Magnetization of a half-quantum vortex in a spinor Bose-Einstein condensate

Magnetization dynamics of a half-quantum vortex in a spin-1 Bose-Einstein condensate with a ferromagnetic interaction are investigated by mean-field and Bogoliubov analyses. The transverse magnetization is shown to break the axisymmetry and form threefold domains. This phenomenon originates from the topological structure of the half-quantum vortex and spin conservation.Comment: 6 pages, 3 figure

Spin-vortex nucleation in a Bose-Einstein condensate by a spin-dependent rotating trap

A method to produce a spin-dependent rotating potential using near-resonant circularly polarized laser beams is proposed. It is shown that half-quantum vortices are nucleated in a spinor Bose-Einstein condensate with an antiferromagnetic interaction. In contrast to the vortex nucleation in a scalar BEC, the spin-vortex nucleation occurs at a low rotation frequency ($\simeq 0.1 \omega_\perp$ with $\omega_\perp$ being the radial trap frequency) in a short nucleation time $\simeq 50$ ms without dissipation. A method for nondestructive measurement of half-quantum vortices is discussed.Comment: 6 pages, 3 figure

Symmetry Breaking and Enhanced Condensate Fraction in a Matter-Wave Bright Soliton

An exact diagonalization study reveals that a matter-wave bright soliton and the Goldstone mode are simultaneously created in a quasi-one-dimensional attractive Bose-Einstein condensate by superpositions of quasi-degenerate low-lying many-body states. Upon formation of the soliton the maximum eigenvalue of the single-particle density matrix increases dramatically, indicating that a fragmented condensate converts into a single condensate as a consequence of the breaking of translation symmetry.Comment: 4 pages, 4 figures, revised versio

Topological defect formation in quenched ferromagnetic Bose-Einstein condensates

We study the dynamics of the quantum phase transition of a ferromagnetic spin-1 Bose-Einstein condensate from the polar phase to the broken-axisymmetry phase by changing magnetic field, and find the spontaneous formation of spinor domain walls followed by the creation of polar-core spin vortices. We also find that the spin textures depend very sensitively on the initial noise distribution, and that an anisotropic and colored initial noise is needed to reproduce the Berkeley experiment [Sadler et al., Nature 443, 312 (2006)]. The dynamics of vortex nucleation and the number of created vortices depend also on the manner in which the magnetic field is changed. We point out an analogy between the formation of spin vortices from domain walls in a spinor BEC and that of vortex-antivortex pairs from dark solitons in a scalar BEC.Comment: 10 pages, 11 figure

Glassy dynamics in thin films of polystyrene

Glassy dynamics was investigated for thin films of atactic polystyrene by complex electric capacitance measurements using dielectric relaxation spectroscopy. During the isothermal aging process the real part of the electric capacitance increased with time, whereas the imaginary part decreased with time. It follows that the aging time dependences of real and imaginary parts of the electric capacitance were primarily associated with change in volume (film thickness) and dielectric permittivity, respectively. Further, dielectric permittivity showed memory and rejuvenation effects in a similar manner to those observed for poly(methyl methacrylate) thin films. On the other hand, volume did not show a strong rejuvenation effect.Comment: 7 pages, 7 figures. Phys. Rev. E (in press

Rayleigh-Taylor instability and mushroom-pattern formation in a two-component Bose-Einstein condensate

The Rayleigh-Taylor instability at the interface in an immiscible two-component Bose-Einstein condensate is investigated using the mean-field and Bogoliubov theories. Rayleigh-Taylor fingers are found to grow from the interface and mushroom patterns are formed. Quantized vortex rings and vortex lines are then generated around the mushrooms. The Rayleigh-Taylor instability and mushroom-pattern formation can be observed in a trapped system.Comment: 5 pages, 4 figure

Quantum Kelvin-Helmholtz instability in phase-separated two-component Bose-Einstein condensates

We theoretically study the Kelvin-Helmholtz instability in phase-separated two-component Bose-Einstein condensates using the Gross-Pitaevskii and Bogoliubov-de Gennes models. A flat interface between the two condensates is shown to deform into sawtooth or Stokes-like waves, leading to the formation of singly quantized vortices on the peaks and troughs of the waves. This scenario of interface instability in quantum fluids is quite different from that in classical fluids.Comment: 5 pages, 4 figure

The Effectiveness of Teacher Training on Environmental Education: Challenges and Strategy for Future Training Program

A professional teacher is a teacher who masters professional knowledge and skills. Increasing their professionalism is needed to achieve Sustainable Development Goals (SDGs). This research attempts to analyze the effectiveness of teacher training programs in environmental education that focus on identifying the challenges and strategy for the future training program. The research method was triangulation, combining quantitative and qualitative data analysis, including document analysis, questionnaire, and interview results. Sixty-five teachers with experience in environmental education were surveyed, and seven were interviewed. The results show that the sustainability context (environmental, economic, and sociocultural dimensions) needs to be embedded into environmental education teacher training. All training materials are currently oriented toward the environmental context. The provided training focuses on imparting knowledge on environmental education and has not yet expanded to include raising awareness or fostering sustainable action. As a result, future teacher programs must emphasize not only knowledge, but also awareness and action to attain sustainability. Schools and other relevant parties must fully support the rollout of the teacher-training initiative.Guru profesional adalah guru yang menguasai pengetahuan dan keterampilan profesional. Peningkatan profesionalisme guru diperlukan untuk mencapai Tujuan Pembangunan Berkelanjutan (SDGs). Penelitian ini bertujuan untuk menganalisis efektivitas program pelatihan guru tentang pendidikan lingkungan yang berfokus pada identifikasi tantangan dan strategi untuk program pelatihan pendidikan lingkungan masa depan. Metode penelitian yang digunakan adalah triangulasi dengan menggabungkan analisis data kuantitatif dan kualitatif meliputi analisis dokumen, angket, dan hasil wawancara. Jumlah guru yang terlibat dalam survei adalah 65 guru yang pernah mengikuti pelatihan pendidikan lingkungan dan 7 guru untuk responden wawancara. Hasilnya menunjukkan bahwa semua materi pelatihan masih berorientasi pada konteks lingkungan padahal pelatihan guru mengenai pendidikan lingkungan harus memperhatikan konteks keberlanjutan (dimensi lingkungan, ekonomi, dan sosial-budaya). Fokus pelatihan yang dilakukan masih sebatas pada pengetahuan pendidikan lingkungan, belum sampai pada kesadaran dan aksi berkelanjutan. Oleh karena itu, program pelatihan guru masa depan tidak hanya berfokus pada pengetahuan saja tetapi juga kesadaran dan tindakan untuk mencapai keberlanjutan. Semua pihak termasuk sekolah dan pemangku kepentingan wajib mendukung pelaksanaan program pelatihan guru ini