Paul Dirac Interview (Göttingen, 1982)

Oh yesterday you give us a short account of a very important development in theoretical physics it started with Einstein's special relativity with the symmetry of space and time and then net to level of development which ended with an utter symmetry the symmetry little particle and antiparticle that was immense uptrend and the key birth for symmetry yes that is so I wanted to emphasize that Einstein was the first to realize the importance of symmetry Lawrence had worked out the mathematics of the transformations the transformations are called Lorentz transformations but Lawrence did not realize the symmetry which was implied by these transformations he thought that there was one frame of reference which was the good frame the physical frame and that other frames of reference were just mathematical fictions and I believe I remember the words he introduced local time as a concept that he said local time different from the real time yeah there he is emphasized that there is one a real absolutist of the easel and there he was quite wrong yes and it took him a long time I believe until 1909 before he accepted the Einstein viewer yes he gave a lecture in gherkin in nineteen nine or ten and he said that perhaps we must give up the concept of the e to the time of the actual equal times but he yeah consent realm few days only girl out K but yes and Stan started off with a different point of view and he showed how he was an independent thinker and with about symmetry in this collection you mean symmetry between time and space correct yes what's imagery was in the central deity has changed in time it first it was exhibited space and time then came out of symmetry symmetry soutien electron it unti electron positive a negative charge and then more recently other symmetries have appeared in physics symmetry between proton and neutron yes and this is only an approximate symmetry what physicists call a broken sir yes but if we're at I would ask you something of foetid form of symmetry in you Oberg that symmetry space-time short it is important if you can start it you of applicati like aggression of the electron in the days before physicists referred the so called floating outline gold on fly shown a face but this equation has the time in a second derivative set was not accepted for you you have before you had constructed the tropical transformation theory and there you need it to concept of probability and the first derivative that is correct yes yes and that forced me into a different kind of equation and this different equation brings in the spin of the electron it was very unexpected to me to see the spin appearing in this way it's filled it means moment of momentum and magnetic moments to get that they both come together yes I thought one would first get a satisfactory theory of a particle without spin and then one would proceed to a more complicated theory of a particle wisping yes but it turned out differently the simplest kind of particle does have a sim yes you mean perhaps our device cope with the scalar theory and yeah physicists saw that they can incorporate any spin into a consequent theory but it is for but more complicated as Europe I agree the simplest the simplest article said codex's forth hell John mrs. peignoir the Edit on that is so yes yes it was a great revelation when this appeared and with them with the solution of any difficulties one was able to concentrate on the one remaining difficulty how one should deal with the negative energy states took quite a while perhaps a year to understand that and to bring in the concept of a vacuum in which all the negative energy states are occupied is it possible to express it to follow manner in this theory of the N eternity let me say the Dirac theory you can treat pairs of particles or positrons electrons in the form of a Walmart achill theory is that if you have scalar spin a scalar particles a poly bicycle Theory you can treat pairs method and only in the form of a many body usually yes that is yes and should we speak a little about general relativity years general relativity was considered by Einstein as his most important discovery he was working entirely alone on new mathematical ideas and it was a big triumph for him to be able to get his ideas straightened out and to introduce a new theory of gravitation bringing in a very powerful kind of symmetry is symmetry is of importance in physics only where gravitational fields occur while the symmetry previously the symmetry of special relativity is of importance in all physics so that this further symmetry introduced by general relativity although it is such a wonderful mathematical theory does not have a big effect on physics and I must say that my recent work has been very much concerned with Einstein's general relativity and I believe that the times and distances which are to be used in Einstein's general relativity or not the same as the times and distances which would be provided by atomic clocks there are good theoretical reasons for believing that that is so and for believing that gravitational forces are getting weaker compared to electric forces as the world gets older there is some observational evidence for that observations of the moon which have been made accurately for centuries with respect to the time provided by the Einstein theory and which have been made since nineteen hundred and fifty five with atomic clocks and there is some evidence of a difference between the two times the evidence is not as complete as one would like to have people are still working on the subject in particular with the Viking Lander which was put onto Mars in 1976 one is able to send radar waves to Mars and get back the reflected waves and then one can measure in atomic time how long it takes these waves to go to Mars and to come back the results that one gets are unfortunately very complicated because there are many disturbances there are disturbances caused eaten by meteors there are many more meteors passing close to Mars than there are Allyson curves by the earth and these disturbances all have to be taken into account well people are still working on this subject and I hope that they will get a definite answer criticism about the question of whether there are these two times the Einstein time and the atomic time with a difference between them your vote is a natural o'clock then Mowgli's today physicists used to say the vibration of a molecule on atoms a natural clock and it's tension of an undisturbed crystal is a natural length that ones would be the natural time and natural length that those are the atomic times the atomic length and that is the best way to define these quantities it may be that quantities defined in this way are not the ones to be used in the Einstein theory for astronomical of civilians should we say Einstein theory then must be changed or completed or can it remained with another interpretation and the equations remain but they are to be applied yes but in Einstein's equations gravitation constant is assumed to be constant yes and in this motor development it is not well whether the gravitational constant really is a constant or not will depend on what units you use because little bit of interpretation yes yes there is no suggestion that Einstein is wrong but it just honor how his equations are to be used is Einstein's theory has turned out to be a wonderful theory so successful in all its applications but there is this question of the interpretation which is not yet settled but now then it can happen that Einstein's general relativistic theory becomes more important nearly so general is so special it is not so important event yes of course it is only to do with cosmology and gravitation yes but faith gravitation one day will be connected with other forces weak forces strong forces electromagnetic forces that is possible but that lies far ahead yes that the fact of 10 to the minus 14th history yes listen I think you both the first who led the attention to these extreme constants you helped to revive this fault 10 to the minus 80 yes yes but he had no exact no certain results the pressure is Auckland there is some evidence from the observations of the moon yeah but one would like to have some confirmation coming from radar observations from Mars yes but it can be say that quantum mechanics also had a great great contribute to whole theory of metal the whole theory of the properties of meta chemistry and so other is a consequence of quantum mechanics in the add on the motion of the electron is slower than that of light yes and treif features of quantum mechanics among relativistic that I would agree and I think that the correct connection between quantum theory and relativity has not yet been discovered can I ask you something of the modern model development now we hope that perhaps in the short time we get a unified theory of the particles now we make differences between stone in Direction electromagnetic interaction weak gravitation is for what are your hopes I think that the pleasant methods which theoretical physicists are using are not the correct methods they use what they call or renormalization technique which involves handling infinite quantities and this is not really mathematically a logical process I will say that it is just a set of working rules rather than a correct mathematical theory and I don't like this whole development at all I think that some other important discoveries will have to be made before these questions are put into order in particular there is the problem of explaining the fine-structure constant the number 130 cells which plays an important role in physics and the question is why should it be 137 step of some other number that has not been explained at all and I feel that it is necessary to get an explanation of that before one will make an important advance understanding atomic theory the fine structure constant Islam of them ultra generation between weak and strong in the action for strong the excavator can say to consist nearly warm really hex warm then the mass the proportion of the masses electron mass or turns upon mass I think that other bottle that is into problems will be connected I think probably yes and quite a different problem ratio of the mass of the proton to the mass of the electron and the question is whether the ratio of the masses remains constant or whether it develops slowly with time you people are now looking into this problem

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Keywords: Physics, Paul Dirac, Quantum Mechanics, Einstein, General Relativity, cosmology, gravitational constant, Nobel laureate, Elementary Particle Physics, Science, Philosophy, Theoretical Physics

Id: Et8-gg6XNDY

Length: 20min 33sec (1233 seconds)

Published: Sun Jun 18 2017