Quantum mechanics is a highly complex and mathematically intricate field of study, and it requires a deep understanding of advanced mathematics and physics. While it is difficult to provide an exact number, it is safe to say that there are many scientists in physics who have a strong grasp of the essence of quantum mechanics.
Quantum mechanics has been extensively studied and developed since its inception in the early 20th century. Numerous physicists, including some of the greatest minds in the field, have made significant contributions to our understanding of quantum mechanics. These include pioneers like Max Planck, Albert Einstein, Niels Bohr, Werner Heisenberg, Erwin Schrödinger, and many others.
Today, there is a large community of physicists actively researching and working with quantum mechanics. This includes researchers in various subfields such as quantum field theory, quantum information theory, quantum optics, quantum computing, and more. Many of these scientists have dedicated their careers to studying and advancing our understanding of quantum mechanics.
It is important to note that quantum mechanics is a vast and continuously evolving field. New discoveries, theories, and experimental results continually shape our understanding of this subject. While not every physicist may have a comprehensive understanding of all aspects of quantum mechanics, there are certainly a significant number of researchers who possess a deep knowledge of its fundamental principles and applications.