Sarma Phase in Trapped Unbalanced Fermi Gases

We consider a trapped unbalanced Fermi gas at nonzero temperatures where the superfluid Sarma phase is stable. We determine in particular the phase boundaries between the superfluid, normal, and phase separated regions of the trapped unbalanced Fermi mixture. We show that the physics of the Sarma phase is sufficient to understand the recent observations of Zwierlein et al. [Science 311, 492 (2006); Nature 442, 54 (2006)] and indicate how the apparent contradictions between this experiment and the experiment of Partridge et al. [Science 311, 503 (2006)] may be resolved.Comment: Replaced with published version; 4 pages, 3 figure

Beetle eater beheerst de aspergekever bij de oogst van groene asperges in 2010

In Canada is een grote stofzuiger die voor of achter een tractor bevestigd kan worden “Beetle Eater” genaamd, gebruikt ter bestrijding van de coloradokever in aardappelen. Biologische telers hebben zo’n apparaat gekocht om hem in te zetten ter bestrijding van de wortelvlieg in peen. De resultaten vielen tegen en het apparaat is na twee jaar experimenteren niet meer gebruikt. In 2010 is de machine getest in groene asperges tegen de aspergekever op een gangbaar bedrijf in Noord - Brabant. Omdat groene asperges bij gunstige weersomstandigheden dagelijks geoogst worden, is het lastig om tegen dit insect gewasbeschermingsmiddelen in te zetten vanwege de veiligheidstermijn. Door de Beetle eater 1 of 2 keer (direct na elkaar) in te zetten worden de aspergekevers met 50 of 74% gereduceerd. De asperge oogsters merkten meteen wanneer de machine was ingezet omdat het aantal eitjes op de aspergestengels duidelijk afnam. Door de Beetle eater regelmatig in te zetten bleven het aantal afgezette eitjes op de stengels beperkt en zijn het gehele seizoen geen groene asperges bij deze teler afgekeurd en geen asperges daardoor aangemerkt als kwaliteit II. Een aandachtspunt is wel dat na iedere behandeling aspergestengels afbreken. Dit komt enerzijds omdat de rijafstand niet correspondeerde met de zuigmonden van de Beetle eater (scheelde 5 cm) en anderzijds omdat bij oudere percelen de aspergestengels verder uit het hart van de rug kunnen groeien. Door de zuigmond aan te passen (verbreden en iets te vergroten) is de verwachting dat het afbreken van de stengels beperkt wordt

Dynamics of cold bosons in optical lattices: Effects of higher Bloch bands

The extended effective multiorbital Bose-Hubbard-type Hamiltonian which takes into account higher Bloch bands, is discussed for boson systems in optical lattices, with emphasis on dynamical properties, in relation with current experiments. It is shown that the renormalization of Hamiltonian parameters depends on the dimension of the problem studied. Therefore, mean field phase diagrams do not scale with the coordination number of the lattice. The effect of Hamiltonian parameters renormalization on the dynamics in reduced one-dimensional optical lattice potential is analyzed. We study both the quasi-adiabatic quench through the superfluid-Mott insulator transition and the absorption spectroscopy, that is energy absorption rate when the lattice depth is periodically modulated.Comment: 23 corrected interesting pages, no Higgs boson insid

Ground states and dynamics of population-imbalanced Fermi condensates in one dimension

By using the numerically exact density-matrix renormalization group (DMRG) approach, we investigate the ground states of harmonically trapped one-dimensional (1D) fermions with population imbalance and find that the Larkin-Ovchinnikov (LO) state, which is a condensed state of fermion pairs with nonzero center-of-mass momentum, is realized for a wide range of parameters. The phase diagram comprising the two phases of i) an LO state at the trap center and a balanced condensate at the periphery and ii) an LO state at the trap center and a pure majority component at the periphery, is obtained. The reduced two-body density matrix indicates that most of the minority atoms contribute to the LO-type quasi-condensate. With the time-dependent DMRG, we also investigate the real-time dynamics of a system of 1D fermions in response to a spin-flip excitation.Comment: 20 pages, 15 figures, accepted for publication in New Journal of Physic

