Friday, May 15, 2009

The Cross Over Point and Time Travel

One of the issues that is evoked by any faster-than-light transport is time paradoxes: causality violations and implications of time travel. As if the faster than light issue wasn’t tough enough, it is possible to construct elaborate scenarios where faster-than-light travel results in time travel. Time travel is considered far more impossible than light travel.


I mean sure how is it one can measure time in energy particulate views when it appears all smeared out? It is the collision process itself and what I see in nature as Cascading particles as microscopic blackholes created and then quickly dissipated as decay in those particle showers.

Seeing muon detections that tunnel, and find their way across the globe is something that is interesting, as we can now use them in measure, as to what passes through to what is fabricated there in the LHC, becomes an interesting new tool of climate change or even gravitational inclination in relativistic approaches.

Length contractions is a key word here in microscopic measure.

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Juan Martín Maldacena and Joseph Polchinski

Dr. Maldacena and Dr. Polchinski each gave brief lectures related to their work. Both included broad overviews of string theory basics, with Dr. Polchinski noting the importance of "thought experiments" to help physicists make advances in the field. He said that physicists are excited about future experiments using particle accelerators such as the Large Hadron Collider at CERN, where some of these "thought experiments" could be validated.

Dr. Maldacena, who was born in Buenos Aires, also spoke about ICTP's important influence on physics in Argentina, noting that many of his professors had spent time at the Centre. Dr. Maldacena himself has participated in ICTP training programmes and was a director of the Spring School on String Theory for four years.

The Dirac Medal is given in honour of P.A.M. Dirac, one of the greatest physicists of the 20th century and a staunch friend of ICTP, to scientists who have made significant contributions to physics. Recipients are announced annually on Dirac's birthday, 8 August. The Medallists also receive a prize of US $5,000.
Noted physicists awarded Dirac Medal


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Juan Martín Maldacena, Institute for Advanced Study, Princeton
Joseph Polchinski, Kavli Institute for Theoretical Physics, University of California at Santa Barbara
and
Cumrun Vafa, Harvard University

Professors Maldacena, Polchinski and Vafa are being honored for their fundamental contributions to superstring theory. Their studies range from early work on orbifold compactifications, physics and mathematics of mirror symmetry, D-branes and black hole physics, as well as gauge theory-gravity correspondence. Their contributions in uncovering the strong-weak dualities between seemingly different string theories have enabled us to learn about regimes of quantum field theory which are not accessible to perturbative analysis. These profound achievements have helped us to address outstanding questions like confinement of quarks and QCD mass spectrum from a new perspective and have found applications in practical calculations in the fluid dynamics of quark gluon plasma.

The dualities have also led string theorists to conjecture that the five different superstring theories in ten space-time dimensions are manifestations of one underlying theory, yet undiscovered, which has been named the M-theory.
See:Dirac Medalists 2008


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Another deep quantum mystery for which physicists have no answer has to do with "tunneling" -- the bizarre ability of particles to sometimes penetrate impenetrable barriers. This effect is not only well demonstrated; it is the basis of tunnel diodes and similar devices vital to modern electronic systems.

Tunneling is based on the fact that quantum theory is statistical in nature and deals with probabilities rather than specific predictions; there is no way to know in advance when a single radioactive atom will decay, for example.

The probabilistic nature of quantum events means that if a stream of particles encounters an obstacle, most of the particles will be stopped in their tracks but a few, conveyed by probability alone, will magically appear on the other side of the barrier. The process is called "tunneling," although the word in itself explains nothing.

Chiao's group at Berkeley, Dr. Aephraim M. Steinberg at the University of Toronto and others are investigating the strange properties of tunneling, which was one of the subjects explored last month by scientists attending the Nobel Symposium on quantum physics in Sweden.

"We find," Chiao said, "that a barrier placed in the path of a tunnelling particle does not slow it down. In fact, we detect particles on the other side of the barrier that have made the trip in less time than it would take the particle to traverse an equal distance without a barrier -- in other words, the tunnelling speed apparently greatly exceeds the speed of light. Moreover, if you increase the thickness of the barrier the tunnelling speed increases, as high as you please.

"This is another great mystery of quantum mechanics."
Signal Travels Farther and Faster Than Light By MALCOLM W. BROWNE


You and I know it as a time machine. Physicists, on the other hand, call it a "closed timelike curve." Below, feast on the concepts and conjectures, the dialects and definitions that physicists rely on when musing about the possibility of time travel. If this list only whets your appetite for more, we recommend you have a gander at the book from which we excerpted this glossary: Black Holes and Time Warps: Einstein's Outrageous Legacy, by Kip S. Thorne (Norton, 1994).


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See Also:
  • Tunnelling in Faster then Light
  • Status of "Warp Drive"
  • Result of Effective Changes in the Cosmos
  • TimeSpeak
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