Field (physics)
In physics, a field is a way of describing and mapping a force that surrounds an object and acts on other objects at a distance, without any visible physical connection between them.[1] It is useful to think of an object as being surrounded in space by a force field, which carries the force to another object some distance away.[2]
Examples
The gravitational field around the Earth, and around every other mass, represents the gravitational force that another mass would feel if it were placed at a given point in the field.[3] In the same way, the electric (Coulomb) force field around any electric charge extends throughout space.[4] This is why, for example, a charged rubber comb can attract small bits of paper without touching them.[5]
Fields instead of action at a distance
Fields help explain how objects can affect each other across a gap. The Stanford Encyclopedia of Philosophy notes that if the world contained only particles, interactions between distant particles could only be understood as "action at a distance"; in a picture that includes fields, the effect is instead passed on locally by the fields between them.[6]
Quantum fields
In modern physics, fields are central to quantum field theory (QFT), the mathematical and conceptual framework for today's high-energy, or particle, physics.[7] In conventional QFT, quantum fields are basic, and field values are assigned to points in space and time.[8] Maxwell's equations for electricity and magnetism already fitted the theory of relativity, and turning them into a quantum theory led directly to the first relativistic quantum field theories.[9] Philosophers of physics still ask what exactly a field is, and whether quantum fields can really be understood as fields at all.[10]
See also
References
- ↑ Urone, Paul Peter; Hinrichs, Roger (2022). "18.4 Electric Field: Concept of a Field Revisited". College Physics 2e. OpenStax. Retrieved 20 October 2026.
A field is a way of conceptualizing and mapping the force that surrounds any object and acts on another object at a distance without apparent physical connection.
- ↑ Urone, Paul Peter; Hinrichs, Roger (2022). "18.4 Electric Field: Concept of a Field Revisited". College Physics 2e. OpenStax. Retrieved 20 October 2026.
It is very useful to think of an object being surrounded in space by a force field . The force field carries the force to another object (called a test object) some distance away.
- ↑ Urone, Paul Peter; Hinrichs, Roger (2022). "18.4 Electric Field: Concept of a Field Revisited". College Physics 2e. OpenStax. Retrieved 20 October 2026.
the gravitational field surrounding the earth (and all other masses) represents the gravitational force that would be experienced if another mass were placed at a given point within the field.
- ↑ Urone, Paul Peter; Hinrichs, Roger (2022). "18.4 Electric Field: Concept of a Field Revisited". College Physics 2e. OpenStax. Retrieved 20 October 2026.
the Coulomb force field surrounding any charge extends throughout space.
- ↑ Urone, Paul Peter; Hinrichs, Roger (2022). "18.4 Electric Field: Concept of a Field Revisited". College Physics 2e. OpenStax. Retrieved 20 October 2026.
a charged rubber comb attracts neutral bits of paper from a distance via the Coulomb force
- ↑ Kuhlmann, Meinard. "Quantum Field Theory". Stanford Encyclopedia of Philosophy. Retrieved 20 October 2026.
In a pure particle ontology the interaction between remote particles can only be understood as an action at a distance . In contrast to that, in a field ontology, or a combined ontology of particles and fields, local action is implemented by mediating fields.
- ↑ Kuhlmann, Meinard. "Quantum Field Theory". Stanford Encyclopedia of Philosophy. Retrieved 20 October 2026.
Quantum Field Theory (QFT) is the mathematical and conceptual framework for contemporary high-energy physics
- ↑ Kuhlmann, Meinard. "Quantum Field Theory". Stanford Encyclopedia of Philosophy. Retrieved 20 October 2026.
quantum fields are basic, with field values being assigned to points in spacetime
- ↑ Kuhlmann, Meinard. "Quantum Field Theory". Stanford Encyclopedia of Philosophy. Retrieved 20 October 2026.
Maxwell's equations of classical electrodynamics were relativistically covariant from inception. The successful quantization of that theory lead directly to the early Relativistic Quantum Field Theories.
- ↑ Kuhlmann, Meinard. "Quantum Field Theory". Stanford Encyclopedia of Philosophy. Retrieved 20 October 2026.
How can one spell out what a field is and can "quantum fields" in fact be understood as fields?