The relativistic spin dynamics defined by the pseudoscalar field of dark matter axions is rigorously determined. The relativistic Hamiltonian in the Foldy–Wouthuysen representation is derived. It ...agrees with the previously obtained nonrelativistic Hamiltonians and the relativistic classical estimation of the axion wind effect. In the relativistic Hamiltonian, the biggest term describes the extraordinary (three orders of magnitude) enhancement of the axion wind effect in storage ring experiments as compared with experiments with immobile particles. This term defines the spin rotation about the longitudinal axis. The effects caused by the axion-induced oscillating EDM and the axion wind consist in the spin rotations about the different horizontal axes and phases of stimulating oscillations differ by
π
/
2
. Experiments in a search for dark matter axions has been discussed. The two experimental designs for axion search experiments in storage rings have been elaborated.
Time-reversal breaking and parity-conserving millistrong interactions, suggested in 1965, still remain a viable mechanism of CP-violation beyond the Standard Model. One of its possible manifestations ...is the T-odd asymmetry in the transmission of tensor-polarized deuterons through a vector-polarized hydrogen gas target. Upon the rotation of the deuteron polarization from the vertical direction into the ring plane, the T-odd asymmetries, odd against the reversal of the proton polarization in the target, will continuously oscillate with first or second harmonics of the spin precession frequency. The Fourier analysis of the oscillating T-odd asymmetries allows for an easy separation from background persistent in conventional experiments employing static vector and tensor polarizations.
The relativistic Foldy–Wouthuysen transformation is used for an advanced description of a free and interacting planar graphene electron. The exact Foldy–Wouthuysen Hamiltonian of a graphene electron ...in a uniform and a nonuniform magnetic field is derived. The exact energy spectrum agreeing with experimental data and exact Foldy–Wouthuysen wave eigenfunctions are obtained. These eigenfunctions describe structured states in (2 + 1)-space. It is proven that the Hermite–Gauss beams exist even in the free space. In the structured Hermite–Gauss states, graphene electrons acquire nonzero effective masses dependent on a quantum number and move with group velocities which are less than the Fermi velocity.
The spin motion is influenced by a pseudoscalar interaction with a dark matter axion field. The relativistic Hamiltonian in the Foldy-Wouthuysen representation describing the manifestation of dark ...matter axions in spin effects is derived. The biggest term in this Hamiltonian describes the extraordinary (three orders of magnitude) enhancement of the axion wind effect in storage ring experiments as compared with experiments with immobile particles. This term defines the spin rotation about the longitudinal axis. The effects caused by the axion-induced oscillating EDM and the axion wind consist in the spin rotations about the different horizontal axes and phases of stimulating oscillations differ by
. The axion wind effect disappears when velocities of the axion and the particle coincide.
Zitterbewegung of Bosons Silenko, A. J.
Physics of particles and nuclei letters,
03/2020, Letnik:
17, Številka:
2
Journal Article
Recenzirano
Odprti dostop
Zitterbewegung of massive and massless scalar bosons and a massive Proca (spin-1) boson is analyzed. The equations describing the evolution of the velocity and position of the scalar boson in the ...generalized Feshbach–Villars representation and the corresponding equations for the massive Proca particle in the Sakata–Taketani representation are equivalent to each other and to the well-known equations for the Dirac particle. However, Zitterbewegung does not appear in the Foldy–Wouthuysen representation. Since the position and velocity operators in the Foldy–Wouthuysen representation and their transforms to other representations are the quantum-mechanical counterparts of the corresponding classical variables, Zitterbewegung is not observable.
The orbital polarization of twisted electrons carrying an intrinsic orbital angular momentum is not influenced by field perturbations in arbitrary magnetic fields. This property means an existence of ...the Siberian snake-like behavior for an orbital polarization of a beam of twisted electrons in cyclotrons with the main magnetic field and magnetic focusing. As a result, the acceleration of twisted electron beams in cyclotrons necessary for their applications in high-energy-physics experiments considerably simplifies.
Fundamental properties of the position and spin operators in relativistic quantum mechanics are defined with the Poincaré group. Quantum-mechanical counterparts of the classical position and spin ...variables are the corresponding operators in the Foldy–Wouthuysen representation but not in the Dirac one. The probabilistic interpretation is valid only for Foldy–Wouthuysen wave functions. The relativistic operators of the position and spin are discussed.
Relativistic-quark interaction is described phenomenologically on the basis of the Dirac equation with the Cornell potential. A general form of the initial equation involving the vector and scalar ...components of the Cornell potential is used for the case of an arbitrary relation between them. The Hamiltonian in the Foldy–Wouthuysen representation is derived in a general form with allowance for electromagnetic interaction. In contrast to earlier investigations, it is relativistic and exact for the zeroth- and first-order terms in the Planck constant and also for those second-order terms that describe contact interactions. General quantum-mechanical equations of motion for the momentum and spin are derived, and the classical limit of the Hamiltonian and for the equations of motion is found for the first time. A relation between the angular velocity of quark spin precession and the force acting on the quark is obtained. The energy of spin–orbit interaction is rather high (on the order of 100 MeV). Terms that describe spin–orbit and contact interactions have opposite signs for the vector and scalar components of the Cornell potential. The evolution of the quark helicity and the spin–spin interaction of the quarks are also calculated.
Relativistic quantum dynamics of twisted (vortex) Dirac particles in arbitrary electric and magnetic fields are constructed for the first time. This allows us to change the controversial contemporary ...situation when the nonrelativistic approximation is used for relativistic twisted electrons. The relativistic Hamiltonian and equations of motion in the Foldy-Wouthuysen representation are derived. A critical experiment for a verification of the results obtained is proposed. The new important effect of a radiative orbital polarization of a twisted electron beam in a magnetic field resulting in a nonzero average projection of the intrinsic orbital angular momentum on the field direction is predicted.
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