What Does a Theoretical Physicist Do?

By Stephanie Dube Dwilson; Updated July 05, 2017
Writing theory of relativity on chalkboard
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Theoretical physicists have a fascinating job that combines observation with mathematics in order to create complex formulas that describe the workings of the universe around us. Among the most famous theoretical physicists are Albert Einstein, Sir Isaac Newton and Stephen Hawking. Theoretical physicists often work for universities, corporations or scientific-focused organizations.

Mysteries of Nature

A theoretical physicist uses calculus-based formulas to propose explanations for the many mysteries of the natural world. A physicist might, for example, use formulas to describe the existence of dark matter in the universe, or why time slows as an object approaches the speed of light. These theories often work hand-in-hand with experimental physics, helping explain what is discovered experimentally. Theoretical physicists many have an easier time pursuing their interests because their funding needs are significantly less than what an experimental physicist needs to perform an experiment.


Theoretical physicists usually start out with a bachelor's degree in physics. Many take classes in theoretical physics along with foundation-building classes in math and generic physics. Students then go on to obtain master's and doctorate degrees in physics. In Einstein's time, theoretical physicists could study many different branches of physics. Today, because physics is much more complex, theoretical physicists need to specialize in one particular branch, such as elemental physics, quantum physics or astrophysics. Physicists might pursue a postdoctoral fellowship that gives them a deeper understanding of their specialization after obtaining their PhD.


A theoretical physicist might work for a scientific organization such as CERN (the European Organization for Nuclear Research), where the Large Hadron Collider (LHC) is located. Here, theoretical physicists use formulas to predict what elementary particles an experimental physicist might discover while using the LHC. They also seek to understand exactly how these elementary particles work. Theoretical physicists might also work for universities, teaching their specialized knowledge to students while also seeking publication in peer-reviewed journals.


A theoretical physicist has a wide range of specializations to choose from. She might study elementary particles like the Higgs boson discovered by the LHC. Or he might focus on extra dimensions or string theory. He might focus on quantum physics and theories such as the often-cited Schrodinger's cat thought experiment. A theoretical physicist might focus on space-time theory and the changes that occur as objects approach the speed of light.

About the Author

With features published by media such as Business Week and Fox News, Stephanie Dube Dwilson is an accomplished writer with a law degree and a master's in science and technology journalism. She has written for law firms, public relations and marketing agencies, science and technology websites, and business magazines.