An Equilibrium for Frustrated Quantum Spin Systems in the Stochastic State Selection Method

We develop a new method to calculate eigenvalues in frustrated quantum spin models. It is based on the stochastic state selection (SSS) method, which is an unconventional Monte Carlo technique we have investigated in recent years. We observe that a kind of equilibrium is realized under some conditions when we repeatedly operate a Hamiltonian and a random choice operator, which is defined by stochastic variables in the SSS method, to a trial state. In this equilibrium, which we call the SSS equilibrium, we can evaluate the lowest eigenvalue of the Hamiltonian using the statistical average of the normalization factor of the generated state. The SSS equilibrium itself has been already observed in un-frustrated models. Our study in this paper shows that we can also see the equilibrium in frustrated models, with some restriction on values of a parameter introduced in the SSS method. As a concrete example, we employ the spin-1/2 frustrated J1-J2 Heisenberg model on the square lattice. We present numerical results on the 20-, 32-, 36-site systems, which demonstrate that statistical averages of the normalization factors reproduce the known exact eigenvalue in good precision. Finally we apply the method to the 40-site system. Then we obtain the value of the lowest energy eigenvalue with an error less than 0.2%.Comment: 15 pages, 12 figure

The Stochastic State Selection Method Combined with the Lanczos Approach to Eigenvalues in Quantum Spin Systems

We describe a further development of the stochastic state selection method, a new Monte Carlo method we have proposed recently to make numerical calculations in large quantum spin systems. Making recursive use of the stochastic state selection technique in the Lanczos approach, we estimate the ground state energy of the spin-1/2 quantum Heisenberg antiferromagnet on a 48-site triangular lattice. Our result for the upper bound of the ground state energy is -0.1833 +/- 0.0003 per bond. This value, being compatible with values from other work, indicates that our method is efficient in calculating energy eigenvalues of frustrated quantum spin systems on large lattices.Comment: 11 page

A constrained stochastic state selection method applied to quantum spin systems

We describe a further development of the stochastic state selection method, which is a kind of Monte Carlo method we have proposed in order to numerically study large quantum spin systems. In the stochastic state selection method we make a sampling which is simultaneous for many states. This feature enables us to modify the method so that a number of given constraints are satisfied in each sampling. In this paper we discuss this modified stochastic state selection method that will be called the constrained stochastic state selection method in distinction from the previously proposed one (the conventional stochastic state selection method) in this paper. We argue that in virtue of the constrained sampling some quantities obtained in each sampling become more reliable, i.e. their statistical fluctuations are less than those from the conventional stochastic state selection method. In numerical calculations of the spin-1/2 quantum Heisenberg antiferromagnet on a 36-site triangular lattice we explicitly show that data errors in our estimation of the ground state energy are reduced. Then we successfully evaluate several low-lying energy eigenvalues of the model on a 48-site lattice. Our results support that this system can be described by the theory based on the spontaneous symmetry breaking in the semiclassical Neel ordered antiferromagnet.Comment: 15 pgaes, 5 figure

Manajemen Kelas oleh Wali Kelas di SMA Negeri 1 Tempunak

Tujuan penelitian adalah untuk mengetahui bagaimana manajemen kelas oleh wali kelas. Dalam penelitian ini peneliti menggunakan metode kualitatif dengan jenis studi kasus. Lokasi penelitian di SMA Negeri 1 Tempunak. Subyek penelitian Kepala Sekolah. Wali Kelas dan siswa. Hasil penelitian, perencanaan manajemen kelas SMA Negeri 1 Tempunak belum terimplementasi dengan baik dan belum jelas, pelaksanaan manajemen kelas oleh wali kelas cukup baik, tetapi belum sesuai dengan ketentuan atau teori manajemen kelas yang seharusnya,dan evaluasi manajemen kelas tidak berjalan secara sistematis, jelas dan terarah, hal ini dibuktikan dengan wali kelas hnaya melakukan evaluasi melalui raport. Faktor penghambat manajemen kelas oleh wali kelas adalah guru yang memiliki tipe kurang demokratis, gaya guru yang monoton, guru yang tidak bersifat fleksibel, peserta didik yang kurangsadar dalam memenuhi tugas dan haknya, keluarga yang bersikap otoriter, fasilitas sekolah yang kurang lengkap. Kata Kunci : Manajemen Kelas, Wali Kelas Abstrack : The research objectives was to determine how management class by homeroom. In this study, researchers used a qualitative method with case study. Location study in SMA Negeri 1 Tempunak Kabupaten Sintang. Subjects were the principal, homeroom, and students. Research, planning management class SMA Negeri 1 Tempunak not been implemented well and unclear implementation by homeroom class management quite well, but not in accordance with the provision or management theory class is supposed to, and evaluation of classroom management is not running in a systematic, clear, and focused. This is evidenced by the homeroom just evaluation through report cards. Inhibiting factors homeroom classroom management by teachers who have less democratic type, style monotonous teachers, teachers who are not flexible, learners who are less conscious in fulfilling the duties and rights, family being authoritarian, facilities that are less complete

