arXiv subjects
Publications and source records attributed to Sho Tanaka.
We attempt to resolve the cosmological constant problem through the key concept of the quantized number of spatial degrees of freedom in the modified Yang's quantized space-time, $n_{\rm {dof}} (V_3^{R(τ)})$.
We emphasized the importance of underlying noncommutative geometry or Lorenz-covariant quantized space-time towards ultimate theory of quantum gravity and Planck scale physics. We focused there our attention on the statistical and substantial understanding of Bekenstein-Hawking's Area-Entropy Law of black holes in terms of Kinematical Holographic Relation (KHR). KHR manifestly holds in Yang's quantized space-time as the result of kinematical reduction of spatial degrees of freedom caused by its own nature of noncommutative geometry and plays an important role in our approach without any recourse to the familiar hypothesis, so-called Holographic Principle. In the present paper, we find out a {\it unified} form of KHR applicable to the whole region ranging from macroscopic to microscopic scales in spatial dimension $ d=3.$ We notice a possibility of nontrivial modification of Area-Entropy Law of Black Holes which becomes most remarkable in the extremely microscopic system close to Planck scale. We finally refer to the historical background of noncommutative geometry or quantized space-time.
In confrontation with serious and fundamental problems towards ultimate theory of quantum gravity and physics of Planck scale, we emphasize the importance of underlying noncommutative space-time such as Snyder's or Yang's Lorentz-covariant quantized space-time. The background of Bekenstein-Hawking's Area-entropy law and Holographic principle is now substantially understood in terms of {\it Kinematical} Holographic Relation [KHR], which holds in Yang's quantized space-time as the result of the kinematical reduction of spatial degrees of freedom caused by its own nature of noncommutative geometry. [KHR] implies a definite proportional relation, $ n^L_{\rm dof} (V_d^L)= {\cal A} (V_d^L) / G_d$, between the number of spatial degrees of freedom $n^L_{\rm dof} (V_d^L)$ inside of any $d-$dimensional spherical volume $V_d^L$ with radius $L $ and its boundary area ${\cal A} (V_d^L).$ It yields a substantial basis for our new area-entropy law of black holes and further enables us to connect "The First Law of Black Hole Mechanics" with "The Thermodynamics of Black Holes," towards our final goal: {\it Statistical} and {\it substantial} understanding of area-entropy law of black holes under a novel concept of noncommutative quantized space-time.
Hideki Yukawa, Sin-itiro Tomonaga and Shoichi Sakata pioneered nuclear and particle physics and left enduring legacies. Their friendly collaboration and severe competition laid the foundation to bring up the active postwar generation of nuclear and particle physicists in Japan. In this presentation we illustrate milestones of nuclear and particle physics in Japan from 1930's to mid-1940's which have been clarified in Yukawa Hall Archival Library, Tomonaga Memorial Room and Sakata Memorial Archival Library.
We investigate the possible inner relation between the familiar Bekenstein-Hawking area-entropy relation and ours presented in a simple $D_0$ brane gas system on the basis of the kinematical holographic relation [KHR] in the Yang's quantized space-time. We find out that the relation between them is well understood through the idea of {\it elementary} Schwarzschild black hole realized on a single $[site]$ of Planckian scale in our scheme. Related arguments explain the origin of a certain kind of universality as seen in $η=1/4$ in the Bekenstein-Hawking relation and lead us to notice the similarity between the effective mass of $D_0$ brane, $μ_S,$ inside black holes and the Hawking radiation temperature, $T_{H.R.} (= 1/(8πM_S))$, both inversely proportional to the black hole mass $M_S$ and having almost the same order of magnitude. Motivated by this fact, we attempt to examine further the physical implication of $η$ by introducing in our scheme an ansatz which enables us self-consistently to equate $μ_S$ to $T_{H.R.}$ and leads us to $η$ slightly shifted from $1/4.$
We investigate a possible inner relation between the familiar Bekenstein-Hawking area-entropy relation and ours presented in a simple $D_0$ brane gas model on the basis of the kinematical holographic relation [KHR] in the Yang's quantized space-time algebra (YSTA). We find out that the relation between them is well understood through the idea of an {\it elementary} Schwarzschild black hole realized on a single $[site]$ of Planckian scale in our scheme. Related arguments possibly explain the origin of a certain kind of universality as seen in $η=1/4$ in the Bekenstein-Hawking relation and lead us to notice the similarity between the effective mass of $D_0$ brane, $μ_S,$ inside black holes and the Hawking radiation temperature, $T_{H.R.} ( = 1/(8πM_S) )$, both inversely proportional to the black hole mass $M_S$ and having almost the same order of magnitude. Motivated by this fact, we introduce in our scheme an ansatz which enables us self-consistently to equate $μ_S$ to $T_{H.R.}$ and leads us to an area-entropy relation with $η$ slightly shifted from $1/4.$
In the preceding paper, we derived a kind of kinematical holographic relation (KHR) in the Lorentz-covariant Yang's quantized space-time algebra (YSTA). It essentially reflects the fundamental nature of the noncommutative geometry of YSTA and its representation, that is, a definite kinematical reduction of spatial degrees of freedom in comparison with the ordinary lattice space. On the basis of the relation and its extension to various spatial dimensions, we derive a new area-entropy relation in a simple $D_0$ brane gas system subject to YSTA, following the idea of M-theory. Furthermore, we make clear its inner relation with the Bekenstein-Hawking area-entropy relation in connection with Schwarzschild black hole.
