Bose-Einstein condensate in gases of rare atomic species

We report on the successful extension of production of Bose-Einstein Condensate (BEC) to rare species. Despite its low natural abundance of 0.13%, $^{168}$Yb is directly evaporatively cooled down to BEC. Our successful demonstration encourages attempts to obtain quantum gases of radioactive atoms, which extends the possibility of quantum many-body physics and precision measurement. Moreover, a stable binary mixture of $^{168}$Yb BEC and $^{174}$Yb BEC is successfully formed.Comment: 5 pages, 3 figures. Accepted for Phys. Rev.

Realization of SU(2)*SU(6) Fermi System

We report the realization of a novel degenerate Fermi mixture with an SU(2)*SU(6) symmetry in a cold atomic gas. We successfully cool the mixture of the two fermionic isotopes of ytterbium 171Yb with the nuclear spin I=1/2 and 173Yb with I=5/2 below the Fermi temperature T_ F as 0.46T_F for 171Yb and 0.54T_F for 173Yb. The same scattering lengths for different spin components make this mixture featured with the novel SU(2)*SU(6) symmetry. The nuclear spin components are separately imaged by exploiting an optical Stern-Gerlach effect. In addition, the mixture is loaded into a 3D optical lattice to implement the SU(2)*SU(6) Hubbard model. This mixture will open the door to the study of novel quantum phases such as a spinor Bardeen-Cooper-Schrieffer-like fermionic superfluid.Comment: 4 pages, 5 figures V2: revised reference

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

An SU(N) Mott insulator of an atomic Fermi gas realized by large-spin Pomeranchuk cooling

The Hubbard model, containing only the minimum ingredients of nearest neighbor hopping and on-site interaction for correlated electrons, has succeeded in accounting for diverse phenomena observed in solid-state materials. One of the interesting extensions is to enlarge its spin symmetry to SU(N>2), which is closely related to systems with orbital degeneracy. Here we report a successful formation of the SU(6) symmetric Mott insulator state with an atomic Fermi gas of ytterbium (173Yb) in a three-dimensional optical lattice. Besides the suppression of compressibility and the existence of charge excitation gap which characterize a Mott insulating phase, we reveal an important difference between the cases of SU(6) and SU(2) in the achievable temperature as the consequence of different entropy carried by an isolated spin. This is analogous to Pomeranchuk cooling in solid 3He and will be helpful for investigating exotic quantum phases of SU(N) Hubbard system at extremely low temperatures.Comment: 20 pages, 6 figures, to appear in Nature Physic

Recent Results from LHD Experiment with Emphasis on Relation to Theory from Experimentalist’s View

he Large Helical Device (LHD) has been extending an operational regime of net-current free plasmas towardsthe fusion relevant condition with taking advantage of a net current-free heliotron concept and employing a superconducting coil system. Heating capability has exceeded 10 MW and the central ion and electron temperatureshave reached 7 and 10 keV, respectively. The maximum value of β and pulse length have been extended to 3.2% and 150 s, respectively. Many encouraging physical findings have been obtained. Topics from recent experiments, which should be emphasized from the aspect of theoretical approaches, are reviewed. Those are (1) Prominent features in the inward shifted configuration, i.e., mitigation of an ideal interchange mode in the configuration with magnetic hill, and confinement improvement due to suppression of both anomalous and neoclassical transport, (2) Demonstration ofbifurcation of radial electric field and associated formation of an internal transport barrier, and (3) Dynamics of magnetic islands and clarification of the role of separatrix

Anesthetic Management of a Surgical Patient with Chronic Renal Tubular Acidosis Complicated by Subclinical Hypothyroidism

A 53-year-old man with chronic renal tubular acidosis and subclinical hypothyroidism underwent lower leg amputation surgery under general anesthesia. Perioperative acid-base management in such patients poses many difficulties because both pathophysiologies have the potential to complicate the interpretation of capnometry and arterial blood gas analysis data; inappropriate correction of chronic metabolic acidosis may lead to postoperative respiratory deterioration. We discuss the management of perioperative acidosis in order to achieve successful weaning from mechanical ventilation and promise a complete recovery from anesthesia