Peningkatan Hasil dan Motivasi Belajar Fisika Siswa melalui Model Quantum Teaching di SMA

This classroom action research aimed to improve students' outcomes and motivation in the static fluid material through quantum teaching model. This research was conducted in two cycles to the eleventh grade of natural science major 2 (XIIPA 2) of Public Senior High School 9 Pontianak with a total of 31 students. The data were collected through the learning outcome test, learning motivation questionnaire and learning observation sheet. The results indicated that there was an improvement in students' learning outcomes from the first to the second cycle by 3,22% from 70,97% to 74,19%, while the improvement in students' learning motivation from the first to the second cycle was 2,10% from 75,40% to 77,40%. Based on the research findings, it was concluded that the quantum teaching model could improve the students' learning outcomes and motivation particularly in the static fluid material. The application of this model should be designed with the best learning media preparation so as to increase students' interest in the material

Higher Order Corrections to the Primordial Gravitational Wave Spectrum and its Impact on Parameter Estimates for Inflation

We study the impact of the use of the power series expression for the primordial tensor spectrum on parameter estimation from future direct detection gravitational wave experiments. The spectrum approximated by the power series expansion may give large deviation from the true (fiducial) value when it is normalized at CMB scale because of the large separation between CMB and direct detection scales. We derive the coefficients of the higher order terms of the expansion up to the sixth order within the framework of the slow-roll approximation and investigate how well the inclusion of higher order terms improves the analytic prediction of the spectrum amplitude by comparing with numerical results. Using the power series expression, we consider future constraints on inflationary parameters expected from direct detection experiments of the inflationary gravitational wave background and show that the truncation of the higher order terms can lead to incorrect evaluation of the parameters. We present two example models; a quadratic chaotic inflation model and mixed inflaton and curvaton model with a quartic inflaton potential.Comment: 25 pages, 7 figures, revised version accepted by JCA

Cosmic Microwave Background Anisotropy with Cosine-Type Quintessence

We study the Cosmic Microwave Background (CMB) anisotropies produced by cosine-type quintessence models. In our analysis, effects of the adiabatic and isocurvature fluctuations are both taken into account. For purely adiabatic fluctuations with scale invariant spectrum, we obtain a stringent constraint on the model parameters using the CMB data from COBE, BOOMERanG and MAXIMA. Furthermore, it is shown that isocurvature fluctuations have significant effects on the CMB angular power spectrum at low multipoles in some parameter space, which may be detectable in future satellite experiments. Such a signal may be used to test the cosine-type quintessence models.Comment: 21 pages, 9 figure

The Hubble constant and dark energy from cosmological distance measures

We study how the determination of the Hubble constant from cosmological distance measures is affected by models of dark energy and vice versa. For this purpose, constraints on the Hubble constant and dark energy are investigated using the cosmological observations of cosmic microwave background, baryon acoustic oscillations and type Ia suprenovae. When one investigates dark energy, the Hubble constant is often a nuisance parameter, thus it is usually marginalized over. On the other hand, when one focuses on the Hubble constant, simple dark energy models such as a cosmological constant and a constant equation of state are usually assumed. Since we do not know the nature of dark energy yet, it is interesting to investigate the Hubble constant assuming some types of dark energy and see to what extent the constraint on the Hubble constant is affected by the assumption concerning dark energy. We show that the constraint on the Hubble constant is not affected much by the assumption for dark energy. We furthermore show that this holds true even if we remove the assumption that the universe is flat. We also discuss how the prior on the Hubble constant affects the constraints on dark energy and/or the curvature of the universe.Comment: 45 pages, 15 figure