Girish S. Agarwal

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

Simultaneous excitation of two noninteracting atoms with time-frequency correlated photon pairs in a superconducting circuit

  1. Wenhui Ren,
  2. Wuxin Liu,
  3. Chao Song,
  4. Hekang Li,
  5. Qiujiang Guo,
  6. Zhen Wang,
  7. Dongning Zheng,
  8. Girish S. Agarwal,
  9. Marlan O. Scully,
  10. Shi-Yao Zhu,
  11. H. Wang,
  12. and Da-Wei Wang
Here we report the first observation of simultaneous excitation of two noninteracting atoms by a pair of time-frequency correlated photons in a superconducting circuit. The strong coupling
regime of this process enables the synthesis of a three-body interaction Hamiltonian, which allows the generation of the tripartite Greenberger-Horne-Zeilinger state in a single step with a fidelity as high as 0.95. We further demonstrate the quantum Zeno effect of inhibiting the simultaneous two-atom excitation by continuously measuring whether the first photon is emitted. This work provides a new route in synthesizing many-body interaction Hamiltonian and coherent control of entanglement.
arxiv pdf