Higgs boson The Higgs boson is named after Peter Higgs, one of six physicists who, in 1964, proposed the mechanism that suggested the existence of such a particle. Although Higgs's name has come to be associated with this theory, several researchers between about 1960 and 1972 each independently developed different parts of it. In mainstream media the Higgs boson has often been called the "God particle", from a 1993 book on the topic; the nickname is strongly disliked by many physicists, including Higgs, who regard it as inappropriate sensationalism.[17][18] In 2013 two of the original researchers, Peter Higgs and François Englert, were awarded the Nobel Prize in Physics for their work and prediction[19] (Englert's co-researcher Robert Brout had died in 2011). A non-technical summary[edit] "Higgs" terminology[edit] Overview[edit] If this field did exist, this would be a monumental discovery for science and human knowledge, and is expected to open doorways to new knowledge in many fields. History[edit]
Units of measurement For example, length is a physical quantity. The metre is a unit of length that represents a definite predetermined length. When we say 10 metres (or 10 m), we actually mean 10 times the definite predetermined length called "metre". The definition, agreement, and practical use of units of measurement have played a crucial role in human endeavour from early ages up to this day. In trade, weights and measures is often a subject of governmental regulation, to ensure fairness and transparency. In physics and metrology, units are standards for measurement of physical quantities that need clear definitions to be useful. Science, medicine, and engineering often use larger and smaller units of measurement than those used in everyday life and indicate them more precisely. In the social sciences, there are no standard units of measurement and the theory and practice of measurement is studied in psychometrics and the theory of conjoint measurement. History[edit] Systems of units[edit] Guidelines[edit]
A Lazy Layman's Guide to Quantum Physics That's an easy one: it's the science of things so small that the quantum nature of reality has an effect. Quantum means 'discrete amount' or 'portion'. Max Planck discovered in 1900 that you couldn't get smaller than a certain minimum amount of anything. The meaning of quantum physics is a bit of a taboo subject, but everyone thinks about it. Copenhagen Interpretation (CI) This is the granddaddy of interpretations, championed by the formidable Niels Bohr of Copenhagen university. The CI has a bit of a cheek calling itself an interpretation, because it essentially says "thou shalt not ask what happens before ye look". When you do try to take Copenhagen seriously you come to the conclusion that consciousness and particle physics are inter-related, and you rush off to write a book called The Dancing Wu-Li Masters. More recently, Henry Stapp at the University of California has written papers such as On Quantum Theories of the Mind (1997). What happens to the cat? What happens to the cat?
Hans Thirring Hans Thirring (March 23, 1888 – March 22, 1976) was an Austrian theoretical physicist, professor, and father of the physicist Walter Thirring. He won the Haitinger Prize of the Austrian Academy of Sciences in 1920.[1] Together with the mathematician Josef Lense, he is known for the prediction of the Lense–Thirring frame dragging effect of general relativity in 1918.[2][3][4] He received a deferment during World War I because he had broken one of his feet while skiing. References[edit] ^ Dazinger, Walter (27 January 2014). External links[edit] Hans Thirring at the Mathematics Genealogy Project
Statistical mechanics Statistical mechanics is a branch of mathematical physics that studies, using probability theory, the average behaviour of a mechanical system where the state of the system is uncertain.[1][2][3][note 1] The present understanding of the universe indicates that its fundamental laws are mechanical in nature, and that all physical systems are therefore governed by mechanical laws at a microscopic level. These laws are precise equations of motion that map any given initial state to a corresponding future state at a later time. There is however a disconnection between these laws and everyday life experiences, as we do not find it necessary (nor easy) to know exactly at a microscopic level the simultaneous positions and velocities of each molecule while carrying out processes at the human scale (for example, when performing a chemical reaction). A common use of statistical mechanics is in explaining the thermodynamic behaviour of large systems. Principles: mechanics and ensembles[edit]
Standard Model The Standard Model of particle physics is a theory concerning the electromagnetic, weak, and strong nuclear interactions, as well as classifying all the subatomic particles known. It was developed throughout the latter half of the 20th century, as a collaborative effort of scientists around the world.[1] The current formulation was finalized in the mid-1970s upon experimental confirmation of the existence of quarks. Since then, discoveries of the top quark (1995), the tau neutrino (2000), and more recently the Higgs boson (2013), have given further credence to the Standard Model. Because of its success in explaining a wide variety of experimental results, the Standard Model is sometimes regarded as a "theory of almost everything". Historical background[edit] The Higgs mechanism is believed to give rise to the masses of all the elementary particles in the Standard Model. Overview[edit] Particle content[edit] Fermions[edit] Gauge bosons[edit] Higgs boson[edit] Main article: Higgs boson E.S.
