%0 Journal Article %T The Stable Wave Packet in the Foundations of Quantum Mechanics %A Antony J. Bourdillon %J Journal of Modern Physics %P 463-471 %@ 2153-120X %D 2015 %I Scientific Research Publishing %R 10.4236/jmp.2015.64050 %X The stable wave packet has been missing in quantum mechanics for a long time. A consistent argument finds, in antimatter, regular group and phase velocities, along with negative energy and negative mass. For this, a new wave function is derived for free antiparticles, consistent with the Feynman-Stueckelberg switching principle. The wave packet, expressing internal periodicity together with external confinement, is ubiquitous in physics. The stable wave packet has many consequences, a few of which are mentioned. They extend to the debate about what is measurable in physics and to localization of quantized properties in entangled particles. %K Stable Wave Packet %K Travelling Wave Group %K Negative Mass %K Antimatter %K Negative Energy %K Quantum Mechanics %K Wave Mechanics %U http://www.scirp.org/journal/PaperInformation.aspx?PaperID=55010