David Bohm's theory, known as Bohmian mechanics or the pilot-wave theory, is an alternative interpretation of quantum mechanics. It provides a different perspective on the nature of particles and their behavior compared to the more widely accepted Copenhagen interpretation.
In Bohmian mechanics, particles are considered to have well-defined positions and trajectories, contrary to the probabilistic nature of standard quantum mechanics. The theory introduces the concept of a "pilot wave" or "guiding wave" that guides the motion of particles. This pilot wave is a mathematical entity that accompanies each particle and influences its behavior.
According to Bohmian mechanics, particles have definite positions even when they are not being measured, and their trajectories are determined by the interaction between their actual positions and the pilot wave. The pilot wave evolves deterministically according to a wave equation, known as the guiding equation or the Schrödinger equation, while the particles themselves follow these determined paths.
This interpretation provides a different perspective on quantum phenomena like the double-slit experiment. In the Bohmian view, particles pass through one slit or the other, guided by the pilot wave, and interference patterns arise due to the interaction of the pilot waves from both slits. This is in contrast to the standard interpretation, which considers particles to exist in a superposition of states and undergo wave-like interference until they are measured.
Bohmian mechanics also introduces the concept of hidden variables, additional properties that exist alongside the observable variables in quantum mechanics. These hidden variables help determine the behavior of particles, and their inclusion in the theory allows for a deterministic framework. However, it's important to note that Bohmian mechanics cannot be experimentally distinguished from standard quantum mechanics, as the predictions for observable quantities remain the same.
While Bohmian mechanics presents an interesting alternative to the Copenhagen interpretation, it is not as widely accepted among physicists. The Copenhagen interpretation and other interpretations like the many-worlds interpretation are more commonly taught and used in practice. Nevertheless, Bohmian mechanics continues to be an active area of research, and its proponents argue that it offers a more intuitive and deterministic understanding of quantum phenomena.