The one-dimensional Bose-Fermi-Hubbard model in the heavy-fermion limit

We study the phase diagram of the zero-temperature, one-dimensional Bose-Fermi-Hubbard model for fixed fermion density in the limit of small fermionic hopping. This model can be regarded as an instance of a disordered Bose-Hubbard model with dichotomic values of the stochastic variables. Phase boundaries between compressible, incompressible (Mott-insulating) and partially compressible phases are derived analytically within a generalized strong-coupling expansion and numerically using density matrix renormalization group (DMRG) methods. We show that first-order correlations in the partially compressible phases decay exponentially, indicating a glass-type behaviour. Fluctuations within the respective incompressible phases are determined using perturbation theory and are compared to DMRG results.Comment: 11 pages, 15 figures, 2nd, revised versio

Ultracold bosons in disordered superlattices: Mott-insulators induced by tunneling

We analyse the phase diagram of ultra-cold bosons in a one-dimensional superlattice potential with disorder using the time evolving block decimation algorithm for infinite sized systems (iTEBD). For degenerate potential energies within the unit cell of the superlattice loophole-shaped insulating phases with non-integer filling emerge with a particle-hole gap proportional to the boson hopping. Adding a small amount of disorder destroys this gap. For not too large disorder the loophole Mott regions detach from the axis of vanishing hopping giving rise to insulating islands. Thus the system shows a transition from a compressible Bose-glass to a Mott-insulating phase with increasing hopping amplitude. We present a straight forward effective model for the dynamics within a unit cell which provides a simple explanation for the emergence of Mott-insulating islands. In particular it gives rather accurate predictions for the inner critical point of the Bose-glass to Mott-insulator transition

Analytic approximations to the phase diagram of the Jaynes-Cummings-Hubbard model with application to ion chains

We discuss analytic approximations to the ground state phase diagram of the homogeneous Jaynes-Cummings-Hubbard (JCH) Hamiltonian with general short-range hopping. The JCH model describes e.g. radial phonon excitations of a linear chain of ions coupled to an external laser field tuned to the red motional sideband with Coulomb mediated hopping or an array of high-$Q$ coupled cavities containing a two-level atom and photons. Specifically we consider the cases of a linear array of coupled cavities and a linear ion chain. We derive approximate analytic expressions for the boundaries between Mott-insulating and superfluid phases and give explicit expressions for the critical value of the hopping amplitude within the different approximation schemes. In the case of an array of cavities, which is represented by the standard JCH model we compare both approximations to numerical data from density-matrix renormalization group (DMRG) calculations.Comment: 9 pages, 5 figures, extended and corrected second versio

Minat Muda-mudi Hkbp Jeruju Terhadap Ansambel Uning Uningan Sebagai Musik Ibadah

This research aims to describe HKBP Jeruju youth's towards the uning-uningan ensemble as the worship music and as the interest of music instrument in uning-uningan ensemble. This research used a survey method in descriptive quantitative type of research. The source of data in this research is the data questionnaire filed by 22 HKBP Jeruju youth as well as the interviewees who has the knowledge and understanding of uning-uningan ensemble. The result of this research is the youth of HKBP Jeruju who has a big interest in uning-uningan ensemble as the worship music with the percentage of 50% for the highest interest. These youth's interest in uning-uningan ensemble is taganing of total 14 people, sulim 3 people, hasapi 5 people, nobody choose hesek

Peningkatkan Keterampilan Memainkan Rekorder Soprano melalui Tangga Nada Kromatis

Tujuan penelitian ini adalah meningkatan kemampuan siswa dalam memainkan rekorder soprano pada pembelajaran seni budaya di kelas VIII Sekolah Menengah Pertama Negeri 1 Jawai. Metode penelitian yang digunakan adalah penelitian tindakan. Peningkatan keterampilan memainkan rekorder soprano melalui tangga nada kromatis kelas VIII SMP Negeri 1 Jawai menggunakan IV siklus. Pembelajaran memainkan rekorder soprano dengan tangga nada kromatis memerlukan teknik pernapasan, penjarian, dan peniupan yang benar. Berdasarkan hasil penelitian dapat disimpulkan bahwa keterampilan memainkan rekorder soprano siswa mengalami peningkatan dari siklus I, siklus II, siklus III, dan siklus IV dalam pembelajaran seni budaya di kelas VIII SMP Negeri 1 Jawai. Kata Kunci: Keterampilan, Rekorder Soprano, Tangga Nada Kromatis Abstrack: The purpose of this research is to improve the students ability in playing soprano recorder in the subject of Art and Culture to the eighth grade of SMP N 1 Jawai. The research mathod that is used is action research. The improvement of the ability in playing soprano rekorder through chromati musical tone on the eighth grade of SMP N 1 Jawai ues four cycles. Learn to play soprano recorder by chromatic musical tone needs correct breathing based on fingering and blowing technique. The result of this research is can be conduded the ability in playing soprano recorder improved from the fisit cycle, secane cycle, third cycle, and fourth cycle in the subject of Art and Culture in SMP N 1 Jawai

Peningkatan Motivasi Belajar Seni Musik melalui Rancangan Pembelajaran Tandur pada Siswa Kelas VII SMP

This research aims to increase the motivation to learn the art of music through learning design TANDUR students of class VII SMP Negeri 2 Toho. The method used in this research is descriptive method with this type of research is a classroom action research. This research was conducted three cycles. Based on initial observations of students' motivation appears at 29.2% with the low category. After the implementation of learning design TANDUR in the first cycle increased to 44.7% in the medium category, and then on the second cycle increased to 62.8% with a high category and the third cycle increased to 77.6% with the higher category. This shows that learning design TANDUR can be used to increase students' motivation in learning the art of music