Editing Conserved current (section)

{{Short description|Concept in physics and mathematics that satisfies the continuity equation}}
{{inline|date=December 2009}}
In [[physics]] a '''conserved current''' is a [[Current (physics)|current]], <math>j^\mu</math>, that satisfies the [[continuity equation]] <math>\partial_\mu j^\mu=0</math>. The continuity equation represents a conservation law, hence the name.

Indeed, integrating the continuity equation over a volume <math>V</math>, large enough to have no net currents through its surface, leads to the conservation law<math display="block"> \frac{\partial}{\partial t}Q = 0\;,</math>where <math display="inline">Q = \int_V j^0 dV</math> is the [[charge (physics)|conserved quantity]].

In [[gauge theory|gauge theories]] the gauge fields couple to conserved currents. For example, the [[electromagnetic field]] couples to the [[charge conservation|conserved electric current]].