Collective modes and the speed of sound in the Fulde-Ferrell-Larkin-Ovchinnikov state

We consider the density response of a spin-imbalanced ultracold Fermi gas in an optical lattice in the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state. We calculate the collective mode spectrum of the system in the generalised random phase approximation and find that though the collective modes are damped even at zero tempererature, the damping is weak enough to have well-defined collective modes. We calculate the speed of sound in the gas and show that it is anisotropic due to the anisotropy of the FFLO pairing, which implies an experimental signature for the FFLO state.Comment: 13 pages, 9 figures (revised version

Bertini intra-nuclear cascade implementation in Geant4

We present here a intra-nuclear cascade model implemented in Geant4 5.0. The cascade model is based on re-engineering of INUCL code. Models included are Bertini intra-nuclear cascade model with exitons, pre-equilibrium model, nucleus explosion model, fission model, and evaporation model. Intermediate energy nuclear reactions from 100 MeV to 3 GeV energy are treated for proton, neutron, pions, photon and nuclear isotopes. We represent overview of the models, review results achieved from simulations and make comparisons with experimental data.Comment: Computing in High Energy and Nuclear Physics, La Jolla, California, March 24-28, 2003 1 tar fil

Superfluid phases of fermions with hybridized ss and pp orbitals

We explore the superfluid phases of a two-component Fermi mixture with hybridized orbitals in optical lattices. We show that there exists a general mapping of this system to the Lieb lattice. By using simple multiband models with hopping between $s$ and $p$-orbital states, we show that superfluid order parameters can have a $\pi$-phase difference between lattice sites, which is distinct from the case with hopping between $s$-orbitals. If the population imbalance between the two spin species is tuned, the superfluid phase may evolve through various phases due to the interplay between hopping, interactions and imbalance. We show that the rich behavior is observable in experimentally realizable systems.Comment: 13 pages, 11 figures. Published versio

Linguistic imitation and patchwriting in EFL:Swedish upper secondary students mimicking linguistic features, structures, and the lexicon

