Supersymmetry Part 1

Supersymmetry is a theory of physics that attempts to unify the fundamental forces and subatomic particles of nature. {Super-, superior + symmetry, similarity of form or arrangement on either side of a dividing line or plane}

Supersymmetry tries to make theoretical advances in the Standard Model of physics. The Standard Model is the widely accepted theory explaining the interactions of elementary particles (particles that are not made of other particles) with the fundamental forces in nature excluding gravity. Symmetries in physics refer to the aspects of a physical system that remain unchanged after certain transformations are applied to the system. For example the particles in a group of related particles, referred to as a multiplet, can be shuffled around and interchanged with each other and the mathematical equations applied to that multiplet will remain the same. In other words the mathematical properties of the multiplet remain unchanged.

There are three distinct multiplets of particles in the Standard Model. Each of these multiplets has its own unique symmetry. The symmetries of these multiplets cannot be combined with each other in a consistent manner, although physicists have manipulated the equations to make them fit. Some physicists have admitted that the equations are so ugly and unwieldy that they cannot possibly be right, but it’s the best that they can do with the current knowledge that they have. Supersymmetry is based on the idea that there are other symmetries beyond those already developed in the standard model. Under supersymmetry all of the particles in the standard model can fit into one multiplet. The equations become much more elegant and relatively simple to work with. Having all the particles in one multiplet without their combined symmetries producing inconsistencies in the equations is a major step in advancing what theorists refer to as a Grand Unification Theory. A Grand Unification Theory tries to combine the four fundamental forces of nature into one grand unifying force governed by a larger symmetry. The four fundamental forces of nature are the electromagnetic force, the weak nuclear force, the strong nuclear force and gravity. Gravity is not included in the standard model because it is the weakest of the four forces and has a negligible affect at the very small scale of the elementary particles.

HTML Forms

I have done some basic work with HTML in the past, but I did not know how to create forms. This week’s lesson on HTML forms has broadened my HTML skills. HTML forms are a great way for visitors of a website to provide feedback to the website’s owner. I have only created basic forms to complete this week’s assignment, but I will probably experiment by adding color and formatting in the future to enhance my skills. JotForm.com is a website that I had never heard of in the past. JotForm.com makes creating forms extremely easy. I will definitely be bookmarking JotForm.com to go back and learn more about creating forms. From the little amount of time that I spent on that website it seems that I’ve only seen the tip of the iceberg. It looks like there are a lot more tools for creating forms that I would like to explore. It appears that you can create some very interesting forms very easily. I will probably spend many hours playing around and creating forms of all sorts. While JotForm.com allows you to easily create forms I think that learning how to create forms from scratch is very important if you plan on using HTML to create web pages. JotForm.com is a great starting place to get familiar with the different types of forms and creation of those forms.

Skydrive

Windows Live Skydrive is a file hosting service that allows you to upload files to a cloud storage and then access those files through a web browser. You may also share those files with other people or keep them private. Skydrive gives you 25GB of storage, but individual files are limited to 100MB in size. It comes in handy if you’re running low on disk space on your local computer or if you want to share your files or photos with your friends. It is also a pretty good place store backups of your files. If you lose any files or they become damaged you can easily replace them with your backups from Skydrive. Skydrive allows you to access your files from anywhere that has access to the Internet and a web browser. Skydrive also provides online versions of Microsoft Word, Excel, Powerpoint, and OneNote which is a nice feature. You need a free Windows Live account to log on to Skydrive. Since UMass uses Windows Live webmail you can access Skydrive when you log into your UMass webmail account. Once you’ve logged on to your webmail account go to the toolbar at the top of the page and select the “more” pull down menu and click on Skydrive. More information on Skydrive can be found at: http://en.wikipedia.org/wiki/Windows_Live_SkyDrive

The History of String Theory Part 2

In the early 1970s physicists were discouraged when many of their experiments with string theory showed that its predictions were at odds with experimental data. String vibrations produce observable properties that can be seen in fundamental particles, but there were other vibration patterns that seemed to have little bearing in reality. These extra vibrations were soon discovered to correspond exactly with gravitons. Gravitons are particles that have not yet been found experimentally, but can be predicted by physicist. The discovery was not well received by the scientific community and string theory was abandoned by all but a few physicists.

In 1984, after over a dozen years of research and much belittling by their colleagues, Michael Green and John Schwarz produced a paper that resolved the conflicts between string theory and quantum mechanics. The paper also showed that string theory could encompass the four fundamental forces and matter. This period became known as the first superstring revolution. Physicist all around the word joined the research on the theory that they had rejected in previous years.