We try to find a possible origin of the holographic principle in the Lorentz-covariant Yang's quantized space-time algebra (YSTA). YSTA, which is intrinsically equipped with short- and long-scale parameters, $λ$ and $R$, gives a finite number of spatial degrees of freedom for any bounded spatial region, providing a basis for divergence-free quantum field theory. Furthermore, it gives a definite kinematical reduction of spatial degrees of freedom, compared with the ordinary lattice space. On account of the latter fact, we find a certain kind of kinematical holographic relation in YSTA, which may be regarded as a primordial form of the holographic principle suggested so far in the framework of the present quantum theory that appears now in the contraction limit of YSTA, $λ\to 0$ and $R \to \infty.$
Electric conduction in thin graphite film was tuned by two gate electrodes to clarify how the gate electric field induces electric carriers in thin graphite. The graphite was sandwiched between two gate electrodes arranged in a top and bottom gate configuration. A scan of the top gate voltage generates a resistance peak in ambiploar response. The ambipolar peak is shifted by the bottom gate voltage, where the shift rate depends on the graphite thickness. The thickness-dependent peak shift was clarified in terms of the inter-layer screening length to the electric field in the double-gated graphite film. The screening length of 1.2 nm was experimentally obtained.
Motivated by the recent proposition by Buniy, Hsu and Zee with respect to discrete space-time and finite spatial degrees of freedom of our physical world with a short- and a long-distance scales, $l_P$ and $L,$ we reconsider the Lorentz-covariant Yang's quantized space-time algebra (YSTA), which is intrinsically equipped with such two kinds of scale parameters, $λ$ and $R$. In accordance with their proposition, we find the so-called contracted representation of YSTA with finite spatial degrees of freedom associated with the ratio $R/λ$, which gives a possibility of the divergence-free noncommutative field theory on YSTA. The canonical commutation relations familiar in the ordinary quantum mechanics appear as the cooperative Inonu-Wigner's contraction limit of YSTA, $λ\to 0$ and $R \to \infty.$
Noncommutative field theory on Yang's quantized space-time algebra (YSTA) is studied. It gives a theoretical framework to reformulate the matrix model as quantum mechanics of $D_0$ branes in a Lorentz-covariant form. The so-called kinetic term ($\sim {\hat{P_i}}^2)$ and potential term ($\sim {[\hat{X_i},\hat{X_j}]}^2)$ of $D_0$ branes in the matrix model are described now in terms of Casimir operator of $SO(D,1)$, a subalgebra of the primary algebra $SO(D+1,1)$ which underlies YSTA with two contraction- parameters, $λ$ and $R$. $D$-dimensional noncommutative space-time and momentum operators $\hat{X_μ}$ and $\hat{P_μ}$ in YSTA show a distinctive spectral structure, that is, space-components $\hat{X_i}$ and $\hat{P_i}$ have discrete eigenvalues, and time-components $\hat{X_0}$ and $\hat{P_0}$ continuous eigenvalues, consistently with Lorentz-covariance. According to the method of Lorentz-covariant Moyal star product proper to YSTA, the field equation of $D_0$ brane on YSTA is derived in a nontrivial form beyond simple Klein-Gordon equation, which reflects the noncommutative space-time structure of YSTA.
Yukawa's space-time approach is briefly summarized, which starts just before his meson theory and finally comes to the theory of elementary domain. Recent rapid development in superstring theory is reviewed, focussing our attention on several important topics, which seem deeply related to Yukawa's concern. The importance of the idea of noncommutative space-time is emphasized.
The present-day significance of Yang's quantized space-time algebra (YST) is pointed out from the holographic viewpoint. One finds that the D-dimensional YST and its modified version (MYST) have the background symmetry SO(D+1,1) and SO(D,2), which are well known to underlie the dS/CFT and AdS/CFT correspondences, respectively. This fact suggests a new possibility of dS/YST and AdS/MYST in parallel with dS/CFT and AdS/CFT, respectively. The spatial components of quantized space-time and momentum operators of YST have discrete eigenvalues and their respective minimums, $a$ and 1/R, without contradiction to Lorentz-covariance. With respect to MYST, the spatial components of space-time operators and the time component (energy) of momentum operators have discrete eigenvalues and their respective minimums, $a$ and 1/R, in contrast to YST. This discrete structure of YST and MYST, which CFT lacks entirely, may provide a theoretical ground for the unified regularization or cutoff of ultraviolet and infrared divergences familiar in the UV/IR connection in the holographic hypothesis.
We propose relativistic second quantization of matrix model of D particles in a general framework of nonlocal field theory based on Snyder-Yang's quantized space-time. Second-quantized nonlocal field is in general noncommutative with quantized space-time, but conjectured to become commutative with light cone time $X^+$. This conjecture enables us to find second-quantized Hamiltonian of D particle system and Heisenberg's equation of motion of second-quantized {\bf D} field in close contact with Hamiltonian given in matrix model. We propose Hamilton's principle of Lorentz-invariant action of {\bf D} field and investigate what conditions or approximations are needed to reproduce the above Heisenberg's equation given in light cone time. Both noncommutativities appearing in position coordinates of D particles in matrix model and in quantized space-time will be eventually unified through second quantization of matrix model.
In order to get the general framework describing a nonlocalizable object beyond the bilocal field theory early proposed by Markov and Yukawa, the quantization of space-time is reconsidered and further developed. Space-time quantities are there not only noncommutative with U-field describing the nonlocalizable object, as in the bilocal field theory, but also become noncommutative among themselves. Under the U-field representation, where the basis vectors of representation are chosen to be eigenvectors of operator U, space-time quantities get a matrix representation of infinite dimension in general. Field equation is considered, which determines the relation between space-time quantities and U-field. The possible inner relation between the recent topics of matrix model in superstring theory and the present approach is discussed.