The one-dimensional Bose gas is an unusual superfluid. In contrast to higher spatial dimensions, the existence of non-classical rotational inertia is not directly linked to the dissipationless motion of infinitesimal ...The one-dimensional Bose gas is an unusual superfluid. In contrast to higher spatial dimensions, the existence of non-classical rotational inertia is not directly linked to the dissipationless motion of infinitesimal impurities. Recently, experimental tests with ultracold atoms have begun and quanti- tative predictions for the drag force experienced by moving obstacles have become available. This topical review discusses the drag force obtained from linear response theory in relation to Lan- dau＇s criterion of superfluidity. Based upon improved analytical and numerical understanding of the dynamical structure factor, results for different obstacle potentials are obtained, including single impurities, optical lattices and random potentials generated from speckle patterns. The dynamical breakdown of superfluidity in random potentials is discussed in relation to Anderson localization and the predicted superfluid-insulator transition in these systems.展开更多
Resorcinol/formaldehyde(RF)foam resin is an attractive material as a low-density target in high-power laser–plasma experiments because of its fine network structure,transparency in the visible region,and low-Z elemen...Resorcinol/formaldehyde(RF)foam resin is an attractive material as a low-density target in high-power laser–plasma experiments because of its fine network structure,transparency in the visible region,and low-Z element(hydrogen,carbon,and oxygen)composition.In this study,we developed disk-shaped RF foam and deuterated RF foam targets with 40–200μm thickness and approximately 100 mg/cm^(3) density having a network structure from 100 nm to a few micrometers cell size.By deuteration,the polymerization rate was drastically slowed down owing to kinetic isotope effects.These targets were used in high-power laser experiments where a megaelectronvolt proton beam was successfully generated.展开更多
文摘The one-dimensional Bose gas is an unusual superfluid. In contrast to higher spatial dimensions, the existence of non-classical rotational inertia is not directly linked to the dissipationless motion of infinitesimal impurities. Recently, experimental tests with ultracold atoms have begun and quanti- tative predictions for the drag force experienced by moving obstacles have become available. This topical review discusses the drag force obtained from linear response theory in relation to Lan- dau＇s criterion of superfluidity. Based upon improved analytical and numerical understanding of the dynamical structure factor, results for different obstacle potentials are obtained, including single impurities, optical lattices and random potentials generated from speckle patterns. The dynamical breakdown of superfluidity in random potentials is discussed in relation to Anderson localization and the predicted superfluid-insulator transition in these systems.
基金the Collaboration Research Program between the National Institute for Fusion Science and the Institute of Laser Engineering at Osaka University(NIFS12KUGK057).
文摘Resorcinol/formaldehyde(RF)foam resin is an attractive material as a low-density target in high-power laser–plasma experiments because of its fine network structure,transparency in the visible region,and low-Z element(hydrogen,carbon,and oxygen)composition.In this study,we developed disk-shaped RF foam and deuterated RF foam targets with 40–200μm thickness and approximately 100 mg/cm^(3) density having a network structure from 100 nm to a few micrometers cell size.By deuteration,the polymerization rate was drastically slowed down owing to kinetic isotope effects.These targets were used in high-power laser experiments where a megaelectronvolt proton beam was successfully generated.
