8787975
Out of equilibrium temperature from holography
Introduction — Unlike equilibrium systems, which are under powerful constraints of thermodynamics, only few general properties are known for systems driven far out of equilibrium. In this paper, we use the holographic principle to define an effective temperature for a class of nonequilibrium steady states and study its properties. We consider branes driven by external energy sources and put them in a heat bath. The heat bath is represented by a bulk geometry with an event horizon. The Hawking temperature at the horizon is identified as the temperature T of the heat bath. Before we turn on the external energy sources, temperature on the brane is the same as that of the bulk. Holographically, this can be seen by the fact that the induced metric on the brane has an event horizon with the same Hawking temperature T.
119110586
Effective temperature of nonequilibrium dense matter in holography
We study properties of effective temperature of non-equilibrium steady states by using the anti-de Sitter spacetime/conformal field theory (AdS/CFT) correspondence. We consider non-equilibrium systems with a constant flow of current along an electric field, in which the current is carried by both the doped charges and those pair created by the electric field. We find that the effective temperature agrees with that of the Langevin systems if we take the limit where the pair creation is negligible. The effect of pair creation raises the effective temperature whereas the current by the doped charges contributes to lower the effective temperature in a wide range of the holographic models.
15165421
Descent relation of tachyon condensation from boundary string field theory
We analyze how lower-dimensional bosonic D-branes further decay, using the boundary string field theory. Especially we find that the effective tachyon potential of the lower-dimensional D-brane has the same profile as that of D25-brane.
17332770
Notes on the S-matrix of bosonic and topological non-critical strings
We show that the equivalence between the c = 1 non-critical bosonic string and the = 2 topologically twisted coset SL(2)/U(1) at level one can be checked very naturally on the level of tree-level scattering amplitudes with the use of the Stoyanovsky-Ribault-Teschner map, which recasts H3+ correlation functions in terms of Liouville field theory amplitudes. This observation can be applied equally well to the topologically twisted SL(2)n/U(1) coset with n > 1, which has been argued recently to be equivalent with a c < 1 non-critical bosonic string whose matter part is defined by a time-like linear dilaton CFT.
59125293
Negative Differential Resistivity from Holography
Negative differential resistivity (NDR) in a (3+1)-dimensional quantum system of strongly correlated charge carriers is theoretically reproduced by using the AdS/CFT correspondence. Our system is microscopically defined, and the analysis does not rely on any phenomenological models of NDR mechanism. The interaction between the heat reservoir and the nonequilibrium charge carriers is also taken into account. The system realizes insulation due to the formation of the neutral bound states of the charge carriers at low temperatures. However, the insulation is broken and the field-induced conductor phase appears by applying the external electric field greater than the critical value. We find that the NDR appears right above the critical electric field in this phase, and the pair creation of the charge carriers is crucial to realize the NDR. The present result suggests a possibility to observe a similar NDR in excitonic insulators or in the strongly interacting quark-gluon plasma, where the insulation originates in the formation of the neutral bound states. Subject Index: 121, 231, 346, 356
31657279
Gravity dual of spatially modulated phase
We show that the five-dimensional Maxwell theory with the Chern-Simons term is tachyonic in the presence of a constant electric field. When coupled to gravity, a sufficiently large Chern-Simons coupling causes instability of the Reissner-Nordstrom black holes in anti-de Sitter space. The instability happens only at nonvanishing momenta, suggesting a spatially modulated phase in the holographically dual quantum field theory in (3+1) dimensions, with spontaneous current generation in a helical configuration. The three-charge extremal black hole in the type IIB superstring theory on AdS_5×S^5 barely satisfies the stability condition.
15481553
Bridging p-wave {pi} production and weak processes in few-nucleon systems with chiral perturbation theory
I study an aspect of chiral perturbation theory ({chi}PT) that enables one to 'bridge' different reactions. That is, an operator fixed in one of the reactions can then be used to predict the other. For this purpose, I calculate the partial-wave amplitude for the p-wave pion production (pp{yields}pn{pi}{sup +}) using the pion production operator from the lowest and the next nonvanishing orders. The operator includes a contact operator whose coupling has been fixed using a matrix element of a low-energy weak process (pp{yields}de{sup +}{nu}{sub e}). I find that this operator does not reproduce the partial-wave amplitude extracted from experimental data, showing that the bridging over the reactions with significantly different kinematics is not necessarily successful. I study the dependence of the amplitude on the various inputs such as the NN potential, the {pi}N{delta} coupling, and the cutoff. I argue the importance of a higher-order calculation. To gain an insight into a higher-order calculation, I add a higher-order counter term to the operator used above and fit the couplings to both the low-energy weak process and the pion production. The energy dependence of the partial-wave amplitude for the pion production is described by the operator consistently with the data. However, Imore » find a result that tells us to be careful about the convergence of the chiral expansion for the pp{yields}pn{pi}{sup +} reaction.« less
85451103
Extraction of Meson Resonances from Three-pions Photo-production Reactions
We have investigated the model dependence of meson resonance properties extracted from the Dalitz-plot analysis of the three-pions photoproduction reactions on the nucleon. Within a unitary model developed in Phys. Rev. D 84, 114019 (2011), we generate Dalitz-plot distributions as data to perform an isobar model fit that is similar to most of the previous analyses of three-pion production reactions. It is found that the resonance positions from the two models agree well when both fit the data accurately, except for the resonance poles near branch points. The residues of the resonant amplitudes extracted from the two models and by the usual Breit-Wigner procedure agree well only for the isolated resonances with narrow widths. For overlapping resonances, most of the extracted residues could be drastically different. Our results suggest that even with high precision data, the resonance extraction should be based on models within which the amplitude parametrization is constrained by three-particle unitarity condition.
1110514
Renormalization group analysis of nuclear force
We study a relation between nuclear forces based on phenomenological approach ( V ph ) and nuclear effective field theory ( V EFT ) from a viewpoint of renormalization group. We find the relation between these two types of nuclear force using Wilsonian renormalization group equation. Considering the fact that V EFT is defined in a certain small model space, we show that a simple contact interaction accurately simulates short-distance physics, and that V EFT is free from dependence on modelling the details of the short-distance physics. Based on our result, we discuss some features of nuclear effective field theory.
119279739
Charged-current and neutral-current coherent pion productions — Theoretical status
The CC and NC coherent pion productions have been studied with PCAC-based models and microscopic models. Current status of the theoretical studies is reviewed.
117947270
Meson spectroscopy with unitary coupled-channels model for heavy-meson decay into three mesons
We develop a model for describing excited mesons decay into three mesons. The properties of the excited mesons can be extracted with this model. The model maintains the three-body unitarity that has been missed in previous data analyses based on the conventional isobar models. We study an importance of the three-body unitarity in extracting hadron properties from data. For this purpose, we use the unitary and isobar models to analyze the same pseudo data of gamma p -> pi+pi+pi-n, and extract the properties of excited mesons. We find a significant difference between the unitary and isobar models in the extracted properties of excited mesons, such as the mass, width and coupling strength to decay channels.