FSH isoform pattern in classic galactosemia

Female classic galactosemia patients suffer from primary ovarian insufficiency (POI). The cause for this long-term complication is not fully understood. One of the proposed mechanisms is that hypoglycosylation of complex molecules, a known secondary phenomenon of galactosemia, leads to FSH dysfunction. An earlier study showed less acidic isoforms of FSH in serum samples of two classic galactosemia patients compared to controls, indicating hypoglycosylation. In this study, FSH isoform patterns of five classic galactosemia patients with POI were compared to the pattern obtained in two patients with a primary glycosylation disorder (phosphomannomutase-2-deficient congenital disorders of glycosylation, PMM2-CDG) and POI, and in five postmenopausal women as controls. We used FPLC chromatofocussing with measurement of FSH concentration per fraction, and discovered that there were no significant differences between galactosemia patients, PMM2-CDG patients and postmenopausal controls. Our results do not support that FSH dysfunction due to a less acidic isoform pattern because of hypoglycosylation is a key mechanism of POI in this disease

Influence of Winter Cow Feeding Strategies on Cow Response

The objective of this study was to investigate the effects of the primary maternal prepartum dietary energy source (forage vs. concentrate) during mid- and late-gestation on dam body weight (BW), body condition score (BCS), pregnancy rate, and economic responses

Comparison of Winter Cow Feeding Strategies on Offspring Performance and Meat Quality

The objective of this study was to investigate the effects of maternal prepartum dietary energy source (forage vs. concentrate) during mid- and late-gestation on offspring growth performance, carcass characteristics and meat quality

‘Good Farmers’ in Sub-Saharan Africa: Evolving Narratives

In this paper the example of cocoa production in Ghana is used to explore how the narratives portraying African farmers have changed over the last 70 years. These evolving narratives are explored through the notion of a ‘good farmer’. The argument is that over this period the image of African farmers has been progressively rehabilitated, from ignorant and tradition-bound to skilled and research-minded. Over the same time period the image of formal research and extension was undermined. With the recent renewed interest in agriculture, narratives around African farmers are again evolving: ‘good farmers’ are now increasingly being defined as those who approach their farming as a proper business.DfI

Finite temperature phase diagram of a polarised Fermi condensate

The two-component Fermi gas is the simplest fermion system displaying superfluidity, and as such finds applications ranging from the theory of superconductivity to QCD. Ultracold atomic gases provide an exceptionally clean realization of this system, where the interatomic interaction and the atom species population are both independent, tuneable parameters. This allows one to investigate the Fermi gas with imbalanced spin populations, which had previously been experimentally elusive, and this prospect has stimulated much theoretical activity. Here we show that the finite temperature phase diagram contains a region of phase separation between the superfluid and normal states that touches the boundary of second-order superfluid transitions at a tricritical point, reminiscent of the phase diagram of $^3$He-$^4$He mixtures. A variation of interaction strength then results in a line of tricritical points that terminates at zero temperature on the molecular Bose-Einstein condensate (BEC) side. On this basis, we argue that tricritical points will play an important role in the recent experiments on polarised atomic Fermi gases.Comment: 6 pages, 4 figures. Manuscript extended and figures modified. For final version, see Nature Physic

Imbalanced Superfluid Phase of a Trapped Fermi Gas in the BCS-BEC Crossover Regime

We theoretically investigate the ground state of trapped neutral fermions with population imbalance in the BCS-BEC crossover regime. On the basis of the single-channel Hamiltonian, we perform full numerical calculations of the Bogoliubov-de Gennes equation coupled with the regularized gap and number equations. The zero-temperature phase diagram in the crossover regime is presented, where the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) pairing state governs the weak-coupling BCS region of a resonance. It is found that the FFLO oscillation vanishes in the BEC side, in which the system under population imbalance turns into a phase separation (PS) between locally binding superfluid and fully polarized spin domains. We also demonstrate numerical calculations with a large particle number O(10^5), comparable to that observed in recent experiments. The resulting density profile on a resonance yields the PS, which is in good agreement with the recent experiments, while the FFLO modulation exists in the pairing field. It is also proposed that the most favorable location for the detection of the FFLO oscillation is in the vicinity of the critical population imbalance in the weak coupling BCS regime, where the oscillation periodicity becomes much larger than the interparticle spacing. Finally, we analyze the radio-frequency (RF) spectroscopy in the imbalanced system. The clear difference in the RF spectroscopy between BCS and BEC sides reveals the structure of the pairing field and local ``magnetization''.Comment: 16 pages, 13 figures, replaced by the version to appear in J. Phys. Soc. Jp