Three-body interaction plays an important role in many-body physics, and quantum computer is efficient in simulating many-body interactions. We have experimentally demonstrated the general three-body interactions in a three-qubit nuclear magnetic resonance ensemble quantum computer. Using a nuclear magnetic resonance computer we implemented general forms of three-body interactions including σ x 1 σ z 2 σ x 3 and σ x 1 σ z 2 σ y 3 The results show good agreement between theory and experiment. We have also given a concise and practical formula for a general n-body interaction in terms of one-and two-body interactions.
The level structure of ^64-70Ge isotopes has been studied within the framework of the interacting boson model-3（IBM-3） . The symmetry character in the proton and neutron degrees of freedom of the energy levels has been investigated. The isospin excitation states（T 〉 Tz） have been assigned for the ^64Ge（N = Z） nucleus. Some intruder states in these nuclei have been suggested. The calculated energy levels and transition probabilities are in good agreement with recent experimental data. The study indicates that the Ge isotopes are in transition from γ-unstable to vibrational.
Angular-momentum-projected energy surface calculations for A ≈ 110 nuclei indicate three distinct energy minima occurring at different angular-momenta. These correspond to normal, super-, and hy- per-deformed shapes coexisting in one nucleus. 110Pd is studied in detail, with a quantitative prediction on super- and hyper-deformed spectra by the Projected Shell Model calculation. It is found that several other neighboring nuclei in the A-110 mass region, with the neutron number around 64, also exhibit clear super- and hyper-deformation minima in the projected calculation.
SUN Yang1,2, ZHANG JingYe3, LONG GuiLu4,5 & WU ChengLi6,7 1 Department of Physics, Shanghai Jiao Tong University, Shanghai 200240, China
The biggest obstacle for long distance quantum communication is the channel loss and the channel noise on photons. In this paper,a method to solve this problem was analyzed using inspection and power insertion (IPI). It is proved that quantum communication may be established over arbitrarily long distance using this technology. The amount of resources required is a polynomial function of the dis-tance. IPI is proposed as a general technique to prolong quantum secure direct communication where secret messages are transmitted directly over a quantum channel.
WANG WanYing1,2,WANG Chuan1,2,ZHANG GuangYu1,3 & LONG GuiLu1,2 1 Department of Physics,Tsinghua University,Beijing 100084,China
