Günther Ludwig (physicist)

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Günther Ludwig (born January 12, 1918 in Gäckerick ; † June 8, 2007 in Marburg ) was a German theoretical physicist .

Life

Louis studied at the University of Berlin Mathematics and Physics and in 1943 with a thesis on applied mathematics doctorate . During the Second World War he was at the Army Research Institute in Peenemünde (department on-board equipment, control and measurement technology, most recently deputy head of the control theory department). From 1946 to 1948 he was Richard Becker's assistant in Göttingen , where he was also influenced by Werner Heisenberg and Pascual Jordan and completed his habilitation in 1948. From 1949 he was associate professor at the Free University of Berlin (from 1952 full professor), where he set up the Institute for Theoretical Physics , and from 1963 at the Philipps University of Marburg (as successor to Siegfried Flügge ), where he retired in 1983.

plant

Ludwig dealt mainly with the fundamentals of physical theories, designed a. a. an axiomatization of quantum mechanics and dealt with the quantum mechanical measurement process and the emergence of irreversibility in quantum mechanics (fundamentals of statistical mechanics ). In the 1940s he also worked on projective relativity ( Pascual Jordan's theory of gravity ), cosmology , quantum field theory, and hydrodynamics .

According to Ludwig, the distinction between microscopic and macroscopic objects is essential for the measuring process of quantum mechanics and quantum mechanics itself cannot be applied to the measuring process. The statements of quantum mechanics are ascribed to microscopic objects, but are only made using macroscopic objects and their statistical correlations, especially macroscopic apparatus for preparation and registration that interact with each other via microscopic quantum objects such as electrons. The statistical information from the preparation of the quantum objects can be encoded in a wave function ( Hilbert space vector ) which, according to Ludwig, always describes an ensemble of quantum objects (and also for the receiver , the recording device). The Heisenberg uncertainty relations are then a statement about the limitations of the preparation. Terms such as (single-particle) state or wave function, which are often used as a basis in discussions about the interpretation of quantum mechanics, are already complex derived constructs for Ludwig.

He developed this approach to quantum mechanics in a mathematically strict way (with an explicit reference to the Bourbaki school) in order not to allow any hidden assumptions to flow in, and based on his treatment of quantum mechanics he developed a general structuralist theory of physical modeling. A physical theory PT then consists of three parts: a mathematical theory MT (which is treated axiomatically), a realm W and mapping principles between W and MT, which represent the interpretation of the theory.

In this context, the relationships between physical theories can also be examined, for example the use of pre-theories to formulate a theory PT (such as the classical mechanical equations of motion in electrodynamics ) or the reduction of physical theories (such as classical mechanics from the special theory of relativity or thermodynamics from quantum statistics ).

Another aspect of Ludwig's formulation is that it also formalizes the finite character of actually recorded measured values; for Ludwig, the use of infinitely small and large mathematical objects are only approximations to physical reality, which is always finite.

Ludwig has only sketched the application to other theories than to quantum mechanics and understands his general theory of physical systems as a program for future research, whereby, just as in quantum mechanics, he is of the opinion that problems in the interpretation of physical theories can only be solved by strict axiomatization to let. Ludwig also sees works by Jürgen Ehlers , Felix Pirani and Alfred Schild on the foundations of general relativity from the 1960s and 1970s as part of his program.

Ludwig first presented his interpretation of quantum mechanics in several essays in the 1950s and then expanded it with his students. His first book on it appeared in 1970, and this found a certain conclusion in his two-volume monograph An axiomatic basis for quantum mechanics in the 1980s and, as far as his general theory of physical systems is concerned, in his book The Basic Structures of a Physical Theory (1978, 1990) and in simplified form in a book with Gérald Thurler , which appeared a year before his death. In his four-volume introduction to the fundamentals of theoretical physics from the late 1970s, he gave a simpler presentation in textbook form with a strong emphasis on conceptual fundamentals.

Ludwig's theory of physical systems was further developed and discussed by his students Joachim Schröter and Heinz-Jürgen Schmidt. Other structuralist theories of physics were developed by the German philosopher Erhard Scheibe (who referred to Ludwig) and the American physicist Joseph D. Sneed .

Ludwig was a member of the Academy of Sciences and Literature in Mainz and the Istituto Lombardo Accademia di Scienze e Lettere in Milan .

Many of his students (post-doctoral candidates and doctoral candidates) became professors, including Gerald Grawert (FU Berlin, Marburg) and Siegfried Großmann , who followed him to Marburg, as well as Arno Bohm (University of Texas at Austin), Karl-Eberhard Hellwig (TU Berlin), Karl Kraus (Würzburg), Hermann Kümmel (Bochum), Horst Rollnik (Bonn, Vienna), Heinz-Jürgen Schmidt (Osnabrück), Joachim Schröter (Paderborn), Georg Süssmann (Munich), Reinhard F. Werner (Hanover) and Wolfgang Weidlich (Stuttgart).

