Quantum Universe
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. -
Department of Physics College of Arts and Sciences Physics
DEPARTMENT OF PHYSICS COLLEGE OF ARTS AND SCIENCES PHYSICS Faculty I. Major in Physics—38 hours William Nettles (2006). Professor of Physics, Department A. Physics 231-232, 311, 313, 314, 420, 424(1-3 Chair, and Associate Dean of the College of Arts and hours), 430, 498—28–30 hours Sciences. B.S., Mississippi College; M.S., and Ph.D., B. Select three or more courses: PHY 262, 325, 350, Vanderbilt University. 360, 395-6-7*, 400, 410, 417, 425 (1-2 hours**), 495* Ildefonso Guilaran (2008). Associate Professor of Physics. C. Prerequisites: MAT 211, 212, 213, 314 B.S., Western Kentucky University; M.S. and Ph.D., *Must be approved Special/Independent Studies Florida State University. **Maximum 3 hours from 424 and 425 apply to major. Geoffrey Poore (2010). Assistant Professor of Physics. B.A., II. Major in Physical Science—44 hours Wheaton College; M.S. and Ph.D., University of Illinois. A. CHE 111, 112, 113, 211, 221—15 hours David A. Ward (1992, 1999). Professor of Physics, B.S. B. PHY 112, 231-32, 311, 310 or 301—22 hours and M.A., University of South Florida; Ph.D., North C. Upper Level Electives from CHE and PHY—7 Carolina State University. hours; maximum 1 hour from 424 and 1 from 498 III. Minor in Physics—24 semester hours Staff Physics 231-232, 311, + 10 hours of Physics electives Christine Rowland (2006). Academic Secretary— except PHY 111, 112, 301, 310 Engineering, Physics, Math, and Computer Science. IV. Teacher Licensure in Physics (Grades 6–12) A. Complete the requirements shown above for the Physics or Physical Science major. -
Supersymmetry Searches at the Tevatron
SUPERSYMMETRY SEARCHES AT THE TEVATRON For CDF and DØ collaborations R. Demina Department of Physics and Astronomy, University of Rochester, Rochester, USA, 14627 CDF and DØ collaborations analyzed up to 200 pb-1 of the delivered data in search for different supersymmetry signatures, so far with negative results. We present results on searches for chargino and neutralino associated production, squarks and gluinos, sbottom quarks, gauge mediated SUSY breaking and long lived heavy particles. Supersymmetry1 is a popular extension of the Standard Model originally suggested over 25 years ago. It postulates the symmetry between fermionic and bosonic degrees of freedom. As a result a variety of hypothetical particles is introduced. With presently available experimental data physicists were able to prove that if supersymmetric particles exist they must be heavier than their Standard Model partners2. In other words the Supersymmetry is broken. One possible exception is supersymmetric top quark (stop), which still has a chance to be lighter or of the same mass as top quark. With 2-4 fb-1 of data Tevatron experiments will be able to extend the limit on stop mass above that of top quark or discover it and thus establish the Supersymmetry3. Theory suggests several possible scenarios of Supersymmetry breaking mediated by gravitational or gauge interactions. In gravity mediated scenarios the number of free parameters in the model is reduced to five because of the unification of masses and couplings imposed at the grand unification scale. These parameters are M0 (M½) – masses of all bosons (fermions) at GUT scale, A0- trilinear coupling and µ0 – something Higgs and tan(β) – ratio of vacuum expectations of the Higgs doublet. -
Quantum Field Theory*
Quantum Field Theory y Frank Wilczek Institute for Advanced Study, School of Natural Science, Olden Lane, Princeton, NJ 08540 I discuss the general principles underlying quantum eld theory, and attempt to identify its most profound consequences. The deep est of these consequences result from the in nite number of degrees of freedom invoked to implement lo cality.Imention a few of its most striking successes, b oth achieved and prosp ective. Possible limitation s of quantum eld theory are viewed in the light of its history. I. SURVEY Quantum eld theory is the framework in which the regnant theories of the electroweak and strong interactions, which together form the Standard Mo del, are formulated. Quantum electro dynamics (QED), b esides providing a com- plete foundation for atomic physics and chemistry, has supp orted calculations of physical quantities with unparalleled precision. The exp erimentally measured value of the magnetic dip ole moment of the muon, 11 (g 2) = 233 184 600 (1680) 10 ; (1) exp: for example, should b e compared with the theoretical prediction 11 (g 2) = 233 183 478 (308) 10 : (2) theor: In quantum chromo dynamics (QCD) we cannot, for the forseeable future, aspire to to comparable accuracy.Yet QCD provides di erent, and at least equally impressive, evidence for the validity of the basic principles of quantum eld theory. Indeed, b ecause in QCD the interactions are stronger, QCD manifests a wider variety of phenomena characteristic of quantum eld theory. These include esp ecially running of the e ective coupling with distance or energy scale and the phenomenon of con nement. -
