arXiv subjects

Shoichi Ichinose

Publications and source records attributed to Shoichi Ichinose.

At least 37 records · Page 2Linked to original sources

arXiv2006

Graphical Representation of Supersymmetry

A graphical representation of supersymmetry is presented. It clearly expresses the chiral flow appearing in SUSY quantities, by representing spinors by {\it directed lines} (arrows). The chiral suffixes are expressed by the directions (up, down, left, right) of the arrows. The SL(2,C) invariants are represented by {\it wedges}. Both the Weyl spinor and the Majorana spinor are treated. We are free from the complicated symbols of spinor suffixes. The method is applied to the 5D supersymmetry. Many applications are expected. The result is suitable for coding a computer program and is highly expected to be applicable to various SUSY theories (including Supergravity) in various dimensions.

hep-th↗

arXiv2006

Graphical Representation of SUSY and C-Program Calculation

We present a graphical representation of the supersymmetry and a C-program for the graphical calculation. Calculation is demonstrated for 4D Wess-Zumino model and for Super QED. The chiral operators are graphically expressed in an illuminating way. The tedious part of SUSY calculation, due to manipulating chiral suffixes, reduces considerably. The application is diverse.

hep-th↗

arXiv2004

Quantum Dynamics of a Bulk-Boundary System

The quantum dynamics of a bulk-boundary theory is closely examined by the use of the background field method. As an example we take the Mirabelli-Peskin model, which is composed of 5D super Yang-Mills (bulk) and 4D Wess-Zumino (boundary). Singular interaction terms play an important role of canceling the divergences coming from the KK-mode sum. Some new regularization of the momentum integral is proposed. An interesting background configuration of scalar fields is found. It is a localized solution of the field equation. In this process of the vacuum search, we present a new treatment of the vacuum with respect to the extra coordinate. The "supersymmetric" effective potential is obtained at the 1-loop full (w.r.t. the coupling) level. This is the bulk-boundary generalization of the Coleman-Weinberg's case. Renormalization group analysis is done where the correct 4d result is reproduced. The Casimir energy is calculated and is compared with the case of the Kaluza-Klein model.

hep-th↗

arXiv2004

Family of Singular Solutions in a SUSY Bulk-Boundary System

A set of classical solutions of a singular type is found in a 5D SUSY bulk-boundary system. The "parallel" configuration, where the whole components of fields or branes are parallel in the iso-space, naturally appears. It has three {\it free} parameters related to the {\it scale freedom} in the choice of the brane-matter sources and the {\it "free" wave} property of the {\it extra component} of the bulk-vector field. The solutions describe brane, anti-brane and brane-anti-brane configurations depending on the parameter choice. Some solutions describe the localization behaviour even after the non-compact limit of the extra space. Stableness is assured. Their meaning in the brane world physics is examined.

hep-th↗

arXiv2004

Graphical Representation of Supersymmetry and Computer Calculation

A graphical representation of supersymmetry is presented. It clearly expresses the chiral flow appearing in SUSY quantities, by representing spinors by {\it directed lines} (arrows). The chiral suffixes are expressed by the directions (up, down, left, right) of the arrows. The SL(2,C) invariants are represented by {\it wedges}. We are free from the messy symbols of spinor suffixes. The method is applied to the 5D supersymmetry. Many applications are expected. The result is suitable for coding a computer program and is highly expected to be applicable to various SUSY theories (including Supergravity) in various dimensions.

