Experimental progress towards quantum computation using neutral atoms

As an important candidate for quantum simulation and quantum computation, a microscopic array of single atoms confined in optical dipole traps is advantageous in controlled interaction, long coherence time and scalability of providing thousands of qubits in a small footprint of less than 1mm$^2$. Recently, several breakthroughs have greatly advanced the application of neutral atom system in quantum simulation and quantum computation, such as atom-by-atom assembling of defect-free arbitrary atomic arrays, single qubit addressing and manipulating in 2D and 3D array, extending coherence time of atomic qubits, C-NOT gate based on Rydberg interactions, high fidelity readout and so on. In this talk, the experimental progress towards quantum computation based on neutral atoms is reviewed, along with several contributions done by our group. First, a magic-intensity trapping technique is developed to mitigate the detrimental decoherence effects which is induced by light shift, and substantially enhanced the coherence time to 225 ms which have improved our previous coherence time by a factor of 100. This technique is later used to improve the single qubit opeartion fidelity to over 0.9999. Second, the difference in the resonant frequencies of the two atoms of different isotopes is exploited to avoid the crosstalk of individually addressing and manipulating nearby atoms. Based on this heteronuclear single atom system, the heteronuclear controlled-NOT (CNOT) quantum gate and entanglement of a Rb-85 atom and a Rb-87 atom is demonstrated via Rydberg blockade for the first time. These results will trigger the quest for new protocols and schemes to use the double species for quantum computation with neutral atoms. In the end, the challenges for further development of neutral atom system in quantum simulation and quantum computation are outlooked.