Quantum fluctuations in superconducting arrays with discrete charge states

김범준

De-Xin Miao, Juju Hu, Yinghua Ji +1 more

Hailan Jin, Cui Yuan-shun

On the basis of the charge quantization,the quantum fluctuations of the charge,the current and the energy in the dissipative mesoscopic circuit are calculated by the character of the minimum shift operator.The results show that,taking account of the charge discreteness,the quantum fluctuation of charge is zero under Fock state,but the fluctuations of the current and the energy aren't zero,which relate with charge quantization,Plank constant and the parameters of the circuits.

Андрей Георгиевич Семенов, Andrei D. Zaikin

Cui Yuan-shun

On the basis of the charge quantization, The quantum fluctuations of the charge, current and energy in the mesoscopic metal ring are calculated by the character of the minimum shift operatorQ∧, the effects of the parameters on the quantum fluctuations are investigated. The results show that, taking account of the charge discreteness, the quantum fluctuations of the charge, energy are not zero under the coherent state, related with the charge quantum and the parameters of the coherent state respectively. In addition, the quantum fluctuations of energy are also determined by the inductance of the mesoscopic metal ring, the external magnetic flux and its time variable rate.

Tetsuro Saso, Yoshikazu Suzumura

Effects of random impurities on one-dimensional interacting electron systems are studied by use of the quantum Monte Carlo method and the phase variable representation of charge density and superconducting fluctuations. The impurities pin the phase variable of charge density fluctuation, whereas the quantum fluctuation around the pinned state reduces the pinning effect yielding increase of the superconducting fluctuation since the charge density and the superconducting fluctuations are complementary to each other. Such interplay between randomness and interactions is shown explicitly by calculating spatial dependence of quantum fluctuations, metastable states and correlation functions for superconductivity. Quantum character of metastable states is discussed. It is found that superconducting state is more sensitive to impurities than charge density wave state when the interaction between electrons is weak.