In quantum field theory, the concepts of virtual and real particles are used to describe different aspects of particle interactions. Here's an explanation of the difference between the two:
Real particles: Real particles are what we typically think of as physical particles that exist in the observable universe. These are the particles that we can directly detect and measure in experiments. For example, electrons, photons, and protons are considered real particles. Real particles have well-defined properties such as mass, charge, and spin, and they follow the laws of quantum mechanics.
Virtual particles: Virtual particles, on the other hand, are not directly observable or detectable as individual particles. They are mathematical constructs that arise in the calculations of quantum field theory to describe the behavior of particle interactions. Virtual particles are associated with the inherent uncertainty and fluctuations present in quantum fields.
According to quantum field theory, the vacuum of space is not empty but rather filled with quantum fields. These fields are associated with different types of particles. When two particles interact or exchange energy, they can temporarily give rise to virtual particles as intermediate states. These virtual particles are not observable because they do not exist as separate entities with well-defined properties. They are essentially a mathematical tool used to describe and calculate the probabilities of particle interactions.
Virtual particles violate certain conservation laws, such as the conservation of energy and momentum, but they can exist for a short period of time that is allowed by the uncertainty principle. The temporary creation and annihilation of virtual particles contribute to the overall behavior and properties of real particles and their interactions.
It's important to note that the term "virtual particle" is a theoretical concept within the framework of quantum field theory and should not be understood as literal particles popping in and out of existence in the physical sense. They are a mathematical description used to explain and calculate the quantum nature of particle interactions.
In summary, real particles are observable and have well-defined properties, while virtual particles are mathematical constructs that arise in calculations of quantum field theory to describe the behavior of particle interactions. Virtual particles are not directly observable and do not exist as independent entities. They are a consequence of the quantum nature of particle interactions.