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

Project Tuva and Feynman Lectures

Jack Dikian

November 2011

I was first introduced to the work of the great Richard Feynman when I came by Surely You're Joking, Mr. Feynman! (Adventures of a Curious Character) when I was 15 or 16. I can’t remember if I borrowed the book from my high school library, bought it at a place called the White Elephant or found it amongst hundreds of old Reader's Digest copies left behind in the family house we moved into around that time.

One thing is for certain. The book was truly enthralling – especially to a boy who grew up building Crystal radio sets, spending summer nights looking at the night skies, reading Parabola and cherishing the wonder of all. So coming across Surely You're Joking, soothed by it’s comforting and lighthearted tone was truly a discovery of a lifetime.

Fast forward – we’ve all debated the features and benefits of Microsoft over Apple, some of us have even queued for hours outside an Apple store in the hope to buy their latest gadget; impress our friends, impress ourselves.

Regardless of our biases there is one thing that musts be said about Microsoft. Their Project Tuva which is an enhanced video player platform released to host the Messenger Lectures series titled The Character of Physical Law given by Richard Feynman in 1964 is a must for all who are interested in theoretical physics and in a strange way history. I say history because apart from a good introduction to topics that are still current in physics there is pleasure in seeing how a college campus looked in the fifties,

The project was a collaborative effort between Bill Gates and Microsoft Research that is designed to demonstrate the potential of enhanced video to teach people about the "core scientific concepts" of Feynman's lectures using interactive media.

According to his video introduction, Gates saw the lectures when he was younger. He enjoyed the physics concepts and Feynman's lecturing style, and later acquired the rights to make the video available to the public. He hopes that this will encourage others to make educational content available for free.

Feynman in his The Character of Physical Law lectures makes the most on-point remark dealing with the difficulty of understanding Quantum mechanics. James Bradford DeLong (commonly known as Brad Delong) in the course of something or rather suggests that the theory of relativity really isn’t all that hard. At least, if your standard of comparison is quantum mechanics.

He goes on – ‘While relativity has a reputation for being intimidatingly difficult, it’s a peculiar kind of difficulty. But anyone who studies the subject appreciates that it’s a series of epiphanies the theory are models of clarity. Quantum mechanics is not like that.”

And Feynman:

There was a time when the newspapers said that only twelve men understood the theory of relativity. I do not believe there ever was such a time. There might have been a time when only one man did, because he was the only guy who caught on, before he wrote his paper. But after people read the paper a lot of people understood the theory of relativity in some way or other, certainly more than twelve. On the other hand, I think I can safely say that nobody understands quantum mechanics.

You can get to project Tuva and the lectures at

http://research.microsoft.com/apps/tools/tuva/

We are living but on a spec of dust looking out into the darkness

Jack Dikian

September 2011

The more I think about just how much we have been able to infer about the universe we live in the more amazing it all seems. I mean, here we are living on an unassuming rock orbiting a star near the outskirts of a galaxy. Our galaxy is estimated to contain 200 to 400 billion stars. Current estimates guess that there are 100 to 200 billion galaxies in the Universe. The universe is vast and we are living but on a spec of dust looking out into the darkness, looking back in time, and trying to make sense of it all.

The WMAP Explorer mission that launched June 2001 to make fundamental measurements of cosmology is analogies to a trapdoor spider coming out of its silk-lined burrow to examine the perimeter surrounding its burrow before it goes back inside to think about how might other terrains be like, what kind of soils, how small puddles of water be compared to vast oceans, and so on and so forth.

But, that’s exactly what the WMAP has been able to achieve. It has been able to study the properties of our universe as a whole. WMAP has been stunningly successful too, producing our new Standard Model of Cosmology. The 7-year data provide compelling evidence that the large-scale fluctuations are slightly more intense than the small-scale ones, a subtle prediction of many inflation models.

