Juan Maldacena (Princeton IAS)
Singularities similar to Singularities of some blackholes in Ads3->suggest no information Transfer
In general, what I really care about and am willing to invest time in trying to carefully understand, are new physical ideas that explain something about particle theory, or new mathematical ideas that might somehow be useful in better understanding particle theory.
Lee Smolin stressed that it is only justifiable if one has a theory that independently predicts the existence of these universes, and that such a theory, to be scientific, must be falsifiable. He argued that most of the universes should have properties like our own and that this need not be equivalent to requiring the existence of observers.
Smolin's own approach invoked a form of natural selection. He argued that the formation of black holes might generate new universes in which the constants are slightly mutated. In this way, after many generations, the parameter distribution will peak around those values for which black-hole formation is maximized. This proposal involves very speculative physics, since we have no understanding of how the baby universes are born. However, it has the virtue of being testable since one can calculate how many black holes would form if the parameters were different.
My impression, if I can say so, is that many cosmologists undervalue the positive successes of CNS. It EXPLAINS otherwise mysterious features of our universe such as the setting of the parameters to make carbon and oxygen abundent-not because of life but because of their role in cooling GMC’s. It also EXPLAINS the hierarchy problem and the scale of the weak interactions-because these can also be understood to be tuned to extremize black hole production. Further, it EXPLAINS two otherwise improbable features of glaxies: why the IMF for star formation is power law and why disk galaxies maintain a steady rate of massive star formation.
Since the COBE discovery, many ground and balloon-based experiments have shown the ripples peak at the degree scale. What CMB experimentalists do is take a power spectrum of the temperature maps, much as you would if you wanted to measure background noise. The angular wavenumber, called a multipole l, of the power spectrum is related to the inverse of the angular scale (l=100 is approximately 1 degree). Recent experiments, noteably the Boomerang and Maxima experiments, have show that the power spectrum exhibits a sharp peak of exactly the right form to be the ringing or acoustic phenomena long awaited by cosmologists:
"How do you actually make a collapsing universe bounce back? No one ever had a good idea about that,” Albrecht said. “What these guys realized was that if they got their wish for an ekpyrotic universe, then they could have the universe bounce back."
Now some of you know that early on in this blog John Baez's view about the soccer ball was most appealing one for consideration, but indeed, the sphere as the closet example could all of a sudden become the ideas for triangulations never crossed my mind. Nor that Max Tegmark would tell us, about the nature of these things.
When I looked at Glast, it seemed a fine way in which to incorporate one more end of the "spectrum" to how we see the cosmo? That we had defined it over this range of possibilties? How could we move further from consideration then, and I fall short in how the probabilties of how we might percieve graviton exchange of information in the bulk could reveal more of that spectrum? A resonance curve?
Variable "constants" would also open the door to theories that used to be off limits, such as those which break the laws of conservation of energy. And it would be a boost to versions of string theory in which extra dimensions change the constants of nature at some places in space-time.
Magueijo started reading Einstein when he was 11, but he wanted to comprehend the theory using mathematics rather than words. So he read a book by Max Born, which explains relativity in the language of mathematics. He quotes Galileo as having said, "The book of nature is written in the language of mathematics."
The high energy nuclear physics experimental group at Columbia University is conducting research to study the collisions of relativistic heavy nuclei to understand the properties of nuclear matter at extremely high densities (similar to the center of neutron stars) and very high temperatures (much hotter than at the center of the sun). In fact, the temperatures and densities reached in these collisions are similar to those found in the early universe a few microseconds after the Big Bang.
PHENIX, the Pioneering High Energy Nuclear Interaction eXperiment, is an exploratory experiment for the investigation of high energy collisions of heavy ions and protons. PHENIX is designed specifically to measure direct probes of the collisions such as electrons, muons, and photons. The primary goal of PHENIX is to discover and study a new state of matter called the Quark-Gluon Plasma
Professor Leggett was awarded a share in the 2003 prize for his research at Sussex in the early 1970s on the theory of superfluids.
There is a special class of fluids that are called superfluids. Superfluids have the property that they can flow through narrow channels without viscosity. However, more fundamental than the absence of dissipation is the behavior of superfluids under rotation. In contrast to the example of a glass of water above, the rotation in superfluids is always inhomogeneous (figure). The fluid circulates around quantized vortex lines. The vortex lines are shown as yellow in the figure, and the circulating flow around them is indicated by arrows. There is no vorticity outside of the lines because the velocity near each line is larger than further away. (In mathematical terms curl v = 0, where v(r) is the velocity field.)