Analysis and Instrumentation for a Xenon-Doped Liquid Argon System
Analysis and instrumentation for a xenon-doped liquid argon system Ryan Gibbons Work completed under the advisement of Professor Michael Gold Department of Physics and Astronomy The University of New Mexico May 27, 2020 1 Abstract Liquid argon is a scintillator frequently used in neutrino and dark matter exper- iments. In particular, is the upcoming LEGEND experiment, a neutrinoless double beta decay search, which will utilize liquid argon as an active veto system. Neutri- noless double beta decay is a theorized lepton number violating process that is only possible if neutrinos are Majorana in nature. To achieve the LEGEND background goal, the liquid argon veto must be more efficient. Past studies have shown the ad- dition of xenon in quantities of parts-per-million in liquid argon improves the light yield, and therefore efficiency, of such a system. Further work, however, is needed to fully understand the effects of this xenon doping. I present a physical model for the light intensity of xenon-doped liquid argon. This model is fitted to data from various xenon concentrations from BACoN, a liquid argon test stand. Additionally, I present preliminary work on the instrumentation of silicon photomultipliers for BACoN. 2 Contents 1 Introduction 4 1.1 Neutrinos and double beta decay . 4 1.2 LEGEND and BACoN . 5 1.3 Liquid argon . 6 2 Physical modeling of xenon-doped liquid argon 8 2.1 Model . 8 2.2 Fits to BACoN Data . 9 2.3 Analysis of Rate Constant . 12 3 Instrumentation of SiPMs 12 4 Conclusions and Future Work 13 3 1 Introduction 1.1 Neutrinos and double beta decay Neutrinos are neutral leptons that come in three flavors: electron, muon, and tao. -
1 Standard Model: Successes and Problems
Searching for new particles at the Large Hadron Collider James Hirschauer (Fermi National Accelerator Laboratory) Sambamurti Memorial Lecture : August 7, 2017 Our current theory of the most fundamental laws of physics, known as the standard model (SM), works very well to explain many aspects of nature. Most recently, the Higgs boson, predicted to exist in the late 1960s, was discovered by the CMS and ATLAS collaborations at the Large Hadron Collider at CERN in 2012 [1] marking the first observation of the full spectrum of predicted SM particles. Despite the great success of this theory, there are several aspects of nature for which the SM description is completely lacking or unsatisfactory, including the identity of the astronomically observed dark matter and the mass of newly discovered Higgs boson. These and other apparent limitations of the SM motivate the search for new phenomena beyond the SM either directly at the LHC or indirectly with lower energy, high precision experiments. In these proceedings, the successes and some of the shortcomings of the SM are described, followed by a description of the methods and status of the search for new phenomena at the LHC, with some focus on supersymmetry (SUSY) [2], a specific theory of physics beyond the standard model (BSM). 1 Standard model: successes and problems The standard model of particle physics describes the interactions of fundamental matter particles (quarks and leptons) via the fundamental forces (mediated by the force carrying particles: the photon, gluon, and weak bosons). The Higgs boson, also a fundamental SM particle, plays a central role in the mechanism that determines the masses of the photon and weak bosons, as well as the rest of the standard model particles. -
A Voyage Through Scales Zoom Into a Cloud
vv Blöschl A VOYAGE T THROUGH SCALES est. 2002 hybo Günter Blöschl Hans Thybo S Hubert Savenije avenije A VOY A GE THROUGH SC GE THROUGH A VOYAGE THROUGH SCALES Zoom into a cloud. Zoom out of a rock. Watch The Earth System in Space and Time the volcano explode, the lightning strike, an aurora undulate. Imagine ice A sheets expanding, retreating – pulsating – while continents continue their LES leisurely collisions. Everywhere there are structures within structures … within structures. A Voyage Through Scales is an invitation to contemplate the Earth’s extraordinary variability extending from milliseconds to billions of years, from microns to the size of the universe. T he E arth S ystem in ystem S pace and pace T ime est. 2002 T 2 A Voyage Through Scales A Voyage Through Scales 3L A VOYAGE THROUGH