基于玻色约瑟夫森结的自旋压缩的相干控制

提出了利用人造原子-基于约瑟夫森结的超导量子比特产生自旋压缩的电路模型,给出了系统的有效哈密顿量.在海森堡绘景下,利用冷冻自旋近似方法得到近似解析解,进而分析了系统自旋压缩效应的调控方法.研究表明,通过调节系统粒子数或者耦合强度与有效非线性相互作用强度的比例,均可有效地调控系统的自旋压缩程度和处于自旋压缩态的时间.外场越弱,粒子数越多,系统的自旋压缩程度越强,处于自旋压缩态的时间越长.

Coherent Control of Spin Squeezing in Boson Josephson Junctions

The superconducting qubit model based on the Josephson junction, whose action likes the artificial atom using for producing the spin squeezing, and its effective Hamiltonian is presented. In the Heisenberg picture, the methods to control the spin squeezing are investigated, where the approximate analytical expressions are obtained by using the frozen-spin approximation. It is demonstrated that the spin squeezing of the system can controlled availably by reasonably adjusting the total atomic number or the proportion of the coupling strength and the strength of the effective nonlinear interactions. Moreover, the extent of spin squeezing and the time scale in spin squeezing state are closely related to the strength of the external field and the atomic number.