Fonts

  • The basic structures of a physical theory. Springer, Hochschultexte, 1978, 2nd edition 1990 (also translated into French).
  • Fundamentals of quantum mechanics. Springer, Grundlehren der Mathematischen Wissenschaften 1954, new edition as The Foundations of Quantum Mechanics 2 volumes, Springer 1983, 1985.
  • Introduction to the basics of theoretical physics. 4 volumes, Vieweg Verlag 1974 to 1979 (volume 1 space-time mechanics. Volume 2 electrodynamics, space, time, cosmos. Volume 3 quantum theory. Volume 4 macrosystems, physics and humans. ).
  • The measurement process. Zeitschrift für Physik, Vol. 135, 1953, pp. 483-511.
  • For the interpretation of the observation in quantum mechanics. Physikalische Blätter, 1955, p. 489, online .
  • Günther Ludwig: On the ergodic theorem and the concept of macroscopic observables. In: Journal of Nature Research A . 12, 1957, pp. 662-663 ( PDF , free full text). , Part 2, Zeitschrift für Physik, Volume 150, 1958, pp. 346-375, Part 3, Zeitschrift für Physik, Volume 152, 1958, pp. 98-115.
  • Axiomatic quantum statistics of macroscopic systems (Ergodic theory). In P. Caldirola, Proceedings of the International School of Physics Enrico Fermi, Course XIV, Academic Press, 1960, pp. 57-132.
  • Solved and unsolved problems of the measurement process in quantum mechanics. In Werner Heisenberg and the physics of our time. Vieweg Braunschweig, 1961, pp. 150-181.
  • To justify thermodynamics on the basis of quantum mechanics. Journal of Physics, Volume 171, 1963, pp. 476-486, Part II Master's equation . Zeitschrift für Physik, Volume 173, 1963, pp. 232-240.
  • Attempt of an axiomatic foundation of quantum mechanics and general physical theories. Zeitschrift für Physik, Volume 181, 1964, pp. 233-260, continued in:
  • Interpretation of the term “physical theory” and axiomatic foundation of the Hilbert space structure of quantum mechanics through the main principles of measurement. Springer, Lecture Notes in Physics, Vol. 4, 1970.
  • An Axiomatic Basis for Quantum Mechanics. 2 volumes, Springer 1985, 1987 (Vol. 1 Derivation of Hilbert Space Structure. Vol. 2 Quantum Mechanics and Macrosystems. ).
  • The cat is dead. In J. Audretsch, K. Mainzer (ed.): How many lives does Schrödinger's cat have? , BI Wissenschaftsverlag 1990, pp. 183-208.
  • Quantum Theory as a Theory of Interactions between Macroscopic Systems which can be Described Objectively. Knowledge, Volume 16, 1981, pp. 359-387.
  • The Christian's scientific worldview. Osnabrück, A. Fromm 1962.
  • Advances in projective relativity. Vieweg 1951.
  • Wave Mechanics - Introduction and Original Texts. WTB paperback 1969 (reprint volume with introduction by Ludwig).
  • With Gerald Thurler: A New Foundation of Physical Theories. Springer 2006.
  • The position of the subject in a physical theory. In Bodo Geyer, Helge Herwig, Helmut Rechenberg (eds.): Werner Heisenberg - physicist and philosopher. Spektrum Verlag 1993, pp. 244-250.
  • Why a New Approach to Found Quantum Theory? In Jagdish Mehra (Ed.): The Physicist's Conception of Nature. Reidel 1972 (Dirac Volume) pp. 702-708.
  • He published further elaborations of his theory in a series of Notes in Mathematical Physics , Department of Physics, University of Marburg.

Web links

Individual evidence

  1. ^ According to Renate Tobies on the part of the DMV
  2. ↑ Renate Tobies, DMV short biographies . Rigorosum on March 24, 1943, doctorate on June 29, 1943. The title of the dissertation was: Favorable choice of the coefficients of a characteristic polynomial, which describes the stability of a vibratory, physical system , speakers were Alfred Klose and Erhard Schmidt (grade sufficient )
  3. ^ Günther Ludwig: The connection between the variation principles of the projective and the four-dimensional relativity theory. In: Journal of Nature Research A . 2, 1947, pp. 3–3 ( PDF , free full text).
  4. ↑ Günther Ludwig: Scalar field of matter in the projective relativity theory with variable gravitational invariants. In: Journal of Nature Research A . 2, 1947, pp. 482-489 ( PDF , free full text).
  5. ↑ Günther Ludwig: On the projective relativity theory with variable gravitational constants. Part 1: Description of the projective metric by five-legged. Zeitschrift für Physik, Volume 124, 1948, pp. 450-457; 2nd communication: Variation principles and field equations for gravity and matter. Zeitschrift für Physik, Volume 125, 1949, pp. 545-562; Advances in Projective Relativity. Vieweg 1951
  6. ↑ Günther Ludwig, Claus Müller: A model of the cosmos and star formation. Annalen der Physik, 6th part, Volume 437, 1948, pp. 76-84
  7. ↑ Günther Ludwig: Approach to a divergence-free quantum electrodynamics. In: Journal of Nature Research A . 5, 1950, pp. 637-641 ( PDF , free full text).
  8. ↑ Günther Ludwig: How can the unitary field theory explain radiation emission, self-energy and lambshift? In: Journal of Nature Research A . 7, 1952, pp. 248-250 ( PDF , free full text).
  9. ↑ Günther Ludwig: Foreword and introduction to the 2nd edition of The basic structures of a physical theory. Springer, 1990
  10. ↑ Joachim Schröter: On the meta-theory of physics. de Gruyter, 1996
  11. ↑ Heinz-Jürgen Schmidt: The Axiomatic Characterization of Physical Geometry , Lecture Notes in Physics, Volume 111, Springer, 1979
  12. ↑ Istituto Lombardo di Scienze e Lettere (ed.): Elenco Completo Membri e Soci . P. 15 ( istitutolombardo.it [PDF; accessed April 24, 2019]).
personal data
SURNAME Ludwig, Günther
BRIEF DESCRIPTION German theoretical physicist
DATE OF BIRTH January 12, 1918
PLACE OF BIRTH Zckerick
DATE OF DEATH June 8, 2007
Place of death Marburg