Diffraction of partial temporal coherence beam from multi slits

We have generalized the notion of Franhoufer diffraction of temporal coherent light from a single slit to the case of arbitrary n slits. A general numerical method has been developed for the simulation of the diffraction pattern of multi-slits which is also used to study the effects of coherence length on the diffraction pattern. The diffraction pattern is investigated for different values of recently introduced parameter, decoherence parameter. It is shown that for multi-slits, the temporal decoherence effects appear for decoherence parameter more or equal to one. The results of our study reproduce the previous studies for perfect temporal case, when coherence length tends to infinity.Comment: 13 pages,7 figure

Influence of Charge Order on the Ground States of TMTTF Molecular Salts

(TMTTF)2AsF6 and (TMTTF)2SbF6 are both known to undergo a charge ordering phase transition, though their ground states are different. The ground state of the first is Spin-Peierls, and the second is an antiferromagnet. We study the effect of pressure on the ground states and the charge-ordering using 13C NMR spectroscopy. The experiments demonstrate that the the CO and SP order parameters are repulsive, and consequently the AF state is stabilized when the CO order parameter is large, as it is for (TMTTF)2SbF6. An extension of the well-known temperature/pressure phase diagram is proposed.Comment: 5pages, 5 figures, Proceeding of ISCOM2003, to appear in Journal de Physique I

The Noncommutative Anandan's Quantum Phase

In this work we study the noncommutative nonrelativistic quantum dynamics of a neutral particle, that possesses permanent magnetic and electric dipole momenta, in the presence of an electric and magnetic fields. We use the Foldy-Wouthuysen transformation of the Dirac spinor with a non-minimal coupling to obtain the nonrelativistic limit. In this limit, we will study the noncommutative quantum dynamics and obtain the noncommutative Anandan's geometric phase. We analyze the situation where magnetic dipole moment of the particle is zero and we obtain the noncommutative version of the He-McKellar-Wilkens effect. We demonstrate that this phase in the noncommutative case is a geometric dispersive phase. We also investigate this geometric phase considering the noncommutativity in the phase space and the Anandan's phase is obtained.Comment: 15 pages, revtex4, version to appear in Physical Review

Effective Hamiltonian Approach to Hyperon Beta Decay with Final-State Baryon Polarization

Using an effective Hamiltonian approach, we obtain expressions for hyperon beta decay final-state baryon polarization. Terms through second order in the energy release are retained. The resulting approximate expressions are much simpler and more compact than the exact expressions, and they agree closely with them.Comment: 1 Figure Will appear in Phys Rev D 60 Article 117505 (Dec 1, 1999

The analysis of phase, dispersion and group delay in InGaAsP/InP microring resonator

The Vernier operation with signal flow graph (SFG) is a graphical approach for analyzing the intricate photonic circuits mathematically and quick calculation of optical transfer function. Analysis of a cascaded microring resonators (CMRR) made of InGaAsP/InP semiconductor is presented using the signal flow graph (SFG) method which enables modelling the transfer function of the passive CMRR. These passive filters are mostly characterized by their frequency response. The theoretical calculations of the system is performed by the Vernier effects analysis. Two MRRs with radius of 100 μm which are vertically coupled together are used to generate resonant peaks. Here, the phase, dispersion and group delay of the generated signals are analyzed

Temporal soliton: generation and applications in optical communications

In general, the temporal and spectral shape of a short optical soliton pulse does not change during propagation in a nonlinear medium due to the Kerr effect which balances the chromatic dispersion. Microring resonators (MRRs) can be used to generate chaotic signals. The smaller MRR is used to form the stopping and filtering system. The employed optical material was InGaAsP/InP, which is suitable for use in the practical devices and systems. The tuning and manipulation of the bandwidth of the soliton signals is recommended to control the output signals. The MRRs can be applied to produce ultra-short pulses, where the medium has a nonlinear condition, thus, using of soliton laser becomes an interesting subject. Therefore, an ultra-short pulse in the scope of pico and femtoseconds soliton pulses can be utilized for many applications in engineering communications. In order to obtain smaller bandwidth of the optical soliton pulses, we propose integrating series of MRRs. In this study, 5 fs soliton pulse could be generated using a series of five MRRs. The soliton signals experience less loss during the propagation, where they are more stable compared to normal conventional laser pulses. Using the series of MRRs connected to an add/drop system, shorter soliton bandwidth and highly multi soliton pulses can be obtained. Therefore, generation of ultra-short multi picosecond (1.2 and 1.3 ps), could be performed, where the radius of the add/drop system has been selected to 50 and 300 μm respectively

Effect of Estradiol and Soy Extract on the Onset of PTZ-Induced Seizure in Ovariectomized Rats: Implications for Nurses and Midwives

Background: In many epileptic women, the ovarian cycle influences the risk and severity of seizures. Previous studies have reported inconsistent findings regarding the neural excitatory effects of estrogen. Soybean is a rich source of plant estrogens. Therefore, soy intake can affect the risk and severity of seizures in women. Nurses and midwives need to be aware of the effects of diets containing estrogen in pregnant and post-menopausal women, as well as during the sexual cycle periods. Objectives: Due to the limitations of human studies, this study aimed to investigate the effect of estradiol and soy extract on the onset of pentylenetetrazol (PTZ)-induced seizures in ovariectomized rats. Materials and Methods: In this experimental study, sixty female Wistar rats were randomly divided into six groups of ten. All of the groups except for the negative control groups were ovariectomized. One group received estradiol (100 µg/kg), one group was treated with alcoholic extract of soy (20 mg/kg), and the other group received vehicle over 28 days. PTZ (90 mg/kg) was used to induce seizure in all groups. Behavioral changes were observed over 30 minutes. All data were analyzed using a two-way analysis of variance with Tukey’s post-hoc test. Results: The mean ± SD of the clonic seizure threshold was 61.84 ± 8.53 in the group that received estradiol, while it was 71.70 ± 10.85 in the control group, 64.69 ± 3.23 in rats with laparotomy without removing the ovaries, 51.30 ± 6.84 in rats with laparotomy and removing the ovaries, 52.7 ± 7.18 in ovariectomized rats that received sesame oil as vehicle, and 59.2 ± 4.91, in the soy groups. Therefore, estradiol significantly increased the clonic seizure threshold, while the alcoholic extract of soy had no effect. Conclusions: We concluded that the chronic administration of estradiol has an anticonvulsant effect in the animal model. However, alcoholic extract of soy has no effect on the onset of clonic seizures

Electron-lattice coupling and the broken symmetries of the molecular salt (TMTTF)2_2SbF6_6

(TMTTF)$_2$SbF$_6$ is known to undergo a charge ordering (CO) phase transition at $T_{CO}\approx156K$ and another transition to an antiferromagnetic (AF) state at $T_N\approx 8K$. Applied pressure $P$ causes a decrease in both $T_{CO}$ and $T_N$. When $P>0.5 GPa$, the CO is largely supressed, and there is no remaining signature of AF order. Instead, the ground state is a singlet. In addition to establishing an expanded, general phase diagram for the physics of TMTTF salts, we establish the role of electron-lattice coupling in determining how the system evolves with pressure.Comment: 4 pages, 5 figure