arXiv subjects

Jurij W. Darewych

Publications and source records attributed to Jurij W. Darewych.

15 recordsLinked to original sources

arXiv2016

Higgs particles interacting via a scalar Dark Matter field

We study a system of two Higgs bound state, interacting via a real scalar Dark Matter mediating field, without imposing $Z_2$ symmetry on the DM sector of the postulated Lagrangian. The variational method in the Hamiltonian formalism of QFT is used to derive relativistic wave equations for the two-Higgs system, using a truncated Fock-space trial state. Approximate solutions of the 2-body relativistic coupled integral equations are presented, and conditions for the existence of Higgs bound states is examined in a broad parameter space of DM mass and coupling constants.

hep-ph↗

arXiv2013

Relativistic wave equations of n-body systems of fermions and antifermions of various masses in quantum electrodynamics

The variational method in a reformulated Hamiltonian formalism of Quantum Electrodynamics is used to derive relativistic wave equations for systems consisting of n fermions and antifermions of various masses. The derived interaction kernels of these equations include one-photon exchange interactions. The equations have the expected Schroedinger non-relativistic limit. Application to some exotic few lepton systems is discussed briefly.

quant-ph↗

arXiv2013

Effect of Virtual Pairs on the Inter-quark Potential

We use the variational method, in a reformulated Hamiltonian formalism of QCD, to derive the wave equation for a heavy quark-antiquark system using a trial state that contains a component with a virtual light quark pair. We examine the quark-antiquark potential in the non-relativistic limit using an approximate trial ground-state wave function. We find that the potential exhibits a confining character due to the inclusion of the virtual pair component in the trial state.

hep-th↗

arXiv2012

Inter-particle potentials in a scalar QFT with a Higgs-like mediating field

We study the inter-particle potentials for few-particle systems in a scalar theory with a non-linear mediating field of the Higgs type. We use the variational method, in a reformulated Hamiltonian formalism of QFT, to derive relativistic three and four particle wave equations for stationary states of these systems. We show that the cubic and quartic non-linear terms modify the attractive Yukawa potentials but do not change the attractive nature of the interaction if the mediating fields are massive.

hep-th↗

arXiv2011

Analysis of inter-quark interactions in classical chromodynamics

The QCD gluon equation of motion is solved approximately by means of the Green function. This solution is used to reformulate the Lagrangian of QCD such that the gluon propagator appears directly in the interaction terms of the Lagrangian. The nature of the interactions is discussed. Their coordinate-space form is presented and analyzed in the static, non-relativistic case.

hep-th↗

arXiv2010

Confinement interaction in nonlinear generalizations of the Wick-Cutkosky model

We consider nonlinear-mediating-field generalizations of the Wick-Cutkosky model. Using an iterative approach and eliminating the mediating field by means of the covariant Green function we arrive at a Lagrangian density containing many-point time-nonlocal interaction terms. In low-order approximations of $ϕ^3{+}ϕ^4$ theory we obtain the usual two-current interaction as well as a three-current interaction of a confining type. The same result is obtained without approximation for a version of the dipole model. The transition to the Hamiltonian formalism and subsequent canonical quantization is performed with time non-locality taken into account approximately. A relativistic three-particle wave equation is derived variationally by using a three-particle Fock space trial state. The non-relativistic limit of this equation is obtained and its properties are analyzed and discussed.

hep-th↗

arXiv2010

Exact two-particle eigenstates in partially reduced QED

We consider a reformulation of QED in which covariant Green functions are used to solve for the electromagnetic field in terms of the fermion fields. It is shown that exact few-fermion eigenstates of the resulting Hamiltonian can be obtained in the canonical equal-time formalism for the case where there are no free photons. These eigenstates lead to two- and three-body Dirac-like equations with electromagnetic interactions. Perturbative and some numerical solutions of the two-body equations are presented for positronium and muonium-like systems, for various strengths of the coupling.

nucl-th↗

arXiv2008

Relativistic corrections to the Zeeman splitting of hyperfine structure levels in two-fermion bound-state systems

A relativistic theory of the Zeeman splitting of hyperfine levels in two-fermion systems is presented. The approach is based on the variational equation for bound states derived from quantum electrodynamics [1]. Relativistic corrections to the g-factor are obtained up to O(alpha^2). Calculations are provided for all quantum states and for arbitrary fermionic mass ratio. In the one-body limit our calculations reproduce the formula for the g-factor (to O((Z*alpha)^2)) obtained from the Dirac equation. The results will be useful for comparison with high-precision measurements.

hep-ph↗

arXiv2007

Relativistic Three-Fermion Wave Equations in Reformulated QED and Relativistic Effects in Muonium Minus

