Steady-state phase error for a phase-locked loop subjected to periodic Doppler inputs

The performance of a carrier phase locked loop (PLL) driven by a periodic Doppler input is studied. By expanding the Doppler input into a Fourier series and applying the linearized PLL approximations, it is easy to show that, for periodic frequency disturbances, the resulting steady state phase error is also periodic. Compared to the method of expanding frequency excursion into a power series, the Fourier expansion method can be used to predict the maximum phase error excursion for a periodic Doppler input. For systems with a large Doppler rate fluctuation, such as an optical transponder aboard an Earth orbiting spacecraft, the method can be applied to test whether a lower order tracking loop can provide satisfactory tracking and thereby save the effect of a higher order loop design

Imaging-based Parametric Resonance in an Optical Dipole Atom Trap

We report sensitive detection of parametric resonances in a high-density sample of ultracold $^{87}Rb$ atoms confined to a far-off-resonance optical dipole trap. Fluorescence imaging of the expanded ultracold atom cloud after a period of parametric excitation shows significant modification of the atomic spatial distribution and has high sensitivity compared with traditional measurements of parametrically-driven trap loss. Using this approach, a significant shift of the parametric resonance frequency is observed, and attributed to the anharmonic shape of the dipole trap potential

Impurity effect of Lambda hyperon on collective excitations of atomic nuclei

Taking the ground state rotational band in $^{24}$Mg as an example, we investigate the impurity effect of $\Lambda$ hyperon on collective excitations of atomic nuclei in the framework of non-relativistic energy density functional theory. To this end, we take into account correlations related to the restoration of broken symmetries and fluctuations of collective variables by solving the eigenvalue problem of a five-dimensional collective Hamiltonian for quadrupole vibrational and rotational degrees of freedom. The parameters of the collective Hamiltonian are determined with constrained mean-field calculations for triaxial shapes using the SGII Skyrme force. We compare the low-spin spectrum for $^{24}$Mg with the spectrum for the same nucleus inside $^{25}_{\Lambda}$Mg. It is found that the $\Lambda$ hyperon stretches the ground state band and reduces the $B(E2:2^+_1 \rightarrow 0^+_1)$ value by $\sim 9$, mainly by softening the potential energy surface towards the spherical shape, even though the shrinkage effect on the average proton radius is only $\sim0.5$.Comment: 16 pages, 5 figures, and 1 tabl

Poverty among households living in slum area of Hlaing Tharyar Township, Yangon City, Myanmar

Background: Slums can be regarded as physical manifestations of urban poverty. Although the world has made dramatic improvement in reducing poverty since 1990, poverty still persists at an unacceptable level. Although current situations highlights the importance of slum areas to be given priority in poverty alleviation, there are limited data on poverty level among people living in urban slums of Myanmar.Methods: A cross-sectional study was conducted among households living in slum areas of Hlaing Tharyar Township, Yangon City, Myanmar during 2016. Multi-staged systematic random sampling and face-to-face interview were applied in selecting the samples and collecting the data, respectively. The new global poverty line (1.9 USD per person per day) was used as a threshold in determining the poverty. Chi-squared test and multivariate logistic regression analysis were utilized in data analysis.Results: Altogether 254 participants were recruited after getting informed consent. The occurrence of poverty among households was 54.3% (95% CI: 48.2%, 60.5%). Head counts of poverty among study population was 58.8%. The education status of household’s head, size of household and the presence of less than 15 years old children in the household were detected as significant determinants of being poor household.Conclusions: Poverty among households living in slum area of Hlaing Tharyar Township, Yangon City was high. Measures to alleviate poverty in urban slums should be intensified. Education level of household’s heads should be improved. Family planning or birth spacing programme should also be strengthened, especially in urban slums.