Abstract. This thesis is a qualitative study that investigates how Swedish upper secondary students mimic linguistic items and structures of a short story The Invisible Japanese Gentlemen by Graham Greene. The data consists of ten student essays that are based on the source text by Graham Greene. This thesis compares and examines the similarity of the student texts and the source text. Additionally, this thesis explores how literary texts could be used in language learning and teaching and discusses what kind of role linguistic mimicry and imitation have in verbal communication and language acquisition. This thesis also offers pedagogical and linguistic perspectives to the current notions of plagiarism and patchwriting. The findings demonstrate that all of the students, regardless of their language proficiency level, mimic the source text on a lexical, morphological and syntactic level. Students with higher linguistic proficiency mimic the punctuation to a greater level than the less-proficient students. The students mimic morphological items of the source text mainly by using identical or similar verbs, verb constructions, and adverbs. The students mimic lexical items most frequently by copying individual words directly from the source text. Many of the students also use synonyms for the original lexical items. On a syntactical level, many of the students mimic phrases and sentences of the source text by copying, imitating, and modifying them. Overall, the findings support the fact that literary texts offer great language exposure for language students, and thus stimulate language acquisition on different linguistic levels. More research on how linguistic imitation contributes to language learning needs to be done. Also, the terms plagiarism and patchwriting should be defined more precisely to universally determine the limit what is considered plagiarism and what patchwriting.Kielellinen imitointi ja tilkkukirjoittaminen englannin kielen oppimisessa : ruotsalaiset lukiolaiset matkimassa kielellisiä piirteitä, rakenteita sekä sanoja. Tiivistelmä. Tämä tutkielma on laadullinen tutkimus, joka tutkii kuinka ruotsalaiset lukiolaiset matkivat kielellisiä yksikköjä sekä rakenteita Graham Greenen novellista The Invisible Japanese Gentlemen (”Näkymättömät japanilaiset herrat”). Tutkielman aineisto koostuu kymmenestä oppilasesseestä, jotka on kirjoitettu Graham Greenin novellin pohjalta. Tutkielmassa vertaillaan ja tarkastellaan oppilasesseiden ja lähdetekstin välisiä samankaltaisuuksia. Tämän lisäksi tutkielmassa pohditaan sitä, miten kaunokirjallisia tekstejä voitaisiin käyttää kielen oppimisessa ja opetuksessa, sekä tutkitaan sitä, millainen rooli kielellisellä matkimisella ja imitaatiolla on verbaalisessa kommunikaatiossa sekä kielen omaksumisessa. Tämä tutkielma tarjoaa myös pedagogisia ja lingvistisiä näkökulmia nykyisiin näkemyksiin plagioinnista ja tilkkukirjoittamisesta (engl. patchwriting). Tutkimustulokset osoittavat, että jokainen oppilas englannin taitotasostaan riippumatta matkii lähdetekstiä leksikaalisella, morfologisella ja syntaktisella tasolla. Ne oppilaat, joilla englannin taitotaso on korkeampi matkivat välimerkkien käyttöä enemmän kuin oppilaat, joiden englannin taitotaso on heikompi. Oppilaat matkivat lähdetekstin sanaluokkia pääasiassa käyttämällä samanlaisia verbejä, verbirakenteita ja adverbeja. Lähdetekstin lekseemejä oppilaat matkivat useimmin kopioimalla yksittäisiä sanoja suoraan lähdetekstistä. Monet oppilaat käyttivät tosin myös synonyymejä lähdetekstin lekseemeistä. Syntaktisella tasolla monet oppilaat matkivat lähdetekstin fraaseja ja lauseita kopioimalla, imitoimalla sekä muokkaamalla niitä. Kaiken kaikkiaan tutkimustulokset tukevat sitä, että kaunokirjalliset tekstit tarjoavat kielten opiskelijoille hyvää kielellistä altistumista ja siten stimuloivat kielen omaksumista eri tasoilla. Enemmän tutkimusta kuitenkin tarvitaan siitä, kuinka kielellinen imitaatio edistää kielen oppimista. Myös plagioinnin termit tulisi määritellä tarkemmin, jotta voidaan täsmentää universaalinen raja niiden välille

Microkelvin thermometry with Bose-Einstein condensates of magnons and applications to studies of the AB interface in superfluid 3^3He

Coherent precession of trapped Bose-Einstein condensates of magnons is a sensitive probe for magnetic relaxation processes in superfluid 3He-B down to the lowest achievable temperatures. We use the dependence of the relaxation rate on the density of thermal quasiparticles to implement thermometry in 3He-B at temperatures below 300 $\mu$K. Unlike popular vibrating wire or quartz tuning fork based thermometers, magnon condensates allow for contactless temperature measurement and make possible an independent in situ determination of the residual zero-temperature relaxation provided by the radiation damping. We use this magnon-condensate-based thermometry to study the thermal impedance of the interface between A and B phases of superfluid 3He. The magnon condensate is also a sensitive probe of the orbital order-parameter texture. This has allowed us to observe for the first time the non-thermal signature of the annihilation of two AB interfaces.Comment: 26 pages, 7 figures, manuscript prepared for EU Microkelvin Collaboration Workshop 2013. Accepted for publication in Journal of Low Temperature Physic

Turbulent Vortex Flow Responses at the AB Interface in Rotating Superfluid 3He-B

In a rotating two-phase sample of 3He-B and magnetic-field stabilized 3He-A the large difference in mutual friction dissipation at 0.20 Tc gives rise to unusual vortex flow responses. We use noninvasive NMR techniques to monitor spin down and spin up of the B-phase superfluid component to a sudden change in the rotation velocity. Compared to measurements at low field with no A-phase, where these responses are laminar in cylindrically symmetric flow, spin down with vortices extending across the AB interface is found to be faster, indicating enhanced dissipation from turbulence. Spin up in turn is slower, owing to rapid annihilation of remanent vortices before the rotation increase. As confirmed by both our NMR signal analysis and vortex filament calculations, these observations are explained by the additional force acting on the B-phase vortex ends at the AB interface.Comment: 6 pages, 6 figure