The Universe is governed by cycles of matter and energy, an intricate series of physical processes in which the chemical elements are formed and destroyed, and passed back and forth between stars and diffuse clouds. It is illuminated with the soft glow of nascent and quiescent stars, fierce irradiation from the most massive stars, and intense flashes of powerful photons and other high energy particles from collapsed objects. Even as the Universe relentlessly expands, gravity pulls pockets of its dark matter and other constituents together, and the energy of their collapse and the resulting nucleosynthesis later work to fling them apart once again.
Two essential conceptual features of the Standard Model theory have fundamentally transformed the understanding of nature. Already in QED the idea arose that empty space may not be as simple a concept as it had seemed. The Standard Model weak interaction theory takes this idea a step further. In formulating that theory, it became evident that the equations did
In the late 1960s a young Italian physicist, named Gabriele Veneziano, was searching for a set of equations that would explain the strong nuclear force, the extremely powerful glue that holds the nucleus of every atom together binding protons to neutrons. As the story goes, he happened on a dusty book on the history of mathematics, and in it he found a 200-year old equation, first written down by a Swiss mathematician, Leonhard Euler. Veneziano was amazed to discover that Euler's equations, long thought to be nothing more than a mathematical curiosity, seemed to describe the strong force.
He quickly published a paper and was famous ever after for this "accidental" discovery.
Dark matter in the high-redshift cluster CL 0152-1357. Gravitational lensing analysis with the Advanced Camera for Surveys (ACS) reveals the complicated dark matter distribution (purple) in unprecedented detail when the Universe was at half its present age. The yellowish galaxies are the visible cluster member galaxies forming a filamentary structure, possibly in the process of merging.
(Jee et al. 2005, Astrophysical Journal)
December 15th, 2005 at 2:35 pm
Tony Smith:
As to the time of Feynman soving the QED problem, in 1941 (according to Mehra’s Feynman biography The Beat of a Different Drum (Oxford 1994)) Feynman had the inspiration from Dirac’s paper of using the Lagrangian method, which led to Feynman’s 1942 Ph.D. thesis. As to that thesis, Mehra says “… Feynman mentioned that “the problem of the form that relativistic quantum mechanics, and the Dirac equation, take from this point of view, remains unsolved. …”. So, Feynman’s Shelter Island relativistic QED solution was developed after his 1942 Ph.D. thesis.
So, “A Week in the Lab” has come to an end. The experiment itself goes on, of course, but the week of blogging the experiment is at an end.
As physics, it wasn’t terribly successful– the experiment didn’t succeed, after all. As a life-in-science blogging event, I think it worked pretty well. I got to cover a fair range of the experimental physics process, from the basic design stuff, to the nuts-and-bolts assembly, to the prelimanry calibration measurements, to the process of figuring things out from sketchy data, to the frustration of an incomplete experiment. I wouldn’t call it the most successful week of my experimental physics career, but I think I might be happier with how this played out than anything else I’ve done on this blog. I’ll have to look back at it again in a couple of weeks and see if I still feel that way, but at least at this early stage, I like the results.
So I thought I would point you to another case. I mean sure there is going to be trials and errors.
The Blind Men and The Quantum (1,338k) - The First Hal Clement Memorial Lecture, given at the Boskone 41 Science Fiction Convention, Boston Sheraton Hotel, February 15, 2004. A 50 minute discussion of quantum paradoxes and interpretations, with emphasis on new data (The Afshar Experiment) that appears to falsify the Copenhagen and Many-Worlds Interpretations, but is consistent with the Transactional Interpretation.
The Transactional Interpretation, which involves a forward/back in time handshake, is one of the few (perhaps the only) interpretation(s) left standing after the Afshar test.
Dear Lubos,
"Therefore we have humiliated Bohr, Heisenberg, Dirac, the Copenhagen interpretation, complementarity, the uncertainty principle, quantum mechanics as well as the rest of physics."
From the content of your response, I can only conclude that you have not fully read my preprint:
www.irims.org/quant-ph/030503/