Pursuing a joint degree in cosmology and quantum mechanics typically involves enrolling in an undergraduate physics program, as most physics degrees include introductory courses in quantum mechanics. Cosmology may be available as a senior-level course or through graduate-level enrollment, depending on the university. Specialization in these fields usually begins at the master's or PhD level, and it's advisable to avoid programs that offer excessive specialization at the undergraduate stage to keep future options open. There are generally no specific majors in quantum mechanics, as it's a fundamental aspect of physics that all physicists must understand to a graduate level. The duration of a physics degree can vary, and adding a joint degree may extend the time required to complete the program, depending on the institution's structure.