Is it infringement to apply for a patent according to the contents of other people's papers without the author's permission?

No infringement, the patent is obtained by the first applicant after the invention is completed, not by the inventor or the technical theory proposer. If you think your technology has patent value, apply first and then publish it, or don't publish it as a technical secret protection.

Just as Einstein's energy is equal to the square of mass multiplied by the speed of light, if he thinks it contains patent value, he can apply for a patent for his invention first, such as a particle gun. Or the equation is not disclosed. Once made public, anyone can use his equation to complete his invention and apply for a patent.