Topological phase separation in 2D quantum lattice Bose-Hubbard system away from half-filling

We suppose that the doping of the 2D hard-core boson system away from half-filling may result in the formation of multi-center topological inhomogeneity (defect) such as charge order (CO) bubble domain(s) with Bose superfluid (BS) and extra bosons both localized in domain wall(s), or a {\it topological} CO+BS {\it phase separation}, rather than an uniform mixed CO+BS supersolid phase. Starting from the classical model we predict the properties of the respective quantum system. The long-wavelength behavior of the system is believed to remind that of granular superconductors, CDW materials, Wigner crystals, and multi-skyrmion system akin in a quantum Hall ferromagnetic state of a 2D electron gas. To elucidate the role played by quantum effects and that of the lattice discreteness we have addressed the simplest nanoscopic counterpart of the bubble domain in a checkerboard CO phase of 2D hc-BH square lattice. It is shown that the relative magnitude and symmetry of multi-component order parameter are mainly determined by the sign of the $nn$ and $nnn$ transfer integrals. In general, the topologically inhomogeneous phase of the hc-BH system away from the half-filling can exhibit the signatures both of $s,d$, and $p$ symmetry of the off-diagonal order.Comment: 12 pages, 6 figure

Pulmonary Rehabilitation in Patients with Idiopathic Pulmonary Fibrosis - A Review

Among the various types of interstitial lung diseases, idiopathicpulmonary fibrosis (IPF) is the most common disorder and has a poorprognosis and a limited response to pharmacological treatment. Inpatients with IPF, functional exercise tolerance and quality of lifehave been shown to be significantly decreased. Current IPF guidelinessuggest only a weak recommendation for pulmonary rehabilitation (PR).However, PR is regarded as a reasonable choice for the majority ofpatients with IPF. This review will summarize all of the availablestudies that have investigated the effects of PR in patients with IPF sofar. Although only a small number of studies have been published todate, most studies have found significant short-term improvements infunctional exercise capacity, quality of life, and level of perceiveddyspnea. Long-term improvements or maintenance strategies of PR in IPFpatients have not been adequately investigated yet. Up to now there isstill no sufficient evidence for the recommendation of PR in IPF.However, physical training seems to be the major component of all PRprograms. The current review will discuss potential exercise trainingregimens for patients with IPF and suggest additional useful modalitiesof a specific multidisciplinary PR program for IPF patients. Based onthe current literature and our own experience, this article will try tohighlight the importance of PR as an additional, beneficial therapeuticoption for patients with IPF

Chiral and herringbone symmetry breaking in water-surface monolayers

We report the observation from monolayers of eicosanoic acid in the L′2 phase of three distinct out-of-plane first-order diffraction peaks, indicating molecular tilt in a nonsymmetry direction and hence the absence of mirror symmetry. At lower pressures the molecules tilt in the direction of their nearest neighbors. In this region we find a structural transition, which we tentatively identify as the rotator-herringbone transition L2d−L2h

Pulmonary rehabilitation in patients with mustard gas lung disease: a study protocol for a randomized controlled trial

Background More than 60,000 people have health problems due to chemical weapons exposure during the Iran–Iraq war. Respiratory consequences of mustard gas exposure are common and disabling; medical interventions have limited effect. Patients complain of cough, sputum, breathlessness and exercise limitation. We hypothesized that patients with this condition would benefit from pulmonary rehabilitation. Methods We outline the protocol for an assessor-blind, two-armed, parallel-design randomized controlled clinical trial (IRCT2016051127848N1). Sixty patients with respiratory disease due to documented sulfur mustard gas exposure will be randomized to either take part in a 6-week pulmonary rehabilitation programme or receive usual care. Inclusion criteria include forced expiratory volume in 1 second < 80% predicted and Medical Research Council dyspnoea score ≥ 3. The primary endpoint will be the change in cycle endurance time at 70% baseline exercise capacity at 6 weeks. Lung function, physical activity, the strength and endurance of the quadriceps muscle, and quality of life will also be compared. Outcomes will be assessed at 6 weeks and 12 months. Health care utilization will also be assessed. Discussion If the study confirms that rehabilitation is effective for patients with mustard gas lung disease this should prompt provision of the intervention to this patient group

Mechanism of carrier-induced ferromagnetism in magnetic semiconductors

Taking into account both random impurity distribution and thermal fluctuations of localized spins, we have performed a model calculation for the carrier (hole) state in Ga$_{1-x}$Mn$_x$As by using the coherent potential approximation (CPA). The result reveals that a {\it p}-hole in the band tail of Ga$_{1-x}$Mn$_x$As is not like a free carrier but is rather virtually bounded to impurity sites. The carrier spin strongly couples to the localized {\it d} spins on Mn ions. The hopping of the carrier among Mn sites causes the ferromagnetic ordering of the localized spins through the double-exchange mechanism. The Curie temperature obtained by using conventional parameters agrees well with the experimental result.Comment: 7 pages, 4 figure

