Apart from strontium atoms 87Sr and 88Sr (as well as their ions 87Sr+ and 88Sr+), many other atoms or ions can also serve as the "pendulum" of clocks, including: ytterbium atoms 171Yb (and its ion 171Yb+), mercury atoms 199Hg (and its ion 199Hg+), thulium atoms 169Tm, beryllium calcium ions 40Ca+ and aluminum ions 27Al+, etc. Due to its advantages such as rich isotopes, extremely long excited state lifetimes of clock transition energy levels and ease of atomic laser cooling, strontium atoms (87Sr) are currently the most studied ones, and the research on their atomic structures is also much more in-depth than that of other candidate elements.

It is difficult for optical clocks with such high precision to be applied in daily life. However, the improvement in the accuracy of time measurement is of great significance for basic scientific research, including providing time-frequency benchmarks for deep space navigation, greatly extending the measurement time of very long baseline interferometry telescopes, and being used for relativistic geodesy and gravity field change detection, etc.

As one of the most accurate timekeeping tools in the world at present, optical lattice clocks have the following main application fields:

- Time reference and Global Positioning System (The extremely high precision of optical lattice clocks can be used to redefine the "second" in the International System of Units. In the future, they will replace the existing cesium atomic clock standard and provide a time reference for satellite navigation systems such as GPS and Beidou).

- Basic scientific research (For example, verifying the general theory of relativity, detecting dark matter and gravitational waves, quantum metrology simulation and relativistic geodesy, etc.).

Optical lattice clocks have important strategic significance for a country's scientific and technological development, including:

- Enhancing the right to speak in international standards, mastering the next-generation time definition technology and strengthening the influence in the global metrology system.

- Promoting breakthroughs in high-end and sophisticated technologies. Optical lattice clocks involve cutting-edge technologies such as laser cooling, quantum control and ultra-stable optics, which can drive the development of industries such as optoelectronics and precision manufacturing.

- Strengthening national defense and information security. High-precision time synchronization is the core foundation of modern warfare and information networks, and independently controllable atomic clock technology is crucial for national strategic security.

The result of "no error within 1 second in 16 billion years" is not obtained through quantum simulation by supercomputers, but through simple data calculation: considering that the systematic uncertainty of the optical clock is 2×10⁻¹⁸ (which indicates that there is an uncertainty of 2×10⁻¹⁸ in the error assessment of the system, and in the worst case, this error accumulates directly over time), therefore, the time required for an error of 1 second is 1/(2×10⁻¹⁸) s ≈ 16 billion years.

It is difficult to predict the long-term development limit of optical lattice clocks from the perspective of technological development. In terms of the measurement accuracy of the main systematic frequency shift items of the current optical lattice atomic clocks, namely the blackbody radiation frequency shift and the lattice light AC Stark frequency shift, it is very difficult to make further breakthroughs after reaching 3×10⁻¹⁹, which means an error of 1 second in 110 billion years.

In recent years, China has frequently achieved excellent results in the field of optical lattice clocks. In terms of precision, optical lattice clocks in China have surpassed those of the European Union and Japan, ranking second only to the United States. This time, the National Time Service Center has successfully developed a strontium atom optical lattice clock with both systematic uncertainty and instability lower than 2×10⁻¹⁸. This means that there are three strontium atom optical lattice clocks in the world with systematic uncertainty lower than 2×10⁻¹⁸. This makes the strontium atom optical lattice clock the first one to fully meet the requirements for the performance of optical clocks put forward by the change in the definition of the optical "second", which may change the route of the change in the definition of the optical "second", and at least enables the strontium atom optical lattice clock to have a greater say in the process of defining the optical "second".