The Standard Quantum Limit of Coherent Beam Combining

Coherent beam combining refers to the process of generating a bright output beam by merging independent input beams with locked relative phases. We report the first quantum mechanical noise limit calculations for coherent beam combining and compare our results to quantum-limited amplification. Our coherent beam combining scheme is based on an optical Fourier transformation which renders the scheme compatible with integrated optics. The scheme can be layed out for an arbitrary number of input beams and approaches the shot noise limit for a large number of inputs

Elliptic flow of resonances at RHIC: probing final state interactions and the structure of resonances

We propose the measurement of the elliptic flow of hadron resonances at the Relativistic Heavy Ion Collider as a tool to probe the amount of hadronic final state interactions for resonances at intermediate and large transverse momenta. This can be achieved by looking at systematic deviations of the measured flow coefficient $v_2$ from the scaling law given by the quark recombination formalism. Our method can be generalized to explore the structure of exotic particles, such as the recently found pentaquark $\Theta^+ (1540)$.Comment: 5 pages, 2 figures; v2: accepted version for publication in Physical Review C rapid communication

Future dynamics in f(R) theories

The $f(R)$ gravity theories provide an alternative way to explain the current cosmic acceleration without invoking dark energy matter component. However, the freedom in the choice of the functional forms of $f(R)$ gives rise to the problem of how to constrain and break the degeneracy among these gravity theories on theoretical and/or observational grounds. In this paper to proceed further with the investigation on the potentialities, difficulties and limitations of $f(R)$ gravity, we examine the question as to whether the future dynamics can be used to break the degeneracy between $f(R)$ gravity theories by investigating the future dynamics of spatially homogeneous and isotropic dust flat models in two $f(R)$ gravity theories, namely the well known $f(R) = R + \alpha R^{n}$ gravity and another by A. Aviles et al., whose motivation comes from the cosmographic approach to $f(R)$ gravity. To this end we perform a detailed numerical study of the future dynamic of these flat model in these theories taking into account the recent constraints on the cosmological parameters made by the Planck team. We show that besides being powerful for discriminating between $f(R)$ gravity theories, the future dynamics technique can also be used to determine the fate of the Universe in the framework of these $f(R)$ gravity theories. Moreover, there emerges from our numerical analysis that if we do not invoke a dark energy component with equation-of-state parameter $\omega < -1$ one still has dust flat FLRW solution with a big rip, if gravity deviates from general relativity via $f(R) = R + \alpha R^n$. We also show that FLRW dust solutions with $f''<0$ do not necessarily lead to singularity.Comment: 12 pages, 8 figures. V2: Generality and implications of the results are emphasized, connection with the recent literature improved, typos corrected, references adde

Lyapunov Spectra in SU(2) Lattice Gauge Theory

We develop a method for calculating the Lyapunov characteristic exponents of lattice gauge theories. The complete Lyapunov spectrum of SU(2) gauge theory is obtained and Kolmogorov-Sinai entropy is calculated. Rapid convergence with lattice size is found.Comment: 7pp, DUKE-TH-93-5

Spin-lattice coupling in the ferrimagnetic semiconductor FeCr2S4 probed by surface acoustic waves

Using surface acoustic waves, the elastomagnetic coupling could be studied in thin single crystalline plates of the ferrimagnetic semiconductor FeCr2S4 by measuring the attenuation and the frequency tracking in the temperature range 4.2 K to 200 K. The data clearly display the anomalies found in low-field magnetization measurements.Comment: 15 pages, 3 figures. To appear in J. Appl. Phys., 99 (2006

Treponema denticola in Disseminating Endodontic Infections

Treponema denticola is a consensus periodontal pathogen that has recently been associated with endodontic pathology. In this study, the effect of mono-infection of the dental pulp with T. denticola and with polymicrobial “red-complex” organisms (RC) (Porphyromonas gingivalis, Tannerella forsythia, and T. denticola) in inducing disseminating infections in wild-type (WT) and severe-combined-immunodeficiency (SCID) mice was analyzed. After 21 days, a high incidence (5/10) of orofacial abscesses was observed in SCID mice mono-infected with T. denticola, whereas abscesses were rare in SCID mice infected with the red-complex organisms or in wildtype mice. Splenomegaly was present in all groups, but only mono-infected SCID mice had weight loss. T. denticola DNA was detected in the spleen, heart, and brain of mono-infected SCID mice and in the spleen from mono-infected wild-type mice, which also had more periapical bone resorption. The results indicate that T. denticola has high pathogenicity, including dissemination to distant organs, further substantiating its potential importance in oral and linked systemic conditions

Hadronization in heavy ion collisions: Recombination and fragmentation of partons

We argue that the emission of hadrons with transverse momentum up to about 5 GeV/c in central relativistic heavy ion collisions is dominated by recombination, rather than fragmentation of partons. This mechanism provides a natural explanation for the observed constant baryon-to-meson ratio of about one and the apparent lack of a nuclear suppression of the baryon yield in this momentum range. Fragmentation becomes dominant at higher transverse momentum, but the transition point is delayed by the energy loss of fast partons in dense matter.Comment: 4 pages, 2 figures; v2: reference [8] added; v3: Eq.(2) corrected, two references added, version to appear in PR

Energy spectra of the ocean's internal wave field: theory and observations

The high-frequency limit of the Garrett and Munk spectrum of internal waves in the ocean and the observed deviations from it are shown to form a pattern consistent with the predictions of wave turbulence theory. In particular, the high frequency limit of the Garrett and Munk spectrum constitutes an {\it exact} steady state solution of the corresponding kinetic equation.Comment: 4 pages, one color figur