Ferromagnetism in the Hubbard model with orbital degeneracy in infinite dimensions

We study the ferromagnetism due to orbital degeneracy in the Hubbard model in infinite dimensions. The model contains the intraorbital repulsion $U$, the interorbital repulsion $U^\prime$, the exchange $J$ (Hund coupling) and the pair hopping $J^\prime$, where all of them originate from the on-site Coulomb interaction. The ground state of the effective one-site problem was obtained by exact diagonalizations. At the 1/4-filling, we found two insulating phases; one is a ferromagnetic phase with alternating orbital order and the other is antiferromagnetic one with uniform orbital order. If electrons are doped into the 1/4-filling, the ferromagnetic phase still survives and becomes metallic, while the antiferromagnetic phase disappears. This result indicates that the double-exchange mechanism is relevant to stabilize metallic ferromagnetism in infinite dimensions.Comment: 4 pages, Revtex, 3 figures, corrected some typos and references, to be published in Phys. Rev. B (Rapid Communication

First measurement and shell model interpretation of the g factor of the 21+ state in self-conjugate radioactive 44Ti

AbstractThe g factor of the 21+ state in radioactive 44Ti has been measured for the first time with the technique of α transfer to 40Ca beams in inverse kinematics in combination with transient magnetic fields, yielding the value, g(21+)=+0.52(15). In addition, the lifetimes of the 21+, τ=3.97(28) ps, and the 41+ states, τ=0.65(6) ps, were redetermined with higher precision using the Doppler shift attenuation method. The deduced B(E2)'s and the g factor were well explained by a full fp shell model calculation using the FPD6 effective NN interaction. The g factor can also be accounted for by a simple rotational model (g=Z/A). However, if one also considers the B(E2)'s and the E(41+)/E(21+) ratios, then an imperfect vibrator picture gives better agreement with the data

Magnetization plateau in a two-dimensional multiple-spin exchange model

We study a multiple-spin exchange model on a triangular lattice, which is a possible model for low-density solid 3He films. Due to strong competitions between ferromagnetic three-spin exchange and antiferromagnetic four-spin one, the ground states are highly degenerate in the classical limit. At least 2^{L/2}-fold degeneracy exists on the L*L triangular lattice except for the SO(3) symmetry. In the magnetization process, we found a plateau at m/m_{sat}=1/2, in which the ground state is "uuud state" (a collinear state with four sublattices). The 1/2-plateau appears due to the strong four-spin exchange interaction. This plateau survives against both quantum and thermal fluctuations. Under a magnetic field which realizes the "uuud" ordered state, a phase transition occurs at a finite temperature. We predict that low-density solid 3He thin films may show the 1/2-plateau in the magnetization process. Experimental observation of the plateau will verify strength of the four-spin exchange. It is also discussed that this magnetization plateau can be understood as an insulating-conducting transition in a particle picture.Comment: 10 pages, RevTeX, 12 figures, added a reference and corrected typos, to be published in Phys.Rev.B (01 APR 99

Ferromagnetism in the one-dimensional Hubbard model with orbital degeneracy: From low to high electron density

We studied ferromagnetism in the one-dimensional Hubbard model with doubly degenerate atomic orbitals by means of the density-matrix renormalization-group method and obtained the ground-state phase diagrams. It was found that ferromagnetism is stable from low to high (0< n < 1.75) electron density when the interactions are sufficiently strong. Quasi-long-range order of triplet superconductivity coexists with the ferromagnetic order for a strong Hund coupling region, where the inter-orbital interaction U'-J is attractive. At quarter-filling (n=1), the insulating ferromagnetic state appears accompanying orbital quasi-long-range order. For low densities (n<1), ferromagnetism occurs owing to the ferromagnetic exchange interaction caused by virtual hoppings of electrons, the same as in the quarter-filled system. This comes from separation of the charge and spin-orbital degrees of freedom in the strong coupling limit. This ferromagnetism is fragile against variation of band structure. For high densities (n>1), the phase diagram of the ferromagnetic phase is similar to that obtained in infinite dimensions. In this case, the double exchange mechanism is operative to stabilize the ferromagnetic order and this long-range order is robust against variation of the band-dispersion. A partially polarized state appears in the density region 1.68<n<1.75 and phase separation occurs for n just below the half-filling (n=2).Comment: 16 pages, 16 figures, final version, references adde