Quantum dynamics of a binary mixture of BECs in a double well potential: an Holstein-Primakoff approach

We study the quantum dynamics of a binary mixture of Bose-Einstein condensates (BEC) in a double-well potential starting from a two-mode Bose-Hubbard Hamiltonian. Focussing on the regime where the number of atoms is very large, a mapping onto a SU(2) spin problem together with a Holstein-Primakoff transformation is performed. The quantum evolution of the number difference of bosons between the two wells is investigated for different initial conditions, which range from the case of a small imbalance between the two wells to a coherent spin state. The results show an instability towards a phase-separation above a critical positive value of the interspecies interaction while the system evolves towards a coherent tunneling regime for negative interspecies interactions. A comparison with a semiclassical approach is discussed together with some implications on the experimental realization of phase separation with cold atoms.Comment: 12 pages, 7 figures, accepted for publication in J. Phys.

Quantum Bose Josephson Junction with binary mixtures of BECs

We study the quantum behaviour of a binary mixture of Bose-Einstein condensates (BEC) in a double-well potential starting from a two-mode Bose-Hubbard Hamiltonian. We focus on the small tunneling amplitude regime and apply perturbation theory up to second order. Analytical expressions for the energy eigenvalues and eigenstates are obtained. Then the quantum evolution of the number difference of bosons between the two potential wells is fully investigated for two different initial conditions: completely localized states and coherent spin states. In the first case both the short and the long time dynamics is studied and a rich behaviour is found, ranging from small amplitude oscillations and collapses and revivals to coherent tunneling. In the second case the short-time scale evolution of number difference is determined and a more irregular dynamics is evidenced. Finally, the formation of Schroedinger cat states is considered and shown to affect the momentum distribution.Comment: 14 pages, 4 figure

The Meaning of Life Wayang Wong Sriwedari Players

The meaning of life is something that is considered important, valuable, and desirable as well as provide special value to one's self. The meaning of life is also worthy life goals. This study aims to find a vision of the meaning of life from the players who are in the wayang wong Sriwedari in Surakarta. This study used a qualitative method using a phenomenological approach. The number of subjects in the study were four people determined purposively. The results obtained from this study is the background in the selection of the fourth subject wayang wong job as a player because it has the talent and have ancestors who are involved in the arts wayang wong. Reason subjects persist in work because they love their work, do not have any other skills, and the desire to work. They also have the same goal in the work is provide for his family. Fourth research subject grateful for what they have earned, and considers his life prosperous. Physical changes to give effect to the subject in the work, other than that obtained in any role the show has been changed into buto figures and waistband. Achievement of the meaning of life is obtained subject of happiness, work wholeheartedly, loving family, successful children, produce works of art, to support my wife and kids, and the third male subjects have in common is their role as a father. Their efforts in achieving the meaning of life is done through the value of work, and the value being the value appreciation

Milestones Achieved for the Fluids and Combustion Facility

In 2004, President Bush outlined a new space exploration vision for NASA. The exploration programs will seek profound answers to questions of our origins, whether life exists beyond Earth, and how we could live in other worlds. In response, research projects from NASA s Fluid Physics Research Program were moved into the Exploration Systems Mission Directorate and realigned to support the major milestones of this directorate. A new goal of this research is to obtain an understanding of the physical phenomena that are important in the design of the many space-based and ground-based fluids systems that utilize multiphase flow, such as life support, propulsion, and power systems

Dynamical Realization of Macroscopic Superposition States of Cold Bosons in a Tilted Double Well

We present exact expressions for the quantum sloshing of Bose-Einstein condensates in a tilted two-well potential. Tunneling is suppressed by a small potential difference between wells, or tilt. However, tunneling resonances occur for critical values of the tilt when the barrier is high. At resonance, tunneling times on the order of 10-100 ms are possible. Furthermore, such tilted resonances lead to a dynamical scheme for creating few-body NOON-like macroscopic superposition states which are protected by the many body wavefunction against potential fluctuations.Comment: 6 pages, 5 figures, final version, only minor changes from previous arXiv versio

The Evaluation of Mechanical Properties of Concrete Due to The Use of Glass Waste as Partial Substitution of Fine Aggregate

Increasing human awareness of the importance of protecting the environment and conserving natural resources requires concrete innovation as an environmentally friendly and sustainable material. Accumulated of solid waste begins to be processed and reused, one of which is as a constituent of concrete. Among the various types of solid waste, glass waste is considered as an alternative that can be used as a substitute for fine aggregate (sand), coarse aggregate (split stone) and cement. This study investigated the use of mix coloured glass waste consisting of clear, green, and brown as partial substitution of sand in concrete. Although the glass colors were mixed, the proportion of each color had been determined in this study, namely 25%, 25%, and 50%. The purpose of determining these proportions is to find out which type of color glass has the most effect on concrete mix. The target characteristic strength of 25 MPa was produced by replacing sand with 20% of mix coloured waste glass. Three combinations of concrete mixes were prepared for this study. Compression tests were conducted at 7, 14, and 28 days. Workability of fresh concrete, density, compressive strength, and failure mode were investigated in this study. Results showed that the use of waste glass was able to increase the workability of fresh concrete. K1, K 2, and K3 obtained slump values which were 4%, 6,7%, and 1,3% higher than normal concrete. Normal concrete and all combinations exhibited similar density values. Only normal concrete achieved the characteristic strength of 25,7 MPa at 28 days. Meanwhile K1, K2, and K3 achieved strengths of 22,4 MPa, 22,1 MPa, and 24,7 MPa, respectively. It was evident that as workability values increased, the compressive strengths were noticed to reduce

Creation of macroscopic quantum superposition states by a measurement

We propose a novel protocol for the creation of macroscopic quantum superposition (MQS) states based on a measurement of a non-monotonous function of a quantum collective variable. The main advantage of this protocol is that it does not require switching on and off nonlinear interactions in the system. We predict this protocol to allow the creation of multiatom MQS by measuring the number of atoms coherently outcoupled from a two-component (spinor) Bose-Einstein condensate.Comment: 4 pages (revtex4), 2 figure