摘要:

Several proposed and performed experiments for the measurement of quantum and gravitational effects in ring interferometers of various types (with neutrons, superconducting electrons and superfluid helium as well as photons) are discussed in a unified framework. The earth's rotation and local gravity have been detected in some but not other of these interferometers. The reasons for this are discussed, as well as the extent to which the results support theories of gravity at the quantum level. Several interferometers have reached the limits of resolution imposed by quantum noise. Experiments under construction aim to detect non-newtonian gravitational effects at the level of 10−9of the effect induced by earth rotation.

ISSN:0010-7514    

DOI:10.1080/00107518508219106

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

In contemporary theories of the structure of matter at very short distance scales, various properties (some of them hypothetical as yet) of the vacuum are of crucial importance. The technical framework for such studies is quantum field theory. The aim of this article is to provide access, for a non-specialist readership, to the physics of the vacuum as presently understood in quantum field theory. To do this, heavy reliance is placed on a fundamental analogy. The basic theoretical entity—the quantum field—is here regarded as analogous to a quantum-mechanical system with (infinitely) many degrees of freedom. A system of interacting quantum fields is then analogous to a complicated system in solid state physics; it can exist in different energy states, namely the ground state and various excited states. The excited states of the field system are characterized by the presence of excitation quanta, which are the particles (electrons, quarks, photons…) of which our material world is composed. In the ground state of the field system there are no excitation quanta, and hence no particles, present: the vacuum is this ground state. Consequently, different features of the vacuum may be modelled by the ground states of various appropriate solid state systems. For example, the vibrational ground state of a crystal models the electromagnetic field vacuum, a semiconductor models the Dirac vacuum, and superconductors may model aspects of the vacuum as regards the strong and weak forces. These and other models are used in qualitative discussions of many phenomena which involve the properties and structure of the vacuum: for example, spontaneous emission and the Lamb shift, pair creation and the associated screening of charge by vacuum polarization, the origin of mass for the W and Z bosons, and the confinement of quarks. Finally, several of the themes are gathered together in a brief introduction to the hypothesis that the universe itself is the grossly inflated result of a vacuum fluctuation.

ISSN:0010-7514    

DOI:10.1080/00107518508219107

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0010-7514    

DOI:10.1080/00107518508219108

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0010-7514    

DOI:10.1080/00107518508219109

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

摘要:

Introduction to Supersymmetry in Particle and Nuclear Physics. Edited by O. Castanos, A. Frank and L. Urrutia. (Plenum Publishing Corporation, 1984.) [Pp.viii+187.] US $29.50, Scope:

ISSN:0010-7514    

DOI:10.1080/00107518508219110

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor

ISSN:0010-7514    

DOI:10.1080/00107518508219111

出版商:Taylor & Francis Group    

年代:1985

数据来源: Taylor