A physicist (by training) and an atheist, here, though I may clarify that I became an atheist at the age of 13 years, much before I did my Masters’ in Physics.
God is supposed to be the creator, preserver and destroyer of the universe.
Physics is, inter alia, all about studying the fundamental laws of nature and the creation of the universe.
The concept of God itself was “created” by human beings at a time when knowledge of Physics was almost non-existent. This happened thousands of years back.
Forget the universe, we did not fully understand even our own solar system, a few hundred years back. Not long ago, it was widely believed that earth was the centre of the universe and that all heavenly bodies revolved around the earth.
Knowledge of modern Physics started developing only in last few hundred years, with Galileo, Copernicus, Newton. Before that, we had very rudimentary knowledge of the laws of Physics; it was an imperfect picture.
And, the concept of God came into existence thousands of years back when we did not understand much about the laws of nature and the creation of the universe. It arose mainly with a need to explain unknown or unexplained things. Anything that could not be explained, could be attributed to God.
However, with the latest researches being made in Physics and other sciences, we are now in a better position to understand about the universe and its creation. This is not to say that we have fully understood everything about these concepts. A few decades down the line, our present-day knowledge about Physics may also perhaps appear to be rudimentary. Our knowledge of Physics is still imperfect, to say the least.
But, with rapid advancements being made in artificial intelligence, many mysteries of the universe are likely to be unravelled in next few decades.
Yet, howsoever imperfect our knowledge of Physics may be, as of today, the fact remains that a true Physicist would never accept any unfounded theory. He would demand proof and evidence. In theory and/or in practice. Many a time, even empirical evidence may also be considered as a temporary working solution in the absence of perfect proof. But, something that is unsubstantiated by any type of proof and evidence, would not convince a Physicist, who is true to his salt.
Merely because someone has won a Nobel Prize in Physics, would not necessarily mean that his word is final in matters which do not have any proof. Frankly speaking, if a Nobel laureate in Physics believes in the existence of God even without asking for any plausible evidence, this may be because of his religious upbringing, but I would not call him a true Physicist.
There may basically be two types of Physicists. Firstly, the real believers in Physics, who would not agree on something unless some proof is visible. Secondly, those who have studied Physics, might also perhaps have won recognition for their work in Physics (which may generally be in one or more specific projects), but who can believe in something even without seeking proof. I would call only the first category of Physicists as the true Physicists, in the real sense of the term. Believing in something without any evidence, whatsoever, and yet calling him Physicist, may appear to be contradiction in terms.
Merely because certain things cannot be explained due to our present knowledge, does not prove the existence of God. Merely because we don’t have a perfect theory of the creation of the universe, does not prove the existence of God.
So, yes, when your question is seen in terms of such true Physicists, I think you are right. I think a true Physicist would generally be an atheist. In fact, one can even say that a true scientist or a true believer in science would generally be an atheist.