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Search Results: 1 - 10 of 198390 matches for " N. Kawamoto "
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Dirac-Kaehler fermion with noncommutative differential forms on a lattice
I. Kanamori,N. Kawamoto
Physics , 2003, DOI: 10.1016/S0920-5632(03)02740-3
Abstract: Noncommutativity between a differential form and a function allows us to define differential operator satisfying Leibniz's rule on a lattice. We propose a new associative Clifford product defined on the lattice by introducing the noncommutative differential forms. We show that this Clifford product naturally leads to the Dirac-K\"ahler fermion on the lattice.
Lattice Chern-Simons Gravity via Ponzano-Regge Model
N. Kawamoto,H. B. Nielsen,N. Sato
Physics , 1999, DOI: 10.1016/S0550-3213(99)00331-4
Abstract: We propose a lattice version of Chern-Simons gravity and show that the partition function coincides with Ponzano-Regge model and the action leads to the Chern-Simons gravity in the continuum limit. The action is explicitly constructed by lattice dreibein and spin connection and is shown to be invariant under lattice local Lorentz transformation and gauge diffeomorphism. The action includes the constraint which can be interpreted as a gauge fixing condition of the lattice gauge diffeomorphism.
Phase diagram at finite temperature and quark density in the strong coupling region of lattice QCD for color SU(3)
A. Ohnishi,N. Kawamoto,K. Miura
Physics , 2007, DOI: 10.1088/0954-3899/34/8/S66
Abstract: We study the phase diagram of quark matter at finite temperature (T) and chemical potential (mu) in the strong coupling region of lattice QCD for color SU(3). Baryon has effects to extend the hadron phase to a larger mu direction relative to Tc at low temperatures in the strong coupling limit. With the 1/g^2 corrections, Tc is found to decrease rapidly as g decreases, and the shape of the phase diagram becomes closer to that expected in the real world.
Brown-Rho Scaling in the Strong Coupling Lattice QCD
A. Ohnishi,N. Kawamoto,K. Miura
Physics , 2008, DOI: 10.1142/S0217732308029587
Abstract: We examine the Brown-Rho scaling for meson masses in the strong coupling limit of lattice QCD with one species of staggered fermion. Analytical expression of meson masses is derived at finite temperature and chemical potential. We find that meson masses are approximately proportional to the equilibrium value of the chiral condensate, which evolves as a function of temperature and chemical potential.
Rejection Sensitivity, Self-Efficacy, and Learning Strategy: Mediating and Moderating the Role of Basic Needs Satisfaction  [PDF]
Miki Terada, Taishi Kawamoto
Psychology (PSYCH) , 2017, DOI: 10.4236/psych.2017.83028
Abstract: Rejection sensitive people often experience interpersonal difficulties, resulting in dissatisfaction with their need for relatedness. However, whether they are satisfied with their autonomy and competence, or experience difficulties from these factors other than in interpersonal relationships, remains largely unexplored. This study examined the influence of rejection sensitivity and need satisfaction (autonomy, competence, and relatedness) on learning strategy and self-efficacy. We found that competence satisfaction mediates the relationship between rejection sensitivity and self-efficacy. In addition, hierarchical regression analysis revealed a significant three-way interaction of rejection sensitivity, autonomy, and competence satisfaction with learning strategy. Competence satisfaction has a positive effect when individuals have low rejection sensitivity and are satisfied with autonomy need, whereas autonomy satisfaction has a positive effect when individuals have high rejection sensitivity and are dissatisfied with their competence levels. This suggests that autonomy and competence satisfaction levels are important for the understanding of psychological difficulties in rejection sensitive individuals.