The thermal evolution of nuclear matter at zero temperature and definite baryon number density in chiral perturbation theory

The thermal properties of cold dense nuclear matter are investigated with chiral perturbation theory. The evolution curves for the baryon number density, baryon number susceptibility, pressure and the equation of state are obtained. The chiral condensate is calculated and our result shows that when the baryon chemical potential goes beyond $1150 \mathrm{MeV}$, the absolute value of the quark condensate decreases rapidly, which indicates a tendency of chiral restoration.Comment: 17 pages, 9 figures, revtex

Possible approach to improve sensitivity of a Michelson interferometer

We propose a possible approach to achieve an 1/N sensitivity of Michelson interferometer by using a properly designed random phase modulation. Different from other approaches, the sensitivity improvement does not depend on increasing optical powers or utilizing the quantum properties of light. Moreover the requirements for optical losses and the quantum efficiencies of photodetection systems might be lower than the quantum approaches and the sensitivity improvement is frequency independent in all detection band.Comment: 8 pages, 3 figures, new versio

Optimum Quantum Error Recovery using Semidefinite Programming

Quantum error correction (QEC) is an essential element of physical quantum information processing systems. Most QEC efforts focus on extending classical error correction schemes to the quantum regime. The input to a noisy system is embedded in a coded subspace, and error recovery is performed via an operation designed to perfectly correct for a set of errors, presumably a large subset of the physical noise process. In this paper, we examine the choice of recovery operation. Rather than seeking perfect correction on a subset of errors, we seek a recovery operation to maximize the entanglement fidelity for a given input state and noise model. In this way, the recovery operation is optimum for the given encoding and noise process. This optimization is shown to be calculable via a semidefinite program (SDP), a well-established form of convex optimization with efficient algorithms for its solution. The error recovery operation may also be interpreted as a combining operation following a quantum spreading channel, thus providing a quantum analogy to the classical diversity combining operation.Comment: 7 pages, 3 figure

JAVANESE ISLAM AND GLOBALIZATION: A STUDY ON THE SUSTAINABILITY THE ABOGE ISLAM COMMUNITY IN INDONESIA

The indigenous religion of Java has a longer historical existence compared to the currently recognized state religions. Similarly, Javanese Islam has evolved through religious syncretism with Javanese culture. Javanese Islam has served as a means to reconcile the two opposing poles of this entity, as well as a way to attract followers. Aboge Islam in Purbalingga, Central Java is one form of Javanese Islam. The existence of Aboge Islam is facing increasing threats, particularly in the era of globalization. This article will provide an overview of the current reality, obstacles, and threats faced by the Aboge Islamic community, and discuss their future. This research is conducted using the qualitative ethnographic method. Data was collected through in-depth interviews with members of the Aboge Muslim community, as well as observations and document studies. The findings revealed that the Aboge Muslim community has undertaken various adaptation processes as a survival strategy to maintain its existence amidst the challenges posed by globalization. This form of adaptation is the inheritance of community values by passing down their traditional values to the younger generation, which includes 'ngormati leluhur' (the practices of ancestor worship), "melu gawe" (a Javanese term for working together), and "Turki" (Tuturan Kaki, oral transmission of knowledge and advice from parents or elders). Through this process, they hope their community will survive in the future.Religi lokal di Jawa memiliki usia lebih tua dari agama yang sekarang diakui oleh negara. Begitu juga Islam Jawa yang merupakan hasil sinkretisme religi dengan kultur Jawa. Islam Jawa menjadi jalan untuk mendamaikan dua kutub ekstrim entitas ini, sekaligus sebagai ‘jalan’ untuk mendapatkan pengikut. Islam Aboge di Purbalingga Jawa Tengah merupakan salah satu bentuk dari Islam Jawa tersebut. Keberadaan Islam Aboge semakin hari kian terancam terutama di era globalisasi. Tulisan ini akan menguraikan keberadaan komunitas Islam Aboge di masa depan, dengan melihat realitas, hambatan dan ancaman yang terjadi sekarang. Penelitian ini dilakukan dengan menggunakan metode kualitatif etnografi. Teknik pengumpulan data dilakukan melalui wawancara mendalam terhadap pemeluk Islam Aboge, observasi, dan studi dokumen. Hasil penelitian menunjukkan bahwa untuk menjaga eksistensi komunitasnya di tengah pusaran globalisasi, mereka telah melakukan sejumlah proses adaptasi sebagai pilihan untuk bertahan. Bentuk adaptasi tersebut adalah pewarisan nilai-nilai komunitas melalui pengajaran kepada anak-anak mereka, seperti ngormati leluhur, melu gawe, dan Turki (Tuturan Kaki, nasehat orangtua). Melalui proses ini mereka berharap komunitas mereka akan tetap bertahan di masa depan