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911.
Stopa M van der Wiel WG De Franceschi S Tarucha S Kouwenhoven LP 《Physical review letters》2003,91(4):046601
We quantitatively describe the main features of the magnetically induced conductance modulation of a Kondo quantum dot-or chessboard pattern-in terms of a constant-interaction double quantum dot model. We show that the analogy with a double dot holds down to remarkably low magnetic fields. The analysis is extended by full 3D spin density functional calculations. Introducing an effective Kondo coupling parameter, the chessboard pattern is self-consistently computed as a function of magnetic field and electron number, which enables us to explain our experimental data quantitatively. 相似文献
912.
We study an LC circuit implemented using a current-biased Josephson junction (CBJJ) as a tunable coupler for superconducting qubits. By modulating the bias current, the junction can be tuned in and out of resonance and entangled with the qubits coupled to it. One can thus implement two-qubit operations by mediating entanglement. We consider the examples of CBJJ and charge-phase qubits. A simple recoupling scheme leads to a generalization to arbitrary qubit designs. 相似文献
913.
We report the realization of a nuclear magnetic resonance computer with three quantum bits that simulates an adiabatic quantum optimization algorithm. Adiabatic quantum algorithms offer new insight into how quantum resources can be used to solve hard problems. This experiment uses a particularly well-suited three quantum bit molecule and was made possible by introducing a technique that encodes general instances of the given optimization problem into an easily applicable Hamiltonian. Our results indicate an optimal run time of the adiabatic algorithm that agrees well with the prediction of a simple decoherence model. 相似文献
914.
M. Liu T. Pauchard M. Sjdin O. Launila P. van der Meulen L.-E. Berg 《Journal of Molecular Spectroscopy》2009,257(1):105-107
A time-resolved experiment on the A2Π state of gaseous calcium hydride has been performed by applying laser spectroscopic methods. The following zero-pressure lifetime was obtained for the CaH A2Π state: τυ´=0 = 33.2 (±3.2) ns and τυ´=1 = 33.7 (±5.2) ns. The lifetime was found to be the same for the A2Π½ and A2Π3/2 states. 相似文献
915.
916.
van den Broek W. A. Engwerda J. C. Schumacher J. M. 《Journal of Optimization Theory and Applications》2003,119(3):565-595
Equilibria in dynamic games are formulated often under the assumption that the players have full knowledge of the dynamics to which they are subject. Here, we formulate equilibria in which players are looking for robustness and take model uncertainty explicitly into account in their decisions. Specifically, we consider feedback Nash equilibria in indefinite linear-quadratic differential games on an infinite time horizon. Model uncertainty is represented by a malevolent input which is subject to a cost penalty or to a direct bound. We derive conditions for the existence of robust equilibria in terms of solutions of sets of algebraic Riccati equations. 相似文献
917.
John E. van den Berg 《Acta Mathematica Hungarica》2005,107(3):177-186
Summary A radical R , in the sense of Kurosh--Amitsur, is said to be compact if, given any collection of radicals X such that R ≤;VX , we have R ≤;VX ' for some finite subcollection X ' of X. A ring A is said to be radical compact if the lower radical on the singleton {A } is compact. This paper explores the relationship between radical compact rings and rings satisfying certain finiteness conditions. Closure properties of the class of all radical compact rings are also investigated. 相似文献
918.
It is known from early work of Gaudin that the quantum system of n
Bosonic particles on the line with a pairwise delta-potential interaction admits a
natural generalization in terms of the root systems of simple Lie algebras. The
corresponding quantum eigenvalue problem amounts to that of a Laplacian in a
convex cone, the Weyl chamber, with linear homogeneous boundary conditions at
the walls. In this paper we study a discretization of this eigenvalue problem, which
is characterized by a discrete Laplacian on the dominant cone of the weight lattice
endowed with suitable linear homogeneous conditions at the boundary. The
eigenfunctions of this discrete model are computed by the Bethe Ansatz method.
The orthogonality and completeness of the resulting Bethe wave functions (i.e.,
the Plancherel formula) turn out to follow from an elementary computation performed
by Macdonald in his study of the zonal spherical functions on p-adic simple
Lie groups. Through a continuum limit, the Plancherel formula for the ordinary
Laplacian in the Weyl chamber with linear homogeneous boundary conditions is
recovered. Throughout this paper we restrict ourselves to the case of repulsive
boundary conditions.
Communicated by Rafael D. Benguriasubmitted 27/05/03, accepted 14/10/03 相似文献
919.
We present a systematic characterization of the domain of a generator of a one parameter group on certain C∗-subalgebras of via finite-dimensional estimates. Our approach yields an example of a densely defined closed symmetric derivation on a C∗-subalgebras of whose domain is not closed with respect to the C1-functional calculus. This completes and complements the earlier example of McIntosh (J. Funct. Anal. 30 (1977) 264). Our methods are partly based on the theory of adjoint C0-semigroups. 相似文献
920.
A neutral polar molecule experiences a force in an inhomogeneous electric field. This electric field can be designed such that a beam of polar molecules is exposed to a harmonic potential in the forward direction. In this potential the longitudinal phase-space distribution of the ensemble of molecules is rotated uniformly. This property is used to longitudinally focus a pulsed beam of ammonia molecules and to produce a beam with a longitudinal velocity spread of 0.76 m/s, corresponding to a temperature of 250 mu K. 相似文献