effects frequency — the (energy) quantum of charge and the Planck, led to precise electrical the oscillator. -
1. Physical Constants 101
1. Physical constants 101 1. PHYSICAL CONSTANTS Table 1.1. Reviewed 2010 by P.J. Mohr (NIST). Mainly from the “CODATA Recommended Values of the Fundamental Physical Constants: 2006” by P.J. Mohr, B.N. Taylor, and D.B. Newell in Rev. Mod. Phys. 80 (2008) 633. The last group of constants (beginning with the Fermi coupling constant) comes from the Particle Data Group. The figures in parentheses after the values give the 1-standard-deviation uncertainties in the last digits; the corresponding fractional uncertainties in parts per 109 (ppb) are given in the last column. This set of constants (aside from the last group) is recommended for international use by CODATA (the Committee on Data for Science and Technology). The full 2006 CODATA set of constants may be found at http://physics.nist.gov/constants. See also P.J. Mohr and D.B. Newell, “Resource Letter FC-1: The Physics of Fundamental Constants,” Am. J. Phys, 78 (2010) 338. Quantity Symbol, equation Value Uncertainty (ppb) speed of light in vacuum c 299 792 458 m s−1 exact∗ Planck constant h 6.626 068 96(33)×10−34 Js 50 Planck constant, reduced ≡ h/2π 1.054 571 628(53)×10−34 Js 50 = 6.582 118 99(16)×10−22 MeV s 25 electron charge magnitude e 1.602 176 487(40)×10−19 C = 4.803 204 27(12)×10−10 esu 25, 25 conversion constant c 197.326 9631(49) MeV fm 25 conversion constant (c)2 0.389 379 304(19) GeV2 mbarn 50 2 −31 electron mass me 0.510 998 910(13) MeV/c = 9.109 382 15(45)×10 kg 25, 50 2 −27 proton mass mp 938.272 013(23) MeV/c = 1.672 621 637(83)×10 kg 25, 50 = 1.007 276 466 77(10) u = 1836.152 672 47(80) me 0.10, 0.43 2 deuteron mass md 1875.612 793(47) MeV/c 25 12 2 −27 unified atomic mass unit (u) (mass C atom)/12 = (1 g)/(NA mol) 931.494 028(23) MeV/c = 1.660 538 782(83)×10 kg 25, 50 2 −12 −1 permittivity of free space 0 =1/μ0c 8.854 187 817 .. -
Three Dimensional Equation of State for Core-Collapse Supernova Matter
University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Doctoral Dissertations Graduate School 5-2013 Three Dimensional Equation of State for Core-Collapse Supernova Matter Helena Sofia de Castro Felga Ramos Pais [email protected] Follow this and additional works at: https://trace.tennessee.edu/utk_graddiss Part of the Other Astrophysics and Astronomy Commons Recommended Citation de Castro Felga Ramos Pais, Helena Sofia, "Three Dimensional Equation of State for Core-Collapse Supernova Matter. " PhD diss., University of Tennessee, 2013. https://trace.tennessee.edu/utk_graddiss/1712 This Dissertation is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a dissertation written by Helena Sofia de Castro Felga Ramos Pais entitled "Three Dimensional Equation of State for Core-Collapse Supernova Matter." I have examined the final electronic copy of this dissertation for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Doctor of Philosophy, with a major in Physics. Michael W. Guidry, Major Professor We have read this dissertation and recommend its acceptance: William Raphael Hix, Joshua Emery, Jirina R. Stone Accepted for the Council: Carolyn R. Hodges Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) Three Dimensional Equation of State for Core-Collapse Supernova Matter A Dissertation Presented for the Doctor of Philosophy Degree The University of Tennessee, Knoxville Helena Sofia de Castro Felga Ramos Pais May 2013 c by Helena Sofia de Castro Felga Ramos Pais, 2013 All Rights Reserved. -
Geometric Justification of the Fundamental Interaction Fields For
S S symmetry Article Geometric Justification of the Fundamental Interaction Fields for the Classical Long-Range Forces Vesselin G. Gueorguiev 1,2,* and Andre Maeder 3 1 Institute for Advanced Physical Studies, Sofia 1784, Bulgaria 2 Ronin Institute for Independent Scholarship, 127 Haddon Pl., Montclair, NJ 07043, USA 3 Geneva Observatory, University of Geneva, Chemin des Maillettes 51, CH-1290 Sauverny, Switzerland; [email protected] * Correspondence: [email protected] Abstract: Based on the principle of reparametrization invariance, the general structure of physically relevant classical matter systems is illuminated within the Lagrangian framework. In a straight- forward way, the matter Lagrangian contains background interaction fields, such as a 1-form field analogous to the electromagnetic vector potential and symmetric tensor for gravity. The geometric justification of the interaction field Lagrangians for the electromagnetic and gravitational interactions are emphasized. The generalization to E-dimensional extended objects (p-branes) embedded in a bulk space M is also discussed within the light of some familiar examples. The concept of fictitious accelerations due to un-proper time parametrization is introduced, and its implications are discussed. The framework naturally suggests new classical interaction fields beyond electromagnetism and gravity. The simplest model with such fields is analyzed and its relevance to dark matter and dark energy phenomena on large/cosmological scales is inferred. Unusual pathological behavior in the Newtonian limit is suggested to be a precursor of quantum effects and of inflation-like processes at microscopic scales. Citation: Gueorguiev, V.G.; Maeder, A. Geometric Justification of Keywords: diffeomorphism invariant systems; reparametrization-invariant matter systems; matter the Fundamental Interaction Fields lagrangian; homogeneous singular lagrangians; relativistic particle; string theory; extended objects; for the Classical Long-Range Forces. -
Executive Summary Research Hub for Fundamental Symmetries
Section A - Executive Summary Research Hub for Fundamental Symmetries, Neutrinos, and Applications to Nuclear Astrophysics: The Inner Space/Outer Space/Cyber Space Connections of Nuclear Physics Intellectual Merit: The first goal of this proposal is to create a coordinated NSF national theory effort at the nuclear physics core of three of the most exciting \discovery" areas of physics: ◦ Neutrino Physics: Beyond-the-standard model (BSM) physics of neutrinos, including their mixing phenomena on earth and in extreme astrophysical environments; the absolute mass scale and the eigenstate behavior under particle-antiparticle conjugation, and the implication of mass and lepton number violation for cosmological evolution; and the relevance of neutri- nos to astrophysics both in transporting energy and lepton number, and as a probe of the otherwise hidden physics that governs the cores of stars and compact objects. ◦ Dense Matter: The recent start of Advanced LIGO Run 1 could well lead to the observation of the gravitational wave signatures from neutron star (NS) mergers by the end of the decade. This follows the observation of a NS of nearly two solar masses by Shapiro delay, and of \black-widow" systems hinting of even higher masses. Current and anticipated observations provide unprecedented opportunities to determine nuclear matter properties at densities and isospins not otherwise reachable, and to relate them to those we measure in laboratory nuclei. ◦ Dark Matter: Definitive evidence that dark matter (DM) dominates our universe is the second demonstration of BSM physics. Nuclear physics can play an important role in this field by helping direct-detection experimenters understand the variety and nature of the possible responses of their nuclear targets, by connecting the stellar processes we study to the feedback mechanisms that can alter galactic structure, and by contributing to the understanding of composite dark matter in cases where lattice QCD methods are relevant.