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Progress in Low Temperature Physics, Volume 10
Interest was heightened by small displays mounted by eight UK firms, of whom three were showing very small mechanical coolers, two were showing mechanical coolers for cryopumps, and one was displaying Joule-Thomson devices. The others were showing associated equipment. The meeting clearly provided a useful opportunity for
discussion both for those already engaged in cryocooler development and marketing, and also for those new to the field. B.A. Hands Department of Engineering Science, University of Oxford, UK
FQVfQ Progress in Low Temperature Physics, Volume 10 Edited by D.F. Brewer North-Holland Physics Publishing, Amsterdam, The Netherlands* 1 986, 446 pp, ISBN 0 444 869867, Dfl. 220.00 Since the appearance of Volume 1 in 1955, 'Progress in Low Temperature Physics' has established a deserved reputation for excellent timely review articles on active areas of low temperature research. It has become an indispensible reference work, broadening the horizons of established workers in the field and enabling beginners, particularly graduate students, to gain a foothold in the subject. It is against this background that Volume 10, the latest addition to the series, must be judged. Just over half of Volume 10 is devoted to an article on Spin-polarized atomic hydrogen by I.F. Silvera and J.T.M. Walraven. This timely, authoritative and comprehensive article describes attempts, pioneered by the authors, to produce sufficiently high densities of spinpolarized atomic hydrogen gas at low enough temperatures for Bose-Einstein condensation to occur. To date the recombination of the atoms to form molecular hydrogen has prevented achievement of this ultimate goal but a lot of very interesting physics has been discovered in the attempt. The authors describe this and discuss in detail the relaxation and recombination processes that have limited the densities achieved. The length and depth of this article are such as to make it more suitable for publication perhaps as a stand-alone monograph; see my general comment below. An article on vortices in rotating superfluid 3He by A.L. Fetter describes in detail the theoretical methods that have been used to calculate the structure of the vortex cores and the texture of the order parameter outside the cores. The complexity of the order parameter ensures a rich variety of possible phenomena, including the existence of ferromagnetic cores. The beautiful experiments at Helsinki which confirmed the existence of such cores and discovered other interesting phenomena are discussed very briefly but it is clear that more work is required to explain these. Unfortunately the explanation of the observed vortex core transition in 3He-B in terms of the existence of non-axisymmetric vortices at low pressures was reported after the article was written and is therefore mentioned only in a note added in proof. The
* In the USA and Canada, the book is available from Elsevier Science Publishers, New York, USA
suggestion that half quantum vortices exist and could be of importance also seems to have arrived too late to be included. D. Rainer's article on ab initio calculations of T~ for superconducting materials describes the steps involved in such a calculation in careful detail. Although a familiarity with the Green's function methods is essential for anyone wishing to follow the calculation in detail, those without this facility should not despair since the author again demonstrates his exceptional talent for giving very readable descriptions of the physics behind the algebra. The problems yet to be overcome are clearly stated. The reader will have to interpret carefully references to 'high T¢ materials' in the text since the article was written before the discovery of superconductivity at liquid nitrogen temperatures and above. Although charge motion in solid helium has not made the headlines, work has been in progress for 26 years so A.J. Dahm's article on the subject is welcome. He succeeds in convincing the reader that despite much experimental and theoretical work the subject is still poorly understood. One general point needs to be made. Since 1955 there has been an enormous increase in the breadth and depth of work in low temperature physics and of the number of workers in the field. This development has been mirrored by the changes that have taken place in 'Progress in Low Temperature Physics'. Volume 1 contained 18 articles with an average length of 22 pages; Richard Feynman's article on the application of quantum mechanics to liquid helium occupied a mere 36 pages. Volume 10 contains just four articles with an average length of 105 pages; a whole nine pages of the Silvera and Walraven article are occupied by just one table. Furthermore, the articles in Volume 1 were written to be understandable to nonspecialists, whereas the articles in Volume 10 are so much more detailed and advanced that they are readily accessible only to specialists in the fields concerned and closely related fields. I wonder if there are more readers who, like me, would welcome, in later volumes in the series, some articles more similar in style to those in Volume 1. J. Hook Department of Physics, University of Manchester, UK