hep-th↗

arXiv2004

Family of Singular Solutions in A SUSY Bulk-Boundary System

hep-th↗

arXiv2004

A Bulk Effect to SUSY Effective Potential in a 5D Super-Yang-Mills Model

Supersymmetric effective potential of a 5D super-Yang-Mills model compactified on $S^1/Z_2$, i.e., on an interval $l$ of extra dimension, is estimated at the 1-loop level by the auxiliary field tadpole method. For the sake of infinite towers of Kaluza-Klein excitation modes of bulk fields involved in the tadpoles, there arises a definite bulk effect of linear growth of the effective potential along with the cutoff ${\mitΛ}$ which is greatly suppressed by $l$ to produce finite contributions. The minimization of the effective potential incorporating the tree potential and a Fayet-Iliopoulos $D$-term reveals an interesting case that the size of $l$ is stabilized at a length corresponding to an intermediate mass scale $10^{12-14}$ GeV.

hep-th↗

arXiv2004

Brane-Anti-Brane Solution and SUSY Effective Potential in Five Dimensional Mirabelli-Peskin Model

A localized configuration is found in the 5D bulk-boundary theory on an $S_1/Z_2$ orbifold model of Mirabelli-Peskin. A bulk scalar and the extra (fifth) component of the bulk vector constitute the configuration. $\Ncal=1$ SUSY is preserved. The effective potential of the SUSY theory is obtained using the background field method. The vacuum is treated in a general way by allowing its dependence on the extra coordinate. Taking into account the {\it supersymmetric boundary condition}, the 1-loop full potential is obtained. The scalar-loop contribution to the Casimir energy is also obtained. Especially we find a {\it new} type which depends on the brane configuration parameters besides the $S_1$ periodicity parameter.

hep-th↗

arXiv2004

Casimir Effect in the Brane World

Taking the Mirabelli-Peskin model, we examine the Casimir effect in the brane world. It is compared with that of the ordinary Kaluza-Klein theory.

hep-th↗

arXiv2003

Graphical Representation of Supersymmetry

A graphical representation of supersymmetry is presented. It clearly expresses the chiral flow appearing in SUSY quantities, by representing spinors by {\it directed lines} (arrows). The chiral suffixes are expressed by the directions (up, down, left, right) of the arrows. The SL(2,C) invariants are represented by {\it wedges}. Both the Weyl spinor and the Majorana spinor are treated. We are free from the messy symbols of spinor suffixes. The method is applied to the 5D supersymmetry. Many applications are expected. The result is suitable for coding a computer program and is highly expected to be applicable to various SUSY theories (including Supergravity) in various dimensions.

hep-th↗

arXiv2002

Fermions in Kaluza-Klein and Randall-Sundrum Theories

The Kaluza-Klein theory and Randall-Sundrum theory are examined comparatively, with focus on the behavior of the five dimensional (Dirac) fermion in the dimensional reduction to four dimensions. They are properly treated using the Cartan formalism. In the KK case, the dual property between the electric and magnetic dipole moments is revealed in relation to the ratio of two massive parameters: the inverse of the radius of the extra-space circle and the 5D fermion mass. The order estimation of the couplings is done. In the RS case, we consider the interaction with the 5D(bulk) Higgs field and the gauge field. The chiral property, localization, anomaly phenomena are examined. We evaluate the bulk quantum effect using the method of the induced effective action. The electric dipole moment term naturally appears. This is a new origin of the CP-violation. In the 4D limit, the dual relation between KK model and RS model appears.

hep-th↗

arXiv2002

Renormalization using Domain Wall Regularization

We formulate the renormalization procedure using the domain wall regularization that is based on the heat-kernel method. The quantum effects of both fermions and bosons (gauge fields) are taken into account. The background field method is quite naturally introduced. With regard to the treatment of the loop-momentum integrals, an interesting contrast between the fermion-determinant part and other parts is revealed. These points are elucidated by considering some examples. The Weyl anomalies for 2D QED and 4D QED are correctly obtained. It is found that the ``chiral solution'' produces (1/2)$^{d/2}$ $\times$ ``correct values'', where $d$ is the spatial dimension. Considering the model of 2D QED, both Weyl and chiral anomalies are directly obtained from the effective action. The mass and wave function renormalization are explicitly performed in 4D QED. We confirm the multiplicative (not additive) renormalization, which demonstrates the advantage of no fine-tuning. The relation with the recently popular higher-dimensional approach, such as the Randall- Sundrum model, is commented on.