SCALES The Earth System in Space and Time T 4 A Voyage Through Scales A Voyage Through Scales L1 PREFACE Patterns of billions of stars on the night skies, cloud patterns, sea ice whirling in the ocean, rivers meandering in the landscape, vegetation patterns on hillslopes, minerals glittering in the sun, and the remains of miniature crea- tures in rocks – they all reveal themselves as complex patterns from the scale of the universe down to the molecu- lar level. A voyage through space scales. From a molten Earth to a solid crust, the evolution and extinction of species, climate fluctuations, continents moving around, the growth and decay of ice sheets, the water cycle wearing down mountain ranges, volcanoes exploding, forest fires, avalanches, sudden chemical reactions – constant change taking place over billions of years down to milliseconds. -
7. Gamma and X-Ray Interactions in Matter
Photon interactions in matter Gamma- and X-Ray • Compton effect • Photoelectric effect Interactions in Matter • Pair production • Rayleigh (coherent) scattering Chapter 7 • Photonuclear interactions F.A. Attix, Introduction to Radiological Kinematics Physics and Radiation Dosimetry Interaction cross sections Energy-transfer cross sections Mass attenuation coefficients 1 2 Compton interaction A.H. Compton • Inelastic photon scattering by an electron • Arthur Holly Compton (September 10, 1892 – March 15, 1962) • Main assumption: the electron struck by the • Received Nobel prize in physics 1927 for incoming photon is unbound and stationary his discovery of the Compton effect – The largest contribution from binding is under • Was a key figure in the Manhattan Project, condition of high Z, low energy and creation of first nuclear reactor, which went critical in December 1942 – Under these conditions photoelectric effect is dominant Born and buried in • Consider two aspects: kinematics and cross Wooster, OH http://en.wikipedia.org/wiki/Arthur_Compton sections http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=22551 3 4 Compton interaction: Kinematics Compton interaction: Kinematics • An earlier theory of -ray scattering by Thomson, based on observations only at low energies, predicted that the scattered photon should always have the same energy as the incident one, regardless of h or • The failure of the Thomson theory to describe high-energy photon scattering necessitated the • Inelastic collision • After the collision the electron departs -
Clinical Update
Clinical Update Femtosecond Laser Brings New Level of Precision to Cataract Procedures The femtosecond laser has increased the the time the eye is open and eases stress on accuracy of the most common surgical the eye’s internal structures. And with such procedure in the United States, according to accuracy at our disposal, we anticipate the laser the surgeon who was instrumental in bringing will open new avenues of treatment that have the advanced tool to the UCLA Stein Eye never been possible before.” Institute last year. Surgeons at Stein Eye have been using the The Alcon LenSx, now used for precision cataract femtosecond laser to assist with several procedures at the Institute’s outpatient surgical steps of cataract surgery, including corneal center, emits optical pulses at the unimaginably incisions to remove the cataract and manage short duration of a femtosecond––one-millionth astigmatism, lens softening, and making an of one-billionth of a second. opening in the capsular bag. “A femtosecond laser can be thought of as For cataract procedures, the femtosecond laser a microscalpel, incising the cornea and lens system is gently docked to the patient’s eye capsule and breaking up the cataract on a and optical coherence tomography imaging Dr. Kevin Miller uses the Alcon LenSx femtosecond laser microscopic scale with an incredible level is used to map the eye’s internal structures. to assist with several steps of cataract surgery, under of precision,” says Kevin M. Miller, MD, Before the operation, the surgeon programs imaging guidance. The femtosecond laser enables Kolokotrones Chair in Ophthalmology. “With the location and size of the incisions as well physicians in the UCLA Stein Eye Institute’s new outpatient surgical center to operate more efficiently a femtosecond laser, I can operate more as the region of the lens to be softened. -
String Theory and Pre-Big Bang Cosmology
