Momentum space conformal three-point functions of conserved currents and a general spinning operator

We construct conformal three-point functions in momentum space with a general tensor and conserved currents of spin $1$ and $2$. While conformal correlators in momentum space have been studied especially in the connection with cosmology, correlators involving a tensor of general spin and scaling dimension have not been studied very much yet. Such a direction is unavoidable when we go beyond three-point functions because general tensors always appear as an intermediate state. In this paper, as a first step, we solve the Ward-Takahashi identities for correlators of a general tensor and conserved currents. In particular we provide their expression in terms of the so-called triple-$K$ integrals and a differential operator which relates triple-$K$ integrals with different indices. For several correlators, closed forms without the differential operator are also found.Comment: 24+16 page

String Regge trajectory on de Sitter space and implications to inflation

We study the spectrum of semiclassical rotating strings on de Sitter space and its consistency. Even though a naive extrapolation of the linear Regge trajectory on flat space implies a violation of the Higuchi bound (a unitarity bound on the mass of higher-spin particles in de Sitter space), the curved space effects turn out to modify the trajectory to respect the bound. Interestingly, there exists a maximum spin for each Regge trajectory as a consequence of accelerated expansion, which is helpful to make the spectrum consistent with the Higuchi bound, but at the same time it could be an obstruction to stringy UV completion based on an infinite higher-spin tower. By pushing further this observation, we demonstrate that the vacuum energy $V$ inflating the universe has to be bounded by the string scale $M_s$ as $V\lesssim M_s^4$, if UV completion is achieved by the leading Regge trajectory with higher spin states up to the 4D Planck scale. Its application to inflation at the early universe implies an upper bound on the tensor-to-scalar ratio, $r\lesssim 0.01\times(M_s/10^{16} \text{GeV})^{4}$, which is within the scope of the near future CMB experiments. We also discuss another possibility that UV completion is achieved by multiple Regge trajectories.Comment: 6 pages, 5 figures; v2: minor revisions, references adde

Successful Treatment of Long-Term Severe Progressive Interstitial Pneumonia with Low-Dose Corticosteroid and Azathioprine in a Patient with Diffuse Systemic Sclerosis

For progressive interstitial pneumonia (progressive IP) that accompanies diffuse systemic sclerosis (diffuse SSc), no treatment guidelines have yet been established, and it is a complication with a poor prognosis. We herein report a case in which combination therapy of a low-dose corticosteroid and low-dose azathioprine was performed for progressive SSc-IP in a 64-year-old female whose respiratory function was severely damaged for a long period of time and for whom improvement was achieved. The beneficial effect has continued for 3 years with no side effects being observed during the course

Simulation study on cascaded terahertz pulse generation in electro-optic crystals

We studied cascaded optical rectification processes for intenseterahertz (THz) pulse generation in electro-optic crystals using simulationsbased on one-dimensional coupled propagation equations of THz and opticalfields. We found that under ideal conditions of perfect phase matching andno absorption, cascaded optical rectification processes produce intense THzpulses with efficiencies exceeding the Manley-Rowe limit. Large red shiftingof the pump light spectrum was observed. Effects of finite optical andTHz absorption, phase mismatches, and pulse width were examined usingparameters of a ZnTe crystal pumped by 800 nm pulses. THz field enhancementby multiple pulse pumping was also studied

Lubrication pressure model in a non-negligible gap for fluid permeation through a membrane with finite permeability

Shintaro Takeuchi, Toshiaki Fukada, Shuji Yamada, Suguru Miyauchi, and Takeo Kajishima, "Lubrication pressure model in a non-negligible gap for fluid permeation through a membrane with finite permeability", Physical Review Fluids, 6(11), 114101, https://doi.org/10.1103/PhysRevFluids.6.114101