One of the problems the Big Bang theory was not able to explain is the horizon problem. Distant regions of space in opposite directions of the sky are so far apart that, assuming standard Big Bang expansion, they could never have been in causal contact with each other. This light travel time between them exceeds the age of the universe. Yet the uniformity of the cosmic microwave background temperature tells us that these regions must have been in contact with each other in the past.

The Inflation Theory, developed by Alan Guth, Andrei Linde, Paul Steinhardt, and Andy Albrecht, offer a solution to this and several other open questions in cosmology. Inflation supposes a burst of exponential expansion in the early universe, assuming distant regions of the universe were actually much closer together prior to Inflation than they would have been with only standard Big Bang expansion. Thus, such regions could have been in causal contact prior to Inflation and could have attained a uniform temperature.

Other reading

Alan H. Guth & Paul J.Steinhardt, "The Inflationary Universe", Scientific American, May 1984.

Andrei Linde, "The Self-Reproducing Inflationary Universe", Scientific American, November 1994.

Scott Watson, "An Exposition on Inflationary Cosmology", WWWarticle, 2000.

Alan H. Guth, "The Inflationary Universe : The Quest for a New Theory of Cosmic Origins", 1998.

Einstein's Biggest Blunder

Jack Dikian

May 2011

A team of planetary scientists using the Anglo-Australian Telescope contributed to the mapping of galaxies over a volume of the Universe and has shown that dark energy responsible for expanding the universe is real and not a mistake by Einstein viz a viz the cosmological constant.

When George Gamow was discussing cosmological problems with Einstein, he (Einstein) had remarked that the introduction of the cosmological term was the biggest blunder of his life.

Einstein introduced his cosmological constant it into his general theory of relativity almost as a last resort wanting to force his theory to yield a static universe as he had thought the universe to be.

We know now the universe is not static and is expanding at an accelerating rate, just as his original field equations were predicting. Einstein was never comfortable with the [constant] and a clue is in his 1917 paper which ends with

“It is to be emphasized, however, that a positive curvature of space is given by our results, even if the supplementary term [cosmological constant] is not introduced. That term is necessary only for the purpose of making possible a quasi-static distribution of matter, as required by the fact of the small velocities of the stars”.

The survey of 200,000 galaxies by an international team, led by Chris Blake of Swinburne University, took four years to complete, aimed to measure the properties of "dark energy" — the concept of which was revived in the late 1990s when astronomers began to realize the universe was expanding at an accelerating rate.

The acceleration was a shocking discovery, indicating the universe is filled with a new kind of energy that is causing it to expand at an increasing speed.

Black Holes Older Than The Universe

Jack Dikian

May 2011

According to the work by Professor Bernard Carr from Queen Mary University in London and Professor Alan Coley from Canada's Dalhousie University published on the pre-press website arXiv.org, some black holes may be primordial. That is some black holes bounce between a contracting and expanding universes.

Coley and Carr speculate that primordial black holes could survive as separate entities and from a previous epoch (assuming of course that a bounce occurs at all and survives singularities).

According to general relativity, the initial state of the universe, at the beginning of the Big Bang, was a singularity - a point in space-time at which the space-time curvature becomes infinite and much of the physics we know breaks down.

Even with the success of quantum mechanics we don't have a good theory of quantum gravity.

Still, such a speculation, as well as pushing the boundaries of our current theories, bounces in the universe may also allow for differences in the fundamental constants of nature such as (say) the speed of light.

I Am Convinced God Does Not Play Dice

Jack Dikian

March 2011

Introduction

The Copenhagen interpretation of quantum mechanics proposes, generally, that the outcome of any measurement cannot be measured with certainty. This leads to the situation where measurements of a property performed on two identical systems can give different answers.

However, can a deeper reality, hidden beneath quantum mechanics, described by a more fundamental theory predict the outcome of measurement with certainty. Einstein, a proponent of a deeper reality (hidden variables) hidden famously insisted that, "I am convinced God does not play dice”.

