Phases and fractal structures of three-dimensional simplicial gravity

We study phases and fractal structures of three-dimensional simplicial quantum gravity by the Monte-Carlo method. After measuring the surface area distribution (SAD) which is the three-dimensional analog of the loop length distribution (LLD) in two-dimensional quantum gravity, we classify the fractal structures into three types: (i) in the hot (strong coupling) phase, strong gravity makes the space-time one crumpled mother universe with small fluctuating branches around it. This is a crumpled phase with a large Hausdorff dimension d_{\mbox{\tiny H}} \simeq 5. The topologies of cross-sections are extremely complicated. (ii) at the critical point, we observe that the space-time is a fractal-like manifold which has one mother universe with small and middle size branches around it. The Hausdorff dimension is d_{\mbox{\tiny H}} \simeq 4. We observe some scaling behaviors for the cross-sections of the manifold. This manifold resembles the fractal surface observed in two-dimensional quantum gravity. (iii) in the cold (weak coupling) phase, the mother universe disappears completely and the space-time seems to be the branched-polymer with a small Hausdorff dimension d_{\mbox{\tiny H}} \simeq 2. Almost all of the cross-sections have the spherical topology $S^2$ in the cold phase.Comment: 14 pages, latex file, 5 Postscript figures, use psfig.st

Common Structures in Simplicial Quantum Gravity

The statistical properties of dynamically triangulated manifolds (DT mfds) in terms of the geodesic distance have been studied numerically. The string susceptibility exponents for the boundary surfaces in three-dimensional DT mfds were measured numerically. For spherical boundary surfaces, we obtained a result consistent with the case of a two-dimensional spherical DT surface described by the matrix model. This gives a correct method to reconstruct two-dimensional random surfaces from three-dimensional DT mfds. Furthermore, a scaling property of the volume distribution of minimum neck baby universes was investigated numerically in the case of three and four dimensions, and we obtain a common scaling structure near to the critical points belonging to the strong coupling phase in both dimensions. We have evidence for the existence of a common fractal structure in three- and four-dimensional simplicial quantum gravity.Comment: 10 pages, latex, 6 ps figures, uses cite.sty and psfig.st

Touch inhibits touch: sanshool-induced paradoxical tingling reveals perceptual interaction between somatosensory submodalities

Human perception of touch is mediated by inputs from multiple channels. Classical theories postulate independent contributions of each channel to each tactile feature, with little or no interaction between channels. In contrast to this view, we show that inputs from two sub-modalities of mechanical input channels interact to determine tactile perception. The flutter-range vibration channel was activated anomalously using hydroxy-α-sanshool, a bioactive compound of Szechuan pepper, which chemically induces vibration-like tingling sensations. We tested whether this tingling sensation on the lips was modulated by sustained mechanical pressure. Across four experiments, we show that sustained touch inhibits sanshool tingling sensations in a location-specific, pressure-level and time-dependent manner. Additional experiments ruled out the mediation of this interaction by nociceptive or affective (C-tactile) channels. These results reveal novel inhibitory influence from steady pressure onto flutter-range tactile perceptual channels, consistent with early-stage interactions between mechanoreceptor inputs within the somatosensory pathway

Combined Effect of Far Infrared Heating on the Quality of Vegetable Oil During Superheated Steam Treatment

大豆油を試料とし, 遠赤外線加熱の併用が過熱水蒸気処理の処理特性に与える影響について検討した. 大豆油の加熱は, 過熱水蒸気180℃, 230℃とセラミックヒーター230℃を任意に組み合わせた加熱条件で行った. 併用法による大豆油のAVは時間と共に増加し, その上昇値は, 単独法(180℃)よりも大きく, 単独法(230℃)よりも小さかった. 併用法で加熱された大豆油のPOVは, 単独法の場合と同様に, 加熱初期に一度増加した後減少した. 過熱水蒸気を用いた各処理法の大豆油粘度上昇は認められず, 加熱前後の色調は, 視覚観察ではほぼ同じであり, 明度を示すL*値, 赤味を示すa*値, 黄色味を示すb*値とも変化は小さかった. 以上の結果より, 過熱水蒸気処理への遠赤外線加熱の併用は, 過熱水蒸気の単独処理と同様に, 大豆油の品質への影響は少ないことを明らかにした.Changes in the quality of soybean oil heated using superheated steam (SHS) combined with far infrared heating (FIH) were compared to those of oil heated using SHS only. Oil quality was measured with respect to acid value (AV), peroxide value (POV) and viscosity. For the SHS treatment, oil was heated at two temperatures (180°C and 230°C). For the combined treatment of SHS with FIH (SHS + FIH), oil temperature was 180°C and the surface temperature of the FIH ceramic heater was 230°C. Changes in oil heated by SHS+FIH were similar to those in the SHS-only treatment. All quality values of SHS+FIH oil were between those of the 180°C SHS-only treatment and the 230°C SHS-only treatment. The results indicate that FIH heating combined with SHS does not significantly affect oil quality compared to SHS-only heating, although the treatment temperatures of both methods influenced oil quality

Three-Dimensional Simplicial Gravity and Degenerate Triangulations

I define a model of three-dimensional simplicial gravity using an extended ensemble of triangulations where, in addition to the usual combinatorial triangulations, I allow degenerate triangulations, i.e. triangulations with distinct simplexes defined by the same set of vertexes. I demonstrate, using numerical simulations, that allowing this type of degeneracy substantially reduces the geometric finite-size effects, especially in the crumpled phase of the model, in other respect the phase structure of the model is not affected.Comment: Latex, 19 pages, 10 eps-figur

Multicanonical simulation of 3D dynamical triangulation model and a new phase structure

We apply the multicanonical technique to the three dimensional dynamical triangulation model, which is known to exhibit a first order phase transition with the Einstein-Hilbert action. We first clarify the first order nature of the phase transition with the Einstein-Hilbert action in several ways including a high precision finite size scaling analysis. We then add a new local term to the action and confirm the conjecture made through the MCRG technique that the line of the first order phase transition extends to the expanded phase diagram, ending at a point. Fractal dimension at the end point is measured to be around three up to the present size.Comment: 20 pages, latex2e(graphic package), 9 figure