Quanto Magazine

Great Scientists: David J. Bohm

If you have already been browsing other articles in this magazine you may have come across a term as baffling as Bohmian. What is Bohmian? Well, so roughly speaking it is possible to say that Bohmian is anyone who sympathizes or is in any way related to the ideas of David Joseph Bohm, a scientist and philosopher. Probably most of you will not have heard of Bohm in life, although there is a certain professor of quantum physics who mentions him in his lectures in speaking of the experiment of the two slits. You can also find some mention about this character in some books of orthodox quantum physics or classic manuals to use. Even if you digress a little you can find in our library a quantum book written by him and containing an alleged dedication to his Spanish colleagues written in pencil on one of the first pages.

David Joseph Bohm was born in 1917 in Wilkes, Barre, Pennsylvania (United States). His first contacts with science came in his readings of science fiction, when he was still a child. No more information was available in that small mining town. David was fascinated by the forces of the universe and the great number of things that are beyond our understanding. He studied physics at the State College, continuing his training at CALTECH, where he did not last long, since he never fit into that atmosphere. The pace of constant problem solving and test-taking made him drop out of high school after the first semester to leave for the University of California at Berkeley. There he investigated during the Second World War the dispersion of nuclear particles under the supervision of J. Robert Oppenheimer. After finishing his doctorate in Berkeley (1943), he became an assistant professor at Princeton University in 1947.

For a physicist of the caliber of Richard Feynman, an area of ​​physics was only interesting if he could find a problem in it, and turned out to be a genius solving all sorts of problems. On the occasions when Bohm encountered a technical difficulty, he always distrusted the too abstract mathematical reasoning. As he pointed out, after all, in any mathematical development, there are things we assume without examining them too much, and the more complicated the mathematics employed, the easier it is for errors to remain. He preferred to proceed always intuitively, rather than logical or mechanical, and preferred to feel the answer and visualize it in his mind clearly before giving the pertinent mathematical steps. It is as if his method in solving problems is carried more by imagination and intuition than by pure logic.

For example, while still in the state of Pennsylvania, he had been trying to understand the functioning of the gyroscope, that puzzle that intrigues the children with their continuous swing. Usually, when we push an object so that its center of gravity falls out of equilibrium, it falls. A gyroscope, however, does not fall, its axis of rotation moves and undergoes precession. When most students of physics face the problem of the gyroscope, we will learn different formulas, such as the conservation of the moment, which lead to a rather incomplete explanation. But Bohm needed a direct perception of the intimate nature of this movement. One day, while walking in the field, he imagined his own person as a gyroscope, and through some kind of internal muscular movement he was able to understand the nature of the movement. In this way, and using his own body, he understood the functioning of the gyroscopes. The formulas and mathematics would come later, as a simple formal tool to explain their internalization.

This particular skill accompanies you throughout your professional life. One of his colleagues said, “Dave always comes to the right conclusions, but his math is terrible. I take his work home and find all kinds of mistakes and I have to spend all night looking for the right demonstration. , The result is the same as Dave directly visualized. ”

To give another example we will take the spin of an electron, a quantum concept far removed from the usual classic resemblance with a balloon circling over itself. This is a concept that begins to move away from common sense. Most physics students would be content to visualize the electron in terms of mathematical manipulations and equations, without explicit reference to anything physical. Bohm, however, found himself able to experience sensations with his body about the way the spin components are combined into something moving in a new direction.

When I was still studying in Berkeley, Bohm did quite new works with plasmas. He discovered that electrons ejected from atoms do not behave as individual particles in a high-temperature gas (known as plasma), but rather as part of an immense and organized whole (an idea that was deeply rooted). An enormous number of electrons would produce quite organized effects, as if an organic process were directing their collective behavior. Shortly after Bohm would say that these collective movements, now known as Bohm-diffusion, gave the impression that the sea of electrons was alive somehow. This was Bohm’s first major discovery in the field of physics, and he is directly engaged with the deep themes of the universe and the interconnections that would characterize his thinking and scientific work. Nevertheless, in his last years of life he elaborated a conception of the universe according to which it consists in the interconnection of all things, a notion to which he would give the name of “implicated order”.

As we were saying some paragraphs ago, Bohm got a parking assistant professor at Princeton University in 1947. While teaching of quantum mechanics in the following years he wrote a book called Quantum Theory (1951), which is still a classic in the Field (this is the book that I talked about in the first paragraph). When he completed this work, Bohm was beginning to befriend Albert Einstein, who was also at Princeton at that time. Einstein apparently told Bohm that he had never seen the quantum theory presented as clearly as it appeared in Bohm’s new book, and the two scientists began to converse more assiduously. As their relationship grew closer they discovered that they had much in common in their basic conceptions of quantum theory, and together they deepened in the interpretations and metaphysical meaning of quantum theory. He would gladly give a large sum of money for being in one of these talks, with Bohm and Einstein putting the quantum to calving.

