14,546 research outputs found
One-parameter extension of the Doi-Peliti formalism and relation with orthogonal polynomials
An extension of the Doi-Peliti formalism for stochastic chemical kinetics is
proposed. Using the extension, path-integral expressions consistent with
previous studies are obtained. In addition, the extended formalism is naturally
connected to orthogonal polynomials. We show that two different orthogonal
polynomials, i.e., Charlier polynomials and Hermite polynomials, can be used to
express the Doi-Peliti formalism explicitly.Comment: 10 page
Finite-volume Hamiltonian method for coupled channel interactions in lattice QCD
Within a multi-channel formulation of scattering, we investigate the
use of the finite-volume Hamiltonian approach to resolve scattering observables
from lattice QCD spectra. The asymptotic matching of the well-known L\"uscher
formalism encodes a unique finite-volume spectrum. Nevertheless, in many
practical situations, such as coupled-channel systems, it is advantageous to
interpolate isolated lattice spectra in order to extract physical scattering
parameters. Here we study the use of the Hamiltonian framework as a
parameterisation that can be fit directly to lattice spectra. We find that with
a modest amount of lattice data, the scattering parameters can be reproduced
rather well, with only a minor degree of model dependence.Comment: 25 pages, 16 figure
Recommended from our members
ELAV links paused Pol II to alternative polyadenylation in the Drosophila nervious system
Alternative polyadenylation (APA) has been implicated in a variety of developmental and disease processes. A particularly dramatic form of APA occurs in the developing nervous system of flies and mammals, whereby various developmental genes undergo coordinate 3' UTR extension. In Drosophila, the RNA-binding protein ELAV inhibits RNA processing at proximal polyadenylation sites, thereby fostering the formation of exceptionally long 3' UTRs. Here, we present evidence that paused Pol II promotes recruitment of ELAV to extended genes. Replacing promoters of extended genes with heterologous promoters blocks normal 3' extension in the nervous system, while extension-associated promoters can induce 3' extension in ectopic tissues expressing ELAV. Computational analyses suggest that promoter regions of extended genes tend to contain paused Pol II and associated cis-regulatory elements such as GAGA. ChIP-seq assays identify ELAV in the promoter regions of extended genes. Our study provides evidence for a regulatory link between promoter-proximal pausing and APA
Destruction of Neel order and appearance of superconductivity in electron-doped cuprates by oxygen annealing process
We use thermodynamic and neutron scattering measurements to study the effect
of oxygen annealing on the superconductivity and magnetism in
PrLaCeCuO. Although the transition temperature
measured by susceptibility and superconducting coherence length increase
smoothly with gradual oxygen removal from the annealing process, bulk
superconductivity, marked by a specific heat anomaly at and the presence
of a neutron magnetic resonance, only appears abruptly when is close to
the largest value. These results suggest that the effect of oxygen annealing
must be first determined in order to establish a Ce-doping dependence of
antiferromagnetism and superconductivity phase diagram for electron-doped
copper oxides.Comment: 5 pages, 4 figures, accepted by Phys. Rev.
Quantum Phase Transition in the Itinerant Antiferromagnet (V0.9Ti0.1)2O3
Quantum-critical behavior of the itinerant electron antiferromagnet
(V0.9Ti0.1)2O3 has been studied by single-crystal neutron scattering. By
directly observing antiferromagnetic spin fluctuations in the paramagnetic
phase, we have shown that the characteristic energy depends on temperature as
c_1 + c_2 T^{3/2}, where c_1 and c_2 are constants. This T^{3/2} dependence
demonstrates that the present strongly correlated d-electron antiferromagnet
clearly shows the criticality of the spin-density-wave quantum phase transition
in three space dimensions.Comment: 4 pages, 4 figure
A key to room-temperature ferromagnetism in Fe-doped ZnO: Cu
Successful synthesis of room-temperature ferromagnetic semiconductors,
ZnFeO, is reported. The essential ingredient in achieving
room-temperature ferromagnetism in bulk ZnFeO was found to be
additional Cu doping. A transition temperature as high as 550 K was obtained in
ZnFeCuO; the saturation magnetization at room
temperature reached a value of per Fe. Large
magnetoresistance was also observed below K.Comment: 11 pages, 4 figures; to appear in Appl. Phys. Let
Observation of Motion Dependent Nonlinear Dispersion with Narrow Linewidth Atoms in an Optical Cavity
As an alternative to state-of-the-art laser frequency stabilisation using
ultra-stable cavities, it has been proposed to exploit the non-linear effects
from coupling of atoms with a narrow transition to an optical cavity. Here we
have constructed such a system and observed non-linear phase shifts of a narrow
optical line by strong coupling of a sample of strontium-88 atoms to an optical
cavity. The sample temperature of a few mK provides a domain where the Doppler
energy scale is several orders of magnitude larger than the narrow linewidth of
the optical transition. This makes the system sensitive to velocity dependent
multi-photon scattering events (Dopplerons) that affect the cavity field
transmission and phase. By varying the number of atoms and the intra-cavity
power we systematically study this non-linear phase signature which displays
roughly the same features as for much lower temperature samples. This
demonstration in a relatively simple system opens new possibilities for
alternative routes to laser stabilization at the sub 100 mHz level and
superradiant laser sources involving narrow line atoms. The understanding of
relevant motional effects obtained here has direct implications for other
atomic clocks when used in relation with ultranarrow clock transitions.Comment: 9 pages (including 4 pages of Supplemental Information), 6 figures.
Updated to correspond to the published versio
Non-linear Spectroscopy of Sr Atoms in an Optical Cavity for Laser Stabilization
We study the non-linear interaction of a cold sample of strontium-88 atoms
coupled to a single mode of a low finesse optical cavity in the so-called bad
cavity limit and investigate the implications for applications to laser
stabilization. The atoms are probed on the weak inter-combination line \lvert
5s^{2} \, ^1 \textrm{S}_0 \rangle \,-\, \lvert 5s5p \, ^3 \textrm{P}_1 \rangle
at 689 nm in a strongly saturated regime. Our measured observables include the
atomic induced phase shift and absorption of the light field transmitted
through the cavity represented by the complex cavity transmission coefficient.
We demonstrate high signal-to-noise-ratio measurements of both quadratures -
the cavity transmitted phase and absorption - by employing FM spectroscopy
(NICE-OHMS). We also show that when FM spectroscopy is employed in connection
with a cavity locked to the probe light, observables are substantially modified
compared to the free space situation where no cavity is present. Furthermore,
the non-linear dynamics of the phase dispersion slope is experimentally
investigated and the optimal conditions for laser stabilization are
established. Our experimental results are compared to state-of-the-art cavity
QED theoretical calculations.Comment: 7 pages, 4 figure
- …