This paper presents a new parameter and state estimation algorithm for single-input single-output systems based on canonical state space models from the given input–output data. Difficulties of identification for state space models lie in that there exist unknown noise terms in the formation vector and unknown state variables. By means of the hierarchical identification principle, those noise terms in the information vector are replaced with the estimated residuals and a new least squares algorithm is proposed for parameter estimation and the system states are computed by using the estimated parameters. Finally, an example is provided. 相似文献
We demonstrate high-performance broadband tunable external-cavity lasers(ECLs) with the metal-organic chemical vapor deposition(MOCVD) grown In As/In P quantum dots(QDs) structures. Without cavity facet coatings, the 3-d B spectral bandwidth of the Fabry–Perot(FP) laser is approximately 10.8 nm, while the tuning bandwidth of ECLs is 45 nm.Combined with the anti-reflection(AR)/high-reflection(HR) facet coating, a 92 nm bandwidth tuning range has been obtained with the wavelength covering from 1414 nm to 1506 nm. In most of the tuning range, the threshold current density is lower than 1.5 k A/cm2. The maximum output power of 6.5 m W was achieved under a 500 m A injection current.All achievements mentioned above were obtained under continuous-wave(CW) mode at room temperature(RT). 相似文献
Optimal two-qubit operation is of significance to quantum information processing. An efficient scheme is proposed for realizing the shortcut to adiabatic two-qubit state swap in a superconducting circuit quantum electrodynamics (QED) via effective drivings. Two superconducting qutrits are coupled to a common cavity field and individual classical drivings. Based on two Gaussian-type Rabi drivings, two-qubit state swap can be adiabatically implemented within a reduced three-state system. To speed up the operation, these two original Rabi drivings are modified in the framework of shortcuts to adiabaticity, instead of adding an extra counterdiabatic driving. Moreover, owing to a shorter duration time, the decoherence effects on the accelerated quantum operation can be mitigated significantly. The strategy could offer an optimized method to construct fast and robust quantum operations on superconducting qubits experimentally.
Journal of Russian Laser Research - Laser aiming is one of the key technologies of laser atmospheric transmission. The beam actually is affected by atmospheric turbulence and mechanical vibration;... 相似文献
Ferroelectric polarization can be switched by an external applied electric field and may also be reversed by a mechanical force via flexoelectricity from the strain gradient.In this study,we report the mechanical writing of an epitaxial BiFeO3(BFO)thin film and the combined action of an applied mechanical force and electric field on domain switching,where the mechanical force and electric field are applied using the tip of atomic force microscopy.When the applied force exceeds the threshold value,the upward polarization of the BFO thin film can be reversed by pure mechanical force via flexoelectricity;when an electric field is simultaneously applied,the mechanical force can reduce the coercive electric field because both the piezoelectricity from the homogeneous strain and the flexoelectricity from strain gradient contribute to the internal electric field in the film.The mechanically switched domains exhibit a slightly lower surface potential when compared with that exhibited by the electrically switched domains due to no charge injection in the mechanical method.Furthermore,both the mechanically and electrically switched domains exhibit a tunneling electroresistance in the BFO ferroelectric tunnel junction. 相似文献
Optimal creation of photon Fock states is of importance for quantum information processing and state engineering.Here an efficient strategy is presented for speeding up generation of photon Fock state in a superconducting circuit via counterdiabatic driving.A transmon qubit is dispersively coupled to a quantized electrical field.We address a ∧-configuration interaction between the composite system and classical drivings.Based on two Gaussian-shaped drivings,a single-photon Fock state can be generated adiabatically.Instead of adding an auxiliary counterdiabatic driving,our concern is to modify these two Rabi drivings in the framework of shortcut to adiabaticity.Thus an accelerated operation with high efficiency can be realized in a much shorter time.Compared with the adiabatic counterpart,the shortcut-based operation is significantly insusceptible to decoherence effects.The scheme could offer a promising way to deterministically prepare photon Fock states with superconducting quantum circuits. 相似文献