Functional Integral Approach to a Many Fermion System with Bound States

The equation of state for a dense system of interacting Fermions is derived using functional integral technique. To investigate the formation of bound states, a Hubbard-Stratonovich transformation is applied which expresses the action as functional of pair fields. The evaluation of the partition function in lowest orders with respect to the pair fields leads to a result which can be interpreted as the contribution of two-particle states, accounting for density corrections as Pauli blocking and self-energy shift. Comparison is performed with results for the equation of state of hot dense matter (plasmas, nuclear matter) obtained within a Green's function approach.     

Bound States in the Quantum Scalar Electrodynamics

The next relativistic correction to α to for bound state mass of two charged scalar particles is calculated in the quantum scalar electrodynamics by the functional integral method. Contribution of the “nonphysical” time variable turned out to be important and leads to nonanalytic dependence of the bound state mass on α.     

Spontaneous Excitation of an Accelerated Detector Interacting with a Massive Scalar Field and Unruh Effect

We study spontaneous excitation of both a static detector (modelled by a two-level atom) immersed in a thermal bath and a uniformly accelerated one in the Minkowski vacuum interacting with a real massive scalar field.Our results show that the mass of the scalar field manifests itself in the spontaneous excitation rate of the static detector in a thermal bath (and in vacuum) in the form of a selection rule for transitions among states of the detector.However,this selection rule disappears for the accelerated ones,demonstrating that an accelerated detector does not necessarily behave the same as an inertial one in a thermal bath.We find the imprint left by the mass is the appearance of a grey-body factor in the spontaneous excitation and de-excitation rates,which maintains the detailed balance condition between them and thus ensures a thermal equilibrium at the Unruh temperature the same as that of the massless case.We also analyze quantitatively the effect of the mass on the rate of change of the detector's energy and find that when the mass is very small,it only induces a small negative correction.However,when it is very large,it then exponentially damps the rate,thus essentially forbidding any transitions among states of the detector.     

Critical Stability of Three-Body Relativistic Bound States with Zero-Range Interaction

For the zero-range interaction providing a given mass M₂ of the two-body bound state, the mass M₃ of the relativistic three-body system is calculated. We have found that the three-body system exists only when M₂ is greater than a critical value M_c ( 1.43 m for bosons and 1.35 m for fermions, m being the constituent mass). For M₂=M_c the mass M₃ turns into zero and for M₂ < M_c there is no solution with real value of M₃.     

Bound States of the Klein-Gordon Equation With Vector and Scalar Wood-Saxon Potentials

In this paper,simultaneously considering the variation of classical mass and the relativistic effect of mass variation with velocity,a relativistic four-covariant equation of variable mass body is built.And the physical meaning of     

具有Poschl-Teller型标量势与矢量势的Klein-Gordon方程和Dirac方程的束缚态

给出了具有Poschl-Teller型标量势与矢量势的Klein-Gordon方程和Dirac方程的s波束缚态解.     

Propagators for Scalar Bound States at Finite Temperature in an NJL Model

We re-examine physical causal propagators for scalar and pseudoscalar bound states at finite temperaturein a chiral Ut(1) x UR(1) NJL model, defined by four-point amputated fimctions subtracted through the gap equation,and prove that they are completely equivalent in the imaginary-time and real-time formalisms by separating carefiullythe imaginary part of the zero-temperature loop integral. It is shown that the same thermal transformation matrix ofthe matrix propagators for these bound states in the real-time formalism is precisely the one of the matrix propagatorfor an elementary scalar particle and this fact shows the similarity of thermodynamic property between a composite andelementary scalar particle. The retarded and advanced propagators for these bound states are also given explicitly fromthe imaginary-time formalism.     

Quantum States of a Neutral Massive Fermion with an Anomalous Magnetic Moment in an External Electric Field

The quantum dynamics of a nonrelativistic neutral massive fermion with an anomalous magnetic moment (AMM) is examined in the external electric field of an infinitely long thin homogeneously charged thread in the plane with a normal directed along the thread. The Hamiltonian of the Dirac–Pauli equation for a neutral fermion with AMM is essentially singular in the considered external field and requires a supplementary extension of the definition in order for it to be treated as a self-adjoint quantum-mechanical operator. All one-parameter self-adjoint extensions of the Hamiltonian of the Dirac–Pauli equation in the considered external field are found in the nonrelativistic approximation. The corresponding Hilbert space of squareintegrable functions, including a singularity point of the Hamiltonian, is specified for each self-adjoint extension of the Hamiltonian. The wave functions of free and bound states, as well as discrete energy levels, are determined by the self-adjoint extension method and their correspondence with similar quantities obtained by the physical regularization procedure is discussed. It is shown that energy levels of bound states are simple poles of the scattering amplitude, which should be extended in definition by introducing the self-adjoint extension parameter into it. Expressions for the scattering amplitude and cross-section, depending on the orientation of the initial-state spin of fermion, are obtained.     

