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61.
A periodic one-dimensional four-state hopping model is proposed. In the model, the substeps betweenarbitrary adjacent states are unequal, and an explicit solution of the master equation is first obtained for the probabilitydistribution as a function of the time and position for any initial distribution with all the transients included. Next, thetransient behaviors in the initial period of time and the characteristic time to reach the steady state for the molecularmotor are discussed. Finally, we compare the steady state results to experiments and illustrate qualitatively the kineticbehaviors of a molecular motor under external load F. 相似文献
62.
Here we prove a limit theorem in the sense of the weak convergence of probability measures in the space of meromorphic functions
for a general Dirichlet series. The explicit form of the limit measure in this theorem is given.
Partially supported by Lithuanian Foundation of Studies and Science 相似文献
63.
Let Um be an m×m Haar unitary matrix and U[m,n] be its n×n truncation. In this paper the large deviation is proven for the empirical eigenvalue density of U[m,n] as m/n→λ and n→∞. The rate function and the limit distribution are given explicitly. U[m,n] is the random matrix model of quq, where u is a Haar unitary in a finite von Neumann algebra, q is a certain projection and they are free. The limit distribution coincides with the Brown measure of the operator quq. 相似文献
64.
O. Wibbelhoff C. Meier A. Lorke P. Schafmeister A. D. Wieck 《Physica E: Low-dimensional Systems and Nanostructures》2004,21(2-4):516
We use frequency-dependent capacitance–voltage spectroscopy to study the dynamic charging of self-assembled InAs quantum dots. With increasing frequency, the AC charging becomes suppressed, beginning with the low-energy states. By applying an in-plane magnetic field, we generate an additional magnetic confinement that alters the tunneling barrier and hence the charging dynamics. In traveling through the potential barrier, the electrons acquire an additional momentum k0, proportional to the magnetic field B. As the tunneling is enhanced, when k0 matches the maximum of the electronic wave function Ψ (in momentum representation), we are able to map out the shape of Ψ by varying B. 相似文献
65.
D. Chithrani R. L. Williams J. Lefebvre P. J. Poole G. C. Aers 《Physica E: Low-dimensional Systems and Nanostructures》2004,21(2-4):290
We discuss the preparation and spectroscopic characterisation of a single InAs/InP quantum dot suitable for long-distance quantum key distribution applications around λ=1.55 μm. The dot is prepared using a site-selective growth technique which allows a single dot to be deposited in isolation at a controlled spatial location. Micro-photoluminescence measurements as a function of exciton occupation are used to determine the electronic structure of the dot. Biexciton emission, shell filling and many-body re-normalization effects are observed for the first time in single InAs/InP quantum dots. 相似文献
66.
In this paper, we investigate the exact distribution of the waiting time for ther-th ℓ-overlapping occurrence of success-runs of a specified length in a sequence of two state Markov dependent trials. The
probability generating functions are derived explicitly, and as asymptotic results, relationships of a negative binomial distribution
of orderk and an extended Poisson distribution of orderk are discussed. We provide further insights into the run-related problems from the viewpoint of the ℓ-overlapping enumeration
scheme. We also study the exact distribution of the number of ℓ-overlapping occurrences of success-runs in a fixed number
of trials and derive the probability generating functions. The present work extends several properties of distributions of
orderk and leads us a new type of geneses of the discrete distributions. 相似文献
67.
Nonlinear susceptibility of a quantum dot (QD) embedded in a two-sided cavity, is studied theoretically from a weak-coupling to a strong-coupling regime. In the relevance of a quantum logic gate, the corresponding nonlinear phase shifts (Kerr effect) are estimated for coherent wavepackets including one photon on average. In the weak-coupling regime, the phase shift enhances strongly as a function of a coupling constant between the cavity photon and QD, and eventually saturates in the strong-coupling regime. We also show transmission spectra to evaluate the efficiency of the phase shift. Although the efficiency decreases monotonically in the weak-coupling regime, it rises in the strong-coupling regime. 相似文献
68.
69.
Mechanisms of ‘environmental decoherence’ such as surface scattering, Elliot–Yafet process and precession mechanisms, as well as their influence on the spin phase relaxation are considered and compared. It is shown that the ‘spin ballistic’ regime is possible, when the phase relaxation length for the spin part of the wave function (L(s)) is much greater than the phase relaxation length for the ‘orbital part’ (L(e)). In the presence of an additional magnetic field, the spin part of the electron's wave function (WF) acquires a phase shift due to additional spin precession about that field. If the structure length L is chosen to be L(s)>L>L(e), it is possible to ‘wash out’ the quantum interference related to the phase coherence of the ‘orbital part’ of the WF, retaining at the same time that related to the phase coherence of the spin part and, hence, to reveal corresponding conductance oscillations. 相似文献
70.
K. L. Janssens B. Partoens F. M. Peeters 《Physica E: Low-dimensional Systems and Nanostructures》2004,21(2-4):349
We investigated theoretically the influence of strain on the exciton in both single and three vertically coupled self-assembled quantum dot systems in the presence of a perpendicular magnetic field. For the single disk, we find that the heavy-hole exciton is the ground state, while for the system of three stacked disks, the light hole state was found to be lower in energy. Results for the diamagnetic shift were compared with experimental results. 相似文献