The driven-damped Jaynes-Cummings model in the regime of strong coupling is found to exhibit a coexistence between the quantum photon blockaded state and a quasicoherent bright state. We characterize ...the slow time scales and the basin of attraction of these metastable states using full quantum simulations. This form of bistability can be useful for implementing a qubit readout scheme that does not require additional circuit elements. We propose a coherent control sequence that makes use of a simple linear chirp of drive amplitude and frequency as well as qubit frequency. By optimizing the parameters of the system and the control pulse, we demonstrate theoretically very high readout fidelities (>98%) and high contrast with experimentally realistic parameters for qubits implemented in the circuit QED architecture.
The cross sections for the formation of the metastable atomic hydrogen in the 2s state in photoexcitation of H{sub 2} and D{sub 2} were measured as a function of the incident photon energy in the ...range of the doubly excited states with their symmetries of the electronic states, {sup 1}{Sigma}{sub u}{sup +} or {sup 1}{Pi}{sub u}, being resolved. It has turned out from the comparison with the cross-section curves for other dissociation processes and the theoretical calculation J. D. Bozek et al., J. Phys. B 39, 4871 (2006) that the Q{sub 2}{sup 1}{Pi}{sub u}(1) doubly excited state of H{sub 2} dissociates into both H(2s) + H(2p) and H(2p) + H(2p). The dissociation dynamics of this state has been discussed in terms of the nonadiabatic transition during neutral dissociations.
A classical concept of a metastable state is a local free energy minimum that may ultimately relax to the stable equilibrium state of a global free energy minimum via an activation process. This ...process is different from the barrier-free relaxation that spontaneously takes place when an unstable state relaxes. In order to be classified as metastable, the lifetime of a metastable state must be longer than the timescale of observation, which in turn is practically limited by experimental equipment and the patience of the observer. In the classical concept of metastable states there is an assumption that the systems are large enough so that there is no need for consideration of size or other kinetic effects on the system. In general, polymers are much more prone to access the metastable region than small molecules. Polymeric materials, with their various hierarchies of microstructure, may have metastable states present due to small phase size, composition, external fields and other causes. In this review, our focus will be on concepts and experimental observations of metastable states in polymer phase transformations where two ordered structures exist. The phase stability relationships of these structures will be discussed with respect to the phase size, namely, the lamellar thickness. The concepts involved in metastable states and metastability are not only important in the scientific understanding of condensed polymer physics, but are also useful for practical materials development and applications.
A self-consistent model of the spatial structure and dynamics of the pulsed direct current (DC) oxygen discharge in oxygen at low pressures has been developed. The dynamics of the electrons in the ...discharge and in the afterglow have been calculated on the base of the PIC MC method and the diffusion-drift approach correspondingly. As a result, nonlocality and anisotropy effects of the electron energy distribution function (EEDF) which are of primary importance in strongly nonuniform electric field have been taken into account. Spatial distributions of charged and neutral species were determined in the diffusion-drift approach. The processes in the active phase of the discharge were found to be essentially transient. The densities of positive and negative ions as well as the EEDF significantly vary during the discharge pulse, although the discharge current density remains approximately constant. The evolution of the EEDF in the discharge is mainly determined by degradation of the beam of /spl gamma/-electrons from the cathode and therefore has a clearly pronounced two-temperature character. The high density of slow electrons produced by beam electrons is the principal condition for negative ion production by the dissociative attachment of these slow electrons to highly excited oxygen molecules in the Herzberg's states A/sup 3//spl Sigma//sub u//sup +/,A'/sup 3//spl Delta//sub u/,c/sup 1//spl Sigma//sub u//sup -/ both in the discharge and in the afterglow. To prove out the presence of high density of slow electrons in the discharge, a special experiment using a high-precision measurement of the EEDF in oxygen DC discharge stimulated by a beam of runaway electrons was carried out. The good agreement between these measurements and our simulation results indirectly confirms a two-temperature character of the EEDF in a pulsed DC oxygen discharge at low pressures.
Emission spectra of the 0–0 band of the
a
1Δ
g
→
X
3Σ
−
g
magnetic dipole transition of S
2 have been observed in the near-infrared spectral region near 4400 cm
−1. The S
2 molecules were generated ...in a fast-flow system by passing S
x
or S
2Cl
2 vapor in Ar carrier gas through a microwave discharge and were excited by electronic-to-electronic energy transfer from metastable singlet oxygen O
2(
a
1Δ
g
). Medium-resolution spectra of the
b
1Σ
+
g
→
X
3Σ
−
g
and
a
1Δ
g
→
X
3Σ
−
g
transitions of S
2 were measured with a Fourier-transform spectrometer. By comparing the bandshape of the 0–0 band of the
a→
X system with a computer simulation calculated with literature data of the rotational constants of the
X and
a states, the origin of the 0–0 band was determined to be
ν
0=4394.25±0.2 cm
−1.
The [formula omitted] transition of Se 2 Setzer, K.D.; Dorn, A.; Lorenz, M. ...
Journal of molecular spectroscopy,
2003, Letnik:
221, Številka:
1
Journal Article
Recenzirano
Emission spectra of the 0–0 and 1–1 bands of the
a
1
Δ
g(a2
g)→X
3
Σ
−
g(X
21
g)
magnetic dipole transition of Se
2 have been observed in the near-infrared spectral region near 3780
cm
−1. The Se
2 ...molecules were generated in a fast-flow system by passing Se
x
vapor in Ar carrier gas through a microwave discharge and were excited by electronic-to-electronic energy transfer from metastable singlet oxygen
O
2(a
1
Δ
g)
. Medium-resolution spectra of the
b
1
Σ
+
g(b0
+
g)→X
3
Σ
−
g(X
21
g)
and
a
1
Δ
g(a2
g)→X
3
Σ
−
g(X
21
g)
transitions were measured with a Fourier-transform spectrometer. By comparing the band shape of the 0–0 band of the
a→
X
2 system with computer simulations, the following spectroscopic constants of the
a
1
Δ
g(a2
g)
state of
80Se
2 were derived (cm
−1):
T
e
=4303.7(1),
B
0=0.08888(5), and Δ
G
1/2=369.6(2), where the numbers in parentheses are estimated error limits of the parameters in units of the last digit.
A nucleation theory has been advanced, in which a metastable system is considered as the sum of statistically independent subsystems. This theory provides a flexible scheme taking into account ...actually all initiating factors, including even a separate “weak” point in a system. In the case of a homogeneous nucleation, the difference between the classical and alternative approaches consists in the expression for the preexponential. Depending on the diameter of the critical nucleus, numerical estimates of this preexponential by the two theories differ by 0–4 orders of magnitude for a supersaturated steam and 1–5 orders of magnitude for a superheated liquid.
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