Showing papers on "Open quantum system published in 1973"
Book•
01 Jan 1973
TL;DR: In this paper, Dirac Formulation of Quantum Mechanics Elementary Quantum Systems Operator Algebra Quantization of the Electromagnetic Field Interaction of Radiation with Matter Quantum Theory of Damping--Density Operator Methods Quantum Theory-Langevin Approach Lamb's Semiclassical Theory of a Laser [1] Statistical properties of a laser Appendices Index
Abstract: Dirac Formulation of Quantum Mechanics Elementary Quantum Systems Operator Algebra Quantization of the Electromagnetic Field Interaction of Radiation with Matter Quantum Theory of Damping--Density Operator Methods Quantum Theory of Damping--Langevin Approach Lamb's Semiclassical Theory of a Laser [1] Statistical Properties of a Laser Appendices Index
2,773 citations
307 citations
TL;DR: In this article, the program of a physical concept of information is outlined in the framework of quantum theory and a proposal is made for how to avoid the intuitive introduction of observables.
Abstract: The program of a physical concept of information is outlined in the framework of quantum theory. A proposal is made for how to avoid the intuitive introduction of observables. The conventional and the Everett interpretations in principle may lead to different dynamical consequences. An ensemble description occurs without the introduction of an abstract concept of information.
166 citations
Book•
01 Jan 1973
TL;DR: The work in this article is based upon work done by the author and his collaborators over a period of approximately twenty years and is dedicated to some selected topics of quantum field theory, which have proved of increasing importance with the passing of time.
Abstract: This volume is based upon work done by the author and his collaborators over a period of approximately twenty years and is dedicated to some selected topics of quantum field theory, which have proved of increasing importance with the passing of time. There are three parts: * Combinatoric Methods * Equations for Green's Functions and Perturbative Expansions * Regularization, Renormalization, and Mass Equations This work will be useful to anyone interested in learning or using quantum field theory, many-body physics and, as well, to many applied mathematicians, because it introduces a number of combinatoric and analytic tools which drastically simplify, and at times bypass, treatments which customarily take up most of the bulk of the standard texts.
123 citations
01 Jan 1973
117 citations
01 Jun 1973
TL;DR: In this article, the implicate order is considered as the independent ground of existence of things, while the ordinary explicate order, which is what should be considered as dependent, is assumed to be a dependent or fortuitous feature of the content.
Abstract: In this paper, we inquire further into the question of the emergence of new orders in physics, first raised in an earlier paper. In this inquiry, we are led to suggest that the quantum theory indicates the need for yet another new order, which we call “enfolded” or “implicate.” One of the most striking examples of the implicate order is to be seen by considering the function of the hologram, which clearly reveals how a total content (in principle extending over the whole of space and time) is “enfolded” in the movement of waves (electromagnetic and other kinds) in any given region. We then come to the notion that the quantum theory indicates that this implicate order is not merely a dependent or fortuitous feature of the content, but rather, that it should be considered as the independent ground of existence of things, while the ordinary explicate order is what should be considered as dependent. Finally, in the appendix we point out how the implicate order is expressed naturally in terms of an algebra similar to that of the quantum theory, which is, however, subject to generalizations going beyond the limits of what has meaning in this theory. Various new directions of further research are indicated, which will be explained in later papers.
83 citations
01 Jan 1973
61 citations
01 Jan 1973
TL;DR: In this article, the authors reviewed many important theoretical ideas and methods in quantum field theory during about twenty years, including symmetry theory, gauge field theory, symmetry breaking and origin of mass,quantizative methods, renormalization and renormalizative effects.
Abstract: This article reviews many important theoretical ideas and methods in quantum field theory during about twenty years.Of which there are the importance of symmetry theory,gauge field theory,symmetry breaking and origin of mass,quantizative methods,renormalization and renormalizative effects.
58 citations
TL;DR: In this article, the authors present a master equation for the reduced density operator (phase space distribution function) of the sub-system of interest, which is derived from the Fokker-Planck type.
Abstract: Publisher Summary This chapter focuses on master equation methods in quantum optics. Some of the methods have been specifically developed to treat the problems in quantum optics. These include the well known phase space methods. In phase space methods, the c-number distribution functions for quantum systems are introduced, which in many physical situations are found to obey equations of the Fokker–Planck type. In quantum optics, the concern is usually related to the study of a subsystem that is a part of a large system. Master equation methods have found applications in many branches of physics, such as in the theory of relaxation processes. The chapter also explains master equations for open systems. Some of the problems, involving open systems, in quantum optics are those of lasers, the relaxation of oscillators and two-level atoms, super-radiance, and parametric oscillators. In problems such as superradiance, the radiation field plays the role of the reservoir. The chapter describes the derivation of the master equation for the reduced density operator (phase space distribution function) of the sub-system of interest.
01 Jan 1973
TL;DR: The problem of measurement in quantum mechanics concerns the question whether the laws of quantum mechanics are consistent with the acquisition of data concerning the properties of quantal systems as discussed by the authors, and this consistency problem arises because the system to be measured as well as the apparatus used for the measurement are themselves systems which are presumed to obey the laws.