hep-th↗

arXiv2002

CP-Violation in Kaluza-Klein and Randall-Sundrum Theories

The Kaluza-Klein theory and Randall-Sundrum theory are examined comparatively, with focus on the five dimensional (Dirac) fermion and the dimensional reduction to four dimensions. They are treated in the Cartan formalism. The chiral property, localization, anomaly phenomena are examined. The electric and magnetic dipole moment terms naturally appear. The order estimation of the couplings is done. This is a possible origin of the CP-violation.

hep-ph↗

arXiv2002

Brane World, Mass Hierarchy and the Cosmological Constant

The brane world based on the 6D gravitational model is examined. It is regarded as a higher dimensional version of the 5D model by Randall and Sundrum >. The obtained analytic solution is checked by the numerical method. The mass hierarchy is examined. Especially the {\it geometrical see-saw} mass relation, between the Planck mass, the cosmological constant, and the neutrino mass, is suggested. Comparison with the 5D model is made.

gr-qc↗

arXiv2001

Some Properties of Domain Wall Solution in the Randall-Sundrum Model

Properties of the domain wall (kink) solution in the 5 dimensional Randall-Sundrum model are examined both {\it analytically} and {\it numerically}. The configuration is derived by the bulk Higgs mechanism. We focus on 1) the convergence property of the solution, 2) the stableness of the solution, 3) the non-singular property of the Riemann curvature, 4) the behaviours of the warp factor and the Higgs field. It is found that the bulk curvature changes the sign around the surface of the wall. We also present some {\it exact} solutions for two simple cases: a) the no potential case, b) the cosmological term dominated case. Both solutions have the (naked) curvature singularity. We can regard the domain wall solution as a singularity resolution of the exact solutions.

hep-th↗

arXiv2001

Wall and Anti-Wall in the Randall-Sundrum Model and A New Infrared Regularization

An approach to find the field equation solution of the Randall-Sundrum model with the $S^1/Z_2$ extra axis is presented. We closely examine the infrared singularity. The vacuum is set by the 5 dimensional Higgs field. Both the domain-wall and the anti-domain-wall naturally appear, at the {\it ends} of the extra compact axis, by taking a {\it new infrared regularization}. The stability is guaranteed from the outset by the kink boundary condition. A {\it continuous} (infrared-)regularized solution, which is a truncated {\it Fourier series} of a {\it discontinuous} solution, is utilized.The ultraviolet-infrared relation appears in the regularized solution.

hep-th↗

arXiv2001

Pole Solution in Six Dimensions and Mass Hierarchy

A solution of the 6D gravitational model, which has the pole configuration, is found. The vacuum setting is done by the 6D Higgs potential and the solution is for a family of the vacuum and boundary parameters. The boundary condition is solved by the $1/k^2$-expansion (thin pole expansion) where $1/k$ is the {\it thickness} of the pole. The obtained analytic solution is checked by the numerical method. This is a dimensional reduction model from 6D to 4D by use of the soliton solution (brane world). It is regarded as a higher dimensional version of the Randall-Sundrum 5D model. The mass hierarchy is examined. Especially the {\it geometrical see-saw} mass relation is obtained. Some physical quantities in 4D world such as the Planck mass, the cosmological constant, and fermion masses are focussed. Comparison with the 5D model is made.

hep-th↗

arXiv2001

Some Properties of Pole Solution in Six Dimensions

A solution with the pole configuration in six dimensions is analysed both analytically and numerically. It is a dimensional reduction model of Randall-Sundrum type. The soliton configuration is induced by the bulk Higgs mechanism. The boundary condition is systematically solved up to the 6th order. The Riemann curvature is finite everywhere. An exact solution for the no potential case is also presented.

hep-th↗