LAMB Willis( The American physicist, Nobel Prize in Physics, 1955)
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Biography LAMB Willis
genus. July 12, 1913
American physicist Willis Lamb was born in Los Angeles (California). His father and namesake was a telephone engineer and his mother Mary Ellen (Metcalf) Lamb - a teacher. L. studied in primary schools in Auckland and Los Angeles. He graduated from Los Angeles high school, where he showed outstanding ability in chemistry. Bachelor of Science in Chemistry A. received in 1934. University of California at Berkeley and remained there to work on my dissertation under the direction of J. Robert Oppenheimer, for which in 1938. he was awarded a doctoral degree. The thesis was devoted to the electromagnetic properties of nuclear particles. It predicted that due to the finite size of a proton to the electric field should differ slightly from the field point particle, such as electron.
Throughout his academic career L. taught physics at several universities: Columbia (1938 ... 1951), Stanford (1951 ... 1956), Harvard (1953 ... 1954), Oxford (1956 ... 1962), Yale (1962 ... 1974). The University of Arizona in 1974. He was appointed professor of physics and optics. His attitude to the duties of the teacher was clearly demonstrated in this episode: learning about the award of the Nobel Prize, A. went to the auditorium to hold another seminar on quantum mechanics, and only then met with representatives of the press.
From 1942 to 1952. L. worked concurrently in the Radiation Laboratory at Columbia University on projects funded the U.S. Army Signal Corps, the Office of Scientific Research Navy and the Department of Research and Innovation. His work has been associated mainly with radar and microwave technology.
Working with IA. Sake and groups involved in molecular beams, L. interested in the metastable states of atoms. Typically, excited, or high-energy, state of the atom decays rapidly, and the atom, emitting radiation, into a state with lower energy. The most strongly excited states decay with the emission of one photon, or photon, in about 10.8 seconds. Metastable states exist for much longer. For example, the lifetime of the so called second excited state of the hydrogen atom at about 700 million. times longer than the life of other excited states. The reason for the 'longevity' is that an atom in the second excited state can emit one photon. The laws of conservation of angular momentum, and properties, called parity, require that an atom emits two photons simultaneously. This process is less likely and therefore is much slower.
Initially L. was a theoretical physicist, but his most zvestnye work associated with a series of extremely delicate experiments, most of which were carried out in collaboration with Robert K. Rutherford at Columbia University. As we expand the scope of their research during the war years the attention of A. attracted the absorption and emission of microwave radiation by atoms. Knowing from the literature on the steps in the 30-ies. unsuccessful attempts to detect the absorption of microwave radiation in a gas consisting of excited hydrogen atoms, R. first took the setback due to inadequate microwave technology. But later he came to the conclusion that the detected absorption interfered with the method that the experimenters chose to excite the atoms. L. decided to use the advanced microwave technology in order to clarify the spectroscopic measurements of various energy levels of hydrogen atom.
. In the hydrogen atom is only one electron moves around the nucleus of one of a series of orbits
. Being in its orbit, the electron has a definite energy. For it to be moved into a higher orbit, the atom must absorb a photon, the energy of which corresponds exactly to the energy difference between the orbits. The same thing happens in the transition of an electron to a lower orbit - the atom should emit a photon with the relevant energy. Such transitions give rise to the spectrum of atomic hydrogen, which consists of some clear lines.
Many lines in the spectrum of hydrogen have the 'fine structure'. If you look at them with a large increase, it becomes evident that they consist of two or more closely spaced lines. This suggests that the orbital energy levels are also split into closely spaced sub-levels. Transitions between adjacent levels of the fine structure requires the absorption or emission of radiation in the microwave range of wavelengths.
In 1928, Mr.. English physicist Paul A. Maurice Dirac derived equation that describes all the known properties of the electron: its wave properties, electric charge, spin, magnetic moment and the relativistic dependence of mass on velocity. As the backbone of much of quantum mechanics, the Dirac equation possible to predict with great accuracy the energy levels of hydrogen atom. In particular, the Dirac equation the equivalence of two singular levels, one of which is metastable: these levels correspond to different states, but nevertheless with the same energy. L. prepared beam of hydrogen atoms in the metastable state. Atoms remained in this state long enough, making it convenient to experiment. He then subjected to microwave radiation beam in an external magnetic field. Some of the atoms absorb the radiation and moved into short-lived state. This meant that the two corresponding energy levels are not identical, but are separated by a small energy difference, known as the Lamb shift. Opening L. prompted Julian C. Schwinger Itiro Tomonaga and Richard Feynman to reconsider the theory of electron Dirac and formulate a new theory, called quantum electrodynamics, which is with remarkable accuracy the Lamb shift. Sam L. in collaboration with Norman M. Kroll theoretically calculated the effect, open them experimentally.
L. was awarded the Nobel Prize in Physics 1955. 'for discoveries concerning the fine structure of the hydrogen spectrum ". L Prize. shared with Polycarp Kushem have fulfilled irrespective similar experiments, and also at Columbia University. Referring to the two winners of a welcome speech, . Ivar Waller of the Royal Swedish Academy said: "Your discoveries have led to a reassessment and reformulation of the theory of interaction of electrons and electromagnetic radiation of quantum electrodynamics, . thus initiating a new phase of development, . had the utmost importance for many fundamental concepts of physics'.,
. Over many years of research A
. has worked in various fields of physics. He is dealing with such problems, . as the theory of beta decay, . path length of fission fragments of the atomic nucleus, . fluctuations in cosmic showers, . emission of electrons by metastable atoms, . field theory of nuclear structure, . theory of interaction of neutrons and matter, . Theory and design of magnetron generators and diamagnetic corrections in experiments on nuclear resonance,
. He has made a significant contribution to the creation of the theory of lasers.
Since 1939. L. married to Ursula chief historian. In leisure hours, he engaged in swimming, sailing, chess and photography.
L. is a member of the National Academy of Sciences of the USA and the American Physical Society, an honorary member of the London Institute of Physical and the Royal Society of Edinburgh. Among the awards he won, Rumford Medal of the American Academy of Arts and Sciences (1953) and reward 'for academic achievements' Research Corporation of America (1955). L. Honorary Doctor of the University of Pennsylvania, Yeshiva College and Gustavus Adolphus.