arXiv subjects

Yan-Hua Zhou

Publications and source records attributed to Yan-Hua Zhou.

3 recordsLinked to original sources

arXiv2024

Non-integer Floquet Sidebands Spectroscopy

In the quantum system under periodical modulation, the particle can be excited by absorbing the laser photon with the assistance of integer Floquet photons, so that the Floquet sidebands appear. Here, we experimentally observe non-integer Floquet sidebands (NIFBs) emerging between the integer ones while increasing the strength of the probe laser in the optical lattice clock system. Then, we propose the Floquet channel interference hypothesis (FCIH) which surprisingly matches quantitatively well with both experimental and numerical results. With its help, we found both Rabi and Ramsey spectra are very sensitive to the initial phase and exhibit additional two symmetries. More importantly, the height of Ramsey NIFBs is comparable to the integer one at larger $g/ω_s$ which indicates an exotic phenomenon beyond the perturbative description. Our work provides new insight into the spectroscopy of the Floquet system and has potential application in quantum technology.

cond-mat.quant-gas↗

arXiv2023

Quantum optimization within lattice gauge theory model on a quantum simulator

Simulating lattice gauge theory (LGT) Hamiltonian and its nontrivial states by programmable quantum devices has attracted numerous attention in recent years. Rydberg atom arrays constitute one of the most rapidly developing arenas for quantum simulation and quantum computing. The $\mathbb{Z}_2$ LGT and topological order has been realized in experiments while the $U(1)$ LGT is being worked hard on the way. States of LGT have local constraint and are fragmented into several winding sectors with topological protection. It is therefore difficult to reach the ground state in target sector for experiments, and it is also an important task for quantum topological memory. Here, we propose a protocol of sweeping quantum annealing (SQA) for searching the ground state among topological sectors. With the quantum Monte Carlo method, we show that this SQA has linear time complexity of size with applications to the antiferromagnetic transverse field Ising model, which has emergent $U(1)$ gauge fields. This SQA protocol can be realized easily on quantum simulation platforms such as Rydberg array and D-wave annealer. We expect this approach would provide an efficient recipe for resolving the topological hindrances in quantum optimization and the preparation of quantum topological state.

quant-ph↗

arXiv2022

Density Shift of Optical Lattice Clock via Multi-Bands Sampling Exact Diagonalization Method

Density shift plays one of the major roles in the uncertainty of optical lattice clock, thus has attracted lots of theoretical and experimental studies. However, most of the theoretical research considered the single-band and collective approximation, so the density shift of the system at higher temperatures can not be analyzed accurately. Here, we design a numerical algorithm that combines Monte Carlo sampling and exact diagonalization and name it as Multi-Band Sampling Exact Diagonalization (MBSED). The MBSED method considers the collision of atoms between multi-bands, so it can provide the density shift of an optical lattice clock with higher precision. Such an algorithm will benefit the numerical simulation of an optical lattice clock, and may also be used in other platforms of quantum metrology. In addition, through our numerical simulation, we also found that the density shift of Rabi spectrum is slightly non-linear with atom number.

quant-ph↗