Adaptively partitioned analog quantum simulation on near-term quantum
  computers: The nonclassical free-induction decay of NV centers in diamond
The idea of simulating quantum physics with controllable quantum devices had
been proposed several decades ago. With the extensive development of quantum
technology, large-scale simulation, such as the analog quantum simulation
tailoring an artificial Hamiltonian mimicking the system of interest, has been
implemented on elaborate quantum experimental platforms. However, due to the
limitations caused by the significant noises and the connectivity, analog
simulation is generically infeasible on near-term quantum computing platforms.
Here we propose an alternative analog simulation approach on near-term quantum
devices. Our approach circumvents the limitations by adaptively partitioning
the bath into several groups based on the performance of the quantum devices.
We apply our approach to simulate the free induction decay of the electron spin
in a diamond NV$^-$ center coupled to a huge number of nuclei and investigate
the nonclassicality induced by the nuclear spin polarization. The simulation is
implemented collaboratively with authentic devices and simulators on IBM
quantum computers. We have also applied our approach to address the
nonclassical noise caused by the crosstalk between qubits. This work sheds
light on a flexible approach to simulate large-scale materials on noisy
near-term quantum computers.
Yun-Hua Kuo Hong-Bin Chen