Quantum M-wave and black 0-brane

The effective action of superstring theory or M-theory is approximated by supergravity in the low energy limit, and quantum corrections to the supergravity are taken into account by including higher derivative terms. In this paper, we consider equations of motion with those higher derivative terms in M-theory and solve them to derive quantum M-wave solution. A quantum black 0-brane solution is also obtained by Kaluza-Klein dimensional reduction of the M-wave solution. The quantum black 0-brane is asymptotically flat and uniquely determined by imposing appropriate conditions. The mass and the R-R charge of the quantum black 0-brane are derived by using the ADM mass and the charge formulae, and we see that only the mass is affected by the quantum correction. Various limits of the quantum black 0-brane are also considered, and especially we show that an internal energy in the near horizon limit is correctly reproduced

Quantum near-horizon geometry of a black 0-brane

We investigate a bunch of D0-branes to reveal their quantum nature from the gravity side. In the classical limit, it is well described by a non-extremal black 0-brane in type IIA supergravity. The solution is uplifted to the eleven dimensions and expressed by a non-extremal M-wave solution. After reviewing the effective action for the M-theory, we explicitly solve the equations of motion for the near-horizon geometry of the M-wave. As a result, we derive a unique solution that includes the effect of the quantum gravity. The thermodynamic properties of the quantum near-horizon geometry of the black 0-brane are also studied by using Wald's entropy formula. Combining our result with that of the Monte Carlo simulation of the dual thermal gauge theory, we find strong evidence for the gauge/gravity duality in the D0-brane system at the level of quantum gravity

Boosted quantum black hole and black string in M-theory, and quantum correction to Gregory-Laflamme instability

We take into account higher derivative R 4 corrections in M-theory and construct quantum black hole and black string solutions in 11 dimensions up to the next leading order. The quantum black string is stretching along the 11th direction and the Gregory-Laflamme instability is examined at the quantum level. Thermodynamics of the boosted quantum black hole and black string are also discussed. Especially we take the near horizon limit of the quantum black string and investigate its instability quantitatively

Pion-induced reactions for charmed baryons

We study pion-induced binary reactions for charmed baryons where is a charmed baryon of ground or excited state. First we estimate charm production rates in comparison with strangeness production using a Regge model, which is dominated by vector ( or ) Reggeon exchange. Then we examine the production rates of various charmed baryons in a quark–diquark model. We find that the production of excited states is not necessarily suppressed, a sharp contrast to strangeness production, which is a unique feature of the charm production with a large momentum transfer

Comments on Takahashi-Tanimoto’s scalar solution

We study the identity-based solution of Witten’s cubic bosonic open string field theory constructed by Takahashi and Tanimoto, which is claimed to describe the tachyon vacuum. We argue that the observables of the solution coincide with those of the tachyon vacuum using the method proposed by Kishimoto and Takahashi. We also discuss how to treat the kinetic term of the string field theory expanded around it

Coherent flavour oscillation and CP violating parameter in thermal resonant leptogenesis

Solving the Kadanoff-Baym (KB) equations in a different method from our previous analysis, we obtain the CP violating parameter ε in the thermal resonant leptogenesis without assuming smallness of the off-diagonal Yukawa couplings. For that purpose, we first derive a kinetic equation for density matrix of RH neutrinos with almost degenerate masses M i ( i = 1 , 2) ~ M . If the deviation from thermal equilibrium is small, the differential equation is reduced to a linear algebraic equation and the density matrix can be solved explicitly in terms of the time variation of (local) equilibrium distribution function. The obtained (CP-violating parameter ε i is proportional to an enhancement factor ( M i 2  −  M j 2 ) M i Γ j /(( M i 2  −  M j 2 ) 2  +  R ij 2 ) with a regulator R ij = M (Γ i + Γ j ), consistent with the previous analysis. The decay width can be determined systematically by the 1PI self-energy of the RH neutrinos in the 2PI formalism

Noncommutative spacetime realized in Ad S n 1 space: Nonlocal field theory out of noncommutative spacetime

In $\kappa$ -Minkowski spacetime, the coordinates are Lie algebraic elements such that time and space coordinates do not commute, whereas space coordinates commute with each other. The noncommutativity is proportional to a Planck-length-scale constant $\kappa ^{-1}$ , which is a universal constant other than the velocity of light, under the $\kappa$ -Poincar transformation. In this sense, the spacetime has a structure called doubly special relativity. Such a noncommutative structure is known to be realized by $SO(1,4)$ generators in 4-dimensional de Sitter space. In this paper, we try to construct a noncommutative spacetime having a commutative $n$ -dimensional Minkowski spacetime based on $AdS_{n+1}$ space with $SO(2,n)$ symmetry. We also study an invariant wave equation corresponding to the first Casimir invariant of this symmetry as a nonlocal field equation expected to yield finite loop amplitudes

A renormalization group method for studying the early universe in the Lorentzian IIB matrix model

We propose a new method for studying the early universe in the Lorentzian version of the IIB matrix model, which is considered to be a nonperturbative formulation of superstring theory. This method is based on the idea of the renormalization group, and it enables us to study the time-evolution of the universe for a much longer time than in the [S.-W. Kim, J. Nishimura, and A. Tsuchiya, Phys. Rev. Lett. 108 , 011601 (2012)], which showed that the SO(9) rotational symmetry is spontaneously broken down to SO(3) after a critical time. We demonstrate how this method works in a simplified model, which is expected to capture the behaviors of the original model when the space is not so large. In particular, we present clear evidence that the 3D space expands exponentially after the critical time in this simplified model

Elliptic inflation: interpolating from natural inflation to R 2 -inflation

We propose an extension of natural inflation, where the inflaton potential is a general periodic function. Specifically, we study elliptic inflation where the inflaton potential is given by Jacobi elliptic functions, Jacobi theta functions or the Dedekind eta function, which appear in gauge and Yukawa couplings in the string theories compactified on toroidal backgrounds. We show that in the first two cases the predicted values of the spectral index and the tensor-to-scalar ratio interpolate from natural inflation to exponential inflation such as R 2 - and Higgs inflation and brane inflation, where the spectral index asymptotes to n s = 1 − 2 /N ≃ 0 . 967 for the e-folding number N = 60. We also show that a model with the Dedekind eta function gives a sizable running of the spectral index due to modulations in the inflaton potential. Such elliptic inflation can be thought of as a specific realization of multi-natural inflation, where the inflaton potential consists of multiple sinusoidal functions. We also discuss examples in string theory where Jacobi theta functions and the Dedekind eta function appear in the inflaton potential

Non-geometric backgrounds based on topological interfaces

We study simple models of the world-sheet CFTs describing non-geometric backgrounds based on the topological interfaces, the ‘gluing condition’ of which imposes T-duality- or analogous twists. To be more specific, we start with the torus partition function on a target space S 1 [base] × ( S 1 × S 1 )[fiber] with rather general values of radii. The fiber CFT is defined by inserting the twist operators consisting of the topological interfaces which lie along the cycles of the world-sheet torus according to the winding numbers of the base circle. We construct the partition functions involving such duality twists. The modular invariance is achieved straightforwardly, whereas ‘unitarization’ is generically necessary to maintain the unitarity. We demonstrate it in the case of the equal fiber radii. The resultant models are closely related to the CFTs with the discrete torsion. The unitarization is also physically interpreted as multiple insertions of the twist/interface operators along various directions