200 research outputs found
Flat wormholes from straight cosmic strings
Special multi-cosmic string metrics are analytically extended to describe
configurations of Wheeler-Misner wormholes and ordinary cosmic strings. I
investigate in detail the case of flat, asymptotically Minkowskian,
Wheeler-Misner wormhole spacetimes generated by two cosmic strings, each with
tension .Comment: 5 pages, latex, no figure
Breathing Relativistic Rotators and Fundamental Dynamical Systems
Recently, it was shown, that the mechanical model of a massive spinning
particle proposed by Kuzenko, Lyakhovich and Segal in 1994, which is also the
fundamental relativistic rotator rediscovered independently 15 years later by
Staruszkiewicz in quite a different context, is defective as a dynamical
system, that is, its Cauchy problem is not well posed. This dynamical system is
fundamental, since its mass and spin are parameters, not arbitrary constants of
motion, which is a classical counterpart of quantum irreducibility.
It is therefore desirable to find other objects which, apart from being
fundamental, would also have well posed Cauchy problem. For that purpose, a
class of breathing rotators is considered. A breathing rotator consists of a
single null vector associated with position and moves in accordance with some
relativistic laws of motion. Surprisingly, breathing rotators which are
fundamental, are also defective as dynamical systems. More generally, it has
been shown, that the necessary condition for a breathing rotator to be
similarly defective, is functional dependence of its Casimir invariants of the
Poincar{\'e} group
De Sitter Invariant Vacuum States, Vertex Operators, and Conformal Field Theory Correlators
We show that there is only one physically acceptable vacuum state for quantum
fields in de Sitter space-time which is left invariant under the action of the
de Sitter-Lorentz group and supply its physical interpretation in
terms of the Poincare invariant quantum field theory (QFT) on one dimension
higher Minkowski spacetime. We compute correlation functions of the generalized
vertex operator , where is a massless scalar
field, on the -dimensional de Sitter space and demonstrate that their
limiting values at timelike infinities on de Sitter space reproduce correlation
functions in -dimensional Euclidean conformal field theory (CFT) on
for scalar operators with arbitrary real conformal dimensions. We
also compute correlation functions for a vertex operator on
the \L obaczewski space and find that they also reproduce correlation functions
of the same CFT. The massless field is the nonlocal transform of
the massless field on de Sitter space introduced by one of us.Comment: 14 pages, LaTeX file We thank Roman Jackiw for bringing to our
attention Ref. 1
Spinor particle. An indeterminacy in the motion of relativistic dynamical systems with separately fixed mass and spin
We give an argument that a broad class of geometric models of spinning
relativistic particles with Casimir mass and spin being separately fixed
parameters, have indeterminate worldline (while other spinning particles have
definite worldline). This paradox suggests that for a consistent description of
spinning particles something more general than a worldline concept should be
used. As a particular case, we study at the Lagrangian level the Cauchy problem
for a spinor particle and then, at the constrained Hamiltonian level, we
generalize our result to other particles.Comment: 10 pages, 1 figur
Infrared limit in external field scattering
Scattering of electrons/positrons by external classical electromagnetic wave
packet is considered in infrared limit. In this limit the scattering operator
exists and produces physical effects, although the scattering cross-section is
trivial.Comment: 12 pages; published version; minor corrections; comments adde
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