Luboš Motl

Czech physicist and translator

Luboš Motl (born 5 December 1973) is a Czech theoretical physicist who works on string theory and conceptual problems of quantum gravity.


  • Perturbatively, fundamental strings are more fundamental than branes or any other objects. In that old-fashioned description, D-branes are "solitons" — configurations of classical fields that arise from the closed strings. They are analogous to magnetic monopoles — which may also be written as classical configurations of the "more fundamental fields" in field theory. In a similar way, D-branes' masses diverge for 𝑔→0. Non-perturbatively, D-branes and other branes are equally fundamental as strings. In fact, when 𝑔 is sent to infinity, some D-branes may become the lightest objects — usually strings of a dual (S-dual) theory. When we include very strongly coupled regimes (high values of the string coupling constant 𝑔), there is a brane democracy.

The Reference FrameEdit

  • In 1980 I was a red kid and no one could have said anything bad about the Soviet Union. At least this is how my grandfather used to remember me. Around 1981, I became a pro-capitalist person and it stuck.
  • Your humble correspondent realizes that many readers are left-wing, anti-string-theory fighters. So they probably smoke marijuana and this is my modest attempt to help them.
  • According to polls, a majority (around 60+ percent) opposes the radar base. But it's not necessarily the sensible part of the Czech population. The demonstrations against the base are usually organized by communists, Islamists, and "peaceful feminists" (which is fortunately not a numerous group).
  • Whether you like it or not, alcohol helps to create emotional links between humans, too.
  • Because the white genes are mutations of the genes of the original men of color - and males are mutations of the original females - we can finally answer the question "Is God black?" The answer is "Yes, She is."
  • Lorentz symmetry might be broken but there doesn't really exist a glimpse of evidence or motivation why it should be broken. Such a breaking might be studied as a possibility, to some extent, but it would cause many problems, it would most likely return us philosophically before 1905, and the people who say that such a breaking is needed in quantum gravity are clearly wrong because string theory satisfies all the required properties of quantum gravity but it also respects the Lorentz invariance in flat space.
  • I wonder how Feynman would feel if he had to be talking to not just a few nuts of this kind but e.g. to 2,500 similar nuts who would be moreover described by the media as good scientists, if not the best ones in the world. ;-) Good for him that he managed to die in time.
  • Greenpeace protesters who lived on the trees right above the planned radar location (Google Maps) and who eat environmentally friendly roots, insect, excrements, and dirt.
  • Clearly, the left-wing groups want to use this carbon theme as a tool for wealth redistribution.
  • Some extreme optimists argue that North Koreans won't know how to mount the bombs on their missiles. Maybe, they have completed the H-bomb but haven't invented the screwdrivers and ropes yet.
  • Why don't you invest all of your money to Rossi's breakthrough yourself? And all of your fellow believers? If it "happens" that nothing will ever come out of it, at least you will help to increase the mankind's IQ by dying of hunger.
  • That should answer your question. I don't have to respond to every cretin, do I? I am already responding to most of them.
  • Weinberg says that "we want to know what's happening out there". But this is just the standard anti-quantum zealots' misunderstanding of the essence of quantum mechanics. Quantum mechanics says that all knowable things about the physical system must be obtained through a measurement whose outcomes are predicted via the Born rule. There is nothing else happening out there, at least nothing else knowable that is happening out there! So quantum mechanics does answer the question what is happening out there and the claim that quantum mechanics is incomplete in this sense is simply a lie.
  • The actual heart of quantum mechanics is that the objects in its equations are connected to the observations very differently than the classical counterparts have been.
  • You can't define whole disciplines of science to agree with random constraints that you invented. Instead, the purpose of disciplines of science is to decide whether your assumptions about the Cosmos and other things are correct. If there is a disagreement between the best theory and your assumptions, it's your assumptions that are wrong according to science.
  • … if one studies quantum gravity, something prevents you from localizing objects and particles with a better precision than one Planck length or so. String theory makes these guesses quantitative in various ways.
  • ... quantum mechanics is a complete, unified, coherent, and mathematically super-elegant scheme for providing us with (probabilistic) answers to all questions that seem to have any empirical sense.

Quotes about MotlEdit

  • While it is difficult to ignore Lubos, it always repays the effort

External linksEdit

Wikipedia has an article about: