Interaction and filling induced quantum phases of dual Mott insulators of bosons and fermions

Many-body effects are at the very heart of diverse phenomena found in condensed-matter physics. One striking example is the Mott insulator phase where conductivity is suppressed as a result of a strong repulsive interaction. Advances in cold atom physics have led to the realization of the Mott insulating phases of atoms in an optical lattice, mimicking the corresponding condensed matter systems. Here, we explore an exotic strongly-correlated system of Interacting Dual Mott Insulators of bosons and fermions. We reveal that an inter-species interaction between bosons and fermions drastically modifies each Mott insulator, causing effects that include melting, generation of composite particles, an anti-correlated phase, and complete phase-separation. Comparisons between the experimental results and numerical simulations indicate intrinsic adiabatic heating and cooling for the attractively and repulsively interacting dual Mott Insulators, respectively

Thermal Infrared Imaging Experiments of C-Type Asteroid 162173 Ryugu on Hayabusa2

The thermal infrared imager TIR onboard Hayabusa2 has been developed to investigate thermo-physical properties of C-type, near-Earth asteroid 162173 Ryugu. TIR is one of the remote science instruments on Hayabusa2 designed to understand the nature of a volatile-rich solar system small body, but it also has significant mission objectives to provide information on surface physical properties and conditions for sampling site selection as well as the assessment of safe landing operations. TIR is based on a two-dimensional uncooled micro-bolometer array inherited from the Longwave Infrared Camera LIR on Akatsuki (Fukuhara et al., 2011). TIR takes images of thermal infrared emission in 8 to 12 μm with a field of view of 16×12∘ and a spatial resolution of 0.05∘ per pixel. TIR covers the temperature range from 150 to 460 K, including the well calibrated range from 230 to 420 K. Temperature accuracy is within 2 K or better for summed images, and the relative accuracy or noise equivalent temperature difference (NETD) at each of pixels is 0.4 K or lower for the well-calibrated temperature range. TIR takes a couple of images with shutter open and closed, the corresponding dark frame, and provides a true thermal image by dark frame subtraction. Data processing involves summation of multiple images, image processing including the StarPixel compression (Hihara et al., 2014), and transfer to the data recorder in the spacecraft digital electronics (DE). We report the scientific and mission objectives of TIR, the requirements and constraints for the instrument specifications, the designed instrumentation and the pre-flight and in-flight performances of TIR, as well as its observation plan during the Hayabusa2 mission

Highly porous nature of a primitive asteroid revealed by thermal imaging

Carbonaceous (C-type) asteroids are relics of the early Solar System that have preserved primitive materials since their formation approximately 4.6 billion years ago. They are probably analogues of carbonaceous chondrites and are essential for understanding planetary formation processes. However, their physical properties remain poorly known because carbonaceous chondrite meteoroids tend not to survive entry to Earth’s atmosphere. Here we report on global one-rotation thermographic images of the C-type asteroid 162173 Ryugu, taken by the thermal infrared imager (TIR) onboard the spacecraft Hayabusa2, indicating that the asteroid’s boulders and their surroundings have similar temperatures, with a derived thermal inertia of about 300 J m−2 s−0.5 K−1 (300 tiu). Contrary to predictions that the surface consists of regolith and dense boulders, this low thermal inertia suggests that the boulders are more porous than typical carbonaceous chondrites and that their surroundings are covered with porous fragments more than 10 centimetres in diameter. Close-up thermal images confirm the presence of such porous fragments and the flat diurnal temperature profiles suggest a strong surface roughness effect. We also observed in the close-up thermal images boulders that are colder during the day, with thermal inertia exceeding 600 tiu, corresponding to dense boulders similar to typical carbonaceous chondrites. These results constrain the formation history of Ryugu: the asteroid must be a rubble pile formed from impact fragments of a parent body with microporosity of approximately 30 to 50 per cent that experienced a low degree of consolidation. The dense boulders might have originated from the consolidated innermost region or they may have an exogenic origin. This high-porosity asteroid may link cosmic fluffy dust to dense celestial bodies.Additional co-authors: Tsuneo Matsunaga, Takeshi Imamura, Takehiko Wada, Sunao Hasegawa, Jörn Helbert, Thomas G. Müller, Jens Biele, Matthias Grott, Maximilian Hamm, Marco Delbo, Naru Hirata, Naoyuki Hirata, Yukio Yamamoto, Seiji Sugita, Noriyuki Namiki, Kohei Kitazato, Masahiko Arakawa, Shogo Tachibana, Hitoshi Ikeda, Masateru Ishiguro, Koji Wada, Chikatoshi Honda, Rie Honda, Yoshiaki Ishihara, Koji Matsumoto, Moe Matsuoka, Tatsuhiro Michikami, Akira Miura, Tomokatsu Morota, Hirotomo Noda, Rina Noguchi, Kazunori Ogawa, Kei Shirai, Eri Tatsumi, Hikaru Yabuta, Yasuhiro Yokota, Manabu Yamada, Masanao Abe, Masahiko Hayakawa, Takahiro Iwata, Masanobu Ozaki, Hajime Yano, Satoshi Hosoda, Osamu Mori, Hirotaka Sawada, Takanobu Shimada, Hiroshi Takeuchi, Ryudo Tsukizaki, Atsushi Fujii, Chikako Hirose, Shota Kikuchi, Yuya Mimasu, Naoko Ogawa, Go Ono, Tadateru Takahashi, Yuto Takei, Tomohiro Yamaguchi, Kent Yoshikawa, Fuyuto Terui, Takanao Saiki, Satoru Nakazawa, Makoto Yoshikawa, Seiichiro Watanabe & Yuichi Tsud

Authentic role of ATP signaling in micturition reflex

Adenosine triphosphate (ATP) is a signaling molecule that regulates cellular processes. Based on previous studies of bladder function over the past decade, bladder ATP signaling was thought to have an essential role in the normal micturition reflex. In this study, we performed detailed analyses of bladder function in purinergic receptor-deficient mice using the automated voided stain on paper method and video-urodynamics. Unexpectedly, a lack of P2X2 or P2X3 receptors did not affect bladder function under normal physiological conditions, indicating that bladder ATP signaling is not essential for normal micturition reflex. In contrast, we found that lipopolysaccharide (LPS) induced markedly high levels of ATP release from the urothelium. In addition, LPS-induced rapid bladder hyperactivity was attenuated in P2X2 -/- and P2X3 -/- mice. Contrary to the previous interpretation, our present findings indicate that bladder ATP signaling has a fundamental role in the micturition reflex, especially in bladder dysfunction, under pathological conditions. Therefore, the bladder ATP signaling pathway might be a highly promising therapeutic target for functional bladder disorders. This study newly defines an authentic role for bladder ATP signaling in the micturition reflex

Thermal inertia of asteroid Ryugu using dawn-side thermal images by TIR on Hayabusa2

A thermal inertia map of the C-type Near-Earth asteroid 162173 Ryugu has been derived using the one-rotation global thermal image sets observed from the Home Position at 20 km altitude [1]. This time the thermal images of the night side areas of the surface just before sunrise were taken during observations from the dawn side. The coldest brightness temperature of the surface indicates another information on the thermal inertia of the surface. The thermal inertia is preliminary estimated at 250 [J m-2K-1s-0.5] or lower, which is consistent with other than those derived from the daytime observations [2]