Closed Systems that Measure Particles

The Measurement Problem has been of fundamental concern since the discovery of Schr\"{o}dinger's equation. We have been developing a framework for which this problem can be considered under the assumption that the particle and detector are jointly considered a closed system. The framework is based on imposing conditions on quantum state evolution that such a closed system meet, including conservation of energy and momentum, no-cloning and no-signaling, gauge invariance, and relativity constraints. Another requirement will be presented, which is a quantum mechanical generalization of Newton's first law. Based on these conditions, we will derive and present several new results.