Accelerating universe and the time-dependent fine-structure constant (2009)
Theoretical background of our proposed relation between the accelerating universe and the time-variability of the fine-structure constant is discussed, based on the scalar-tensor theory, with...
Role of Regularization in Quantum Corrections to the Scalar-Tensor Theories of Gravity (2009)
We show that regularizing divergent integrals is crucially important when applied to the loop diagrams corresponding to quantum corrections to the coupling of the \gravitational " scalar eld due...
How successful can the scalar-tensor theory be in understanding the accelerating universe? (2009)
The accelerating universe is closely related to today's version of the cosmological constant problem; fine-tuning and coincidence problems. We show how successfully the scalar-tensor theory, a rather...
Attractor Universe in the Scalar-Tensor Theory of Gravitation (2009)
Maeda, Kei-ichi, Fujii, Yasunori
In the scalar-tensor theory of gravitation it seems nontrivial to establish if solutions of the cosmological equations in the presence of a cosmological constant behave as attractors independently of...
Revised fits to $\Delta\alpha/\alpha$ in consistency with the accelerating universe (2008)
An attempt is made for a new type of analysis of the time-variability of the fine-structure constant trying to fit the most recent result from the laboratory measurements, the Oklo constraint and the...
Accelerating universe, WEP violation and antihydrogen atoms (2008)
Apart from the suspected violation of the CPT invariance, we might expect if the measurements of antihydrogen atoms provide testing Weak Equivalence Principle (WEP) in the gravitational phenomena. We...
Conformal transformation in the scalar-tensor theory applied to the accelerating universe (2007)
The scalar-tensor theory is plagued by nagging questions if different conformal frames, in particular the Jordan and Einstein conformal frames, are equivalent to each other. As a closely related...
Choosing a Conformal Frame in Scalar-Tensor Theories of Gravity with a Cosmological Constant (2007)
Cosmological solutions of the Brans-Dicke theory with an added cosmological constant are investigated with an emphasis to select a conformal frame in order to implement the scenario of a decaying...
We present a theoretical calculation on the time-variability of the fine-structure constant to fit the result of the recent precise analysis of the measurement of the QSO absorption lines. We find...
Fujii, Yasunori, Sasaki, Misao
The effect of the massless gravitational scalar field assumed to couple directly to the Maxwell field to the solar-system experiments is estimated. We start with discussing the theoretical...
Fujii, Yasunori, Iwamoto, Akira
We review our argument on the nature of the so-called meteorite constraint on the possible time-dependence of the fine-structure constant, emphasizing that dating meteorites at the present time is...
The measurement of $\Delta\alpha/\alpha$ from the QSO absorption lines of Fe_II taken at two different redshifts (Quast et al, Levshakov et al) is compared with the result based on the 23 data points...
Some aspects of the scalar-tensor theory (2004)
The scalar-tensor theory of gravitation has been and still is one of the most widely discussed "alternative theories" to General Relativity (GR). Despite nearly half a century of its age, it...
$\Delta\alpha/\alpha$ from QSO absorption lines driven by an oscillating scalar field (2004)
Fujii, Yasunori, Mizuno, Shuntaro
The new result on the QSO absorption lines from VLT-UVES sample is compared with the past reports on the time-variability of the fine-structure "constant" derived from the Keck/HIRES observation, on...
Oklo Constraint on the Time-Variability of the Fine-Structure Constant (2003)
The Oklo phenomenon, natural fission reactors which had taken place in Gabon about 2 billion years ago, provides one of the most stringent constraints on the possible time-variability of the...
Re/Os constraint on the time-variability of the fine-structure constant (2003)
Fujii, Yasunori, Iwamoto, Akira
We argue that the accuracy by which the isochron parameters of the decay $^{187}{\rm Re}\to ^{187}{\rm Os}$ are determined by dating iron meteorites may not directly constrain the possible...
The data from the QSO absorption lines indicating a nonzero time-variability of the fine-structure constant has been re-analyzed on the basis of a "damped-oscillator" fit, as motivated by the same...
Mass of the dilaton and the cosmological constant (2002)
One might raise a question if the gravitational scalar field (dilaton) mediates a finite-range force between local objects still behaving globally as being massless to implement the scenario of a...
