Biographical Memoirs Volume 87 (2005) / Chapter Skim
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Melvin Lax
Melvin Lax
Pages 250-273
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From page 251... ...
His classic 1951 Reviews of Modern Physics paper on multiple scattering theory has been used in many areas of physics. For example, it led to the coherent potential approximation for disordered systems.
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From page 252... ...
Most recently he worked in the area of inverse scattering techniques needed to extract information from noisy measurements, such as using light scattering to study clouds with lidar (light detection and ranging) techniques; searching for oil-bearing layers using acoustic backscattering; and detecting possible tumor nodules in the human breast using pulsed, noninvasive infrared light.
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From page 253... ...
He early realized the importance of computer typesetting of scientific manuscripts and served on a committee of the American Physical Society that explored the best way to have physics manuscripts prepared for electronic submission to the APS journals. As a result, APS initiated its Compuscript program, initially accepting manuscripts in TROFF (a documentprocessing system)
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From page 254... ...
Mel was confident that he could solve the spherical model, including long-range as well as short-range dipole-dipole interactions, and he ingeniously overcame the difficulties that are encountered in a straightforward generalization of the Berlin and Thomsen work. In his 1952 paper "Dipoles on a Lattice: The Spherical Model" he also proved that in the spherical model a permanent dipole lattice is equivalent to an induced dipole lattice with an effective polarizability, and he pointed out that the generality of his results is due to the fact that they have been expressed in terms of the eigenvalues rather than the interaction energies.
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From page 255... ...
And, despite various family attempts to re-educate Mel to the pleasures of some spicy dishes, his preference was clear and unchangeable. Mel was very deeply affected by three global events during his lifetime: the Great Depression of the 1930s, World War II, and the Shoa (Holocaust)
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From page 256... ...
During his career he consulted for the Army Research Office in Durham, Aberdeen Proving Grounds, and various other Navy and Air Force offices of scientific research. As far as we know, all this work was classified, and we have no direct knowledge of specifics of the projects on which he worked.
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From page 257... ...
He was president of the math club and editor of the student newspaper. Growing up during the Great Depression left Mel deeply concerned with being financially secure.
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in physics in 1942. MASSACHUSETTS INSTITUTE OF TECHNOLOGY After graduating from NYU, Mel was admitted to the graduate school of the Massachusetts Institute of Technology with a Fellowship in Applied Mathematics; later he was a teaching assistant and research associate in physics en route to his M.S.
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From page 259... ...
was developing rapidly, stimulated by the invention of the transistor at Bell Labs in 1947. Mel became convinced that solidstate physics was an important emerging area and decided to move his research interests in that direction.
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From page 260... ...
. Mel found it amusing that his entry paper to solid-state theory became a citation classic and commented that perhaps this was because of its innovative approach to a long-standing problem.
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From page 261... ...
His published work during that period on theories of magnetism, phonons, optical properties of solids, and multiple scattering brought him growing attention as a major young theoretical physicist in the rapidly developing solid-state physics community and led to his being recruited to join the new Theory Department at Bell Laboratories in Murray Hill, New Jersey.
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From page 262... ...
He served as a member of the technical staff from 1955 to 1972, as chairman of the Theoretical Physics Department from 1962 to 1964, and continued as a consultant to the Physics Research Laboratory until his death. By 1958, when Mel recruited John Hopfield, the department was fast becoming the preeminent condensed matter theory group in the world.
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From page 263... ...
Much of Mel's work was stimulated by the steady outpouring of extraordinary experimental results on semiconductor physics at Bell Labs. One of the major directions this took was the study of optical properties of solids, for example, the investigation of the frequency dependence of the optical absorption coefficient in the infrared region of the spectrum, due to creation/emission of phonons.
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From page 264... ...
Another important direction of Mel's work in those years at Bell Laboratories was investigation of the crystal lattice normal modes or phonons for those crystals important in semiconductor studies, such as silicon, germanium, gallium arsenide, and related materials. Part of this work required doing the symmetry analysis, and the complementary part required detailed calculation of the dispersion of the phonon frequencies as a function of wavelength or wave vector of the phonon waves.
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From page 265... ...
This topic rapidly grew into a major subject of investigations: the effect of "hot electrons" on the nonlinear conductivity. With characteristic focus Mel carefully investigated analytical and numerical techniques for solving the coupled Boltzmann transport equations for the distri
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From page 266... ...
When Mel accepted a post at City College in 1971, he retained a position at Bell Labs as a consultant to the electronics division, where he collaborated with many experimental groups, particularly that of V Narayanamurti on high field effects on semiconductor transport.
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Many of them have since gone on to major academic, industrial, and government laboratory careers in the United States and overseas. At City College Mel taught and carried out theoretical research in condensed matter physics, laser physics, coherence and fluctuations in classical and quantum systems, and nonlinear interaction of light and sound in solids.
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From page 268... ...
During his last years Mel worked in the area of inverse scattering techniques needed to extract information from noisy measurements. Applications included the use of light scattering to study clouds using lidar techniques, searching for oil-bearing layers using acoustic backscattering, and the detection of possible tumor nodules in the human breast using pulsed, noninvasive infrared light.
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From page 269... ...
Cai, and Min Xu, Mel developed the analytical theory to the extent possible and then the algorithms and codes needed for detailed numerical analysis. Not surprisingly some of this work was an echo of his earlier work on light scattering in the dense atmosphere with inclusions of particulate matter.
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From page 270... ...
His early work for the American Physical Society as chair of its Publications Committee was instrumental in creating the present system of electronic submission and processing of manuscripts, which is now practically universal. Mel served on the editorial boards of Physical Review and of Quantum Optics, as a member of the advisory board of World Scientific's Modern Physics Letters B and International Journal of Modern Physics, and as editor of Advanced Series in Applied Physics.
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From page 271... ...
W Anderson collected in the volume CCNY Physics Symposium: In celebration of Melvin Lax's Sixtieth Birthday.1 We also acknowledge contributions of material by Mel's family and colleagues, including Judy Lax, David Lax, Eric Lax, Eli Burstein, Wei Cai, Harry Frisch, Charles Henry, John Hopfield, Donald Nelson, Takashi Odagaki, and Michael Lubell.
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From page 272... ...
32:25-64. 1965 Subgroup techniques in crystal and molecular physics.
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From page 273... ...
R Alfano, Analytical solution of the polarized photon transport equation in an infinite uniform medium using cumulant expansion.
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