These discussions led Bohm to seriously consider the validity of the classical interpretation of quantum mechanics (Vienna circle). Encouraged by the confidence that his association with Einstein gave him, Bohm embarked on a great undertaking: revising the foundations of quantum theory, which led to his peculiar formulation of the same and eventually lead to a crusade for life In search of the knowledge and understanding that allowed him to describe all reality (a theory of everything).

By the same time Bohm brought out another important example of his peculiar way of being. Had some problems with American justice, since he had to appear before the Committee on Un – American Activities (1949) under the accusation baseless, he and some other lab partners radiation Berkeley sympathized the with communism. During World War II Oppenheimer referred to the FBI the names of supposedly philomarxist friends and acquaintances. Apparently, Bohm was one of them. As he passionately believed in freedom he refused to declare, for reasons of principle, what earned him the accusation of contempt of congress. After a trial he was acquitted. His Princeton students asked that he be reinstated in his post, and Einstein was said to want Bohm to become his personal assistant, but his contract, after an unfortunate incident, was not renewed, and would never again be taught in the States United. Einstein himself, who spent many years futilely searching for his own alternative theory of quantum mechanics, referred to Bohm as his “intellectual successor” saying that “if anyone can do it, that will be Bohm.”

Bohm moved to Brazil (1951), to the University of Sao Paulo, where he would be professor until 1955. The embassy requisitioned him the passport, with which he lost his nationality. There he worked on his second book, Causality and Chance in Modern Physics (1957), which is still used in some universities. From Brazil he went to the Technion Institute in Haifa, Israel, and then to the University of Bristol in England. There, he and a student in 1959 made another original contribution to quantum theory. He discovered with Yakir Aharonov what is now known as the Aharonov-Bohm effect. They showed that quantum mechanics predicts that the movement of charged particles is conditioned by the presence of magnetic fields, even when they do not penetrate where they are confined. Several experiments have confirmed this effect.

He was later acquitted of the contempt charge by allowing him to return to the United States, but it was too late for him, he settled permanently at Birkbeck College in London.

In the next thirty years the work of David Bohm focused on the foundations of quantum theory and the theory of relativity and its implications in various fields. As is often the case with advanced physicists, in later life he became interested in philosophical matters, holding interminable talks with Indian spiritual director J. Krishnamurti.

In this new stage of his life he elaborated a conception of the universe according to which it consists in the interconnection of all things, a notion to which it would give the name of “implicated order”. He wrote more books of physics ( Theory of Relativity in 1966), philosophy ( Wholeness and the Implicate Order in 1980), and even the nature of consciousness ( Science, Order and Creativity in 1987 with David Peat).

He died of a heart attack in 1992 when, in collaboration with other scientists, he was preparing a new volume on quantum mechanics. His friends and colleagues remind him of a man who was not only brilliant and audacious but also extraordinarily frank, polite and generous.

From Bohm we have his alternative theory of quantum mechanics, which came to light more than forty years ago but has been ignored until recently. This theory, completely braided and absolutely different, also accounts for all known subatomic phenomena. In it chance plays no role and every material object always occupies a particular region of space. In addition, its laws form a unique set, applicable equally to all physical objects, even if we have to admit the nonlocality. In any case, the theory has not yet surpassed the relativistic test, which in these times would take it to the box of definitive oblivion. Meanwhile, a small group of Bohmians from around the world are facing the dominant majority, armed with hidden variables and pilot trajectories seeking to realize that dream that Einstein and Bohm wove in the afternoons of Princeton.

if you want to delve into the life and work of this scientist, take a look at https://en.wikipedia.org/wiki/David_Bohm Another valuable source of documents and links is the library of Birkbeck College, University of London, where Bohm was Professor of Theoretical Physics: http://www.bbk.ac.uk/lib/about/hours/bohm

Gustav Dalen

A good part of our “technological world” passes every day unnoticed, either by the force of habit, or because there are so many technologies that we take for granted. Many everyday technological developments were at one time engineering triumphs, and before that, the science or dream of a visionary.