Quantization of Even-Dimensional Actions of Chern-Simons Form with Infinite Reducibility
N. Kawamoto,K. Suehiro,T. Tsukioka,H. Umetsu
Physics , 1998, DOI: 10.1016/S0550-3213(98)00465-9
Abstract: We investigate the quantization of even-dimensional topological actions of Chern-Simons form which were proposed previously. We quantize the actions by Lagrangian and Hamiltonian formulations {\`a} la Batalin, Fradkin and Vilkovisky. The models turn out to be infinitely reducible and thus we need infinite number of ghosts and antighosts. The minimal actions of Lagrangian formulation which satisfy the master equation of Batalin and Vilkovisky have the same Chern-Simons form as the starting classical actions. In the Hamiltonian formulation we have used the formulation of cohomological perturbation and explicitly shown that the gauge-fixed actions of both formulations coincide even though the classical action breaks Dirac's regularity condition. We find an interesting relation that the BRST charge of Hamiltonian formulation is the odd-dimensional fermionic counterpart of the topological action of Chern-Simons form. Although the quantization of two dimensional models which include both bosonic and fermionic gauge fields are investigated in detail, it is straightforward to extend the quantization into arbitrary even dimensions. This completes the quantization of previously proposed topological gravities in two and four dimensions.
Phase diagram at finite temperature and quark density in the strong coupling limit of lattice QCD for color SU(3)
N. Kawamoto,K. Miura,A. Ohnishi,T. Ohnuma
Physics , 2005, DOI: 10.1103/PhysRevD.75.014502
Abstract: We study the phase diagram of quark matter at finite temperature (T) and finite chemical potential (mu) in the strong coupling limit of lattice QCD for color SU(3). We derive an analytical expression of the effective free energy as a function of T and mu, including baryon effects. The finite temperature effects are evaluated by integrating over the temporal link variable exactly in the Polyakov gauge with anti-periodic boundary condition for fermions. The obtained phase diagram shows the first order phase transition at low temperatures and the second order phase transition at high temperatures separated by the tri-critical point in the chiral limit. Baryon has effects to reduce the effective free energy and to extend the hadron phase to a larger mu direction at low temperatures.
Lattice supersymmetry in 1D with two supercharges
S. Arianos,A. D'Adda,N. Kawamoto,J. Saito
Physics , 2007,
Abstract: A consistent formulation of a fully supersymmetric theory on the lattice has been a long standing challenge. In recent years there has been a renewed interest on this problem with different approaches. At the basis of the formulation we present in the following there is the Dirac-Kahler twisting procedure, which was proposed in the continuum for a number of theories, including N=4 SUSY in four dimensions. Following the formalism developed in recent papers, an exact supersymmetric theory with two supercharges on a one dimensional lattice is realized using a matrix-based model. The matrix structure is obtained from the shift and clock matrices used in two dimensional non-commutative field theories. The matrix structure reproduces on a one dimensional lattice the expected modified Leibniz rule. Recent claims of inconsistency of the formalism are discussed and shown not to be relevant.
Transfer Matrix Formalism for Two-Dimensional Quantum Gravity and Fractal Structures of Space-time
H. Kawai,N. Kawamoto,T. Mogami,Y. Watabiki
Physics , 1993, DOI: 10.1016/0370-2693(93)91131-6
Abstract: We develop a transfer matrix formalism for two-dimensional pure gravity. By taking the continuum limit, we obtain a "Hamiltonian formalism'' in which the geodesic distance plays the role of time. Applying this formalism, we obtain a universal function which describes the fractal structures of two dimensional quantum gravity in the continuum limit.
Recursive sampling simulations of 3D gravity coupled to scalar fermions
J. Ambjorn,D. V. Boulatov,N. Kawamoto,Y. Watabiki
Physics , 2000, DOI: 10.1016/S0370-2693(00)00411-1
Abstract: We study numerically the phase structure of a model of 3D gravity interacting with scalar fermions. We measure the 3D counterpart of the "string" susceptibility exponent as a function of the inverse Newton coupling $\alpha$. We show that there are two phases separated by a critical point around $\alpha_c \simeq 2$. The numerical results support the hypothesis that the phase structures of 3D and 2D simplicial gravity are qualitatively similar, the inverse Newton coupling in 3D playing the role of the central charge of matter in 2D.
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