IL NUOVO CIMENTO 38 C (2015) 160 DOI 10.1393/ncc/i2015-15160-8 Colloquia: VILASIFEST String theory and pre-big bang cosmology M. Gasperini(1)andG. Veneziano(2) (1) Dipartimento di Fisica, Universit`a di Bari - Via G. Amendola 173, 70126 Bari, Italy and INFN, Sezione di Bari - Bari, Italy (2) CERN, Theory Unit, Physics Department - CH-1211 Geneva 23, Switzerland and Coll`ege de France - 11 Place M. Berthelot, 75005 Paris, France received 11 January 2016 Summary. — In string theory, the traditional picture of a Universe that emerges from the inflation of a very small and highly curved space-time patch is a possibility, not a necessity: quite different initial conditions are possible, and not necessarily unlikely. In particular, the duality symmetries of string theory suggest scenarios in which the Universe starts inflating from an initial state characterized by very small curvature and interactions. Such a state, being gravitationally unstable, will evolve towards higher curvature and coupling, until string-size effects and loop corrections make the Universe “bounce” into a standard, decreasing-curvature regime. In such a context, the hot big bang of conventional cosmology is replaced by a “hot big bounce” in which the bouncing and heating mechanisms originate from the quan- tum production of particles in the high-curvature, large-coupling pre-bounce phase. Here we briefly summarize the main features of this inflationary scenario, proposed a quarter century ago. In its simplest version (where it represents an alternative and not a complement to standard slow-roll inflation) it can produce a viable spectrum of density perturbations, together with a tensor component characterized by a “blue” spectral index with a peak in the GHz frequency range. -
Basic Statistics Range, Mean, Median, Mode, Variance, Standard Deviation
Kirkup Chapter 1 Lecture Notes SEF Workshop presentation = Science Fair Data Analysis_Sohl.pptx EDA = Exploratory Data Analysis Aim of an Experiment = Experiments should have a goal. Make note of interesting issues for later. Be careful not to get side-tracked. Designing an Experiment = Put effort where it makes sense, do preliminary fractional error analysis to determine where you need to improve. Units analysis and equation checking Units website Writing down values: scientific notation and SI prefixes http://en.wikipedia.org/wiki/Metric_prefix Significant Figures Histograms in Excel Bin size – reasonable round numbers 15-16 not 14.8-16.1 Bin size – reasonable quantity: Rule of Thumb = # bins = √ where n is the number of data points. Basic Statistics range, mean, median, mode, variance, standard deviation Population, Sample Cool trick for small sample sizes. Estimate this works for n<12 or so. √ Random Error vs. Systematic Error Metric prefixes m n [n 1] Prefix Symbol 1000 10 Decimal Short scale Long scale Since 8 24 yotta Y 1000 10 1000000000000000000000000septillion quadrillion 1991 7 21 zetta Z 1000 10 1000000000000000000000sextillion trilliard 1991 6 18 exa E 1000 10 1000000000000000000quintillion trillion 1975 5 15 peta P 1000 10 1000000000000000quadrillion billiard 1975 4 12 tera T 1000 10 1000000000000trillion billion 1960 3 9 giga G 1000 10 1000000000billion milliard 1960 2 6 mega M 1000 10 1000000 million 1960 1 3 kilo k 1000 10 1000 thousand 1795 2/3 2 hecto h 1000 10 100 hundred 1795 1/3 1 deca da 1000 10 10 ten 1795 0 0 1000 -
ANTIMATTER a Review of Its Role in the Universe and Its Applications
A review of its role in the ANTIMATTER universe and its applications THE DISCOVERY OF NATURE’S SYMMETRIES ntimatter plays an intrinsic role in our Aunderstanding of the subatomic world THE UNIVERSE THROUGH THE LOOKING-GLASS C.D. Anderson, Anderson, Emilio VisualSegrè Archives C.D. The beginning of the 20th century or vice versa, it absorbed or emitted saw a cascade of brilliant insights into quanta of electromagnetic radiation the nature of matter and energy. The of definite energy, giving rise to a first was Max Planck’s realisation that characteristic spectrum of bright or energy (in the form of electromagnetic dark lines at specific wavelengths. radiation i.e. light) had discrete values The Austrian physicist, Erwin – it was quantised. The second was Schrödinger laid down a more precise that energy and mass were equivalent, mathematical formulation of this as described by Einstein’s special behaviour based on wave theory and theory of relativity and his iconic probability – quantum mechanics. The first image of a positron track found in cosmic rays equation, E = mc2, where c is the The Schrödinger wave equation could speed of light in a vacuum; the theory predict the spectrum of the simplest or positron; when an electron also predicted that objects behave atom, hydrogen, which consists of met a positron, they would annihilate somewhat differently when moving a single electron orbiting a positive according to Einstein’s equation, proton. However, the spectrum generating two gamma rays in the featured additional lines that were not process. The concept of antimatter explained. In 1928, the British physicist was born.