Ke Zhang

Synthesizing five-body interaction in a superconducting quantum circuit

  1. Ke Zhang,
  2. Hekang Li,
  3. Pengfei Zhang,
  4. Jiale Yuan,
  5. Jinyan Chen,
  6. Wenhui Ren,
  7. Zhen Wang,
  8. Chao Song,
  9. Da-Wei Wang,
  10. H. Wang,
  11. Shiyao Zhu,
  12. Girish S. Agarwal,
  13. and Marlan O. Scully
Synthesizing many-body interaction Hamiltonian is a central task in quantum simulation. However, it is challenging to synthesize interactions including more than two spins. Borrowing
tools from quantum optics, we synthesize five-body spin-exchange interaction in a superconducting quantum circuit by simultaneously exciting four independent qubits with time-energy correlated photon quadruples generated from a qudit. During the dynamic evolution of the five-body interaction, a Greenberger-Horne-Zeilinger state is generated in a single step with fidelity estimated to be 0.685. We compare the influence of noise on the three-, four- and five-body interaction as a step toward answering the question on the quantum origin of chiral molecules. We also demonstrate a many-body Mach-Zehnder interferometer which potentially has a Heisenberg-limit sensitivity. This study paves a way for quantum simulation involving many-body interactions and high excited states of quantum circuits.
arxiv pdf

Extensible 3D architecture for superconducting quantum computing

  1. Qiang Liu,
  2. Mengmeng Li,
  3. Kunzhe Dai,
  4. Ke Zhang,
  5. Guangming Xue,
  6. Xinsheng Tan,
  7. Haifeng Yu,
  8. and Yang Yu
Using a multi-layered printed circuit board, we propose a 3D architecture suitable for packaging supercon- ducting chips, especially chips that contain two-dimensional qubit arrays.
In our proposed architecture, the center strips of the buried coplanar waveguides protrude from the surface of a dielectric layer as contacts. Since the contacts extend beyond the surface of the dielectric layer, chips can simply be flip-chip packaged with on-chip receptacles clinging to the contacts. Using this scheme, we packaged a multi-qubit chip and per- formed single-qubit and two-qubit quantum gate operations. The results indicate that this 3D architecture provides a promising scheme for scalable quantum computing.
arxiv pdf