Varying Fine-Structure Constant and the Cosmological Constant Problem (2002)
We start with a brief account of the latest analysis of the Oklo phenomenon providing the still most stringent constraint on time-variability of the fine- structure constant $\alpha$. Comparing this...
Nuclear Data in Oklo and Time-Variability of Fundamental Coupling Constants (2002)
Fujii, Yasunori, Iwamoto, Akira, Fukahori, Tokio, Ohnuki, Toshihiko, Nakagawa, Masayuki, Hidaka, Hiroshi, ...
We re-examined Shlyakhter's analysis of the Sm data in Oklo. With a special care of minimizing contamination due to the inflow of the isotope after the end of the reactor activity, we confirmed that...
In 1976, Shlyakhter showed that the Sm data from Oklo results in the upper bound on the time-variability of the fine-structure constant: $|\dot{\alpha}/\alpha| \lsim 10^{-17}{\rm y}^{-1}$, which has...
Cosmological Constant, Quintessence and Scalar-Tensor Theories of Gravity (2000)
We show how the scalar field, a candidate of quintessence, in a proposed model of the scalar-tensor theories of gravity provides a way to understand a small but nonzero cosmological constant as...
Quintessence, scalar-tensor theories and non-Newtonian gravity (1999)
We discuss some of the issues which we encounter when we try to invoke the scalar-tensor theories of gravitation as a theoretical basis of quintessence. One of the advantages of appealing to these...
A two-scalar model for a small but nonzero cosmological constant (1999)
We revisit a model of the two-scalar system proposed previously for understanding a small but nonzero cosmological constant. The model provides solutions of the scalar-fields energy $\rho_s$ which...
The nuclear interaction at Oklo 2 billion years ago (1998)
Fujii, Yasunori, Iwamoto, Akira, Fukahori, Tokio, Ohnuki, Toshihiko, Nakagawa, Masayuki, Hidaka, Hiroshi, ...
We re-examine the effort to constrain the time-variability of the coupling constants of the fundamental interactions by studying the anomalous isotopic abundance of Sm observed at the remnants of the...
What can we do on gravity with antihydrogens? (1998)
We discuss the implications of the proposed gravitational redshift experiment on antihydrogens. We show that the result should be the same as on hydrogens in spite of different free-fall...
Nonzero $\Omega_{\Lambda}$ and a new type of the dissipative structure (1998)
We revisit the proposed theoretical model for a small but nonzero cosmological constant which seems supported increasingly better by recent observations. The model features two scalar fields which...
Choosing a conformal frame in scalar-tensor theories of gravity with a cosmological constant (1997)
Cosmological solutions of the Brans-Dicke theory with an added cosmological constant are investigated with an emphasis to select a conformal frame in order to implement the scenario of a decaying...
Role of Regularization in Quantum Corrections to the Scalar-Tensor Theories of Gravity (1996)
We show that regularizing divergent integrals is crucially important when applied to the loop diagrams corresponding to quantum corrections to the coupling of the ``gravitational" scalar field due to...
Brans-Dicke Cosmology Corrected for a Quantum Effect due to the Scalar-Matter Coupling (1996)
Cosmological solutions of the Brans-Dicke theory are investigated by including a quantum effect coming from 1-loop correction of matter fields that couple to the scalar field. As the most serious...
A Mechanism for a small but nonzero cosmological constant (1996)
Based on a thoeretical model in which scalar fields play crucial roles, we propose a mechanism to better understand a cosmological constant expected to be small (nearly comparable with the critical...
How natural is a small but nonzero cosmological constant? (1995)
Based on our previous attempt, we propose a better way to understand a small but nonzero cosmological constant, as indicated by a number of recent observational studies. We re-examine the assumptions...
Induced Violation of Weak Equivalence Principle in the Brans-Dicke Theory (1994)
A quantum correction to the Brans-Dicke theory due to interactions among matter fields is calculated, resulting in violation of WEP, hence giving a constraint on the parameter $\omega$ far more...
藤井, 保紀, フジイ, ヤスノリ, FUJII, Yasunori
近年、企業価値を向上させるバリュードライバーとして無形資産の研究が国際的に盛んである。本書は日本発の無形資産会計のモデル構築を念頭に...