Lecture explores string theory

first_imgString theory, a so-called “theory of everything” in physics, is a popular topic among more than just scientists. Juan Maldacena, professor of theoretical and astrophysics at the Institute for Advanced Study and one of the foremost researchers in the field of string theory, delivered a lecture Wednesday on the subject of chromodynamics, string theory and black holes. Maldacena is most well-known for his 1997 paper on the large N limit of superconformal field theories and supergravity, which is the most-cited high energy physics paper of all time. Maldacena began his talk by discussing the close relationship between quantum chromodynamics, a type of quantum field theory, and gravity theories, namely quantum gravity. “The equality between these two things would be that the quantum field theory living on some space is equal to the quantum gravity living in the interior of that space,” Maldacena said. “The idea is that the physics in the interior can be described by the physics that happens on the boundary.” In particular, Maldacena discussed supersymmetric versions of this theory using the maximum number of supersymmetries, although these versions are difficult to experimentally confirm. One of the reasons for the maximum supersymmetry assumption in the theory is that is greatly simplifies the case and makes complicated physics a more tractable problem, Maldacena said. “There’s this joke about a farmer who had a cow, and he needed to increase milk production,” Maldacena said. “So he hires a veterinarian and a physicist to help him and the veterinarian tells him, ‘Well you should feed the cows better, exercise, blah, blah, blah.’ And then the physicist says, ‘Well, let’s first assume that we have a spherical cow.’ So this theory can be called a hyperbolic cow.” In order to work out these theories, Maldacena used anti-de Sitter’s space, which comes from the de Sitter space used to describe cosmological expansion. “In some sense, anti-de Sitter space is like a gravitational box that does not allow massive particles to reach the boundaries,” Maldacena said. “So if you sit in the middle of anti-de Sitter space and you throw a rock, after awhile the rock will come back to you. If you shoot a gun, then that’s not a very good idea.” Using this approach, a natural duality arises between quantum field and gravity theories, which allows researchers to investigate fundamental questions in physics, he said. “Duality in this relationship means, ‘Take some parameter, and when the parameter takes some set of values, say small ones, then one description is easy,’” Maldacena said. “‘Then if it takes another set of values, let’s large ones, then the other description is simple.’” When looking at systems of weakly-interacting gluons, essentially free ones, the string theory is the simplest description. When there are strongly-interacting gluons, the problem is still well-defined but difficult to analyze with string theory, in which case gravitational descriptions are better because the radius in the space is much larger. This leads to a good approximation of more complicated string theory by relatively simple gravity ones, Maldacena said. “The good thing that gravity does for us is it allows us to solve the quantum field theory in a simple way,” Maldacena said. “However, there are things that we can learn about gravity from the field theory. A particularly interesting thing is that it’s useful for understanding quantum aspects of a black hole.” Black holes are gravitational collapses, where nothing can escape once the event horizon, a sort of boundary of the black hole, is passed, Maldacena said. But according to quantum dynamics, they can emit radiation, where the temperature at which the radiation is emitted is inversely proportional to the size of the black hole. “This effect implies that the smaller you make the black hole, the hotter the temperature is,” he said. “You can have the paradoxical equation of a black hole that can be white. So you have white black holes.” In physics the notion is that whenever there’s a temperature, something is moving, Maldacena said, and one of the hot questions in the field is to describe what goes on in the interior of a black hole. Maldacena said these complex descriptions of black holes can also be applied in a more generalized way to hydrodynamics, underscoring the fundamental nature of his research and the discipline of physics as a whole. “As physicists, one of the laws of physics is that you take a problem and investigate by making it simpler,” Maldacena said.last_img read more

Chelsea, Barcelona and Manchester City all want Miralem Pjanic

first_imgChelsea, Barcelona and Manchester City all want Miralem Pjanic, but it’d take a bid of over €80m to bring Juventus to to the table, reports say.The Bosnian international is a key part of Massimiliano Allegri’s side, and has so far given no indication that he wants to be sold.Indeed, this morning’s Gazzetta dello Sport reports that the midfielder is excited to play with Cristiano Ronaldo, and has been offered a new €6m per season deal in Turin.That doesn’t completely rule out a sale though, with interest from Chelsea, Manchester City and Barcelona.Juve don’t want to sell, but would at least listen to offers above €80m.If Pjanic were to leave, the Bianconeri would look at Adrien Rabiot of Paris Saint-Germain, whose contract expires in the summer of 2019.(Source: klix)last_img read more


