Modern Physics Concepts

These flashcards cover key concepts from modern physics related to quantum mechanics, including the Heisenberg Uncertainty Principle, wave-packet relationships, quantum wells, and potential barriers.

What is the Heisenberg Uncertainty Relation used for?

It relates the uncertainty in position and momentum of a particle, allowing estimation of minimum possible kinetic energy.

How does the confinement of a proton affect its kinetic energy?

A proton confined to a region of 5 [fm] has a minimum possible kinetic energy that can be calculated using the uncertainty relation.

What modification occurs to the proton's kinetic energy if it is confined in a three-dimensional box?

The kinetic energy is typically lower due to three-dimensional confinement, affecting the uncertainty in momentum.

What relationship must be proved for a relativistic free particle?

The velocity of the particle must equal the velocity of the corresponding wave packet.

What is the definition of probability for an electron in a quantum mechanical well with n = 2?

It is the likelihood of finding the electron within a specified region of the well, such as between x=0 and x=L/3.

What is meant by the expectation value of position for a quantum state?

It is the average position of a particle described by a wave function, calculated for a specific quantum state.

What happens to particle waves with energies E > U0 and E < U0 when they encounter a potential barrier?

They reflect or transmit through the barrier, which must be illustrated through wave diagrams.

What do boundary conditions in the context of wave functions signify?

They define how the wave functions behave at the edges of potential barriers and must be set up without solving the equations.