Inconsistences in Interacting Agegraphic Dark Energy Models

It is found that the origin agegraphic dark energy tracks the matter in the matter-dominated epoch and then the subsequent dark-energy-dominated epoch becomes impossible. It is argued that the difficulty can be removed when the interaction between the agegraphic dark energy and dark matter is considered. In the note, by discussing three different interacting models, we find that the difficulty still stands even in the interacting models. Furthermore, we find that in the interacting models, there exists the other serious inconsistence that the existence of the radiation/matter-dominated epoch contradicts the ability of agegraphic dark energy in driving the accelerated expansion. The contradiction can be avoided in one of the three models if some constraints on the parameters hold.Comment: 12 pages, no figure; analysis is added; conclusion is unchange

Quantum decoherence of excitons in a leaky cavity with quasimode

For the excitons in the quantum well placed within a leaky cavity, the quantum decoherence of a mesoscopically superposed states is investigated based on the factorization theory for quantum dissipation. It is found that the coherence of the exciton superposition states will decrease in an oscillating form when the cavity field interacting with the exciton is of the form of quasimode. The effect of the thermal cavity fields on the quantum decoherence of the superposition states of the exciton is studied and it is observed that the higher the temperature of the environment is, the shorter the decoherence characteristic time is.Comment: 1 figure, 7 page

Scalable superconducting qubit circuits using dressed states

We study a coupling/decoupling method between a superconducting qubit and a data bus that uses a controllable time-dependent electromagnetic field (TDEF). As in recent experiments, the data bus can be either an LC circuit or a cavity field. When the qubit and the data bus are initially fabricated, their detuning should be made far larger than their coupling constant, so these can be treated as two independent subsystems. However, if a TDEF is applied to the qubit, then a "dressed qubit" (i.e., qubit plus the electromagnetic field) can be formed. By choosing appropriate parameters for the TDEF, the dressed qubit can be coupled to the data bus and, thus, the qubit and the data bus can exchange information with the assistance of the TDEF. This mechanism allows the scalability of the circuit to many qubits. With the help of the TDEF, any two qubits can be selectively coupled to (and decoupled from) a common data bus. Therefore, quantum information can be transferred from one qubit to another.Comment: 10 pages, 5 figure

A Hybrid Method on the Design of C Band Microwave Rectifiers

Microwave rectifiers have been developed in various forms since the microwave power transmission (MPT) began to attract researchers' attention. A hybrid simulation method is implemented by the combination of IE3D and ADS simulation to realize a fast and accurate rectifier design in this paper. A 5.8 GHz microstrip rectifier based on HSMS 286 Schottky diode is realized and fabricated based on the proposed method for demonstration. Microstrip structures are light and easy to be integrated into rectennas in a MPT system. The whole circuit is compact with a dimension of 55 mm by 18 mm. The measured MW-to-DC conversion efficiency is 68%, which is obtained at an input microwave power of 16 dBm. The simulated and measured results agree well, which proves the validity of the proposed design method.published_or_final_versio