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Chen Cheng

Publications and source records attributed to Chen Cheng.

128 records · Page 8Linked to original sources

Exotic phase separation in one-dimensional hard-core boson system with two- and three-body interactions

We investigate the ground state phase diagram of hard-core boson system with repulsive two-body and attractive three-body interactions in one-dimensional optic lattice. When these two interactions are comparable and increasing the hopping rate, physically intuitive analysis indicates that there exists an exotic phase separation regime between the solid phase with charge density wave order and superfluid phase. We identify these phases and phase transitions by numerically analyzing the density distribution, structure factor of density-density correlation function, three-body correlation function and von Neumann entropy estimator obtained by density matrix renormalization group method. These exotic phases and phase transitions are expected to be observed in the ultra-cold polar molecule experiments by properly tuning interaction parameters, which is constructive to understand the physics of ubiquitous insulating-superconducting phase transitions in condensed matter systems.

cond-mat.stat-mech↗

Non-monotonic field dependence of Kondo conductance in a single-electron transistor driven by microwave field

The interplay between magnetic field and microwave applied in a single-electron transistor(SET) has a profound influence on the Kondo effect, as shown in a recent experiment[B. Hemingway, S. Herbert, M. Melloch and A. Kogan, arXiv:1304.0037(2013)]. For a given microwave frequency, the Kondo differential conductance shows a non-monotonic magnetic field dependence, and a very sharp peak is observed for certain field applied. Additionally, the microwave frequency is found to be larger of about one order than the corresponding Zeeman energy. These two features are not understood in the current theory. Here we propose a phenomenological mechanism to explain these observations. When both magnetic field and microwave are applied in the SET, if the frequency matches the (renormalized) Zeeman energy, it is assumed that the microwave is able to induce spin-flip in the SET, which leads to two consequences. One is the dot level shifts down and the other is the renormalization of the Zeeman energy. This picture can not only explain qualitatively the main findings in the experiment but also further stimulate the related experimental study of the dynamic response of the Kondo effect in out-of-equilibrium devices.

cond-mat.str-el↗