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Canonical transformation
About: Canonical transformation is a research topic. Over the lifetime, 1854 publications have been published within this topic receiving 38019 citations.
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TL;DR: The BRST charges corresponding to various (equivalent) ways of writing the action of the diffeomorphism group on p -form gauge fields are canonically related by a canonical transformation in the extended phase space which is explicitly constructed.
5 citations
TL;DR: In this article, it was shown that one can construct an exactly soluble two-dimensional higher-derivative fermionic quantum field theory with only derivatives of even order whose classical Lagrangian exhibits chiralgauge invariance.
Abstract: It has been suggested that the chiral symmetry can be implemented only in classical Lagrangians containing higher covariant derivatives of odd order. Contrary to this belief, it is shown that one can construct an exactly soluble two-dimensional higher-derivative fermionic quantum field theory containing only derivatives of even order whose classical Lagrangian exhibits chiralgauge invariance. The original field solution is expressed in terms of usual Dirac spinors through a canonical transformation, whose generating function allows the determination of the new Hamiltonian. It is emphasized that the original and transformed Hamiltonians are different because the mapping from the old to the new canonical variables depends explicitly on time. The violation of cluster decomposition is discussed and the general Wightman functions satisfying the positive-definiteness condition are obtained.
5 citations
TL;DR: In this article, the dynamical effective interactions between two swift ions due to surface-plasmon exchange are calculated by a canonical transformation, and the alignment effect discovered in the bulk case is also found as a function of the distance from the surface.
Abstract: The dynamical effective interactions between two swift ions due to surface-plasmon exchange are calculated by a canonical transformation. The alignment effect discovered in the bulk case is also found as a function of the distance from the surface. We can show that another kind of force appears which tends to make the ion pair stand up perpendicular to the surface.
5 citations
TL;DR: In this paper, the authors studied variational wave functions of the product form, factorizing according to the wave vectors k, for the ground state of a system of bosons interacting via positive pair interactions with a positive Fourier transform.
Abstract: We study variational wave functions of the product form, factorizing according to the wave vectors k, for the ground state of a system of bosons interacting via positive pair interactions with a positive Fourier transform. Our trial functions are members of different orthonormal bases in Fock space. Each basis contains a quasiparticle vacuum state and states with an arbitrary finite number of quasiparticles. One of the bases is that of Valatin and Butler (VB), introduced fifty years ago and parametrized by an infinite set of variables determining Bogoliubov's canonical transformation for each k. In another case, inspired by Nozieres and Saint James the canonical transformation for k=0 is replaced by a shift in the creation/annihilation operators. For the VB basis we prove that the lowest energy is obtained in a state with {approx}{radical}(volume) quasiparticles in the zero mode. The number of k=0 physical particles is of the order of the volume and its fluctuation is anomalously large, resulting in an excess energy. The same fluctuation is normal in the second type of optimized bases, the minimum energy is smaller and is attained in a vacuum state. Associated quasiparticle theories and questions about the gap in their spectrum are also discussed.
5 citations
TL;DR: An adequate canonical transformation of the hamiltonian permitted the full observance of the specific Pauli commutation relations and the elimination of the main quasiparticle non-conservative term.
5 citations