High-Energy Physics

BLACK HOLES AND CURVED SPACETIME

Most stars end their lives as white dwarfs or neutron stars. When a very massive star collapses at the end of its life, however, not even the mutual repulsion between densely packed neutrons can support the core against its own weight. If the remaining mass of the star’s core is more than about three times that of the Sun (\(M_{\text{Sun}}\)), our theories predict that no known force can stop it from collapsing forever! Gravity simply overwhelms all other forces and crushes the core until it occupies an infinitely small volume. A star in which this occurs may become one of the strangest objects ever predicted by theory—a black hole.

SPACE-TIME GEOMETRY

In 1906 Poincaré showed that the Lorentz transformation can be regarded as a rotation in a 4-dimensional Euclidean space-time introduced by adding an imaginary fourth space-time coordinate \(ict\) to the three real spatial coordinates. In 1908 Minkowski reformulated Einstein’s Special Theory of Relativity in this 4-dimensional Euclidean space-time vector space and concluded that the spatial variables \(q_i\), where \((i = 1, 2, 3)\), plus the time \(q_0 = ict\) are equivalent variables and should be treated equally using a covariant representation of both space and time. The idea of using an imaginary time axis \(ict\) to make space-time Euclidean was elegant, but it obscured the non-Euclidean nature of space-time as well as causing difficulties when generalized to non-inertial accelerating frames in the General Theory of Relativity. As a consequence, the use of the imaginary \(ict\) has been abandoned in modern work. Minkowski developed an alternative non-Euclidean metric that treats all four coordinates \((ct, x, y, z)\) as a four-dimensional Minkowski metric with all coordinates being real, and introduces the required minus sign explicitly.

MATTER-ANTIMATTER-SYMMETRY

According to the Standard Model of elementary particle physics, to each particle there exists an antiparticle that is supposed to behave exactly the same way. But this postulate is difficult to prove, since it is almost impossible to perform measurements on antimatter: whenever an antiparticle meets is matter-counterpart, both particles annihilate, accompanied by the creation of energy. A recent research in Quantum Optics has found a way to overcome this hurdle: an experiment was carried out by trapping an antiproton inside a helium atom. As due to a new cooling technique the helium atoms are almost at rest, high precision spectroscopy measurements are made possible. For the mass of the antiproton relative to the electron, the outcome of the research has achieved the unprecedented accuracy of 800 parts per trillion.

LORENTZ TRANSFORMATIONS ON SPACE & TIME

According to general relativity differnt observers in different frames of reference measure different values for lengths and the time intervals. We can gain further insight into how the postulates of relativity change the Newtonian view of time and space by examining the transformation equations that give the space and time coordinates of events in one inertial reference frame in terms of those in another. We first examine how position and time coordinates transform between inertial frames according to the view in Newtonian physics. Then we examine how this has to be changed to agree with the postulates of relativity. Finally, we examine the resulting Lorentz transformation equations and some of their consequences in terms of four-dimensional space-time diagrams, to support the view that the consequences of special relativity result from the properties of time and space itself, rather than electromagnetism.

ELECTRON - HIGGS FIELD INTERACTION

e Higgs boson (a particle of the Higgs field) is a particle associated with the electroweak-symmetry breaking mechanism which is an inmportant aspect of quantum physics and is a vital component of the Standard Model of particle physics. It is believed that all fundamental particles in the known Universe that have mass — for example electrons, or the quarks that live inside protons and neutrons — acquire this mass as a result of interacting with an omnipresent field through Higgs bosons. Massless particles, such as photons, pass through the field without interacting with it.

Everything that we can touch and see and feel has substance. All this substance that makes up our Universe is courtesy of the familiar atom, which gives us all the matter around us. An atom is comprised of lightweight electrons orbiting and bound to a bulky nucleus of protons and neutrons, which themselves are made of quarks. .