Microstates of black holes in expanding universe from interacting branes

Thermodynamics of the near extremal black p-branes can be described by collective motions of gravitationally interacting branes. This proposal is called the p-soup model. In this paper, we check this proposal in the case of black brane system which is asymptotically Friedmann-Lemaitre-Robertson-Walker universe in an infinite distance. As a result, we can show that the gravitationally interacting branes explain free energy, entropy, temperature and other physical quantities in these systems. This implies that the microstates of this kind of brane system can be also understood in the p-soup model.Comment: 18 page

Entanglement Entropy of Disjoint Regions in Excited States : An Operator Method

We develop the computational method of entanglement entropy based on the idea that $Tr\rho_{\Omega}^n$ is written as the expectation value of the local operator, where $\rho_{\Omega}$ is a density matrix of the subsystem $\Omega$. We apply it to consider the mutual Renyi information $I^{(n)}(A,B)=S^{(n)}_A+S^{(n)}_B-S^{(n)}_{A\cup B}$ of disjoint compact spatial regions $A$ and $B$ in the locally excited states defined by acting the local operators at $A$ and $B$ on the vacuum of a $(d+1)$-dimensional field theory, in the limit when the separation $r$ between $A$ and $B$ is much greater than their sizes $R_{A,B}$. For the general QFT which has a mass gap, we compute $I^{(n)}(A,B)$ explicitly and find that this result is interpreted in terms of an entangled state in quantum mechanics. For a free massless scalar field, we show that for some classes of excited states, $I^{(n)}(A,B)-I^{(n)}(A,B)|_{r \rightarrow \infty} =C^{(n)}_{AB}/r^{\alpha (d-1)}$ where $\alpha=1$ or 2 which is determined by the property of the local operators under the transformation $\phi \rightarrow -\phi$ and $\alpha=2$ for the vacuum state. We give a method to compute $C^{(2)}_{AB}$ systematically.Comment: 22 pages; v3, typos corrected, published versio

Half-magnetization plateau stabilized by structural distortion in the antiferromagnetic Heisenberg model on a pyrochlore lattice

Magnetization plateaus, visible as anomalies in magnetic susceptibility at low temperatures, are one of the hallmarks of frustrated magnetism. We show how an extremely robust half-magnetization plateau can arise from coupling between spin and lattice degrees of freedom in a pyrochlore antiferromagnet, and develop a detailed symmetry of analysis of the simplest possible scenario for such a plateau state. The application of this theory to the spinel oxides CdCr2O4 and HgCr2O4, where a robust half magnetization plateau has been observed, is discussed.Comment: 4 pages, 4 figure

A Quantum Perfect Lattice Action for Monopoles and Strings

A quantum perfect lattice action in four dimensions can be derived analytically as a renormalized trajectory when we perform a block spin transformation of monopole currents in a simple but non-trivial case of quadratic monopole interactions. The spectrum of the lattice theory is identical to that of the continuum theory. The perfect monopole action is transformed exactly into a lattice action of a string model. A perfect operator evaluating a static potential between electric charges is also derived explicitly. If the monopole interactions are weak as in the case of infrared SU(2) QCD, the string interactions become strong. The static potential and the string tension is estimated analytically by the use of the strong coupling expansion and the continuum rotational invariance is restored completely.Comment: 16 pages, 1 figure; to be published in Phys. Lett.

Monopole action and condensation in SU(2) QCD

An effective monopole action for various extended monopoles is derived from vacuum configurations after abelian projection in the maximally abelian gauge in $SU(2)$ QCD. The action appears to be independent of the lattice volume. Moreover it seems to depend only on the physical lattice spacing of the renormalized lattice, not on $\beta$. Entropy dominance over energy of monopole loops is seen on the renormalized lattice with the spacing $b>b_c\simeq 5.2\times10^{-3} \Lambda_L^{-1}$. This suggests that monopole condensation always (for all $\beta$) occurs in the infinite-volume limit of lattice QCD.Comment: 15 Pages+7 figures, KANAZAWA 94-1

Risks after Disasters: A Note on the Effects of Precautionary Saving on Equity Premiums

This paper studies the effects on equity premiums of grisks after disastersh, which are defined as a sharp rise in volatility of real per capita GDP growth rates immediately following disasters. This paper makes three contributions. First, we analytically demonstrate that if and only if the degree of relative prudence is higher than 2, risks after disasters decrease equity premiums. Second, we find that the differences between equity premiums with and without risks after disasters are quantitatively significant. Third, equity premiums are still higher in the case of disaster than without a disaster.

Risks after disasters: a note on the effects of precautionary saving on equity premiums

This paper studies the effects on equity premiums of Âgrisks after disastersÂh, which are defined as a sharp rise in volatility of real per capita GDP growth rates immediately following disasters. This paper makes three contributions. First, we analytically demonstrate that if and only if the degree of relative prudence is higher than 2, risks after disasters decrease equity premiums. Second, we find that the differences between equity premiums with and without risks after disasters are quantitatively significant. Third, equity premiums are still higher in the case of disaster than without a disaster.

A perfect monopole action for SU(2) QCD

We found a quantum perfect lattice action in the 4-dimensional monopole current theory which is known as an effective theory in the infrared region of QCD. The perfect monopole action is transformed exactly into a lattice action of a string model. When the monopole interactions are weak as in the case of infrared SU(2) QCD, the string interactions are strong. The static potential and the string tension in this region can be estimated analytically by the use of the strong coupling expansion.Comment: Lattice99:Confinement sessio