Quantum Phases of Dipolar Bosons in Bilayer Geometry

We investigate the quantum phases of hard-core dipolar bosons confined to a square lattice in a bilayer geometry. Using exact theoretical techniques, we discuss the many-body effects resulting from pairing of particles across layers at finite density, including a novel pair supersolid phase, superfluid and solid phases. These results are of direct relevance to experiments with polar molecules and atoms with large magnetic dipole moments trapped in optical lattices.Comment: 7 pages, 5 figure

The Impact of Sports on Expressing One’s Feelings

The benefits of joining sports activities are quite many. Doing sports helps in socializing the individual by increasing the number of friends around the individual, and it also helps establishing an organized and disciplined life. Physical activities may also assist people to overcome aggression easily and express their feelings in a better way. This research aims at examining the impact of sports on expressing Fırat University students’ feelings based on different factors (age, gender, academic program). Screening model was applied to their search sample. Data collected from the students during the Fall Semester, 2015-2016. Their search sample included 175 students studying at Fırat University. The emotion expressing’s callused in this research was developed by Kingand Emmons (1990) as data collection tool to measure individuals’ tendencies in expressing their feelings. Kuzucu (2006) adopted this scale to Turkish society. A 15- item Likert-type questionnaire is designed to measure the tendencies in expressing emotions as positive, negative or warm feelings. Items score between 1 (Strongly Disagree) to 7 (Strongly Agree) where high scores in dictated high tendency in expressing feelings. In the scale, reverse-scoring is applied to item 6 and to item 14.The data obtained is analyzed using SPSS software. The independent samples t-test and one-way analysis of variance tests are used for data analyses purpose.As result of there search, Sports Sciences Faculty students were ableto Express their feelings in a beter way than other faculties’ students

Quantum magnetism and counterflow supersolidity of up-down bosonic dipoles

We study a gas of dipolar Bosons confined in a two-dimensional optical lattice. Dipoles are considered to point freely in both up and down directions perpendicular to the lattice plane. This results in a nearest neighbor repulsive (attractive) interaction for aligned (anti-aligned) dipoles. We find regions of parameters where the ground state of the system exhibits insulating phases with ferromagnetic or anti-ferromagnetic ordering, as well as with rational values of the average magnetization. Evidence for the existence of a novel counterflow supersolid quantum phase is also presented.Comment: 8 pages, 6 figure

Glide and Superclimb of Dislocations in Solid 4^4He

Glide and climb of quantum dislocations under finite external stress, variation of chemical potential and bias (geometrical slanting) in Peierls potential are studied by Monte Carlo simulations of the effective string model. We treat on unified ground quantum effects at finite temperatures $T$. Climb at low $T$ is assisted by superflow along dislocation core -- {\it superclimb}. Above some critical stress avalanche-type creation of kinks is found. It is characterized by hysteretic behavior at low $T$. At finite biases gliding dislocation remains rough even at lowest $T$ -- the behavior opposite to non-slanted dislocations. In contrast to glide, superclimb is characterized by quantum smooth state at low temperatures even for finite bias. In some intermediate $T$-range giant values of the compressibility as well as non-Luttinger type behavior of the core superfluid are observed.Comment: Updated version submitted to JLTP as QFS2010 proceedings; 11 pages, 6 figure

Effective spin physics in two-dimensional cavity QED arrays

We investigate a strongly correlated system of light and matter in two-dimensional cavity arrays. We formulate a multimode Tavis–Cummings (TC) Hamiltonian for two-level atoms coupled to cavity modes and driven by an external laser field which reduces to an effective spin Hamiltonian in the dispersive regime. In one-dimension we provide an exact analytical solution. In two-dimensions, we perform mean-field study and large scale quantum Monte Carlo simulations of both the TC and the effective spin models. We discuss the phase diagram and the parameter regime which gives rise to frustrated interactions between the spins. We provide a quantitative description of the phase transitions and correlation properties featured by the system and we discuss graph-theoretical properties of the ground states in terms of graph colourings using Pólya's enumeration theorem

On The Mobile Behavior of Solid 4^4He at High Temperatures

We report studies of solid helium contained inside a torsional oscillator, at temperatures between 1.07K and 1.87K. We grew single crystals inside the oscillator using commercially pure $^4$He and $^3$He-$^4$He mixtures containing 100 ppm $^3$He. Crystals were grown at constant temperature and pressure on the melting curve. At the end of the growth, the crystals were disordered, following which they partially decoupled from the oscillator. The fraction of the decoupled He mass was temperature and velocity dependent. Around 1K, the decoupled mass fraction for crystals grown from the mixture reached a limiting value of around 35%. In the case of crystals grown using commercially pure $^4$He at temperatures below 1.3K, this fraction was much smaller. This difference could possibly be associated with the roughening transition at the solid-liquid interface.Comment: 15 pages, 6 figure

Interplay of non-linear elasticity and dislocation-induced superfluidity in solid Helium-4

The mechanism of the roughening induced partial depinning of gliding dislocations from Helium-3 impurities is proposed as an alternative to the standard "boiling off". We give a strong argument that Helium-3 remains bound to dislocations even at large temperatures due to very long equilibration times. A scenario leading to the similarity between elastic and superfluid responses of solid Helium-4 is also discussed. Its main ingredient is a strong suppression of the superfluidity along dislocation cores by dislocation kinks (D. Aleinikava, et. al., arXiv:0812.0983). These kinks, on one hand, determine the temperature and Helium-3 dependencies of the generalized shear modulus and, on the other hand, control the superfluid response. Several proposals for theoretical and experimental studies of solid Helium-4 are suggested.Comment: final version accepted to the special JLTP issue on Supersolid, 16 pages, 6 figures: typos corrected, more explanations give

Structural changes caused by high-temperature holding of powder shape memory alloy 66% Fe - 14% Mn - 6% Si - 9% Cr - 5% Ni

Shape memory alloy Fe – 14Mn – 6Si – 9Cr – 5Ni (wt.%) obtained by cold pressing and sintering of a mixture of powder elements or of mechanically alloyed powder is studied. To compact the alloy additionally the specimens are subjected to hot rolling. Solution treatment of different duration (0.6 – 4.8 ksec) at 1473 K in low vacuum, nitrogen or argon is performed. The structure of the alloy after such treatments is studied by the methods of x-ray diffraction and optical and scanning electron microscopy.status: publishe