Quantum mechanics puzzle

Quantum mechanics creates the puzzling situation in which a measurement of one system can "poison" the measurement of the other system, no matter what the distance between them. One could imagine the two measurements were so far apart in space that special relativity would prohibit any influence of one measurement over the other.

For example, say, in a neutral-Pion decay, where two photons travel some light years apart – if the spin of one photon is measured, quantum mechanic suggests that that measurement instantaneously forces the second photon into a state of well-defined spin - even though it is light years away from the first.

Einstein, Podolsky, and Rosen (EPR) argued that elements of reality must be added to quantum mechanics and postulated that the existence of unknown properties should account for the discrepancy – that there is a deeper reality.

A conundrum

How do we reconcile the fact that the second photon "knows" that the spin of the first photo has been measured, even though they are separated by light years of space and far too little time has passed for information to have traveled to it according to special relativity?

We can accept the postulates of quantum mechanics its seemingly uncomfortable coexistence with special relativity, or we may believe that quantum mechanics is not complete:

What is time

Jack Dikian

Sep 2012

Again, as so often these days, casual remarks made in late night conversations sets me thinking about those ideas we hold with seemingly little need for scrutiny. These are ideas that involve everyday concepts, that, on the surface, are supposedly well understood, defined, and seem as natural as day and night. I’m talking about time.

How hard can it be to explain the passage of time. After all, we can measure time precisely and we all have an innate ability to gauge the flow of time.

The question, perhaps overly simplified: is time a "real thing" that is "all around us", or is it nothing more than a way of speaking about and measuring events.

Psychologically, time can seem to take forever or be over before we know it. The past only exists as memory. The future is something we can’t remember. So, there is really only the present. In the novel “The Merry-Go-Round in the Sea”, by Randolph Stow, a novel I couldn't put down when I was 12, Rob's life is "jolted" by the impending war comes to the realisation “I am six years and two weeks old. I will never be that old again”.

Time is one of the seven fundamental physical quantities in the International System of Units. An operational definition of time, wherein one says that observing a certain number of repetitions of one or another standard cyclical event (such as the passage of a free-swinging pendulum) constitutes one standard unit such as the second.

There are two distinct views on the meaning of time. One view is that time is part of the fundamental structure of the universe, a dimension in which events occur in sequence. This is the realist view, to which Isaac Newton subscribed, in which time itself is something that can be measured.

A contrasting view is that time is part of the fundamental intellectual structure (together with space and number) within which we sequence events, quantify the duration of events and the intervals between them, and compare the motions of objects. In this view, time does not refer to any kind of entity that "flows", that objects "move through", or that is a "container" for events. This view is in the tradition of Gottfried Leibniz and Immanuel Kant, in which time, rather than being an objective thing to be measured, is part of the mental measuring system.

According to John A. Wheeler, Princeton cosmologist, "Time is the most mysterious of the four usual dimensions of our space-time continuum. It's not so much that there's something strange about time, the thing that's strange is what's going on inside time. He continues, we will first understand how simple the universe is when we recognize how strange time is.

Einstein’s in his Special Theory of Relativity he united space and time into one entity - space-time. Within this new continuum, time slows down as you move faster, the time dilation effect.

So time can be viewed as both a psychological construction which we use to interpret our world and a mathematical kind of time, the most basic estimate of which is reflected on our watches and clocks. Also, the direction that time points to can be delineated by a number of physical and psychological phenomena.

• The Psychological Arrow of Time is our subjective sense of time, the fact that we remember events in one direction of time, the past, but not the other, the future.
• The Electromagnetic Arrow of Time as described by Maxwell's equations providing solutions to the propagation of radio waves, and light.
• The Cosmological Arrow of Time sees the history of the universe moving forward in time in an irreversible manner.
• The Thermodynamic Arrow involving the Law of Entropy, explaining the behavior that all the universe progresses from order to disorder