Before String Theory

I mentioned earlier that I’ve wanted to try and get some (basic) understanding of String Theory over the coming holiday period. I wondered if a survey of the topic might help me gain a better understanding of the underlying assumptions, tools, theories and techniques which forms a substrate on which String Theory is built upon. Like any highly specialized field, String Theory has been constructed on top of a vast array of mathematical concepts, mechanics, and physics.

Gerard 't Hooft Institute for Theoretical Physics Universiteit Utrecht) offers a menu of subjects (topics) which look to be a prerequisite in understanding and competence in order to make sense of this theory. Here is that list.

• Languages
• Primary Mathematics
• Classical Mechanics
• Optics
• Statistical Mechanics and Thermodynamics
• Electronics
• Electromagnetism
• Quantum Mechanics
• Atoms and Molecules
• Solid State Physics
• Nuclear Physics
• Plasma Physics
• Advanced Mathematics
• Special Relativity
• Advanced Quantum Mechanics
• Phenomenology
• General Relativity
• Quantum Field Theory
• Superstring Theory

An unimaginably massive object

I woke up today with the strange thought - tried to imagine what it would be like when a black hole is swallowed up by another larger monster.

Now I knew a few things about Quasars so looking for an orbiting black hole system would point me closer to black holes potentially coming into each other’s deadly embrace. And quasar OJ-287 doesn’t disappoint. This is a monster lurking some 3.5 Billion light years away.

In fact OJ-287 contains the largest black hole detected in the universe to date. OJ-287 has produced quasi-periodic optical outbursts going back approximately 120 years, as first apparent on photographic plates from 1891.

Its central supermassive black hole is among the largest known, with a mass of 18 billion solar masses. As this system tears each other apart the resultant black hole will be unimaginably massive not to mention its ability to bend space-time.

Object information

Speaking of space-time, this system provided further evidence for general relativity. 

The theory predicts that the smaller hole's orbit itself should rotate, or precess, over time, so that the point at which it comes nearest its neighbor moves around in space - an effect seen in Mercury's orbit around the Sun, albeit on a smaller scale.

Sequence information below.

Ghosts lurking around in advanced physics

Jack Dikian

February 2012

Lurking deep at the core of Gauge Quantum Field Theory are two Russian ghosts called Faddeev and Popov - somewhat reminiscent of the ghost monsters in the old video game; Munchkin. Luckily for us, these ghosts are also thought to be “good ghosts”. The bad ghosts, which apparently also exist in the strange and schizophrenic world of quantum mechanics are another thing altogether.

As the theory goes, these ghosts where send for so as to avoid the over-counting in the complex area of theoretical physics, to fix gauges and make path integrals right.

In high school, we were taught classical mechanics (remember fiction, momentum, force, gravitation, etc) and one of the things we learned was that the path of say a moving object (think of a ball thrown across the room) was that for which the action is a single unique trajectory, i.e., a stationary action [formulation].

In the world of the quantum mechanics, however, the stationary action formulation of classical mechanics extends to the path integral formulation, where a physical system follows simultaneously an infinity of possible trajectories with associated probability amplitudes for each path being determined by the action for the path. Now, path integral formulation should yield unambiguous, non-singular solutions; which they don’t. To modify the action such that these calculations yield applicable results, the good ghosts are used to break the gauge symmetries and make things right.

So every gauge field has an associated ghost, and where the gauge field acquires a mass, the associated ghost field acquires the same mass in some cases.

The Search for the God particle in Europe

Jack Dikian

December 2011

The Higgs Boson, nicknamed the God particle is the quantum of the theoretical Higgs field expected to have a non-zero vacuum expectation value thus, as the theory goes giving mass to every elementary particle that couples with the Higgs field, including the Higgs boson itself.

Experiments attempting to find the particle are currently being performed using the Large Hadron Collider at CERN. Now, CERN may have confirmed this theory. Scientists hunting for Higgs boson say they've found "intriguing hints" but not definitive proof that it exists, narrowing down the search and hope to reach a conclusion on whether the particle exists by next year. So if it does exist, it can help explain why there is mass in the universe.

It seems the data indicates the particle itself may have a mass of between roughly 114 and 130 billion electron volts. One billion electron volts is roughly the mass of a proton. The most likely mass of the Higgs boson is around 124 to 126 billion electron volts.

This Innocuous 1923 Photographic Plate made our Milky Way far less special

Jack Dikian

December 2011

One of the framed pictures I have hanging in my study is the 1923 photographic plate made with the Mt. Wilson Observatory's 100 inch telescope. Edwin Hubble was examining photographic plates of the Andromeda Nebula M31, looking for a novae.

On the night of October 5-6, 1923, Hubble located three novae, each marked with an "N” on this plate. Later he discovered that one was actually a Cepheid star - crossing out the "N" he wrote "Var!" (see upper right of the plate).

Harvard astronomer Henrietta Leavitt (who because of her gender was not allowed to actually use the telescope) provided one of the most important keys in astronomy discovering that Cepheids, regularly varying, pulsating stars, could be used as "standard candle" distance indicators, or in other words an objective gauge to measure distance.

So Hubble, by identifying such a star realized that Andromeda wasn’t a small cluster of stars and gas within our own galaxy, but a large galaxy in its own right at a substantial distance from the Milky Way. Right there and then, in that instant, mankind understood that the galaxy our star is in is just one galaxy in a universe filled with galaxies.