first_imgA piper leads Donegal Person of the Year Liam O Cuinneagain and Martin Mc Gettigan, President, Donegal Person of the Year, into the award function in Dublin on Saturday night.Archbishop of Dublin Diarmuid Martin with Liam and Anne Ui Chuinneagain at the Donegal Person of the Year function in Dublin on Saturday night.Dolores Nic Geidigh, Cllr David Alcorn, Lorraine Mc Gettigan and MEP Pat the Cope Gallagher at the Donegal Person of the Year award in Dublin.Sean Mc Elwee, Charlie ‘Dora’ Mc Ginley and Minister of State Dinny Mc Ginley TD at the Donegal Person of the Year function in Dublin.Martin Mc Gettigan, President, Donegal Association in Dublin presenting Liam O Cuinnegain with the 2013 Donegal Person of the Year Award in Dublin last night Saturday.DONEGAL PERSON OF THE YEAR LIAM O CUINNEAGAIN’S BIG NIGHT – PIC SPECIAL was last modified: March 2nd, 2014 by StephenShare this:Click to share on Facebook (Opens in new window)Click to share on Twitter (Opens in new window)Click to share on LinkedIn (Opens in new window)Click to share on Reddit (Opens in new window)Click to share on Pocket (Opens in new window)Click to share on Telegram (Opens in new window)Click to share on WhatsApp (Opens in new window)Click to share on Skype (Opens in new window)Click to print (Opens in new window) Tags:donegalDublin AssociationLIAM Ó CUINNEAGÁINPerson Of Yearlast_img read more

Bings World Cup Predictions are only for English regions

first_imgBing’s World Cup Predictions are only for English regions by Martin Brinkmann on June 14, 2018 in Microsoft – 4 commentsCompanies like Microsoft showcase computer technologies that can be used to predict outcomes of events regularly. The football World Cup 2018 starts today and it should not come as a surprise that Microsoft took the opportunity to predict the outcome of all group stage world cup matches.When you search for world cup predictions on Bing, you may get a neat listing of all group stage matches of the World Cup 2018 and predictions on which team Bing thinks will win the game.Predictions are not up for all games but they are provided for most games. There are not that many surprises as Microsoft’s AI concluded that favorites such as Germany, Brazil, or France will win their group stage games.Tip: You can also search for matches directly and may get predictions for those even if the full list of matches and results does not provide those at the time.Bing predicts, for example, that Spain will win against Portugal, when you search for FIFA World Cup 2018 Portugal vs Spain 15/06/2018. Just replace country names and the date to get predictions for other matches.But this article is not really about the World Cup or match predictions but about Microsoft’s constant neglecting of users who don’t live in the United States.Bing is a global search engine that provides localized results and is even used as the default (and only) search engine of the Windows 10 operating system if you keep web search functionality enabled.If you search for world cup predictions, you get the neat listing of game predictions by Bing only if you use the United States version of Bing or have set Bing to another English-speaking region. If you search using localized versions of Bing, you don’t get the list if predictions at all. It is as if they don’t exist, and that is even if you have set the interface language to English.It can’t be something technical that prevents Bing or Microsoft from displaying resultsYou can switch to United States in Bing to use the United States version; it is highly suggested that you do as it is quite common that Microsoft publishes new features only (or first) there.It can be something small like predictions on who is going to win the World Cup 2018 in Russia, but also major changes that add new features to Bing.Do the following to switch to another region:Go to Bing if you are not on the site already.Select Menu > Settings.Click on Country/region, or load https://www.bing.com/account/general directly.Select “change your country/region” on the page under Country/Region.Select United States – English.Scroll down and click on save.Bing is switched to United States in the process. You can select a different English-speaking region instead and will get the predictions as well but you will still miss out on new features that are more often than exclusive to the U.S. version of Bing.Now You: Is Microsoft shooting itself in the foot by restricting features to certain regions? And, which team is going to win the world cup?Related articlesBing’s Wallpaper of the Day as your Windows desktop backgroundBing Visual Search: search in imagesWhy Bing Video Search is better than YouTube SearchSummaryArticle NameBing’s World Cup Predictions are only for English regionsDescriptionWhen you search for world cup predictions on Bing, you may get a neat listing of all group stage matches of the World Cup 2018 and predictions on which team Bing thinks will win the game.Author Martin BrinkmannPublisher Ghacks Technology NewsLogo Advertisementlast_img read more