The Pryce(e)spin and position operators of the quantum theory of Dirac's free field were re-defined and studied recently with the help of a new spin symmetry and suitable spectral representations[Eur.Phys.J.C 82,1...The Pryce(e)spin and position operators of the quantum theory of Dirac's free field were re-defined and studied recently with the help of a new spin symmetry and suitable spectral representations[Eur.Phys.J.C 82,1073(2022)].This approach is generalized here,associating a pair of integral operators acting directly on particle and antiparticle wave spinors in momentum representation to any integral operator in configuration representation,acting on mode spinors.This framework allows an effective quantization procedure,giving a large set of one-particle operators with physical meaning as the spin and orbital parts of the isometry generators,the Pauli-Lubanski and position operators,or other spin-type operators proposed to date.Special attention is paid to the operators that mix the particle and antiparticle sectors whose off-diagonal associated operators have oscillating terms producing Zitterbevegung.The principal operators of this type,including the usual coordinate operator,are derived here for the first time.As an application,it is shown that an apparatus measuring these new observables may prepare and detect oneparticle wave packets moving uniformly without Zitterbewegung or spin dynamics,spreading in time normally as any other relativistic or even non-relativistic wave packet.展开更多
The problem of the flat limits of the scalar and spinor fields on the de Sitter expanding universe is considered in the traditional adiabatic vacuum and in the new rest frame vacuum we proposed recently,in which the f...The problem of the flat limits of the scalar and spinor fields on the de Sitter expanding universe is considered in the traditional adiabatic vacuum and in the new rest frame vacuum we proposed recently,in which the frequencies are separated in the rest frames as in special relativity.It is shown that only in the rest frame vacuum can the Minkowskian flat limit be reached naturally fbr any momentum,whereas in the adiabatic vacuum,this limit remains undefined in rest frames in which the momentum vanishes.An important role is played by the phases of the fundamental solutions in the rest frame vacuum,which must be regularized to obtain the desired Minkowskian flat limits.This procedure fixes the phases of the scalar mode functions and Dirac spinors,resulting in their definitive expressions derived here.The physical consequenee is that,in the rest frame vacuum,the flat limits of the oneparticle operators are simply the corresponding operators of special relativity.展开更多
文摘The Pryce(e)spin and position operators of the quantum theory of Dirac's free field were re-defined and studied recently with the help of a new spin symmetry and suitable spectral representations[Eur.Phys.J.C 82,1073(2022)].This approach is generalized here,associating a pair of integral operators acting directly on particle and antiparticle wave spinors in momentum representation to any integral operator in configuration representation,acting on mode spinors.This framework allows an effective quantization procedure,giving a large set of one-particle operators with physical meaning as the spin and orbital parts of the isometry generators,the Pauli-Lubanski and position operators,or other spin-type operators proposed to date.Special attention is paid to the operators that mix the particle and antiparticle sectors whose off-diagonal associated operators have oscillating terms producing Zitterbevegung.The principal operators of this type,including the usual coordinate operator,are derived here for the first time.As an application,it is shown that an apparatus measuring these new observables may prepare and detect oneparticle wave packets moving uniformly without Zitterbewegung or spin dynamics,spreading in time normally as any other relativistic or even non-relativistic wave packet.
文摘The problem of the flat limits of the scalar and spinor fields on the de Sitter expanding universe is considered in the traditional adiabatic vacuum and in the new rest frame vacuum we proposed recently,in which the frequencies are separated in the rest frames as in special relativity.It is shown that only in the rest frame vacuum can the Minkowskian flat limit be reached naturally fbr any momentum,whereas in the adiabatic vacuum,this limit remains undefined in rest frames in which the momentum vanishes.An important role is played by the phases of the fundamental solutions in the rest frame vacuum,which must be regularized to obtain the desired Minkowskian flat limits.This procedure fixes the phases of the scalar mode functions and Dirac spinors,resulting in their definitive expressions derived here.The physical consequenee is that,in the rest frame vacuum,the flat limits of the oneparticle operators are simply the corresponding operators of special relativity.
