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Noboru Nakanishi

Publications and source records attributed to Noboru Nakanishi.

15 recordsLinked to original sources
arXiv2012

An Interpretation of "Superluminal Neutrino" Compatible with Relativity in the Framework of Standard Model

According to the measurement of muon-neutrino experiment done by the OPERA collaboration, the speed of high-energy neutrino exceeds that of light in vacuum by 25ppm. Assuming that this result is correct, a possible resolution of the dilemma between it and the validity of relativity is proposed without changing the framework of the Standard Model of elementary particles. The essential idea is based on a possible resolution, proposed previously, of the color confinement problem of quantum chromodynamics.

hep-ph↗
arXiv2007

An Attempt to Remove Quadratic Divergences in the Standard Theory

The quadratic divergences caused by Yukawa interactions in the standard theory of elementary particle physics is shown to be removed by introducing finite-mass complex-ghost regulator fields. In this modification of the standard theory, its manifest covariance, renormalizability, gauge invariance and unitarity are retained, and no new observable particles are introduced.

hep-th↗
arXiv2007

Unobservable Higgs Boson and Spontaneous Violation of Lorentz Invariance

The standard theory of elementary particle physics is modified in such a way that the Higgs boson becomes unobservable and Lorentz invariance is slightly violated at the level of the S-matrix. The basic technique of realizing these properties without violating the unitarity of the physical S-matrix is the use of the complex-ghost quantum field theory.

hep-th↗
arXiv2006

Question on the Existence of Gravitational Anomalies

The existence of gravitational anomalies claimed by Alvarez-Gaume and Witten is examined critically. It is pointed out that they were unaware of the essential difference between T-product quantities and T*-product quantities. Field equations and, therefore, the Noether theorem are, in general, violated in the case of T*-product quantities, that is, those directly calculable from Feynman integrals. In the 2-dimensional case, it is explicitly confirmed that the energy-momentum tensor is strictly conserved if the above stated property of the T*-product quantities is correctly taken into account. The non-existence of gravitational anomalies is explicitly demonstrated for the BRS-formulated 2-dimensional quantum gravity in the Heisenberg picture.

hep-th↗
arXiv2006

Spacetime in the Ultimate Theory

If we assume that there is the ultimate thoery at all, how should the concept of the spacetime be formulated? The following essay is my consideration on such a question. The use of mathematical expressions is suppressed as long as possible. Any criticism on my opinion is welcome.

hep-th↗
arXiv2006

Wightman-Function Approach to the Relativistic Complex-Ghost Field Theory

The relativistic complex-ghost field theory is covariantly formulated in terms of Wightman functions. The Fourier transform of the 2-point Wightman function of a complex-ghost pair is explicitly calculated, and its spontaneous breakdown of Lorentz invariance is compared with that of the corresponding Feynman integral.

hep-th↗
arXiv2001

Exact Solutions to the Two-dimensional BF and Yang-Mills Theories in the Light-cone Gauge

It is shown that the BRS-formulated two-dimensional BF theory in the light-cone gauge (coupled with chiral Dirac fields) is solved very easily in the Heisenberg picture. The structure of the exact solution is very similar to that of the BRS-formulated two-dimensional quantum gravity in the conformal gauge. In particular, the BRS Noether charge has anomaly. Based on this fact, a criticism is made on the reasoning of Kato and Ogawa, who derived the critical dimension D=26 of string theory on the basis of the anomaly of the BRS Noether charge. By adding the $\widetilde{B}^2$ term to the BF-theory Lagrangian density, the exact solution to the two-dimensional Yang-Mills theory is also obtained.

hep-th↗
arXiv1999

Perturbative or Path-Integral Approach versus Operator-Formalism Approach

In the conformal-gauge two-dimensional quantum gravity, the solution obtained by the perturbative or path-integral approach is compared with the one obtained by the operator-formalism approach. Treatments of the anomaly problem in both approaches are different. This difference is found to be essentially caused by the fact that the perturbative or path-integral approach is based on the T*-product (covariantized T-product), which generally violates field equations. Indeed, this fact induces some extra one-loop Feynman diagrams, which would not exist unless a nonzero contribution arose from a zero field. Some demerits of the path-integral approach are explicitly demonstrated.

hep-th↗
arXiv1998

Construction of an Identically Nilpotent BRS Charge in the Kato-Ogawa String Theory

In previous work, the conformal-gauge two-dimensional quantum gravity in the BRS formalism has been solved completely in terms of Wightman functions. In the present paper, this result is extended to the closed and open bosonic strings of finite length; the open-string case is nothing but the Kato-Ogawa string theory. The field-equation anomaly found previously, which means a slight violation of a field equation at the level of Wightman functions, remains existent also in the finite-string cases. By using this fact, a BRS charge nilpotent even for $D\not=26$ is explicitly constructed in the framework of the Kato-Ogawa string theory. The FP-ghost vacuum structure of the Kato-Ogawa theory is made more transparent; the appearance of half-integral ghost numbers and the artificial introduction of indefinite metric are avoided.

hep-th↗
arXiv1998

D=26 and Exact Solution to the Conformal-Gauge Two-Dimensional Quantum Gravity

The conformal-gauge two-dimensional quantum gravity is formulated in the framework of the BRS quantization and solved completely in the Heisenberg picture: All n-point Wightman functions are explicitly obtained. The field-equation anomaly is shown to exist as in other gauges, but there is no other subtlety. At the critical dimension D=26 of the bosonic string, the field-equation anomaly is shown to be absent. However, this result is not equivalent to the statement that the conformal anomaly is proportional to D-26. The existence of the FP-ghost number current anomaly is seen to be an illusion.

hep-th↗
arXiv1997

Question on D=26 --- String Theory versus Quantum Gravity ---

In the covariant-gauge two-dimensional quantum gravity, various derivations of the critical dimension D=26 of the bosonic string are critically reviewed, and their interrelations are clarified. It is shown that the string theory is not identical with the proper framework of the two-dimensional quantum gravity, but the former should be regarded as a particular aspect of the latter. The appearance of various anomalies is shown to be explainable in terms of a new type of anomaly in a unified way.

hep-th↗
arXiv1997

Proof of the Gauge Independence of the Conformal Anomaly of Bosonic String in the Sense of Kraemmer and Rebhan

Kraemmer and Rebhan claimed the gauge independence of the conformal anomaly of bosonic string for various gauge fixings in the framework of the perturbation theory of two-dimensional quantum gravity. It is pointed out that their proof is wrong. The gauge independence is proved for the gauge-fixings which reduce to the linearized de Donder gauge in the flat limit of the background metric. Similar remarks are made also for the Rebhan-Kraemmer current anomaly.

hep-th↗
arXiv1997

Anomaly Problem in a Simple Model Analogous to the Lightcone-Gauge Two-Dimensional Quantum Gravity

It was found in the two-dimensional quantum gravity both in the de Donder gauge and in the lightcone gauge that one of field equations breaks down at the level of the representation, though the breakdown is very little. It is shown that this anomalous behavior occurs also in a very simple model analogous to the lightcone-gauge two-dimensional quantum gravity. This model, however, can be transformed into a free field theory by a nonsingular transformation. Of course, the latter has no anomaly. The cause of the discrepancy is analyzed.

hep-th↗