1984-86 saw thousands of papers published on string theory. These papers showed that the features of the standard model could be logically and naturally derived from the new string theory. A major drawback was that the equations where so difficult that their exact form could not be determined and approximations had to be used to replace their complex forms. Physicist became frustrated with these complex equations and once again abandoned string theory for other projects.

At a conference at the University of Southern California in 1995 Edward Witten announced a comprehensive plan to move past the approximations used during the first superstring revolution. Witten’s plan has sparked the second superstring revolution and will have physicist exploring ever deeper into the complexities of string theory.

The History of String Theory Part 1

Theorists have long sought a “theory of everything” that would unify all of the forces of nature along with matter into one mathematical model. Their main objective is to unify the general theory of relativity with quantum mechanics. The general theory of relativity deals with natural occurring phenomena on the very large scale and Quantum mechanics deals with natural occurring phenomena on the very small scale. These two theories are mathematically incompatible. Physicists had developed the “standard model” to try and correct the incompatibilities of the two theories, but many physicists found the standard model to be incomplete. The parameters of the mathematical equations of the standard model have to be adjusted continuously in certain experimentally measured values to make successful prediction.

The incompatibility between general relativity and quantum mechanics has been called the “central conflict” of modern theoretical physics. In quantum mechanics there is a randomness at the sub-planck-length level called the “quantum foam” that destroys the smooth geometric fabric of space-time that is central to the functioning of general relativity. Calculations that attempt to merge general relativity and quantum mechanics produce infinite answers. The impossible results from these calculation prompted physicists to search for a better theory.

In 1968 Gabriele Veneziano, while researching at CERN (a European particle accelerator lab), observed that many properties of the strong nuclear force are perfectly described by a two hundred year old formula known as the Euler beta function. This started a flurry of research in which other physicists noted that nuclear interactions of elementary particles modeled as one-dimensional strings instead of zero-dimensional particles where described exactly by the Euler beta function. This was the beginning of string theory.

Supergravity

Supergravity is a theory of gravity that includes supersymmetry in its equations. The theory of supergravity arose from the problem of incorporating the uncertainty principle with general relativity. When the equations of these two theories were combined a number of infinities appeared in the solutions. These infinities were troublesome to physicists. It was apparent to them that something was missing.

All particles exhibit a property known as spin. There is no definite definition of spin. Although physicists do not have a deep understanding of what spin is they do have a mathematical description of how it behaves. This allows them to compare spin's behavior to the behavior of other things that they feel that they understand better. Fermions have half-integer spin and their ground state energies (lowest energy level) are negative. Bosons have integer spin and their ground state energies are positive. The infinities resulting in combining the uncertainty principle with general relativity are the result of having an unequal number of fermions to bosons. When the supersymmetric particles suggested by supersymmetry are added to the equations the number of fermions is exactly equal to the number of bosons. The negative ground state energies of the fermions cancel out the positive ground state energies of the bosons eliminating the infinities. By eliminating these infinities the equations make more sense to physicists.

The equations of supergravity, as well as the equations of string theory, work best if you consider the universe to contain 11 dimensions. That is 10 dimensions of space and one dimension of time. When any other number of dimensions is considered the equations become unstable and produce anomalies. Some physicists believe that the reason that gravity is so weak compared to the other forces is because it is spread out among the other dimensions. The reason that we do not see the other dimensions is that they are too small to be seen.

Availability of Information

The availability of information provided by the Internet is astounding. It has truly changed the world and how we perceive it. Someone once said that knowledge is power, but I can’t remember who. Well, I’ll just plug that phrase into google. Voilà! Sir Francis Bacon said it. The information on the Internet is the culmination of our collective knowledge. The Internet allows every one of us access to that power. Whether we’re catching up on current events, doing some online shopping, or doing some research for work or school the Internet gives us access to the information that we desire at our fingertips anytime and, with the proliferation of mobile devices, anywhere.
 
The availability of information through the Internet has affected many industries. The retail industry has been profoundly affected. Retail stores can promote themselves online by advertising sales and discounts. Customers can look at the websites of different stores to compare prices and read reviews by other customers on the products that they wish to purchase. In the education industry the Internet has almost done away with the need to have actual books made from paper. Many books are available in electronic format. We can purchase a book online and download it to our computers or mobile devices. A lot of the information on the Internet that can be used by teachers is free. The Internet can be a great teaching tool if used carefully. A lot of information on the Internet is invalid and unverified. It is up to the user to judge whether the information is correct or not. When I want to learn something about a particular topic I will usually visit many websites that feature that topic and then try to sort out what is true and what is nonsense.