Bound States of the S-Wave Equation with Equal Scalar and Vector Standard Eckart Potential

A supersymmetric technique for the bound-state solutions of the s-wave Klein-Gordon equation with equal scalar and vector standard Eckart-type potential is proposed. Its exact solutions are obtained. Possible generalization of our approach is outlined.     

Teleportation of Mixture of Diagonal Bell States via Bound Entangled States

We propose a protocol for teleportation of arbitrary mixture of diagonal Bell states, it is shown that the channel can be constructed with either pure maximally entangled states or mixed bound entangled states. We also present protocols to realize the controlled teleportation of mixture of diagonal Bell states via multi-particle mixed states. Our results show that bound entangled states are also important and useful resources in quantum communication tasks.     

Triality and Quantization of Singularities in Massive Fermion

It is proved that fermions can acquire the mass through the additional non-integrable exponential factor. For this propose the special vector potential associated with the spinor field was introduced. Such a vector potential has closk relation with the. triality property in Dirac spinors and plays crucial role in the construction of massive term. It is shown that the change in phase of a wavefunction round any closed curve with the possibility of there being singularities in our vector potential will lead to the law of quantization of physical constants including the mass. The triality properties of Dirac's spinors are studied and it leads to a double covering vector representation of Dirac spinor field. It is proved that massive Dirac equation in the bosonic representation is self-dual.     

Upper and Lower Bound States for Zero Dimensional Space in Scalar Quantum Field Theory

International Journal of Theoretical Physics - The varational method with the Hamiltonian formalism of quantum field theory (QFT) is used to study the bound state for scalar particle and...     

A Relativistic Coupled-Channel Formalism for Electromagnetic Form Factors of 2-Body Bound States

We discuss a Poincaré invariant coupled-channel formalism which is based on the point-form of relativistic quantum mechanics. Electromagnetic scattering of an electron by a 2-body bound state is treated as a 2-channel problem for a Bakamjian-Thomas-type mass operator. In this way retardation effects in the photon-exchange interaction are fully taken into account. The electromagnetic current of the 2-body bound state is then extracted from the one-photon-exchange optical potential. As an application we calculate electromagnetic pion and deuteron form factors. Wrong cluster properties, inherent in the Bakamjian-Thomas framework, are seen to cause spurious (unphysical) contributions in the current. These are separated and eliminated in an unambiguous way such that one is left with a current that has all the desired properties.     

Oscillatory Behavior of In-medium Interparticle Potential in Hot Gauge System with Scalar Bound States

We investigate the in-medium interparticle potential of hot gauge system with bound states by employing the QED and scalar QED coupling. At the finite temperature an oscillatory behavior of the potential has been found as well as its variation in terms of different free parameters. We expect the competition among the parameters will lead to an appropriate interparticle potential, which could be extended to discuss the fluid properties of QGP with scalar bound states.     

Renormalized Non-Perturbative Scalar and Fermion Models in Covariant Light-Front Dynamics

Within the framework of the covariant formulation of light-front dynamics, we develop a general non-perturbative renormalization scheme, based on the Fock decomposition of the state vector and its truncation. The explicit dependence of our formalism on the orientation of the light front, defined by a light-like four-vector ω, is essential in order to analyze the structure of the counterterms needed to renormalize the theory. We illustrate our framework for scalar and fermion models.     

q变形带电Fermion相干态和q’变形的SU（3）电荷、超荷Fermion相干态

利用ｑ变形的Ｆｅｒｍｉｏｎ振子代数讨论了ｑ变形的带电Ｆｅｒｍｉｏｎ相干态和ｑ变形的ＳＵ（３）电荷、超荷Ｆｅｒｍｉｏｎ相干态．利用ｑ－ＦｅｒｍｉｏｎＦｏｃｋ空间中的基失的完闭性，得到上述两种相干态的具体表现形式．将ｑ变形的结果与普通结果比较发现：在变形参数ｑ＝１时，ｑ变形的带电Ｆｅｒｍｉｏｎ相干态和ＳＵ（３）电荷、超荷Ｆｅｒｍｉｏｎ相干态自然回到普通的带电Ｆｅｒｍｉｏｎ相干态和ＳＵ（３）电荷、超荷Ｆｅｒｍｉｏｎ相干态．