Experiment Even very young children perform rudimentary experiments in order to learn about the world. An experiment is an orderly procedure carried out with the goal of verifying, refuting, or establishing the validity of a hypothesis. Controlled experiments provide insight into cause-and-effect by demonstrating what outcome occurs when a particular factor is manipulated. Controlled experiments vary greatly in their goal and scale, but always rely on repeatable procedure and logical analysis of the results. A child may carry out basic experiments to understand the nature of gravity, while teams of scientists may take years of systematic investigation to advance the understanding of a phenomenon. Overview[edit] In the scientific method, an experiment is an empirical method that arbitrates between competing models or hypotheses.[1][2] Experimentation is also used to test existing theories or new hypotheses in order to support them or disprove them.[3][4] History[edit] G. Types of experiment[edit]
Before the Big Bang? Inflationary universe? Matter and radiation are gravitationally attractive, so in a maximally symmetric spacetime filled with matter, the gravitational force will inevitably cause any lumpiness in the matter to grow and condense. That's how hydrogen gas turned into galaxies and stars. But vacuum energy comes with a high vacuum pressure, and that high vacuum pressure resists gravitational collapse as a kind of repulsive gravitational force. Inflationary models also solve the horizon problem. But how does Inflation work? The vacuum energy that drives the rapid expansion in an inflationary cosmology comes from a scalar field that is part of the spontaneous symmetry breaking dynamics of some unified theory particle theory, say, a Grand Unified Theory or string theory. A testable prediction? It's always good to have testable predictions from a theory of physics, and the inflation theory has a distinct prediction about the density variations in the cosmic microwave background.
Frame-dragging Effect of general relativity In 2015, new general-relativistic extensions of Newtonian rotation laws were formulated to describe geometric dragging of frames which incorporates a newly discovered antidragging effect.[4] Effects Rotational frame-dragging (the Lense–Thirring effect) appears in the general principle of relativity and similar theories in the vicinity of rotating massive objects. Under the Lense–Thirring effect, the frame of reference in which a clock ticks the fastest is one which is revolving around the object as viewed by a distant observer. Also, an inner region is dragged more than an outer region. Another interesting consequence is that, for an object constrained in an equatorial orbit, but not in freefall, it weighs more if orbiting anti-spinward, and less if orbiting spinward. Linear frame dragging is the similarly inevitable result of the general principle of relativity, applied to linear momentum. Experimental tests Astronomical evidence Mathematical derivation See also
Phase transition This diagram shows the nomenclature for the different phase transitions. Types of phase transition[edit] Examples of phase transitions include: The transitions between the solid, liquid, and gaseous phases of a single component, due to the effects of temperature and/or pressure: (see also vapor pressure and phase diagram) A small piece of rapidly melting argon ice simultaneously shows the transitions from solid to liquid to gas. Comparison of phase diagrams of carbon dioxide (red) and water (blue) explaining their different phase transitions at 1 atmosphere At the phase transition point (for instance, boiling point) the two phases of a substance, liquid and vapor, have identical free energies and therefore are equally likely to exist. It is sometimes possible to change the state of a system diabatically (as opposed to adiabatically) in such a way that it can be brought past a phase transition point without undergoing a phase transition. Classifications[edit] Ehrenfest classification[edit]
Complex analysis Murray R. Spiegel described complex analysis as "one of the most beautiful as well as useful branches of Mathematics". Complex analysis is particularly concerned with the analytic functions of complex variables (or, more generally, meromorphic functions). Because the separate real and imaginary parts of any analytic function must satisfy Laplace's equation, complex analysis is widely applicable to two-dimensional problems in physics. History[edit] Complex analysis is one of the classical branches in mathematics with roots in the 19th century and just prior. Complex functions[edit] For any complex function, both the independent variable and the dependent variable may be separated into real and imaginary parts: and where are real-valued functions. In other words, the components of the function f(z), can be interpreted as real-valued functions of the two real variables, x and y. Holomorphic functions[edit] See also: analytic function, holomorphic sheaf and vector bundles. Major results[edit]
State of matter Historically, the distinction is made based on qualitative differences in properties. Matter in the solid state maintains a fixed volume and shape, with component particles (atoms, molecules or ions) close together and fixed into place. Matter in the liquid state maintains a fixed volume, but has a variable shape that adapts to fit its container. The four fundamental states Solid A crystalline solid: atomic resolution image of strontium titanate. In a solid the particles (ions, atoms or molecules) are closely packed together. In crystalline solids, the particles (atoms, molecules, or ions) are packed in a regularly ordered, repeating pattern. Liquid Structure of a classical monatomic liquid. A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a (nearly) constant volume independent of pressure. Gas The spaces between gas molecules are very big. A gas is a compressible fluid. Plasma Like a gas, plasma does not have definite shape or volume. Glass