Cryogenics 1987 Vol 27 October 593
discussion both for those already engaged in cryocooler development and marketing, and also for those new to the field. B.A. Hands Department of Engineering Science, University of Oxford, UK
FQVfQ Progress in Low Temperature Physics, Volume 10 Edited by D.F. Brewer North-Holland Physics Publishing, Amsterdam, The Netherlands* 1 986, 446 pp, ISBN 0 444 869867, Dfl. 220.00 Since the appearance of Volume 1 in 1955, 'Progress in Low Temperature Physics' has established a deserved reputation for excellent timely review articles on active areas of low temperature research. It has become an indispensible reference work, broadening the horizons of established workers in the field and enabling beginners, particularly graduate students, to gain a foothold in the subject. It is against this background that Volume 10, the latest addition to the series, must be judged. Just over half of Volume 10 is devoted to an article on Spin-polarized atomic hydrogen by I.F. Silvera and J.T.M. Walraven. This timely, authoritative and comprehensive article describes attempts, pioneered by the authors, to produce sufficiently high densities of spinpolarized atomic hydrogen gas at low enough temperatures for Bose-Einstein condensation to occur. To date the recombination of the atoms to form molecular hydrogen has prevented achievement of this ultimate goal but a lot of very interesting physics has been discovered in the attempt. The authors describe this and discuss in detail the relaxation and recombination processes that have limited the densities achieved. The length and depth of this article are such as to make it more suitable for publication perhaps as a stand-alone monograph; see my general comment below. An article on vortices in rotating superfluid 3He by A.L. Fetter describes in detail the theoretical methods that have been used to calculate the structure of the vortex cores and the texture of the order parameter outside the cores. The complexity of the order parameter ensures a rich variety of possible phenomena, including the existence of ferromagnetic cores. The beautiful experiments at Helsinki which confirmed the existence of such cores and discovered other interesting phenomena are discussed very briefly but it is clear that more work is required to explain these. Unfortunately the explanation of the observed vortex core transition in 3He-B in terms of the existence of non-axisymmetric vortices at low pressures was reported after the article was written and is therefore mentioned only in a note added in proof. The
* In the USA and Canada, the book is available from Elsevier Science Publishers, New York, USA
suggestion that half quantum vortices exist and could be of importance also seems to have arrived too late to be included. D. Rainer's article on ab initio calculations of T~ for superconducting materials describes the steps involved in such a calculation in careful detail. Although a familiarity with the Green's function methods is essential for anyone wishing to follow the calculation in detail, those without this facility should not despair since the author again demonstrates his exceptional talent for giving very readable descriptions of the physics behind the algebra. The problems yet to be overcome are clearly stated. The reader will have to interpret carefully references to 'high T¢ materials' in the text since the article was written before the discovery of superconductivity at liquid nitrogen temperatures and above. Although charge motion in solid helium has not made the headlines, work has been in progress for 26 years so A.J. Dahm's article on the subject is welcome. He succeeds in convincing the reader that despite much experimental and theoretical work the subject is still poorly understood. One general point needs to be made. Since 1955 there has been an enormous increase in the breadth and depth of work in low temperature physics and of the number of workers in the field. This development has been mirrored by the changes that have taken place in 'Progress in Low Temperature Physics'. Volume 1 contained 18 articles with an average length of 22 pages; Richard Feynman's article on the application of quantum mechanics to liquid helium occupied a mere 36 pages. Volume 10 contains just four articles with an average length of 105 pages; a whole nine pages of the Silvera and Walraven article are occupied by just one table. Furthermore, the articles in Volume 1 were written to be understandable to nonspecialists, whereas the articles in Volume 10 are so much more detailed and advanced that they are readily accessible only to specialists in the fields concerned and closely related fields. I wonder if there are more readers who, like me, would welcome, in later volumes in the series, some articles more similar in style to those in Volume 1. J. Hook Department of Physics, University of Manchester, UK
Cryogenics 1987 Vol 27 October 593