The variational method, within the Hamiltonian formalism of reformulated QED is used to determine relativistic wave equations for a system of three fermions of arbitrary mass interacting electromagnetically. The interaction kernels of the equations are, in essence, the invariant $\mathcal{M}$ matrices in lowest order. The equations are used to obtain relativistic $O(α^2)$ corrections to the non-relativistic ground state energy levels of the Muonium negative ion ($μ^+ e^- e^-$) as well as of $\mathrm{Ps}^-$ and $\mathrm{H}^-$, using approximate variational three-body wave functions. The results are compared with other calculations, where available. The relativistic correction for Mu$^-$ is found to be $-1.0773 \times 10^{-4}$ eV.

physics.atom-ph↗

arXiv2007

Hyperfine Structure and Zeeman Splitting in Two-Fermion Bound-State Systems

A relativistic wave equation for bound states of two fermions with arbitrary masses which are exposed to a magnetic field is derived from quantum electrodynamics. The interaction kernels are based upon the generalized invariant M-matrices for inter-fermion and fermion-field interactions. As an application we calculate the energy corrections in a weak homogeneous B field to obtain the Zeeman splitting of the hyperfine structure and g-factors in the lowest order (i.e. to alpha^4). Lande g-factors are presented for several of the first excited states of hydrogen, muonium, and muonic-hydrogen.

hep-ph↗

arXiv2006

Bound-State Variational Wave Equation For Fermion Systems In QED

We present a formulation of the Hamiltonian variational method for QED which enables the derivation of relativistic few-fermion wave equation that can account, at least in principle, for interactions to any order of the coupling constant. We derive a relativistic two-fermion wave equation using this approach. The interaction kernel of the equation is shown to be the generalized invariant M-matrix including all orders of Feynman diagrams. The result is obtained rigorously from the underlying QFT for arbitrary mass ratio of the two fermions. Our approach is based on three key points: a reformulation of QED, the variational method, and adiabatic hypothesis. As an application we calculate the one-loop contribution of radiative corrections to the two-fermion binding energy for singlet states with arbitrary principal quantum number $n$, and $l =J=0$. Our calculations are carried out in the explicitly covariant Feynman gauge.

hep-th↗

arXiv2004

Variational Derivation of Relativistic Fermion-Antifermion Wave Equations in QED

We present a variational method for deriving relativistic two-fermion wave equations in a Hamiltonian formulation of QED. A reformulation of QED is performed, in which covariant Green functions are used to solve for the electromagnetic field in terms of the fermion fields. The resulting modified Hamiltonian contains the photon propagator directly. The reformulation permits one to use a simple Fock-space variational trial state to derive relativistic fermion-antifermion wave equations from the corresponding quantum field theory. We verify that the energy eigenvalues obtained from the wave equation agree with known results for positronium.

hep-th↗

arXiv2003

Variational Two Fermion Wave Equations in QED: Muonium Like Systems

We consider a reformulation of QED in which covariant Green functions are used to solve for the electromagnetic field in terms of the fermion fields. The resulting modified Hamiltonian contains the photon propagator directly. A simple Fock-state variational trial function is used to derive relativistic two-fermion equations variationally from the expectation value of the Hamiltonian of the field theory. The interaction kernel of the equation is shown to be, in essence, the invariant M-matrix in lowest order. Solutions of the two-body equations are presented for muonium like system for small coupling strengths. The results compare well with the observed muonium spectrum, as well as that for hydrogen and muonic hydrogen. Anomalous magnetic moment effects are discussed.

hep-ph↗

arXiv1998

Some exact solutions of reduced scalar Yukawa theory

The scalar Yukawa model, in which a complex scalar field interact via a real scalar field, is reduced by using covariant Green functions. It is shown that exact few-particle eigenstates of the truncated QFT Hamiltonian can be obtained in the Feshbach-Villars formulation if an unorthodox "empty" vacuum state is used. Analytic solutions for the two-body case are obtained for massless chion exchange in 3+1 dimensions and for massive chion exchange in 1+1 dimensions. Comparison is made to ladder Bethe-Salpeter, Feynman-Schwinger and quasipotential results for massive chion exchange in 3+1. Equations for the three-body case are also obtained.

nucl-th↗

arXiv1997

Exact solutions and triviality of lambda (phi^*phi)^2 theory in the Feshbach-Villars formulation

The complex scalar quantum field theory with a lambda (phi^*phi)^2 interaction is considered in the Feshbach-Villars formulation. It is shown that exact few-particle eigenstates of the QFT Hamiltonian can be obtained. The resulting relativistic few-body equations correspond to Klein-Gordon particles interacting via delta-function, or ``contact'', potentials. Momentum-space solutions of the two-body equation yield a `trivial' unity S-matrix.

hep-ph↗