Abstract: The problem of measurement in quantum mechanics concerns the question whether the laws of quantum mechanics are consistent with the acquisition of data concerning the properties of quantal systems. This consistency problem arises because the system to be measured as well as the apparatus used for the measurement are themselves systems which are presumed to obey the laws of quantum mechanics. Therefore the evolution of the state of such systems is governed by a Schrodinger-equation.
TL;DR: In this article, a review of recent work on quantum electrodynamics is reviewed, some speculations about the theory are made, and some conceivable future experimental implications are discussed.
Abstract: Recent work on quantum electrodynamics is reviewed, some speculations about the theory are made, and some conceivable future experimental implications are discussed. (auth)
01 Jan 1973
TL;DR: In this paper, it was shown that turning off the coupling need not restore the theory to a free theory, and this effect may arise for covariant non-renormalizable quantum field theories, and heuristic arguments were developed to support this proposal.
Abstract: Qualitative features of quantum theories are examined with the aid of models. Attention is focussed on the fact that for sufficiently singular interaction potentials turning off the coupling need not restore the theory to a free theory. This effect is illustrated in a simple, single degree of freedom system. Analysis of the causes leads us to suggest that this effect may arise for covariant nonrenormalizable quantum field theories, and heuristic arguments are developed to support this proposal. For certain soluble noncovariant nonrenormalizable quantum field theories we verify the reality of the effect and comment on its significance, especially for perturbation analyses.
01 Jan 1973
TL;DR: This introductory chapter has two purposes: to provide a brief resume of the quantum theory that is assumed to be familiar to the reader and, in particular, those results that are used later.
Abstract: This introductory chapter has two purposes. The first is to provide a brief resume of the quantum theory that is assumed to be familiar to the reader and, in particular, those results that are used later. A deep discussion of the foundations of quantum mechanics will not be given and in this chapter the results will be quoted without proof; the justification for this policy is that there are a number of excellent texts available. Nevertheless, some of the mathematics employed in this presentation is discussed in more detail later. For example, an acquaintance with vector and matrix algebra is assumed here, although Chapter 2 is devoted to this subject.
TL;DR: In this article, the authors studied the short distance behavior of the Green's functions of two operators in a soluble one-dimensional model of quantum field theory with dimensionless coupling constant.
Abstract: We study the short distance behavior of the Green's functions of two operators in a soluble one‐dimensional model of quantum field theory with dimensionless coupling constant. Integer power behavior does not occur. The leading terms of the Wilson expansion of two operators at short distances are determined.
TL;DR: In this article, the Callan-Symanzik equations were used to study the short-distance behavior of the gauge-invariant axial-vector current in quantum electrodynamics.
Abstract: Using the Callan-Symanzik equations as a tool to study the short-distance behavior of the gauge-invariant axial-vector current in quantum electrodynamics, we conclude that as a consequence of Ward identities the axial-vector current is required to scale noncanonically. The Wilson-Crewther calculation of the anomaly cannot be carried out, although its use is legitimate in phenomenological applications treating electromagnetism to lowest order.
TL;DR: In this paper, it was shown that a potential V(x) can be in the limit circle case at ∞ even if the classical travel time to ∞ is infinite.
Abstract: Two examples are presented: The first shows that a potentialV(x) can be in the limit circle case at ∞ even if the classical travel time to ∞ is infinite. The second shows thatV(x) can be in the limit point case at ∞ even though the classical travel time to infinity is finite. The first example illustrates the reflection of quantum waves at sharp steps. The second example illustrates the tunnel effect.
TL;DR: In this article, it is shown how to restore the classical initial condition constants at the quantum level by quantum mechanical equations of motion alone, without the need for extra postulates (e.g., a projection postulate).
Abstract: Accepted quantum description is stochastic, yet history is nonstochastic, i.e., not representable by a probability distribution. Therefore ordinary quantum mechanics is unsuited to describe history. This is a limitation of the accepted quantum theory, rather than a failing of mechanics in general. To remove the limitation, it would be desirable to find a form of quantum mechanics that describes the future stochastically and the past nonstochastically. For this purpose it proves sufficient to introduce into quantum mechanics, by means of a perfected formal correspondence, certain analogs of the classical initial-condition constants. Through the restoration of such parameters at the quantum level one accomplishes a natural accommodation of time anisotropy, wave-function reduction, and “event” description by quantum mechanical equations of motion alone, without the need for extra postulates (e.g., a projection postulate). This requires a complete restructuring of quantum measurement theory.
01 Jan 1973
TL;DR: This paper takes a particular approach in starting from the idea of a quantum logic, not a peculiar ‘empirical’ logic, but a specification of a general logic of temporal statements, that is of statements on facts and possibilities.
Abstract: The title1 ‘Classical and quantum descriptions’ is a technical version of the problem of a semantical interpretation of quantum theory The question is: what does quantum theory mean? Hence the task is not to improve quantum theory by new additions, but to understand it Its mathematical structure is not disputed On the existing interpretation — usually called the Copenhagen interpretation — there have been decades of discussion They have their origin in the fact that we can only accept this interpretation if we take some rather fundamental philosophical decisions In this paper I do not try to argue for these decisions except for an attempt to contribute to a clarification of their meaning I take a particular approach in starting from the idea of a quantum logic This is in my view not a peculiar ‘empirical’ logic, but a specification of a general logic of temporal statements, that is of statements on facts and possibilities Statements on facts are ‘classical descriptions’, statements on possibilities are embodied in the quantum state vectors