One of the greatest awards for a technological advance is the Nobel prize. The history books say that the Swedish Alfred Nobel, was tormented by his fortune amassed in the industry arms of dynamite (of which he was the inventor) and wanted to remove the awards that bore his name. According to his testament :


“The totality of what that remains of my fortune be disposed of as follows : capital, invested in securities insurance by my executors , shall constitute one fund whose interest will be distributed each year in the form of prizes among those who during the year preceding have made the greater benefit to mankind. These interests are divided into five parts equal, which will be distributed in the following way: one part to the person who has made the discovery or invention more important within the field of physics; one part to the person which has made the discovery or improvement more important in the chemistry ; one part to the person who has made the discovery more important in the field of physiology and medicine ; one part to the person who has produced the work most outstanding of trend idealist in the field of literature , and one part to the person who has worked more or better in favor of fraternity between the nations , the abolition or reduction of armies existing and celebration and promotion of processes of peace . the awards for the physics and chemistry will be awarded by the Academy Swedish of the Sciences , that of physiology and medicine will be awarded by the Institute Karolinska of Stockholm ; that of literature , by the Academy of Stockholm , and the advocates of peace , by one committee formed by five people elected by the Storting ( Parliament ) Norwegian . It is my express wish that , by granting these awards , not be in consideration the nationality of the candidates , but they are the most deserving those who receive the prize , whether Scandinavian or not. “

It is since then very complicated the role of the different institutions responsible for choosing the winners based on their contribution to the benefit of humanity, and more when those contributions can not be neither obvious nor immediate.

For example, the prize Nobel of Physics has moved always between the extremes reflected in the will of Alfred : discoveries and inventions. The award has been split between work of theorists such as Van der Waals or effect Photoelectric of Einstein and others with more practical work such as the instruments optical of Michelson or telegraphy by Marconi and Braun. Today we’ll talk about an unknown Gustaf Dalen.
The prize awarded to Gustaf Dalen in 1912 may be one of the most curious of all the history of the award. It could favor him his nationality was Swedish and also the fact of that during that same year lost sight in a serious accident during a test with acetylene, a very dangerous explosive substance. What you do not put in doubt is that he contributed to saving lives and therefore the benefit of humanity .

He born in a farm and supported by his mother her was able to study. He constantly invented things.

The main achievement of Gustaf came from for his work with acetylene. Capable of producing the lights in headlights. Developing one new porous materials, improving the safety of the storage of acetylene and discovered the way in which the flame of acetylene works.

In addition it incorporated one valve solar, which was at the tune the only lamp to work during the night. An invention that the own Edison doubted that would work and that required a demonstration to the patents office . With all this work he managed to reduce the consumption of the lamp by 94%.

valve

The “Dalen Light”, is thus named in honor of its inventor. It increased the efficiency of the headlights, not depending on the then little reliable supply electricity. With this technology, headlamps immediately illuminated Sweden and the channel of Panama till the 1960’s. Even in 1980 an electrified lighthouse Blockhusudden was discovered which a valve that had been running continuously since 1912 without one single revision!

In spite of his accident Dalen continued his work until his death in 1937. He was an active participant in public life and policy of his country was a member of the Royal Academy Swedish of Sciences and of Science and Engineering .

Refs and photos:

http://en.wikipedia.org/wiki/Sun_valve

http://en.wikipedia.org/wiki/ Gustaf_Dal % C3 % A9n

http://en.wikipedia.org/wiki/Alfred_Nobel

Interview with Christopher Fernandez Pineda

Here at Quanto we wanted to know something about the history of The University of Madrid. So we went to talk to Christopher D. Fernández Pineda, and after a bit of conversation discovered that the story of the classroom is the history of the Faculty, its spirit and its people. Professor Fernandez Pineda tells the liveliness that characterizes some of the events that happened at the Faculty in the sixties in the twilight of the Franco dictatorship. Here’s what he said.

“It was a really difficult time, at the Faculty hard times were lived because they were already the last years of the dictatorship and probably the university was the only place where you could talk a little freely, but you had to be careful, because anything that was said could be heard by the police in class. There were people in class sitting and we knew they were cops. At that time there was a police headquarters here at the Faculty. In the old department there was a thing called the police Faculty of Science, and it had about thirty guards there .. and three or four secret policemen, one of them was known as ‘the vampire’. They were hard times for both the teachers and the students.”

“The photos that I will show you was taken in the optics laboratory and through cracks in the window with shutters he pulled”.

Here’s the bridge, and water hose to the fourth floor, which was where the delegation of students was. The water had green paint in it, it made it so that you could not walk down the street. You were painted green and people knew that you had been in the mess. Of course there were democratic cravings. By then the Faculty of Physics was reputed to be a faculty which strived for this. The Faculty has changed a lot in that respect. Then, of course, when democracy arrived, the University was not a political discussion forum.”

In the classroom Magna, currently 1 D. Christopher received his first class and also taught his first class as a teacher. Then he tells some anecdotes about this classroom.

“The Classroom 1 has a great democratic tradition. I remember coming to class and sometimes could not teach because there was a hullabaloo and then a show of hands was made. Those who wanted to give class to raise their hands, those who do not want to teach raise your hands.. it’s a vote… One day, some students went to the dean and said they wanted elections. I was very young then. What happened next is that there was an election planned for May 1 … Sure, I got there on May 1, at that time we wore gowns, I put on my robe and went to class. When I got to school I found the classroom and the hallway and all full. Then I saw the police turn to me and say: “where are you going?”, and I answer that I presided over elections and they took me to the barracks. I told them to call the Dean and ask him why this had happened and why I’d been shut up there with thirty policemen. Eventually they called the Dean, but they left me a couple of hours there. Good thing they did not take me to the Directorate General of Security. So the next time elections were held, students again asked me.

“In my time there were very few professors, there were five or six compared to forty now. I think the faculty in education had a fairly acceptable level. Right now, it is working well and is being published in many journals. But during the time of the dictatorship, the issue of Physics in Spain was very weak. This has been a very strong evolution from the seventies or so. Physics has risen and, in general, Scientific and number publications. People began to publish abroad also because we were very scared to publish here. Today, here at the Faculty there are very good level. I repeat the phrase of D. Carlos Sánchez del Río, Dean of the Faculty few years ago. He promised to find someone who knew about any subject of Physics in 24 hours, here, within the Faculty. The weirdest thing that may be of Physics, in 24 hours we will look for one of the Faculty of Physics at the Complutense who knows the subject. This faculty is very complete, the average value is quite high. We are being published enough.”

“In the old system of recruitment of staff it was different. There was one thing, which in my view was very important, which is the thesis. I did a dissertation. Before when you finished the essay you could talk to people in the department, and you got a little job as you started to investigate. In that year you had time to start researching the literature, start driving magazines and to work independently. It gave you a good basis for further work.The first salary I had was 22,000 pesetas per year, some 1,800 monthly. and when I had graduated I had a salary of around 3,000 pesetas a month, but no Professor earned much then.”

Christopher Fernandez Pineda holding the chair which was once occupied Don Julio Palacios. Many other issues were discussed in our talk with Professor Fernández Pineda, a fascinating man. 

Great Scientists: Hendrik Antoon Lorentz

This Dutch farmer’s son is undoubtedly one of the great theoretical physicists of history not only for his numerous scientific contributions but also for his dedication and effort in pursuit of the progress of physics and its teaching. In this last field, the fact that he was responsible for the physicians for a long time received an appropriate training in physics,, and that even after being retired at the age of seventy of from his post at Leyden University, he continued to teach until a few weeks before his death.

Lorentz was the first to use the term electron, although initially to designate elementary particles, introducing the atomistic theories in Maxwell’s theory and creating models Which would explain the interaction between radiation and matter, convinced that the latter had an atomic structure. As a result of these works, he framed Maxwell’s theory in a microscopic theory of electromagnetism considering the existing fields within matter in the void spaces between particles. All this led to what would be one of the greatest successes of his career as a theoretical physicist, the exact prediction of the normal Zeeman effect by which he received the Nobel Prize in Physics in 1902 along with Pieter Zeeman, ie by the effect of a field Magnetic uniform over spectral lines. It is curious that the normal Zeeman effect described by Lorentz is the less usual, having to frame his study within the quantum theories of radiation and that by coincidence coincides in its results with those obtained classically by Lorentz.

Undoubtedly the name of Lorentz is familiar to us above all by the Lorentz-Einstein transformation of application in special relativity when changing reference system. To explain the negative result of the Michelson-Morley experiment Lorentz adhered to Fitzgerald’s hypothesis that every moving body in the ether would undergo a longitudinal contraction. Lorentz introduced the idea of ​​local time as mathematical artifice to work with this contraction resulting from the internal tensions produced by the movement of the body in the ether. This local time as mathematical artifice would be endowed by Einstein shortly after a clear physical sense by abandoning the concept of Newtonian absolute time. Lorentz was always a classic physicist maintaining his reserves towards the ideas of Einstein but doing a fundamental work in the development of the same ones. The classical idea of ​​physics was more clearly seen with the advent of quantum theory, resisting admitting the death of determinism and the introduction of new concepts such as the quantization of energy or the fact that the position and momentum of a Particles became blurred concepts. Lorentz died in 1927, the year in which Schrödinger showed the world his equation and the concept of wave function burst in with all its force.

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